Apparatus, method, and program

Abstract

[Solution] A device according to the present invention comprises: an irradiation unit that periodically irradiates an object with light and heats the object; an output switching unit that switches the output of the light with which the object is irradiated by the irradiation unit, at least between first output in which the maximum output during one period is a first maximum output, and second output in which the same is a second maximum output; a first temperature distribution acquisition unit that acquires a first temperature distribution, which is the temperature distribution of the object that has been heated by the light during the first output; a second temperature distribution acquisition unit that acquires a second temperature distribution, which is the temperature distribution of the object that has been heated by the light during the second output; and a specification unit that, on the basis of the first temperature distribution and the second temperature distribution, specifies information relating to the thermal conductivity of the object.

Description

[Technical Field]

[0001] This invention relates to an apparatus, method, and program. [Background technology]

[0002] Patent Document 1 discloses a thermal conductivity measuring device that has a refrigerant storage tank surrounding a test specimen, cools the specimen by placing a refrigerant in the refrigerant storage tank, and measures the thermal conductivity of the specimen at a temperature below room temperature. The device is made by filling the refrigerant storage tank with a porous material that can disperse the refrigerant, and by homogenizing the temperature of the specimen in the refrigerant storage tank with the refrigerant dispersed in the porous material, thereby enabling accurate measurement of the thermal conductivity of the specimen. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2002-90322 [Overview of the project] [Problems that the invention aims to solve]

[0004] Incidentally, for example, in order to understand the quality of a product in the manufacturing process, it has sometimes been necessary to non-contactually identify information regarding the thermal conductivity of the object being measured.

[0005] The techniques disclosed herein aim to identify information regarding the thermal conductivity of a sample by novel methods. [Means for solving the problem]

[0006] To this end, the technology disclosed herein is an apparatus comprising: an irradiation unit that periodically irradiates an object with light to heat the object; an output switching unit that switches the output of the light irradiated by the irradiation unit to at least a first output, where the maximum output in one cycle is a first maximum output, and a second output, where the maximum output is a second maximum output; a first temperature distribution acquisition unit that acquires a first temperature distribution, which is the temperature distribution of the object heated by the light of the first output; a second temperature distribution acquisition unit that acquires a second temperature distribution, which is the temperature distribution of the object heated by the light of the second output; and an identification unit that identifies information regarding the thermal conductivity of the object based on the first temperature distribution and the second temperature distribution. Here, the identifying unit may obtain a first temperature amplitude distribution, which is the distribution of temperature amplitudes in the object heated by the light of the first output, based on the first temperature distribution, and obtain a second temperature amplitude distribution, which is the distribution of temperature amplitudes in the object heated by the light of the second output, based on the second temperature distribution, and identify information regarding the thermal conductivity of the object based on the first temperature amplitude distribution and the second temperature amplitude distribution. Furthermore, the identifying unit may obtain a first maximum temperature distribution, which is the distribution of the maximum temperature at various points on the object heated by the first output light, based on the first temperature distribution, and obtain a second maximum temperature distribution, which is the distribution of the maximum temperature at various points on the object heated by the second output light, based on the second temperature distribution, and identify information regarding the thermal conductivity of the object based on the first maximum temperature distribution and the second maximum temperature distribution. Furthermore, it is preferable to include a thermal diffusivity determination unit that identifies information regarding thermal diffusivity based on the time response of the temperature distribution of the object heated by the first output light. Furthermore, it is preferable to include a specific heat identification unit that identifies information regarding the specific heat of the object based on the information regarding the thermal conductivity of the object identified by the identification unit. Furthermore, it is preferable to include a fatigue information identification unit that identifies information regarding the fatigue of the object based on the information regarding the thermal conductivity of the object identified by the identification unit. Furthermore, the irradiation unit may irradiate light over a wider area than the region in which the temperature distribution of the object is measured, and the identification unit may identify information regarding the thermal conductivity in the thickness direction of the object. Furthermore, the irradiation unit may irradiate light onto a region extending in one direction on the surface of the object, and the identification unit may identify information regarding the thermal conductivity of the object in the in-plane direction. Furthermore, the irradiation unit can switch between a first mode in which light is irradiated over a wider area than the region in which the temperature distribution on the object is measured, and a second mode in which light is irradiated over a region extending in one direction on the surface of the object. The identification unit may, in the first mode, identify information regarding the thermal conductivity in the thickness direction of the object, and in the second mode, identify information regarding the thermal conductivity in the in-plane direction of the object.

[0007] From another perspective, the technology disclosed herein is a method comprising the steps of: periodically irradiating an object with light to heat the object; switching the output of the light irradiated onto the object between a first output, where the maximum output in one period is a first maximum output, and a second output, where the maximum output is a second maximum output; obtaining a first temperature distribution, which is the temperature distribution of the object heated by the light of the first output; obtaining a second temperature distribution, which is the temperature distribution of the object heated by the light of the second output; and identifying information regarding the thermal conductivity of the object based on the first and second temperature distributions.

[0008] From another perspective, the technology disclosed herein is a program that causes a computer to perform the following functions: a function to periodically irradiate an object with light to heat the object; a function to switch the output of the light irradiated onto the object between a first output, where the maximum output in one cycle is a first maximum output, and a second output, where the maximum output is a second maximum output; a function to acquire a first temperature distribution, which is the temperature distribution of the object heated by the light of the first output; a function to acquire a second temperature distribution, which is the temperature distribution of the object heated by the light of the second output; and a function to identify information regarding the thermal conductivity of the object based on the first and second temperature distributions.

[0009] From another perspective, the technology disclosed herein is an apparatus comprising: an irradiation unit that periodically irradiates an object with light to heat the object; an output switching unit that switches the output of the light irradiated by the irradiation unit to at least a first output, where the maximum output in one cycle is a first maximum output, and a second output, where the maximum output is a second maximum output; a first temperature distribution acquisition unit that acquires a first temperature distribution, which is the temperature distribution of the object heated by the light of the first output; a second temperature distribution acquisition unit that acquires a second temperature distribution, which is the temperature distribution of the object heated by the light of the second output; and an identification unit that identifies information relating to the specific heat of the object based on the first and second temperature distributions.

[0010] From another perspective, the technology disclosed herein is a method comprising the steps of: periodically irradiating an object with light to heat the object; switching the output of the light irradiated onto the object between a first output, where the maximum output in one period is a first maximum output, and a second output, where the maximum output is a second maximum output; obtaining a first temperature distribution, which is the temperature distribution of the object heated by the light of the first output; obtaining a second temperature distribution, which is the temperature distribution of the object heated by the light of the second output; and identifying information regarding the specific heat of the object based on the first and second temperature distributions.

[0011] From another perspective, the technology disclosed herein is a program that causes a computer to perform the following functions: a function to periodically irradiate an object with light to heat the object; a function to switch the output of the light irradiated onto the object between a first output, where the maximum output in one cycle is a first maximum output, and a second output, where the maximum output is a second maximum output; a function to acquire a first temperature distribution, which is the temperature distribution of the object heated by the light of the first output; a function to acquire a second temperature distribution, which is the temperature distribution of the object heated by the light of the second output; and a function to identify information regarding the specific heat of the object based on the first and second temperature distributions.

[0012] From another perspective, the technology disclosed herein is an apparatus comprising: an irradiation unit that periodically irradiates an object with light to heat the object; an output switching unit that switches the output of the light irradiated by the irradiation unit to at least a first output, where the maximum output in one cycle is a first maximum output, and a second output, where the maximum output is a second maximum output; a first temperature distribution acquisition unit that acquires a first temperature distribution, which is the temperature distribution of the object heated by the light of the first output; a second temperature distribution acquisition unit that acquires a second temperature distribution, which is the temperature distribution of the object heated by the light of the second output; and an identification unit that calculates the thermal conductivity of the object and identifies information regarding the fatigue of the object based on the first and second temperature distributions.

[0013] From another perspective, the technology disclosed herein is a method comprising the steps of: periodically irradiating an object with light to heat the object; switching the output of the light irradiated onto the object between a first output, where the maximum output in one cycle is a first maximum output, and a second output, where the maximum output is a second maximum output; obtaining a first temperature distribution, which is the temperature distribution of the object heated by the light of the first output; obtaining a second temperature distribution, which is the temperature distribution of the object heated by the light of the second output; and calculating the thermal conductivity of the object and identifying information regarding the fatigue of the object based on the first and second temperature distributions.

[0014] From another perspective, the technology disclosed in this specification causes a computer to perform functions including periodically irradiating an object with light to heat the object, switching at least the output of the light irradiated onto the object between a first output whose maximum output in one cycle is a first maximum output and a second output whose maximum output is a second maximum output, obtaining a first temperature distribution which is the temperature distribution of the object heated by the light of the first output, obtaining a second temperature distribution which is the temperature distribution of the object heated by the light of the second output, calculating the thermal conductivity of the object based on the first temperature distribution and the second temperature distribution, and specifying information regarding the fatigue of the object.

Advantages of the Invention

[0015] According to the technology disclosed in this specification, information regarding the thermal conductivity of a measurement target can be specified by a new method.

Brief Description of the Drawings

[0016] [Figure 1] It is a schematic configuration diagram showing a thermal property evaluation apparatus according to a first embodiment. [Figure 2] It is a functional configuration diagram of a computer. [Figure 3] It is a diagram showing an example of the hardware configuration of a computer. [Figure 4] (A) and (B) are diagrams showing the principle of measuring thermal properties in the first embodiment. [Figure 5] (A) and (B) are diagrams showing a model of the measurement principle in the first embodiment. [Figure 6] It is a diagram showing the measurement principle of specific heat capacity in the first embodiment. [Figure 7] It is a flowchart for explaining the fatigue evaluation determination operation by a thermal property evaluation apparatus. [Figure 8] It is a flowchart for explaining the fatigue evaluation process by a thermal property evaluation apparatus. <00001​(A) through (E) show the first measurement results. [Figure 10] (A) through (D) show the second measurement results. [Figure 11] (A) through (E) show the second measurement results. [Figure 12] This is a schematic diagram showing a thermophysical property evaluation apparatus according to the second embodiment. [Figure 13] Figures (A) and (B) show the principle of measuring thermophysical properties in the second embodiment. [Figure 14] Figures (A) and (B) show a model of the measurement principle in the second embodiment. [Figure 15] This figure shows the measurement principle of specific heat capacity in the second embodiment. [Figure 16] (A) to (C) show the results of the third measurement. [Figure 17] This is a schematic diagram showing a thermophysical property evaluation apparatus according to the third embodiment. [Figure 18] Figures (A) through (D) show the principle of measuring thermophysical properties in the third embodiment. [Figure 19] This figure shows the measurement principle of specific heat capacity in the third embodiment. [Figure 20] This is a schematic diagram showing a thermophysical property evaluation apparatus according to the fourth embodiment. [Figure 21] Figures (A) through (D) show the principle for measuring thermophysical properties in the fourth embodiment. [Figure 22] This diagram shows the principle of measuring specific heat capacity. [Figure 23] This diagram illustrates the measurement condition control unit in modified example 1. [Modes for carrying out the invention]

[0017] This embodiment will be described in detail below with reference to the attached drawings. <First Embodiment> <Configuration of the thermophysical property evaluation device 100> Figure 1 is a schematic diagram showing a thermophysical property evaluation apparatus 100 according to the first embodiment. First, with reference to Figure 1, the configuration of the thermophysical property evaluation apparatus 100 to which this embodiment is applied will be described.

[0018] As shown in Figure 1, the thermophysical property evaluation apparatus 100 to which this embodiment is applied includes a diode laser 10 that functions as a light source for heating the sample to be measured 1, a light guide unit 20 that guides the laser light from the diode laser 10 to the sample to be measured 1, a support unit 30 that supports the sample to be measured 1, an infrared thermograph (lock-in thermograph) 40 provided opposite the sample to be measured 1, a computer 50 that receives signals from the infrared thermograph 40, and a periodic signal generator 70 that generates periodic signals and outputs them to the diode laser 10 and the computer 50.

[0019] Here, the diode laser 10 and the light guide unit 20 irradiate the surface of the flat plate-shaped measurement sample 1 with light that has a uniform intensity distribution. The diode laser 10 is a surface heating light source. This diode laser 10 outputs so-called multimode diode laser light (e.g., TEM01) in which the transverse mode is not single mode (TEM00).

[0020] The light guide unit 20 includes a fiber 21, which is a transmission path for transmitting laser light emitted from the diode laser 10; a light concentrator 23 provided at the tip of the fiber 21 for controlling the intensity distribution of the laser light emitted from the fiber 21; and a mirror 25 for reflecting the laser light emitted from the light concentrator 23.

[0021] Here, fiber 21 is composed of a multimode fiber capable of propagating laser light of different spatial modes in a mixed manner. Inside fiber 21, the laser light emitted from diode laser 10 is divided into meridional rays and skew-ray rays by controlling the incident angle. In addition, the laser light emitted from diode laser 10 undergoes multiple reflections inside fiber 21, which homogenizes the intensity distribution on the irradiated surface. In the illustrated example, fiber 21 has a core diameter of 100 μm and a length of 3 m.

[0022] The light-gathering device 23 is composed of multiple lenses and functions as a variable-focus optical device. This light-gathering device 23 focuses (or diffuses) the laser light emitted from the fiber 21. The laser light emitted from the light-gathering device 23 propagates through space while spreading out. Therefore, the light-gathering device 23 can be considered as a beam expander that expands the beam diameter of the laser light emitted from the fiber 21.

[0023] The mirror 25 is made of a well-known optical mirror, such as a glass substrate coated with a thin film of metal or dielectric. The mirror 25 reflects the laser light emitted from the light condenser 23 toward the sample 1 to be measured.

[0024] In the thermophysical property evaluation apparatus 100 configured in this way, the laser light emitted from the diode laser 10 is irradiated onto the first surface 103 of the measurement sample 1 via the fiber 21, the condenser 23, and the mirror 25. The measurement sample 1 is periodically heated by the laser light. Here, as shown in Figure 1(B), the laser light that has passed through the fiber 21, the condenser 23, and the mirror 25 is controlled so that the intensity distribution on the irradiated surface is leveled, resulting in a so-called top-hat shaped intensity distribution.

[0025] Furthermore, the temperature of the sample 1, which is periodically heated by the laser light of the diode laser 10, is measured by an infrared thermograph 40 from the second surface 105 of the sample 1. A periodic signal is input to the infrared thermograph 40 from a periodic signal generator 70. The temperature distribution data, which is the temperature data measured by the infrared thermograph 40, is output to the computer 50. The infrared thermograph 40 captures (measures) an infrared image of a predetermined range within the region periodically heated by the diode laser 10. In other words, the diode laser 10 irradiates the entire portion of the sample 1 corresponding to the region observed by the infrared thermograph 40 with laser light. That is, the region of the sample 1 irradiated by the diode laser 10 is larger (wider) than the region observed by the infrared thermograph 40.

[0026] The support section 30 includes a holder 31 that holds the end of the measurement sample 1 and an aperture 33 that defines the observation area of ​​the measurement sample 1 by the infrared thermography 40. The holder 31 is driven by a tensile testing machine (not shown) to apply a tensile load to the measurement sample 1. The aperture 33 determines the measurement area of ​​the measurement sample 1 by the infrared thermography 40. In the illustrated example, a portion (central part) of the second surface 105 of the measurement sample 1 is measured by the infrared thermography 40. By determining the measurement area of ​​the measurement sample 1 with this aperture 33, the measurement accuracy of the measurement sample 1 can be improved.

[0027] The computer 50, in conjunction with the infrared thermography 40, continuously performs infrared image acquisition and calculation based on a predetermined frame rate, and creates an averaged image from the temperature change amount that changes over time (lock-in method). To further explain, the data obtained from the infrared thermography 40 is processed by the computer 50 to calculate the thermal conductivity in the thickness direction of the measurement sample 1. In addition, the data obtained from the infrared thermography 40 is processed by the computer 50 to calculate information regarding the thermal properties of the measurement sample 1 (details will be described later).

[0028] In the following explanation, the direction along the surface of the measurement sample 1 in Figure 1, i.e., the left-right direction in the figure, may be referred to as the x-direction. Also, the up-down direction in Figure 1 may be referred to as the z-direction. Furthermore, the depth direction of the paper in Figure 1 may be referred to as the y-direction.

[0029] <Functional Configuration of Computer 50> Figure 2 is a functional configuration diagram of computer 50. Next, the functional configuration of the computer 50 to which this embodiment is applied will be described with reference to Figures 1 and 2.

[0030] As shown in Figure 2, the computer 50 to which this embodiment is applied includes a data acquisition unit 51 that acquires temperature distribution data and periodic signals input from an infrared thermography 40 (see Figure 1), a calculation unit 52 that calculates each measured value based on the temperature distribution data and periodic signals acquired by the data acquisition unit 51, and a calculation result output unit 59 that outputs the calculated calculation results to a liquid crystal display (not shown) or the like.

[0031] Here, the calculation unit 52 includes a phase lag distribution calculation unit 53, a temperature amplitude distribution calculation unit 54, a thermal diffusivity distribution calculation unit 55, a thermal conductivity calculation unit 56, a specific heat calculation unit 57, and a fatigue evaluation calculation unit 58.

[0032] The phase lag distribution calculation unit 53 calculates the phase lag distribution based on the temperature distribution data and periodic signal acquired by the data acquisition unit 51. The temperature amplitude distribution calculation unit 54 calculates the temperature amplitude distribution based on the temperature distribution data and periodic signal acquired by the data acquisition unit 51. The thermal diffusivity distribution calculation unit 55 calculates the thermal diffusivity distribution based on the phase lag calculated by the phase lag distribution calculation unit 53. The thermal conductivity calculation unit 56 calculates the thermal conductivity based on the temperature amplitude distribution calculated by the temperature amplitude distribution calculation unit 54. The specific heat calculation unit 57 calculates the specific heat based on the thermal diffusivity calculated by the thermal diffusivity distribution calculation unit 55 and the thermal conductivity calculated by the thermal conductivity calculation unit 56. The fatigue evaluation calculation unit 58 calculates the fatigue evaluation (described later), which is an evaluation of the fatigue of the measurement sample 1 (see Figure 1), based on the specific heat calculated by the specific heat calculation unit 57.

[0033] The thermal diffusivity distribution calculation unit 55 calculates the thermal diffusivity based on equation (2), which will be described later. The thermal conductivity calculation unit 56 calculates the thermal conductivity based on equation (6), which will be described later. The specific heat calculation unit 57 calculates the specific heat based on equation (1), which will be described later.

[0034] In this embodiment, the computer 50 evaluates the measurement sample 1 (see Figure 1) based on the temperature distribution of the measurement sample 1 detected by the infrared thermography 40, that is, it evaluates the thermal properties and fatigue of the measurement sample 1 (described later).

[0035] Here, thermal properties include thermal diffusivity, thermal conductivity, and specific heat. In addition, the computer 50 in this embodiment calculates at least one of the distributions of thermal diffusivity, thermal conductivity, and specific heat of the measurement sample 1 (see Figure 1) based on the temperature distribution of the measurement sample 1 detected by the infrared thermography 40. Fatigue, which will be described later, may also be included in the thermal properties.

[0036] <Fatigue Assessment> Here, we will explain the evaluation of fatigue in this embodiment. First, fatigue state refers to the degree of material alteration that occurs when the measurement sample 1 is subjected to continuous or repeated stress. Furthermore, evaluation of fatigue state refers to the evaluation of the degree of fatigue. Here, as fatigue progresses, crack initiation due to fatigue damage, fatigue crack propagation, and fracture occur in the measurement sample 1.

[0037] Here, we will first describe the fatigue properties of a carbon fiber reinforced composite material, which is an example of a measurement sample 1, and then explain the principle of the measurement method in this embodiment. Carbon fiber reinforced plastics (CFRP), an example of measurement sample 1, are expected to have applications in fields such as the transportation and aerospace industries due to their advantages such as high specific strength, corrosion resistance, and fatigue resistance. However, the fatigue properties of carbon fiber reinforced plastics, i.e., fatigue characteristics, vary greatly depending on manufacturing quality and operating environment. Therefore, it is necessary to understand the fatigue characteristics of carbon fiber reinforced plastics. Understanding these fatigue characteristics is expected to extend the design life of products, for example.

[0038] When carbon fiber reinforced composite materials are repeatedly subjected to loads, cracks (fatigue cracks) may occur. As these fatigue cracks propagate, they can develop into interlaminar delamination and fiber fracture within the carbon fiber reinforced composite material, ultimately leading to fatigue failure of the entire material. In addition, minute interlaminar delamination (micro-delamination) may occur and propagate, causing larger delamination. The origin of these is thought to be microvoids (tiny air spaces) within the material that occur during manufacturing, areas where the distance between fibers is close and the resin layer is thin, and stress concentration points such as between laminated layers. It is believed that minute cracks and minute delaminations originate and grow from these stress concentration points, leading to macroscopic fatigue cracks and delamination. By quantifying this process, it may be possible to diagnose the fatigue characteristics or fatigue state of the material.

[0039] Methods for detecting the origin and propagation morphology of fatigue cracks in carbon fiber reinforced composite materials include image analysis and X-ray CT. However, image analysis can only extract information from the surface of the sample, making internal evaluation impossible. Furthermore, X-ray CT has a small observation area, requiring an enormous amount of time to evaluate the entire sample. Also, X-ray CT requires sample cutting, making observation of large components difficult. Therefore, in this embodiment, the fatigue state of the sample 1 is calculated by measuring at least one of the following using non-contact heating with a laser: macro-scale thermal diffusivity distribution, thermal conductivity, and specific heat.

[0040] To further explain, microcracks and microdelaminations in the measurement sample 1 are accompanied by the formation of crack interfaces within the measurement sample 1. These interfaces then act as thermal resistance, causing localized changes in thermal diffusivity, thermal conductivity, and specific heat within the measurement sample 1. To further explain, for example, the presence of microcracks can be detected by measuring the thermal diffusivity, thermal conductivity, and specific heat in the in-plane direction of the measurement sample 1. In this embodiment, these changes in thermal conductivity, thermal conductivity, and specific heat are utilized to quantify the increasing trend of microcracks and microdelaminations using a laser, enabling diagnosis of the fatigue state of the measurement sample 1. This allows for non-destructive and more comprehensive quantification of the fatigue state of the measurement sample.

[0041] In this embodiment, for example, it is possible to detect the increasing trend of minute cracks and minute delaminations that are not visible to the naked eye, thereby detecting the initial deterioration of the measurement sample 1. Furthermore, although minute cracks and minute delaminations were described above as examples, the material alteration that occurs inside the measurement sample 1 is not limited to these. Examples of material alteration include lattice defects and bond breaks that occur inside the measurement sample 1. In this embodiment, these material alterations can also be quantified by utilizing changes in thermal diffusivity, thermal conductivity, and specific heat, which are examples of thermophysical properties.

[0042] In this embodiment, the fatigue evaluation of the measurement sample 1 is performed using at least one of the thermal diffusivity, thermal conductivity, and specific heat, as described above. For example, the specific heat in an undamaged state is compared with the specific heat after a predetermined number of loads are applied, and the difference in specific heat, or more precisely, the change in specific heat, is evaluated as a function of the number of loads. The larger this evaluation function is, the more advanced the fatigue is, i.e., the more significant the fatigue. To further explain, for example, a threshold value for the evaluation function may be predetermined, and the fatigue state may be evaluated by comparing with this threshold value. In other words, by monitoring the evaluation function, it becomes possible to diagnose the fatigue state.

[0043] Furthermore, in this embodiment, the specific heat distribution of the sample 1 can be measured. Areas with different specific heat distributions compared to other parts can be diagnosed as experiencing fatigue. In other words, in this embodiment, the fatigue state can be diagnosed by monitoring the specific heat distribution of the sample 1.

[0044] <Hardware configuration of Computer 50> Figure 3 shows an example of the hardware configuration of computer 50. As shown in Figure 3, the computer 50 comprises a CPU (Central Processing Unit) 501, which is a calculation means, and a main memory 503 and an HDD (Hard Disk Drive) 505, which are storage means. The CPU 501 executes various programs such as the OS (Operating System) and application software. The main memory 503 is a storage area that stores various programs and data used for their execution. The HDD 505 is a storage area that stores input data for various programs and output data from various programs. These components of the computer 50 then execute the various functional configurations described in Figure 2 and above.

[0045] The computer 50 is equipped with a communication interface (communication I / F) 507 for communicating with external devices such as the infrared thermograph 40. In addition, the program executed by the CPU 501 (for example, the program for calculating the thermal properties mentioned above) can be stored in the main memory 503 in advance, or it can be provided to the CPU 501 from a storage medium such as a CD-ROM, or it can be provided to the CPU 501 via a network (not shown).

[0046] <Measurement principle> Next, the principle of measuring thermophysical properties in the first embodiment will be explained. <Specific heat> First, the formula for calculating specific heat in this embodiment will be explained. Specific heat Cp is a function of thermal conductivity k, thermal diffusivity D, and density ρ, as shown in equation (1) below.

[0047]

number

[0048] In this embodiment, the specific heat Cp is calculated based on the above formula (1). Specifically, the thermal conductivity k is measured using a thermophysical property evaluation device 100 that employs a lock-in thermography periodic heating method. The thermal diffusivity D is also measured using the thermophysical property evaluation device 100. Furthermore, the density ρ is measured using a well-known technique such as the Archimedes method. Then, the specific heat Cp is calculated based on the above formula (1).

[0049] Furthermore, if density ρ is not measured, the thermal conductivity k and thermal diffusivity D are measured using the thermophysical property evaluation device 100, and the specific heat capacity ρCp per unit volume is calculated based on the above formula (1).

[0050] In the following description, the thermal diffusivity D is measured by a lock-in thermographic periodic heating method via a thermophysical property evaluation device 100, but this method is not limited to this. Any known measurement method that allows for the measurement of thermal diffusivity D may be used.

[0051] <Specific heat distribution in the thickness direction> Figures 4(A) and 4(B) illustrate the principle of measuring thermal properties in the first embodiment. Here, Figure 4(A) shows the principle of measuring thermal diffusivity, and Figure 4(B) shows the principle of measuring thermal conductivity.

[0052] Next, the general principle of measurement in this embodiment will be explained with reference to Figures 4(A) and (B). Here, we will explain how to measure the specific heat distribution of the sample 1 from the thickness direction.

[0053] First, as shown in Figure 4(A), the thermal diffusivity is measured using the thermal property evaluation device 100. Specifically, as shown in Figures 4(A-1) to (A-3), the measurement sample 1 is periodically heated while maintaining the power of the laser light irradiated from the diode laser 10 and changing the frequency, thereby measuring the frequency dependence of the temperature amplitude (see Figure 4(A-4)) and the frequency dependence of the phase lag (see Figure 4(A-4)). Then, the thermal diffusivity distribution is calculated from the measured frequency dependence of the temperature amplitude and the frequency dependence of the phase lag.

[0054] Furthermore, as shown in Figures 4(B-1) to (B-3), the power dependence of the temperature amplitude (see Figure 4(B-4)) is measured by periodically heating the sample 1 while maintaining the frequency of the laser light emitted from the diode laser 10 and changing the power. Then, the thermal conductivity distribution is calculated from the measured power dependence of the temperature amplitude. In other words, in this embodiment, the thermal conductivity distribution is determined from the relationship between temperature amplitude decay and laser power.

[0055] Then, using the measured thermal diffusivity distribution and thermal conductivity distribution, and the density distribution measured by a well-known technique, the specific heat distribution is calculated from equation (1) above.

[0056] Figures 5(A) and (B) show a model of the measurement principle in the first embodiment. Here, Figures 5(A) and (B) show the heating conditions. Next, the measurement principle in this embodiment will be described in detail with reference to Figures 5(A) and (B).

[0057] As shown in Figures 5(A) and (B), the measurement sample 1, which is roughly plate-shaped, has a thickness d. This measurement sample 1 has a thermal conductivity k and a thermal diffusivity D. The first surface 103, which is one side of the measurement sample 1, is uniformly heated periodically at an angular frequency ω by laser light L1. In this example, the first surface 103 is heated by the laser light L1.

[0058] The symbols used in the following explanation are as follows: p: Absorption power per unit area (W / m²) 2 ) k: Thermal conductivity (W / m·K) D: Thermal diffusivity (m 2 / s) d: Thickness (m) ω: Angular frequency (1 / s)

[0059] The temperature of the second surface 105, which is one side of the heated sample 1, is expressed by equation (2).

[0060]

number

[0061] Furthermore, λ is a complex wave number and is expressed by equation (3).

[0062]

number

[0063] The temperature amplitude A is expressed by equation (4) from the absolute value of the temperature T.

[0064]

number

[0065] The phase lag obtained from the angle of change of temperature T is expressed by equation (5).

[0066]

number

[0067] Therefore, the relationship in equation (6) holds true.

[0068]

number

[0069] Figure 6 shows the measurement principle of specific heat capacity in the first embodiment. Next, the measurement principle of specific heat capacity in this embodiment will be explained with reference to Figure 6.

[0070] First, the thermal diffusivity D in the thickness direction is obtained by measuring the temperature amplitude (see reference numeral 601) and phase lag (see reference numeral 603) while varying the frequency, and then fitting the resulting curve with the temperature amplitude from equation (4) and the phase lag from equation (5) (see reference numerals 607 and 613 in the figure).

[0071] Next, the thermal conductivity k in the thickness direction is obtained by fixing the frequency and measuring the temperature amplitude (see reference numeral 605) while varying the laser power, and then taking the linear slope of the laser power dependence of the temperature amplitude (see reference numerals 609 and 615 in the figure). In addition, in this embodiment, the distribution of the thermal conductivity k in the thickness direction is output as an image (see reference numeral 609 in the figure).

[0072] The specific heat capacity ρCp is calculated from the thermal diffusivity D in the thickness direction and the thermal conductivity k in the thickness direction based on the above equation (1) (see reference numerals 611 and 617). In addition, in this embodiment, the distribution of the specific heat capacity ρCp is output as an image (see reference numeral 611).

[0073] <Fatigue Assessment Action> Figure 7 is a flowchart illustrating the fatigue evaluation and determination operation by the thermophysical property evaluation device 100 (see Figure 1).

[0074] Next, the fatigue evaluation operation by the thermophysical property evaluation device 100 in this embodiment will be described with reference to Figures 1 and 7. In this example, a tensile load is repeatedly applied to the measurement sample 1 using a tensile testing machine (not shown). Then, at the timing when the number of loads reaches a predetermined number, the fatigue evaluation operation is performed by the thermophysical property evaluation device 100. For example, the fatigue evaluation operation is performed at the timing when the number of loads reaches 1,000, 10,000, and 100,000. It is assumed that the fatigue state of the measurement sample 1 is measured when the number of loads is 0, i.e., in an undamaged state.

[0075] As shown in Figure 7, in the fatigue evaluation operation, a tensile test is first performed on a tensile testing machine (not shown) (S701). After a predetermined number of tensile tests have been performed, the thermophysical property evaluation device 100 performs the fatigue evaluation (S702).

[0076] Next, the fatigue evaluation calculation unit 58 determines whether to terminate the tensile test, that is, whether the number of load cycles has reached a set value (S703). If the tensile test is terminated (YES in S703), the calculation result output unit 59 outputs the calculation result for the measurement sample 1 to a display area (not shown), such as a liquid crystal display (S704). On the other hand, if the tensile test is not terminated (NO in S703), the tensile test is performed by the tensile testing machine (S701).

[0077] <Fatigue level evaluation process> Figure 8 is a flowchart illustrating the fatigue evaluation process using the thermophysical property evaluation device 100 (see Figure 1). Next, the fatigue evaluation process of the thermophysical property evaluation device 100 in this embodiment will be described with reference to Figures 1 and 8.

[0078] First, the phase delay distribution calculation unit 53 calculates the phase delay distribution (S801). Specifically, the sample 1 is periodically heated by the laser light emitted from the diode laser 10. The phase delay distribution calculation unit 53 acquires the temperature distribution via the infrared thermography 40 while changing the frequency of the laser light emitted from the diode laser 10, and calculates the phase delay distribution. Then, based on the calculated phase delay distribution, the thermal diffusivity distribution calculation unit 55 calculates the thermal diffusivity distribution (S802).

[0079] Next, the temperature amplitude distribution calculation unit 54 sets the frequency to be used for temperature amplitude distribution measurement (S803).

[0080] Next, the temperature amplitude distribution calculation unit 54 calculates the temperature amplitude distribution (S804). Specifically, the measurement sample 1 is periodically heated by the laser light emitted from the diode laser 10. The temperature amplitude distribution calculation unit 54 acquires the temperature distribution via the infrared thermography 40 while changing the laser power of the laser light emitted from the diode laser 10, and calculates the temperature amplitude distribution. Then, based on the calculated temperature amplitude distribution, the thermal conductivity calculation unit 56 calculates the thermal conductivity distribution (S805).

[0081] Next, the specific heat calculation unit 57 calculates the specific heat distribution (S806). Then, based on this calculated specific heat distribution, the fatigue evaluation calculation unit 58 calculates the fatigue evaluation of the measurement sample 1 (S807).

[0082] Note that the optimal frequency for measuring the temperature amplitude by the temperature amplitude distribution calculation unit 54 varies depending on the physical properties of the sample 1 being measured. Therefore, in the illustrated example, before measuring the temperature amplitude by the temperature amplitude distribution calculation unit 54, the phase delay distribution calculation unit 53 is performed. Then, within the frequency range set by the phase delay distribution calculation unit 53, the frequency for measuring the temperature amplitude is set (S803). This makes the measurement of the temperature amplitude by the temperature amplitude distribution calculation unit 54 more efficient.

[0083] Furthermore, the order in which the phase delay is measured by the phase delay distribution calculation unit 53 and the temperature amplitude is measured by the temperature amplitude distribution calculation unit 54 is not particularly limited. For example, if the physical properties of the sample 1 are known, the temperature amplitude may be measured by the temperature amplitude distribution calculation unit 54 before the phase delay is measured by the phase delay distribution calculation unit 53.

[0084] <Measurement result 1> Figures 9(A) to (E) show the first measurement results. Specifically, Figure 9(A) shows the first sample 101, which is an example of the measurement sample 1. Figure 9(B) shows the distribution of the laser power dependence of the temperature amplitude. Figure 9(C) shows the thermal conductivity distribution. Figure 9(D) shows the thermal diffusivity distribution. Figure 9(E) shows the specific heat distribution per unit volume.

[0085] Next, the first measurement results using the first sample 101 will be explained with reference to Figure 9. This first sample 101 is a composite material with a width of 36 mm, a length of 120 mm, and a thickness of 1 mm, specifically a carbon fiber reinforced resin. The observation area of ​​the first sample 101 is 36 mm wide and 45 mm long.

[0086] Furthermore, the laser frequency used for calculating the phase lag distribution (first measurement, see S801 in Figure 8 above) is varied in the range of 0.3 to 0.54 Hz with a width of 0.02 Hz. The laser power of this laser is 1750 mW. Also, the laser power used for calculating the temperature amplitude distribution (second measurement, see S804 in Figure 8 above) is varied in the range of 500 to 2000 mW with a width of 250 mW. Here, the laser frequency is 0.125 Hz. Changing the laser power here means switching the maximum output (maximum power) of the laser beam used for periodic heating in one cycle. In other words, changing the laser power means switching the maximum output of the laser beam between at least a first maximum output and a second maximum output. To put it another way, changing the laser power means changing the irradiation amplitude of the laser beam.

[0087] As shown in Figures 9(B) to (E), the distribution of the laser power dependence of the temperature amplitude, the thermal conductivity distribution, the thermal diffusivity distribution, and the specific heat distribution per unit volume were calculated for the first sample 101. This demonstrates that the specific heat of the first sample 101 can be measured non-destructively and non-contact. Furthermore, Figures 10(B) to (E) show that the specific heat distribution of the first sample 101 can be detected by the thermophysical property evaluation device 100 (see Figure 1).

[0088] <Measurement result 2> Figures 10(A) to (D) show the results of the second measurement. Specifically, Figures 10(A) to (D) show the results of evaluating the degree of fatigue deterioration with increasing load cycles using specific heat. To further explain, Figure 10(A) shows the specific heat distribution per unit volume of the first sample 101 (see Figure 9) which is undamaged, i.e., has 0 load cycles (N). Similarly, Figure 10(B) shows the specific heat distribution with 10 load cycles. 3 Figure 10(C) shows the number of load cycles as 10 4 Figure 10(D) shows the number of load cycles as 10 5 The specific heat distribution per unit volume is shown. As shown in Figures 10(A) to (D), it was confirmed that the specific heat distribution per unit volume in the first sample 101 changed with increasing load cycles.

[0089] Furthermore, Figures 11(A) to (E) show the results of the second measurement. Specifically, Figures 11(A) to (D) show the change in specific heat calculated from the specific heat distribution shown in Figures 10(A) to (D), respectively. To further explain, in Figures 11(A) to (D), the horizontal axis represents the specific heat per unit volume, and the vertical axis represents the count. Figure 11(E) shows the change in specific heat capacity according to the number of load cycles.

[0090] As shown in Figures 11(A) to (D), it was observed that the specific heat changed with increasing load cycles. Furthermore, as shown in Figure 11(E), a tendency for the specific heat, i.e., entropy, to increase with increasing load cycles was observed. To further explain, Figures 11(A) to (E) show that the degree of fatigue degradation of the first sample 101 can be measured by specific heat using the thermophysical property evaluation device 100 (see Figure 1).

[0091] As described above, the thermal property evaluation device 100 (see Figure 1) makes it possible to measure thermal conductivity non-destructively and non-contactively. To further explain, the thermal property evaluation device 100 can measure the thermal conductivity of a measurement sample 1 that has already been completed as a product, for example, in situ. In addition, the thermal property evaluation device 100 can measure the thermal conductivity non-destructively even if the measurement sample 1 is a rare sample.

[0092] Here, differential scanning calorimetry (DSC) has been used as a well-known technique for measuring specific heat. However, the DSC method requires destructive testing, i.e., cutting or grinding the sample. Furthermore, structural changes may occur during the grinding process, potentially altering the measured value. In addition, the DSC method requires a reference material (standard material) with a known specific heat value. Moreover, while the DSC method can obtain the average specific heat value of a sample, it is difficult to measure the specific heat distribution.

[0093] In contrast, the thermophysical property evaluation device 100 (see Figure 1) allows for non-destructive and non-contact in-situ measurement of specific heat. Furthermore, the thermophysical property evaluation device 100 eliminates the need for a reference material for specific heat measurement, potentially improving the reliability of the measurement. Additionally, the thermophysical property evaluation device 100 allows for the measurement of the specific heat distribution, enabling the detection of areas with different physical properties in the measurement sample 1 (damage detection).

[0094] <Second Embodiment> <Configuration of the thermophysical property evaluation device 200> Figure 12 is a schematic diagram showing a thermophysical property evaluation apparatus 200 according to the second embodiment. Next, with reference to Figure 12, the configuration of the thermophysical property evaluation apparatus 200 to which the second embodiment is applied will be described. In the following description, the same reference numerals are used for parts that are the same as those in the above embodiment, and detailed descriptions of them may be omitted.

[0095] In the above description, surface heating was performed on the first surface 103 of the measurement sample 1, but the method is not limited to this. For example, as shown in the thermophysical property evaluation apparatus 200 in Figure 12, line heating may be performed on the first surface 103 of the measurement sample 1.

[0096] Specifically, as shown in Figure 12(A), the thermophysical property evaluation apparatus 200 to which this embodiment is applied includes a diode laser 110 that functions as a light source for heating the sample to be measured 1, a light guide unit 210 that guides the laser light from the diode laser 110 to the sample to be measured 1, and a holder 310 that holds the sample to be measured 1.

[0097] Here, as shown in Figure 12(B), the diode laser 110 heats a portion of the surface of the measurement sample 1 that extends in one direction (heating region Hp). In other words, the diode laser 110 is a light source for line heating.

[0098] Now, as shown in Figure 12(A), the light guide unit 210 includes a mirror 211 that reflects the laser light emitted from the diode laser 110, a beam expander 213 that expands the beam diameter of the laser light from the mirror 211, and a cylindrical lens 215 that converts the laser light from the beam expander 213 into sheet light.

[0099] In the thermophysical property evaluation apparatus 200, the laser light emitted from the diode laser 110 passes through the mirror 211, beam expander 213, and cylindrical lens 215 before irradiating the sample 1. More specifically, the laser light emitted from the diode laser 110 is irradiated in a direction perpendicular to the first surface 103 of the sample 1. In this sample 1, the area irradiated by the laser light (the area extending in one direction) is periodically heated. That is, a specific area (heated area Hp) on the first surface 103 of the sample 1 is spot-periodically heated.

[0100] The computer 50, in conjunction with the infrared thermography 40, continuously performs infrared image acquisition and calculation based on a predetermined frame rate, and creates an averaged image from the temperature change amount that changes over time (lock-in method). To further explain, the data obtained from the infrared thermography 40 is processed by the computer 50 to calculate the thermal conductivity of the measurement sample 1 in the planar direction. In addition, the data obtained from the infrared thermography 40 is processed by the computer 50 to calculate information regarding the thermal properties of the measurement sample 1.

[0101] In the first embodiment described above, the thermophysical property evaluation apparatus 100 irradiates the surface of the measurement sample 1 with light having a uniform intensity distribution using a diode laser 10 and a light guide unit 20. On the other hand, the thermophysical property evaluation apparatus 200 does not require a configuration to uniformize the light.

[0102] <Specific heat distribution in the in-plane direction> Figures 13(A) and (B) illustrate the principle of measuring thermal properties in the second embodiment. Here, Figure 13(A) shows the principle of measuring thermal diffusivity, and Figure 13(B) shows the principle of measuring thermal conductivity.

[0103] Next, with reference to Figures 13(A) and (B), the general principle of the measurement in the second embodiment will be explained. Here, the specific heat distribution of the sample 1 is measured from the in-plane direction.

[0104] First, as shown in Figure 13(A), the thermal diffusivity is measured using the thermal property evaluation device 200. Specifically, as shown in Figure 13(A-1), the distance dependence of the temperature amplitude (see Figures 13(A-2) and (A-3)) and the distance dependence of the phase delay (see Figures 13(A-4) and (A-5)) are measured by periodically heating the sample 1 while maintaining the power and frequency of the laser light irradiated from the diode laser 10. Then, the thermal diffusivity distribution is calculated from the measured distance dependence of the temperature amplitude and the distance dependence of the phase delay.

[0105] Next, as shown in Figures 13(B-1) to (B-3), the power dependence of the temperature amplitude (see Figure 13(B-4)) is measured by periodically heating the sample 1 while maintaining the frequency of the laser light emitted from the diode laser 10 and changing the power. Then, the thermal conductivity distribution is calculated from the measured power dependence of the temperature amplitude. In other words, in this embodiment, the thermal conductivity distribution is determined from the relationship between the temperature amplitude decay and the laser power.

[0106] Then, using the measured thermal diffusivity distribution and thermal conductivity distribution, and the density distribution measured by a well-known technique, the specific heat distribution is calculated from equation (1) above.

[0107] Figures 14(A) and (B) show a model of the measurement principle in the second embodiment. Here, Figures 14(A) and (B) show the heating conditions. Next, the measurement principle in this embodiment will be described in detail with reference to Figures 14(A) and (B).

[0108] As shown in Figures 14(A) and (B), the measurement sample 1, which is roughly plate-shaped, has a thickness d. This measurement sample 1 is a thermally thin object. This measurement sample 1 has a thermal conductivity k and a thermal diffusivity D. The first surface 103, which is one side of the measurement sample 1, is uniformly heated periodically at an angular frequency ω by laser light L2. In this example, the first surface 103 is linearly heated by the laser light L2. The heated region Hp on the first surface 103, which is the area heated by the laser light L2, is a band-shaped region along the y direction at x=0.

[0109] The symbols used in the following explanation are as follows: p: Absorption power per unit area (W / m²) 2 ) k: Thermal conductivity (W / m·K) D: Thermal diffusivity (m 2 / s) d: Thickness (m) ω = 2πf (rad / s)

[0110] First, the temperature at a distance x from the heated region Hp on the second surface 105, which is one side of the heated sample 1, is expressed by equation (7).

[0111]

number

[0112] The temperature amplitude A is expressed by equation (8).

[0113]

number

[0114] The phase lag is expressed by equation (9).

[0115]

number

[0116] Therefore, the relationship in equation (10) holds true.

[0117]

number

[0118] Figure 15 shows the measurement principle of specific heat capacity in the second embodiment. Next, the measurement principle of specific heat capacity in this embodiment will be explained with reference to Figure 15.

[0119] First, the thermal diffusivity D in the in-plane direction is obtained by measuring the distance dependence of the temperature amplitude (see reference numeral 1501) and the distance dependence of the phase lag (see reference numeral 1503), respectively, and fitting the resulting curve with the temperature amplitude from equation (8) and the phase lag from equation (9) (see reference numeral 1513 in the figure).

[0120] Next, the in-plane thermal conductivity k is obtained by measuring the temperature amplitude (see reference numeral 1505) and taking the linear gradient of the laser power dependence of the temperature amplitude (see reference numeral 1515 in the figure).

[0121] The specific heat capacity ρCp is calculated from the thermal diffusivity D in the thickness direction and the thermal conductivity k in the thickness direction based on the above equation (1) (see reference numeral 1517).

[0122] <Measurement result 3> Figures 16(A) to (C) show the results of the third measurement. Specifically, Figure 16(A) shows the laser power dependence of the temperature amplitude. Figure 16(B) shows the laser power dependence of the phase. Figure 16(C) shows the laser power dependence of the temperature amplitude.

[0123] Next, referring to FIG. 16, the third measurement result is shown. The measurement sample 1 in this measurement is a composite material. Also, the frequency of the laser for calculating the phase retardation distribution (see S801 in FIG. 8 above) is changed in a range of 0.3 to 0.54 Hz with a width of 0.02 Hz. The laser power of this laser is 150 mW. Also, the laser power of the laser for calculating the temperature amplitude distribution (see S804 in FIG. 8 above) is changed in a range of 150 to 300 mW with a width of 25 mW. The frequency of this laser is 0.05 Hz.

[0124] As shown in FIG. 16(A), it was confirmed that the temperature amplitude depends on the laser power. On the other hand, as shown in FIG. 16(B), it was observed that the phase does not depend on the laser power. The thermophysical property values calculated from FIGS. 16(A) to (C) are as follows. That is, the in-plane thermal diffusivity is 1.06 (m 2 / s), the in-plane thermal conductivity is 1.84 (W / m·K), and the specific heat capacity is calculated as 1641.1 (kJ / m 3 K).

[0125] <Third Embodiment> <Configuration of Thermophysical Property Evaluation Apparatus 200> FIG. 17 is a schematic configuration diagram showing a thermophysical property evaluation apparatus 300 according to the third embodiment. Next, referring to FIG. 17, the configuration of the thermophysical property evaluation apparatus 300 to which the third embodiment is applied will be described. In the following description, the same parts as those in the configuration of the above embodiment may be denoted by the same reference numerals, and detailed descriptions thereof may be omitted.

[0126] In the above description, the creation of an averaged image from the temperature change amount that changes with time (lock-in method) has been described, but it is not limited thereto. For example, as in the thermophysical property evaluation apparatus 300 shown in FIG. 17, a high-intensity uniform laser may be irradiated once on the first surface 103 of the measurement sample 1 in a short time, that is, in a pulsed irradiation mode.

[0127] Specifically, the thermophysical property evaluation apparatus 300 to which this embodiment is applied includes a diode laser 10 that functions as a light source for heating the sample to be measured 1, a light guide unit 20 that guides the laser light from the diode laser 10 to the sample to be measured 1, a holder 310 that holds the sample to be measured 1, an infrared thermograph 40, and a computer 50. Here, the thermophysical property evaluation apparatus 300 does not include a periodic signal generator 70 (see Figure 1).

[0128] In the explanation of Figure 1 above, periodic heating was described, but in the thermophysical property evaluation device 300, a high-intensity, uniform laser pulse is emitted once for a short time, heating the surface of the measurement sample 1.

[0129] <Specific heat distribution in the thickness direction> Figures 18(A) to (D) show the principle of measuring thermal properties in the third embodiment. Here, Figure 18(A) shows a heating laser, Figure 18(B) shows the principle of measuring thermal diffusivity, and Figures 18(C) and (D) show the principle of measuring thermal conductivity.

[0130] Next, with reference to Figures 18(A) to (D), the general principle of the measurement in the third embodiment will be explained. Here, the specific heat distribution of the sample 1 is measured from the thickness direction.

[0131] First, as shown in Figure 18(A), the sample 1 is heated by a pulsed laser from the diode laser 10. This heating allows for the measurement of the time dependence of the temperature (see Figure 13(B)), i.e., temperature decay. Then, the thermal diffusivity distribution is calculated from the measured time dependence of the temperature.

[0132] Next, as shown in Figure 18(C), the power dependence of the maximum temperature is measured by heating the sample 1 while changing the power of the laser light irradiated from the diode laser 10. Then, as shown in Figure 18(D), the thermal conductivity distribution is calculated from the measured power dependence of the maximum temperature. In other words, in this embodiment, the thermal conductivity distribution is determined from the relationship between the maximum temperature and the laser power.

[0133] Then, using the measured thermal diffusivity distribution and thermal conductivity distribution, and the density distribution measured by a well-known technique, the specific heat distribution is calculated from equation (1) above.

[0134] Next, the measurement principle in this embodiment will be described in detail. Here, we will explain using a measurement sample 1 that is roughly plate-shaped, as shown in Figures 5(A) and (B) above. This measurement sample 1 has a thickness d. Furthermore, the measurement sample 1 is assumed to have a thermal conductivity k and a thermal diffusivity D. The first surface 103, which is one side of the measurement sample 1, is uniformly heated by laser light L1. In this example, the first surface 103 is surface-heated by laser light L1.

[0135] The symbols used in the following explanation are as follows: p: Absorption power per unit area (W / m²) 2 ) k: Thermal conductivity (W / m·K) D: Thermal diffusivity (m 2 / s) d: Thickness (m) t: time (s)

[0136] The temperature of the second surface 105, which is one side of the heated sample 1, is expressed by equation (11).

[0137]

number

[0138] Figure 19 shows the measurement principle of specific heat capacity in the third embodiment. Next, the measurement principle of specific heat capacity in this embodiment will be explained with reference to Figure 19.

[0139] First, the thermal diffusivity D in the thickness direction is obtained by measuring the time dependence of temperature, i.e., the exponential decay of temperature (see reference numeral 1901), and fitting a well-known calculation formula (see reference numeral 1913) to the resulting curve (see reference numeral 1907 in the figure). In the calculation formula shown, the exponential decay is defined as the time t until the temperature rise reaches 50% of the maximum value. 0.5 The thermal diffusivity D is calculated by specifying this value.

[0140] Next, the thermal conductivity k in the thickness direction is obtained by measuring the maximum temperature (see reference numeral 1903) at each pixel (each location) and taking the linear gradient of the laser power dependence of the maximum temperature (see reference numerals 1909 and 1915 in the figure).

[0141] The specific heat capacity ρCp is then calculated from the thermal diffusivity D in the thickness direction and the thermal conductivity k in the thickness direction based on equation (1) above (see reference numerals 1911 and 1917).

[0142] <Fourth Embodiment> <Configuration of the thermophysical property evaluation device 400> Figure 20 is a schematic diagram showing a thermophysical property evaluation apparatus 400 according to the fourth embodiment. Next, with reference to Figure 20, the configuration of the thermophysical property evaluation apparatus 400 to which the fourth embodiment is applied will be described. In the following description, the same reference numerals are used for parts that are the same as those in the above embodiments, and detailed descriptions of them may be omitted.

[0143] The thermophysical property evaluation apparatus 400 shown in Figure 20 may be configured to irradiate a region extending in one direction on the first surface 103 of the measurement sample 1 with pulses.

[0144] Specifically, the thermophysical property evaluation apparatus 400 to which this embodiment is applied includes a diode laser 110 that functions as a light source for heating the sample to be measured 1, a light guide unit 210 that guides the laser light from the diode laser 110 to the sample to be measured 1, a holder 310 that holds the sample to be measured 1, an infrared thermograph 40, and a computer 50. Here, the thermophysical property evaluation apparatus 400 does not include a periodic signal generator 70 (see Figure 1).

[0145] In the explanation of Figure 12 above, periodic heating was described, but in the thermophysical property evaluation device 400, a high-intensity, uniform laser pulse is emitted once for a short time, and the surface of the measurement sample 1 is heated.

[0146] <Specific heat distribution in the in-plane direction> Figures 21(A) to (D) show the principle of measuring thermal properties in the fourth embodiment. Here, Figure 21(A) shows a heating laser, Figure 21(B) shows the principle of measuring thermal diffusivity, and Figures 21(C) and (D) show the principle of measuring thermal conductivity.

[0147] Next, with reference to Figures 21(A) to (D), the general principle of the measurement in the fourth embodiment will be explained. Here, we will explain how to measure the specific heat distribution of the sample 1 from the in-plane direction.

[0148] First, as shown in Figure 21(A), the sample 1 is heated by a pulsed laser from the diode laser 10. This heating allows for the measurement of the time dependence of the temperature (see Figure 21(B)), i.e., temperature decay. Then, the thermal diffusivity distribution is calculated from the measured time dependence of the temperature.

[0149] Next, as shown in Figure 21(C), the power dependence of the maximum temperature is measured by heating the sample 1 while changing the power of the laser light irradiated from the diode laser 10. Then, as shown in Figure 21(D), the thermal conductivity distribution is calculated from the measured power dependence of the maximum temperature. In other words, in this embodiment, the thermal conductivity distribution is determined from the relationship between the maximum temperature and the laser power.

[0150] Then, using the measured thermal diffusivity distribution and thermal conductivity distribution, and the density distribution measured by a well-known technique, the specific heat distribution is calculated from equation (1) above.

[0151] Next, the measurement principle in this embodiment will be described in detail. Here, we will explain using a measurement sample 1 that is roughly plate-shaped, as shown in Figures 14(A) and (B) above. This measurement sample 1 has a thickness d. This measurement sample 1 is assumed to have a thermal conductivity k and a thermal diffusivity D. Then, one side of the measurement sample 1, the first surface 10, is heated by laser light L2. In this example, the first surface 103 is linearly heated by laser light L2.

[0152] The symbols used in the following explanation are as follows: p: Absorption power per unit area (W / m²) 2 ) k: Thermal conductivity (W / m·K) D: Thermal diffusivity (m 2 / s) d: Thickness (m) l: Half the width of the heating region

[0153] The temperature of the second surface 105, which is one side of the heated sample 1, is expressed by equation (12).

[0154]

number

[0155] Here, the initial conditions are expressed by equation (13).

[0156]

number

[0157] Figure 22 shows the principle of measuring specific heat capacity. Next, the measurement principle of specific heat capacity in this embodiment will be explained with reference to Figure 22.

[0158] First, the in-plane thermal diffusivity D is obtained by measuring the time dependence of temperature, i.e., the exponential decay of temperature (see reference numeral 2201), and fitting the resulting curve to, for example, a well-known calculation formula (see reference numeral 2213). In the calculation formula shown in the figure, the exponential decay is defined as the time t until the temperature rise reaches 50% of the maximum value. 0.5 The thermal diffusivity D is calculated by specifying the parameters. Furthermore, C(r) is an instrument constant that depends on the measurement system. This C(r) depends on the relative distance r from the laser beam to the measurement point (which can be obtained from the infrared thermography image 40) in the x-direction.

[0159] Next, the in-plane thermal conductivity k is obtained by measuring the maximum temperature at each pixel (see reference numeral 2203) and taking the linear gradient of the laser power dependence of the maximum temperature (see reference numeral 2215 in the figure).

[0160] The specific heat capacity ρCp is then calculated from the thermal diffusivity D in the in-plane direction and the thermal conductivity k in the thickness direction based on the above equation (1) (see reference numeral 2217).

[0161] <Example 1> Figure 23 is a diagram illustrating the measurement condition control unit 550 in modified example 1. In the above description, surface heating and periodic heating (see Figure 1), line heating and periodic heating (see Figure 12), surface heating and pulse heating (see Figure 17), and line heating and pulse heating (see Figure 20) are described as being performed by independent thermophysical property evaluation devices 100, but the description is not limited to these. For example, the thermophysical property evaluation device 100 may be configured to switch between heating conditions, i.e., measurement conditions.

[0162] For example, as shown in Figure 23, the computer 50 may be configured to include a measurement condition control unit 550. This measurement condition control unit 550 includes a heating area switching unit 570 that switches the heating area between surface heating and line heating, and a heating mode switching unit 590 that switches the heating mode between periodic heating and pulse heating.

[0163] The heating region switching unit 570 has an in-plane direction measuring unit 571 and a thickness direction measuring unit 573. The in-plane direction measuring unit 571 controls the in-plane direction measuring mechanism 220. The in-plane direction measuring mechanism 220 performs line heating, for example, via a light guide unit 210 (see Figure 12). The thickness direction measuring unit 573 controls the thickness direction measuring mechanism 230. The thickness direction measuring mechanism 230 performs surface heating, for example, via a light guide unit 20 (see Figure 1).

[0164] The heating region switching unit 570 includes a periodic heating measurement unit 591 and a pulse heating measurement unit 593. The periodic heating measurement unit 591 performs periodic heating by controlling the diode laser 10 via a periodic signal generator 70. The pulse heating measurement unit 593 performs pulse heating by controlling the diode laser 10.

[0165] Then, the measurement condition control unit 550, which has received the specification of measurement conditions from the computer 50, switches the measurement conditions using the heating area switching unit 570 and the heating mode switching unit 590.

[0166] As described above, by switching the measurement conditions, a wider range of thermophysical properties of the sample 1 can be measured. For example, by performing measurements in both the thickness direction and the in-plane direction on the sample 1, the anisotropy of the thermal conductivity can be measured.

[0167] <Modification 2> In the above description, the first surface 103 (front) of the sample 1 is heated by the diode laser 10 and the second surface 105 (back) of the sample 1 is measured by the infrared thermography 40, but the description is not limited to this. For example, the heating of the sample 1 by the diode laser 10 and the measurement of the sample 1 by the infrared thermography 40 may be performed on the same surface.

[0168] Furthermore, while the example shown in Figure 1 above describes heating the measurement sample 1 with the diode laser 10 and the light guide unit 20, this is not limited to this, as long as the intensity distribution of the irradiated surface of the measurement sample 1 is made uniform. For example, an array of multiple LEDs (Light Emitting Diodes) may be used as the light source. Also, other heating methods such as induction heating or resistance heating may be used if it is possible to heat the entire area of ​​the measurement sample 1. In addition, a diffuser plate such as frosted glass that diffuses the light from the light source may be used instead of at least one of the fiber 21 and the light concentrator 23, or together with the fiber 21 and the light concentrator 23. Furthermore, a diode laser 10 with a relatively large Gaussian distribution may be used. To explain further, the intensity distribution of the irradiated surface of the measurement sample 1 may be made uniform by using a portion of the laser light exhibiting a relatively large Gaussian distribution where the light intensity is constant.

[0169] Furthermore, although the above description explains that an aperture 39 is provided between the measurement sample 1 and the infrared thermograph 40, a configuration without an aperture 39 is also possible.

[0170] Furthermore, in the example shown in Figure 12 above, the laser beam from the diode laser 10 toward the cylindrical lens 215 is described as being orthogonal to the first surface 103 of the measurement sample 1, but this is not limited to this. That is, if the heating region Hp on the first surface 103 of the measurement sample 1 is elongated in one direction, the laser beam from the diode laser 10 may be irradiated in an oblique direction.

[0171] Furthermore, although the above embodiment describes using a cylindrical lens 215 to create a heated area Hp that is elongated in one direction, the invention is not limited to this. For example, instead of the cylindrical lens 215, a masking member may be provided to shield a portion of the laser light and create a heated area Hp that is elongated in one direction. Also, instead of the diode laser 10, a sheet laser that emits sheet light may be used as the light source. Alternatively, the heated area Hp may be made elongated in one direction by irradiating the upper surface 11 of the measurement sample 1 at an oblique angle without using the cylindrical lens 215 or the like.

[0172] Furthermore, the heating of the measurement sample 1 performed by the diode laser 10 is not limited to the laser. Other heating methods such as induction heating or resistance heating may be used as long as it is possible to heat the measurement sample 1 locally.

[0173] Furthermore, the measurement sample 1 is not particularly limited. For example, glass, artificial diamond, semiconductor, polymer film, liquid crystal, etc. may be used as the measurement sample 1. When glass or the like is used as the measurement sample 1, voids and cracks formed inside the measurement sample 1 can be detected. In other words, information regarding the density of the measurement sample 1 can be obtained as part of the sample evaluation of the measurement sample 1. This information regarding density refers to information that allows the density of the measurement sample 1 to be determined. This information regarding density includes not only the density value of the measurement sample 1, but also a relative evaluation of the density (e.g., density) and the presence or absence of voids inside the measurement sample 1.

[0174] Furthermore, in the above embodiment, carbon fiber reinforced resin was used as the measurement sample 1. The type of carbon fiber reinforced resin is not particularly limited, and may be, for example, recycled carbon fiber reinforced resin. Also, for example, the measurement sample 1 may be an uncured material of carbon fiber reinforced resin before molding (curing) by heating / pressure, i.e., an intermediate material. Furthermore, the measurement sample 1 may be a sample composed of multiple types of materials with different thermal conductivity. Also, the measurement sample 1 may be something other than a composite material. For example, glass, semiconductors, polymer films, liquid crystals, etc. may be used as the measurement sample 1.

[0175] Furthermore, a product currently in operation (such as an automobile, aircraft, or sporting goods) may be used as the measurement sample 1. For example, in the structural components of an aircraft that uses many composite materials, fatigue tests and thermal diffusivity evaluations can be performed during the manufacturing stage on parts where fatigue damage would have a significant impact on airworthiness. Then, as part of the maintenance task during heavy maintenance in operation, the fatigue state of the part can be diagnosed by measuring the specific heat, etc., on the aircraft side. This is possible because this embodiment is a portable, non-contact, and non-destructive testing method using thermography and laser heating. If the fatigue state can be evaluated and diagnosed, it becomes possible to determine the need to extend or shorten the design life specified by the flight cycle, thereby extending the lifespan and improving the reliability of the aircraft. Furthermore, by reflecting this data in the design, it is possible to accurately estimate the design life considering the effects of actual operation, thereby contributing to extending the lifespan. To explain further, for example, in the structure of a building (for example, suspension ropes of bridge piers), the condition of the part can be detected by measuring the specific heat, etc., as described above. Furthermore, the specific heat and other properties described above may be measured in mechanical devices (e.g., turbines), structures such as yachts and rockets, and residential structures such as window sashes (joinery) to detect the condition of the relevant parts.

[0176] Furthermore, while it has been explained that the difference in thermal conductivity or specific heat from a standard undamaged state is used for fatigue evaluation, this is not the only method. For example, the ratio of specific heat coefficients or the absolute value of specific heat may be used for fatigue evaluation. In addition to using the undamaged state as the standard, or in addition to using the undamaged state as the standard, fatigue evaluation may be performed using the state in which fatigue life has been reached, or pre-evaluation data or theoretical values ​​as the standard. Furthermore, information regarding fatigue includes not only the values ​​calculated as the fatigue evaluation of the measurement sample 1, but also the relative evaluation of fatigue (e.g., the degree of fatigue progression), whether or not fatigue life has been reached, the estimated time or number of times it can be used before fatigue life is reached, and the presence or absence of microcracks or microdelaminations inside the measurement sample 1.

[0177] Furthermore, the information regarding thermal diffusivity, thermal conductivity, and specific heat obtained in the process of calculating fatigue information for the measurement sample 1 may be output and stored together with the fatigue information, or in place of the fatigue information. Here, the information regarding thermal diffusivity, thermal conductivity, and specific heat is not particularly limited, but may include, for example, the distribution of thermal conductivity, values ​​of thermal conductivity (including average, maximum, and minimum values), relative evaluations of thermal conductivity (for example, the magnitude of thermal diffusivity), and comparison results with prior evaluation data and theoretical values.

[0178] Furthermore, information regarding the lifespan of the measurement sample 1 may be output and stored together with, or in place of, the fatigue information of the measurement sample 1. Here, the information regarding lifespan includes whether or not the fatigue lifespan has been reached, the estimated time or number of times it can be used before reaching the fatigue lifespan, and the degree of fatigue progression (e.g., percentage) based on the fatigue lifespan.

[0179] Furthermore, while the above description explains how fatigue information of the measurement sample 1 is obtained through a tensile test using a tensile testing machine (not shown), it is not limited to this. Fatigue information of the measurement sample 1 may also be obtained through other load tests, such as a plane bending fatigue test, a rotational bending fatigue test, or an ultrasonic fatigue test, as long as a load is applied to the measurement sample 1. Note that the tensile testing machine (not shown) may be included in the thermophysical property evaluation device 100, or it may not be included.

[0180] Furthermore, while the above description explains that the calculation result display unit 59 displays (outputs) calculation results such as thermal conductivity and specific heat as sample evaluation results on a display (not shown), it is not limited to this. For example, the calculation result of at least one of the thermal diffusivity, thermal conductivity, and specific heat may be transmitted to another device other than the computer 50, or stored in the device itself.

[0181] Furthermore, it is not mandatory to output all information regarding thermal diffusivity, thermal conductivity, and specific heat. In other words, it is acceptable to output one or some combinations of information regarding thermal diffusivity, thermal conductivity, and specific heat.

[0182] Alternatively, the above measurement method may be programmed into a well-known thermophysical property measuring device (not shown). For example, the above measurement method may be provided via a network (not shown).

[0183] Now, although various embodiments and modifications have been described above, these embodiments and modifications can of course be combined to form a complete system. Furthermore, this disclosure is not limited in any way to the embodiments described above, and can be implemented in various forms without departing from the gist of this disclosure.

[0184] Note that the measurement sample 1 is an example of an object. The diode laser 10 is an example of an irradiation unit. The temperature amplitude distribution calculation unit 54 is an example of an output switching unit, a first temperature distribution acquisition unit, and a second temperature distribution acquisition unit. The thermal conductivity calculation unit 56 is an example of a specificity unit. The thermal diffusivity distribution calculation unit 55 is an example of a thermal diffusivity specificity unit. The specific heat calculation unit 57 is an example of a specific heat specificity unit and a specificity unit. The fatigue evaluation calculation unit 58 is an example of a fatigue information specificity unit and a specificity unit. [Explanation of Symbols]

[0185] 1…Thermophysical property evaluation device, 10…Diode laser, 20…Light guide unit, 21…Fiber, 23…Concentrator, 39…Aperture, 40…Infrared thermography, 50…Computer, 55…Thermal diffusivity distribution calculation unit, 56…Thermal conductivity calculation unit, 57…Specific heat calculation unit

Claims

1. An irradiation unit that periodically irradiates an object with light to heat the object, An output switching unit that switches the output of the light irradiated by the irradiation unit onto the object between a first output, where the maximum output in one cycle is the first maximum output, and a second output, where the maximum output is the second maximum output. A first temperature distribution acquisition unit acquires a first temperature distribution, which is the temperature distribution of the object heated by the first output light, A second temperature distribution acquisition unit acquires a second temperature distribution, which is the temperature distribution of the object heated by the light of the second output, A specific unit that identifies information regarding the thermal conductivity of the object based on the first and second temperature distributions. Equipped with, The specified part is, Based on the first temperature distribution, a first temperature amplitude distribution is obtained, which is the distribution of temperature amplitude in the object heated by the first output light. Based on the second temperature distribution, a second temperature amplitude distribution is obtained, which is the temperature amplitude distribution in the object heated by the second output light. Based on the first temperature amplitude distribution and the second temperature amplitude distribution, information regarding the thermal conductivity of the object is identified. Device.

2. The specified part is, Based on the first temperature distribution, a first maximum temperature distribution is obtained, which is the distribution of the maximum temperature at various points on the object heated by the first output light. Based on the second temperature distribution, a second maximum temperature distribution is obtained, which is the distribution of the maximum temperature at various points on the object heated by the second output light. Based on the first and second maximum temperature distributions, information regarding the thermal conductivity of the object is identified. The apparatus according to claim 1.

3. The system includes a thermal diffusivity identification unit that identifies information regarding the thermal diffusivity based on the response of the time change in the temperature distribution of the object heated by the first output light. The apparatus according to claim 1 or 2.

4. The system includes a specific heat identification unit that identifies information regarding the specific heat of the object based on the information regarding the thermal conductivity of the object identified by the identification unit. The apparatus according to any one of claims 1 to 3.

5. The system includes a fatigue information identification unit that identifies information regarding the fatigue of the object based on the information regarding the thermal conductivity of the object identified by the identification unit. The apparatus according to any one of claims 1 to 4.

6. The irradiation unit irradiates light over a wider area than the region in which the temperature distribution of the object is measured. The specified part identifies information regarding the thermal conductivity of the object in the thickness direction. The apparatus according to any one of claims 1 to 5.

7. The irradiation unit irradiates light onto a region extending in one direction on the surface of the object, The specified part identifies information regarding the thermal conductivity of the object in the in-plane direction. The apparatus according to any one of claims 1 to 6.

8. The irradiation unit switches between a first mode in which it irradiates light over a wider area than the region in which the temperature distribution on the object is measured, and a second mode in which it irradiates light over a region extending in one direction on the surface of the object. In the first embodiment, the specified part identifies information regarding the thermal conductivity of the object in the thickness direction, and in the second embodiment, it identifies information regarding the thermal conductivity of the object in the in-plane direction. The apparatus according to any one of claims 1 to 7.

9. A step of periodically irradiating an object with light to heat the object, The steps include switching the output of the light irradiated onto the object between a first output, where the maximum output in one cycle is a first maximum output, and a second output, where the maximum output is a second maximum output, A step of obtaining a first temperature distribution, which is the temperature distribution of the object heated by the light of the first output; A step of obtaining a second temperature distribution, which is the temperature distribution of the object heated by the light of the second output; A step of identifying information regarding the thermal conductivity of the object based on the first temperature distribution and the second temperature distribution. Equipped with, In the aforementioned step of identification, Based on the first temperature distribution, a first temperature amplitude distribution is obtained, which is the distribution of temperature amplitude in the object heated by the first output light. Based on the second temperature distribution, a second temperature amplitude distribution is obtained, which is the temperature amplitude distribution in the object heated by the second output light. Based on the first temperature amplitude distribution and the second temperature amplitude distribution, information regarding the thermal conductivity of the object is identified. method.

10. On the computer, A function that periodically irradiates an object with light to heat the object, A function to switch the output of the light irradiated onto the object between a first output, where the maximum output in one cycle is the first maximum output, and a second output, where the maximum output is the second maximum output, A function to acquire a first temperature distribution, which is the temperature distribution of the object heated by the light of the first output, A function to acquire a second temperature distribution, which is the temperature distribution of the object heated by the light of the second output, Based on the first and second temperature distributions, a function is provided to identify information regarding the thermal conductivity of the object. Make it run, In the aforementioned specified function, Based on the first temperature distribution, a first temperature amplitude distribution is obtained, which is the distribution of temperature amplitude in the object heated by the first output light. Based on the second temperature distribution, a second temperature amplitude distribution is obtained, which is the temperature amplitude distribution in the object heated by the second output light. Based on the first temperature amplitude distribution and the second temperature amplitude distribution, information regarding the thermal conductivity of the object is identified. program.

11. An irradiation unit that periodically irradiates an object with light to heat the object, An output switching unit that switches the output of the light irradiated by the irradiation unit onto the object between a first output, where the maximum output in one cycle is the first maximum output, and a second output, where the maximum output is the second maximum output. A first temperature distribution acquisition unit acquires a first temperature distribution, which is the temperature distribution of the object heated by the first output light, A second temperature distribution acquisition unit acquires a second temperature distribution, which is the temperature distribution of the object heated by the light of the second output, A specific unit that identifies information regarding the specific heat of the object based on the first temperature distribution and the second temperature distribution. Equipped with, The specified part is, Based on the first temperature distribution, a first temperature amplitude distribution is obtained, which is the distribution of temperature amplitude in the object heated by the first output light. Based on the second temperature distribution, a second temperature amplitude distribution is obtained, which is the temperature amplitude distribution in the object heated by the second output light. Based on the first temperature amplitude distribution and the second temperature amplitude distribution, information regarding the specific heat of the object is identified. Device.

12. A step of periodically irradiating an object with light to heat the object, The steps include switching the output of the light irradiated onto the object between a first output, where the maximum output in one cycle is a first maximum output, and a second output, where the maximum output is a second maximum output, A step of obtaining a first temperature distribution, which is the temperature distribution of the object heated by the light of the first output; A step of obtaining a second temperature distribution, which is the temperature distribution of the object heated by the light of the second output; A step of identifying information regarding the specific heat of the object based on the first temperature distribution and the second temperature distribution. Equipped with, In the aforementioned step of identification, Based on the first temperature distribution, a first temperature amplitude distribution is obtained, which is the distribution of temperature amplitude in the object heated by the first output light. Based on the second temperature distribution, a second temperature amplitude distribution is obtained, which is the temperature amplitude distribution in the object heated by the second output light. Based on the first temperature amplitude distribution and the second temperature amplitude distribution, information regarding the specific heat of the object is identified. method.

13. On the computer, A function that periodically irradiates an object with light to heat the object, A function to switch the output of the light irradiated onto the object between a first output, where the maximum output in one cycle is the first maximum output, and a second output, where the maximum output is the second maximum output, A function to acquire a first temperature distribution, which is the temperature distribution of the object heated by the light of the first output, A function to acquire a second temperature distribution, which is the temperature distribution of the object heated by the light of the second output, A function to identify information regarding the specific heat of the object based on the first temperature distribution and the second temperature distribution. Make it run, In the aforementioned specified function, Based on the first temperature distribution, a first temperature amplitude distribution is obtained, which is the distribution of temperature amplitude in the object heated by the first output light. Based on the second temperature distribution, a second temperature amplitude distribution is obtained, which is the temperature amplitude distribution in the object heated by the second output light. Based on the first temperature amplitude distribution and the second temperature amplitude distribution, information regarding the specific heat of the object is identified. program.

14. An irradiation unit that periodically irradiates an object with light to heat the object, An output switching unit that switches the output of the light irradiated by the irradiation unit onto the object between a first output, where the maximum output in one cycle is the first maximum output, and a second output, where the maximum output is the second maximum output. A first temperature distribution acquisition unit acquires a first temperature distribution, which is the temperature distribution of the object heated by the first output light, A second temperature distribution acquisition unit acquires a second temperature distribution, which is the temperature distribution of the object heated by the light of the second output, Based on the first and second temperature distributions, a specific unit calculates the thermal conductivity of the object and identifies information regarding the fatigue of the object. Equipped with, The specified part is, Based on the first temperature distribution, a first temperature amplitude distribution is obtained, which is the distribution of temperature amplitude in the object heated by the first output light. Based on the second temperature distribution, a second temperature amplitude distribution is obtained, which is the temperature amplitude distribution in the object heated by the second output light. Based on the first and second temperature amplitude distributions, the thermal conductivity of the object is calculated, and information regarding the fatigue of the object is identified. Device.

15. A step of periodically irradiating an object with light to heat the object, The steps include switching the output of the light irradiated onto the object between a first output, where the maximum output in one cycle is a first maximum output, and a second output, where the maximum output is a second maximum output, A step of obtaining a first temperature distribution, which is the temperature distribution of the object heated by the light of the first output; A step of obtaining a second temperature distribution, which is the temperature distribution of the object heated by the light of the second output; The steps include: calculating the thermal conductivity of the object based on the first and second temperature distributions, and identifying information regarding the fatigue of the object; Equipped with, In the aforementioned step of identification, Based on the first temperature distribution, a first temperature amplitude distribution is obtained, which is the distribution of temperature amplitude in the object heated by the first output light. Based on the second temperature distribution, a second temperature amplitude distribution is obtained, which is the temperature amplitude distribution in the object heated by the second output light. Based on the first and second temperature amplitude distributions, the thermal conductivity of the object is calculated, and information regarding the fatigue of the object is identified. method.

16. On the computer, A function that periodically irradiates an object with light to heat the object, A function to switch the output of the light irradiated onto the object between a first output, where the maximum output in one cycle is the first maximum output, and a second output, where the maximum output is the second maximum output, A function to acquire a first temperature distribution, which is the temperature distribution of the object heated by the light of the first output, A function to acquire a second temperature distribution, which is the temperature distribution of the object heated by the light of the second output, Based on the first and second temperature distributions, the thermal conductivity of the object is calculated, and information regarding the fatigue of the object is identified. Make it run, In the aforementioned specified function, Based on the first temperature distribution, a first temperature amplitude distribution is obtained, which is the distribution of temperature amplitude in the object heated by the first output light. Based on the second temperature distribution, a second temperature amplitude distribution is obtained, which is the temperature amplitude distribution in the object heated by the second output light. Based on the first and second temperature amplitude distributions, the thermal conductivity of the object is calculated, and information regarding the fatigue of the object is identified. program.

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