Stress recording material, stress recording structure, stress recording method, stress recording system, and method of use as a stress recording material

Abstract

To provide a stress recording material that is free from influence of dark reaction caused by chemical reaction, is excellent in quantitativity and long-term record retention, and allows stress application to be known ex post facto only by observing the afterglow.SOLUTION: A material has a composition represented by general formula LixNayNbO3+(x+y-1) / 2+Σ(zk*Lk / 2): M1z1, M2z2, M3z3 (where M1 is any one metal ion selected from among rare earth ions and transition metal ions; M2 or M3 is none or any one metal ion selected from rare earth ions and transition metal ions; zk is a generalized representation of z1 to z3; Lk is a generalized representation of L1, L2 and L3, which are the valences of the M1, M2 and M3 ions, respectively; if M2 is none then z2 is 0; and if M3 is none then z3 is 0), provided that x=0.02 to 2, y=0.01 to 1, and z1+z2+z3=0.0001 to 0.2.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a stress recording material, a stress recording structure, and ,Response Force recording method 、 Stress Recording System and method of use as stress recording material Regarding. [Background technology]

[0002] Conventionally, mechanoluminescent materials are known as materials that emit luminescence correlated with the energy of a mechanical stimulus.

[0003] Mechanoluminescent materials with these properties are being applied in a wide variety of fields, including sensors, non-destructive testing, visualization of stress distribution, stress sensing, and detection of abnormalities and dangers in structures.

[0004] The stress-luminescent material can be made into a paint or dispersed in a resin sheet, and this can be applied or stuck to the surface of the object to be measured for stress to form a detection area, making it possible to observe the stress applied to this detection area.

[0005] However, because mechanoluminescent materials are materials that emit light the moment stress is applied, it is possible to observe the moment stress is applied, i.e., to know in real time that stress has been applied, but it is not possible to know after the fact.

[0006] Therefore, a stress recorder has been proposed in which a light-reactive functional material such as a photosensitive body is combined with a stress-luminescent material so that the applied stress can be known after the fact (see, for example, Patent Document 1).

[0007] With such a stress recording system, the applied stress can be known after the fact by examining the presence or absence of photosensitive traces and the photosensitive intensity of the mechanoluminescent light recorded on the photoreactive functional material. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-053679 Summary of the Invention [Problem to be solved by the invention]

[0009] However, the stress recording medium obtained by combining the above-mentioned conventional photoreactive functional material has a complicated structure, and is not satisfactory in terms of the problem of dark reaction of the photoreactive layer, quantitativeness, and long-term record retention.

[0010] The present invention has been made in view of the above circumstances, and provides a stress recording material which is not affected by dark reactions due to chemical reactions, has excellent quantitative properties and long-term record retention, and allows the application of stress to be known after the fact simply by observing the afterglow.

[0011] The present invention also provides a stress recording structure, a stress recording body, a stress recording body forming agent, a stress recording coating film forming paint, a stress recording method, and a stress recording system using the above stress recording material. [Means for solving the problem]

[0012] In order to solve the above-mentioned conventional problems, one embodiment of the stress recording material according to the present invention is a material comprising: (1) a compound represented by the general formula Li x Na y NbO 3+(x+y-1) / 2+Σ(zk*Lk / 2) :M1 z1 ,M2 z2 ,M3 z3 (wherein M1 is any one metal ion selected from rare earth ions and transition metal ions, M2 or M3 is none or any one metal ion selected from rare earth ions and transition metal ions, zk is a generalized expression of z1 to z3, Lk is a generalized expression of the valence L1 of the ion of M1, the valence L2 of the ion of M2, and the valence L3 of the ion of M3, and when M2 is none, z2 is 0, and when M3 is none, z3 is 0), and x=0.02 to 2, y=0.01 to 1, and z1+z2+z3=0.0001 to 0.2. By irradiating the recordable area with readout light having a wavelength of 200-480 nm and observing the difference between afterglow having a peak in the 500-1100 nm band before stress application and afterglow having a peak in the 500-1100 nm band that changes depending on the past load history of the object to be measured, it is possible to know information about the stress that the object to be measured has received after the fact, and furthermore, the traces of the recorded stress can be erased by irradiating reset light having approximately the same wavelength as the readout light and an intensity 100 to 1000 times that of the readout light.It was decided. Also, (2) general formula Li x Na y NbO 3+(x+y-1) / 2+Σ(zk*Lk / 2) :M1 z1 ,M2 z2 ,M3 z3 (wherein M1 is any one metal ion selected from rare earth ions and transition metal ions, M2 or M3 is none or any one metal ion selected from rare earth ions and transition metal ions, zk is a generalized expression of z1 to z3, Lk is a generalized expression of the valence L1 of the ion of M1, the valence L2 of the ion of M2, and the valence L3 of the ion of M3, and when M2 is none, z2 is 0, and when M3 is none, z3 is 0), and a stress recording material (wherein, in the general formula Li (1-P)(1+α) Na P NbO 3 :Q R (However, Q is at least one metal ion selected from transition metal ions, and materials in which the value of P is in the range of 0.10 to 0.98, the value of R is in the range of 0.0001 to 0.2, and α is 0 or more are excluded.) It was decided.

[0013] Furthermore, one aspect of the stress recording structure according to the present invention is 3 ) A stress recording material is applied to a predetermined area of ​​the object to be measured. Powder of Dispersed in a light-transmitting resin matrix Let it exist Formed as a coating layer or sheet layer It has a recordable area, and the recordable area After the stress is applied, the reading light is irradiated and the afterglow appears, and the measurement object is The system is configured so that it is possible to know after the fact that stress has been applied to the object.

[0019] Furthermore, one aspect of the stress recording system according to the present invention is 4 a recording area for recording stress formed in a measurement object; a reading light irradiating unit that irradiates the recording area with excitation light for afterglow emission; an afterglow intensity acquiring unit that acquires information about the afterglow intensity of the recording area; and an afterglow intensity notifying unit that notifies the information about the afterglow intensity, wherein the recording area comprises: General formula Li x Na y NbO 3+(x+y-1) / 2+Σ(zk*Lk / 2) :M1 z1 ,M2 z2 ,M3 z3 (wherein M1 is any one metal ion selected from rare earth ions and transition metal ions, M2 or M3 is none or any one metal ion selected from rare earth ions and transition metal ions, zk is a generalized expression of z1 to z3, Lk is a generalized expression of the valence L1 of the ion of M1, the valence L2 of the ion of M2, and the valence L3 of the ion of M3, and when M2 is none, z2 is 0, and when M3 is none, z3 is 0), and x=0.02 to 2, y=0.01 to 1, and z1+z2+z3=0.0001 to 0.2. The stress recording material is placed in a predetermined area of ​​the object to be measured. The stress recording system includes a reset light irradiation unit that irradiates the recordable area with high-intensity reset light having substantially the same wavelength as the excitation light for the afterglow emission. .

[0020] In addition, as an optional aspect of the stress recording system according to the present invention, it is also characterized in the following respects. (5 ) a memory unit that stores information on the afterglow intensity of the measurement object in the recordable area before it is subjected to stress and information on the afterglow intensity of the measurement object after it is subjected to stress, which information is obtained from the afterglow intensity acquisition unit; and a difference information generation unit that generates information on the difference between the information on the afterglow intensity of the measurement object before it is subjected to stress and the information on the afterglow intensity of the measurement object after it is subjected to stress, and the afterglow intensity notification unit is capable of reporting the information on the difference. ( 6 ) The storage unit is capable of storing information on the difference, and the afterglow intensity notification unit is capable of notifying information on the difference or predetermined afterglow intensity stored in the storage unit. ( 7 ) The afterglow intensity information is image information of the afterglow. One embodiment of the method for using the material as a stress recording material is a compound represented by the general formula (8) Li x Na y NbO 3+(x+y-1) / 2+Σ(zk*Lk / 2) :M1 z1 ,M2 z2 ,M3 z3 (wherein M1 is any one metal ion selected from rare earth ions and transition metal ions, M2 or M3 is none or any one metal ion selected from rare earth ions and transition metal ions, zk is a generalized expression of z1 to z3, Lk is a generalized expression of the valence L1 of the ion of M1, the valence L2 of the ion of M2, and the valence L3 of the ion of M3, and when M2 is none, z2 is 0, and when M3 is none, z3 is 0.) where x = 0.02 to 2, y = 0.01 to 1, and z1 + z2 + z3 = 0.0001 to 0.2 is placed in a recordable area formed in a predetermined area of ​​an object to be measured, and the material is used as a stress recording material for emitting afterglow, which allows information about the stress received by the object to be measured to be known after the fact from the difference between an afterglow image before stress application and an afterglow image after stress application, which are observed by irradiating the recordable area with readout light of a predetermined wavelength. [Effects of the Invention]

[0021] According to the stress recording material of the present invention, the general formula Li x Na y NbO 3+(x+y-1) / 2+Σ(zk*Lk / 2) :M1 z1 ,M2 z2 ,M3 z3 (wherein M1 is any one metal ion selected from rare earth ions and transition metal ions, M2 or M3 is none or any one metal ion selected from rare earth ions and transition metal ions, zk is a generalized expression of z1 to z3, Lk is a generalized expression of the valence L1 of the ion of M1, the valence L2 of the ion of M2, and the valence L3 of the ion of M3, and when M2 is none, z2 is 0, and when M3 is none, z3 is 0), and x=0.02 to 2, y=0.01 to 1, and z1+z2+z3=0.0001 to 0.2. By irradiating the recordable area with readout light having a wavelength of 200-480 nm and observing the difference between the afterglow having a peak in the 500-1100 nm band before stress application and the afterglow having a peak in the 500-1100 nm band that changes depending on the past load history of the object to be measured after stress application, it is possible to know information about the stress that the object to be measured has received after the fact, and furthermore, the recorded trace of stress can be erased by irradiating reset light having approximately the same wavelength as the readout light and an intensity 100 to 1000 times that of the readout light. x Na y NbO 3+(x+y-1) / 2+Σ(zk*Lk / 2) :M1 z1 ,M2 z2 ,M3 z3 (wherein M1 is any one metal ion selected from rare earth ions and transition metal ions, M2 or M3 is none or any one metal ion selected from rare earth ions and transition metal ions, zk is a generalized expression of z1 to z3, Lk is a generalized expression of the valence L1 of the ion of M1, the valence L2 of the ion of M2, and the valence L3 of the ion of M3, and when M2 is none, z2 is 0, and when M3 is none, z3 is 0), and a stress recording material (wherein, in the general formula Li (1-P)(1+α) Na P NbO 3 :Q R (However, Q is at least one metal ion selected from transition metal ions, and materials in which the value of P is in the range of 0.10 to 0.98, the value of R is in the range of 0.0001 to 0.2, and α is 0 or more are excluded.) Therefore, it is possible to provide a stress recording material that is free from the influence of dark reactions due to chemical reactions, has excellent quantitative properties and long-term record retention, and allows the application of stress to be known after the fact simply by observing the afterglow.

[0022] Furthermore, according to the stress recording structure of the present invention, a stress recording material is provided in a predetermined region of an object to be measured. Powder of Dispersed in a light-transmitting resin matrix Let it exist Formed as a coating layer or sheet layer It has a recordable area, and the recordable area After the stress is applied, the reading light is irradiated and the afterglow appears, and the measurement object is Since the stress applied to the sample can be known after the fact, the stress is not affected by dark reactions due to chemical reactions, and the stress recording structure has excellent quantitative properties and long-term record retention. In addition, the stress recording structure can be known after the fact by simply observing the afterglow.

[0028] Furthermore, a stress recording system according to the present invention includes a recordable area for recording stress formed in a measurement object, a read light irradiating unit that irradiates the recordable area with excitation light for afterglow emission, an afterglow intensity acquiring unit that acquires information about the afterglow intensity of the recordable area, and an afterglow intensity notifying unit that notifies the information about the afterglow intensity, wherein the recordable area is General formula Li x Na y NbO 3+(x+y-1) / 2+Σ(zk*Lk / 2) :M1 z1 ,M2 z2 ,M3 z3 (wherein M1 is any one metal ion selected from rare earth ions and transition metal ions, M2 or M3 is none or any one metal ion selected from rare earth ions and transition metal ions, zk is a generalized expression of z1 to z3, Lk is a generalized expression of the valence L1 of the ion of M1, the valence L2 of the ion of M2, and the valence L3 of the ion of M3, and when M2 is none, z2 is 0, and when M3 is none, z3 is 0), and x=0.02 to 2, y=0.01 to 1, and z1+z2+z3=0.0001 to 0.2. Formed by placing a stress recording material in a predetermined area of ​​the measurement object a reset light irradiation unit that irradiates the recordable area with high-intensity reset light having substantially the same wavelength as that of excitation light for afterglow emission;This makes it possible to provide a stress recording system that is free from the influence of dark reactions due to chemical reactions, has excellent quantitative properties and long-term record retention, and allows the application of stress to be known after the fact simply by observing the afterglow.

[0029] The recording medium further includes a memory unit that stores information on the afterglow intensity of the object to be measured in the recordable area before it is subjected to stress, which information is obtained from the afterglow intensity acquisition unit, and information on the afterglow intensity of the object to be measured after it is subjected to stress, and a difference information generation unit that generates information on the difference between the information on the afterglow intensity of the object to be measured before it is subjected to stress and the information on the afterglow intensity of the object to be measured after it is subjected to stress.If the afterglow intensity notification unit is capable of reporting the difference information, it can remove noise and background that exist before and after the application of stress and obtain information on the afterglow intensity that occurs in response to the stress.

[0030] Furthermore, if the memory unit is capable of storing information on the difference, and the afterglow intensity notification unit is capable of reporting information on a predetermined afterglow intensity or information on the difference stored in the memory unit, it is possible to store and display the history of stress exposure.

[0031] Furthermore, if the information on the afterglow intensity is image information on the afterglow, the information on the afterglow intensity can be notified in a manner that is excellent in viewability.

[0032] Furthermore, if a reset light irradiation unit is provided that irradiates the recordable area with high-intensity reset light having approximately the same wavelength as the excitation light for the afterglow emission, it is possible to erase the recorded traces of stress. [Brief explanation of the drawings]

[0033] [Figure 1] FIG. 2 is an explanatory diagram showing an SEM image of the stress recording material according to the embodiment. [Figure 2] FIG. 2 is an explanatory diagram showing the appearance of the prepared stress recording pellet. [Figure 3] FIG. 2 is an explanatory diagram showing the configuration of a test device. [Figure 4] FIG. 10 is an explanatory diagram showing a test situation. [Figure 5] FIG. 2 is an explanatory diagram showing the state of stress-luminescence emitted from a stress-recording pellet. [Figure 6] FIG. 10 is an explanatory diagram showing the state of afterglow emitted by a stress recording pellet. [Figure 7] FIG. 10 is an explanatory diagram showing the results of an FEM analysis. [Figure 8] 1 is a graph showing the relationship between stress distribution and stress recording distribution intensity. [Figure 9] 1 is a graph showing the long-term retention of stress records. [Figure 10] FIG. 10 is an explanatory diagram showing the relationship between the number of weightings and MR. [Figure 11] FIG. 10 is an explanatory diagram of stress recording intensity under maximum load. [Figure 12] FIG. 1 is an explanatory diagram of an experiment to examine the spatial resolution of stress history. [Figure 13] FIG. 10 is an explanatory diagram showing the results of an experiment examining the spatial resolution of stress history. [Figure 14] FIG. 10 is an explanatory diagram showing the results of line distribution analysis. DETAILED DESCRIPTION OF THE INVENTION

[0034] The present invention provides a stress recording material capable of recording applied stress, which is not particularly affected by dark reactions due to chemical reactions, has excellent quantitative properties and long-term record retention, and allows the application of stress to be known after the fact simply by observing the afterglow.

[0035] As mentioned above, there have been several conventional stress recording means that are configured to enable the applied stress to be known after the fact.

[0036] Specifically, in addition to stress recording media that combine a mechanoluminescent material with a photoreactive functional material, as in Patent Document 1, there are also devices that apply writing pressure to a silicone gel with stress recording properties, and then allow the stress record to be obtained (hereinafter also referred to as readout) using a thermoluminescence camera (Zhuang et al. Light: Science & Applications 9:182 (2020)), and devices that use microcapsules containing a specified core substance as a stress detection means, form a coating or resin sheet with these scattered on the surface of the object to be measured, and then observe the core substance released from the microcapsules that are crushed by the application of stress, making it possible to obtain the stress record.

[0037] However, the stress recording means using the above-mentioned silicone gel requires heating for reading, so reading is not possible at room temperature.Furthermore, the stress recording means using microcapsules cannot be reused by its nature, because the destruction of the microcapsules is irreversible.

[0038] In this regard, the stress recording material according to this embodiment allows for the recording (traces) of stress to be read at room temperature (hereinafter also referred to as room temperature readout), and also allows for repeated recording and reading (hereinafter also referred to as repeated recording and reading). Furthermore, by using this as a means for detecting stress, it is possible to realize a stress recording structure, stress recording body, stress recording body forming agent, stress recording coating film forming paint, stress recording method, and stress recording system that are capable of room temperature readout and repeated recording and reading.

[0039] Additionally, previous mechanoluminescent materials were not capable of reading out recorded stress through afterglow. That is, previous mechanoluminescent materials possessed mechanoluminescence (ML) properties and could only measure mechanical information in real time, requiring a separate recording means and the construction of a complex stress recording system. Furthermore, in addition to the complex structure, there were issues with the dark reaction of the photoreactive layer, as well as stability, quantitativeness, and long-term data retention. Furthermore, the readout system required heating, making the system cumbersome. This is because previous mechanoluminescent materials themselves were not capable of recording applied stress.

[0040] In contrast, the present invention provides a material that can quantitatively record stress history and easily read and display it simply by observing the afterglow after irradiation with a readout light of a predetermined wavelength. That is, it can be said that the present invention provides a material with stress recording (mechanical recording, MR) and stress history display (mechanical report) functions, and a stress recording material that can record applied stress itself.

[0041] This invention was completed after the inventors discovered that LiNaNbO3 (LNNO) can newly exhibit a stress recording (mechanical recording, MR) function, i.e., a material that can record and read out past load application information and stress history at any time using light. In addition, this invention is based on the new discovery of stress recording, that is, it is possible to read out stress recording (MR) that correlates with luminescence intensity using only afterglow.

[0042] In particular, whereas previous mechanoluminescent materials could only measure mechanical information in real time, mechanoluminescent materials with MR functionality are extremely useful in that they can not only measure in real time but also extract information on past load application and the history of stress distribution.

[0043] Specific experiments and results will be described later, but as a multi-piezoelectric element, LiNaNbO3 (LNNO) powder was synthesized using a solid-phase method, and this synthesized powder was mixed with epoxy resin. The resulting resin pellets were also used to evaluate the ML / MR characteristics using a materials testing machine and a camera system with LED illumination, and the MR function was evaluated using optical readout images (afterglow images) after light irradiation before and after stress application.

[0044] As a result, when a load was applied, a luminescence image proportional to the dynamic stress distribution was displayed. After the load was applied, the mechanoluminescence disappeared, but by irradiating it with an LED and observing the afterglow image, it was possible to read out the record of the stress application, and by comparing the MR images before and after the load test, it was found that the recorded image was proportional to the history of the stress distribution.

[0045] As described above, previous mechanoluminescent materials showed no difference in afterglow before and after stress history, making it impossible to read out the recorded stress history through afterglow. However, with the present invention, stress history can be quantitatively recorded and read out simply by observing the afterglow after LED irradiation. MR can also record and read out past load application information and stress history at any time using light. It can be said to be a new principle and material with a non-volatile memory function that has never been seen before, and it has excellent stability and retention, allowing long-term recording without the need for electrical or thermal energy. It also has excellent quantitative recording capabilities for stress distribution. Furthermore, mechanoluminescent materials with MR functionality can not only measure in real time, but also retrieve past load application information and stress distribution history.

[0046] The stress recording material according to this embodiment can be said to be a lithium sodium niobium composite oxide to which one or more metal ions are added, and is characterized by the general formula Li x Na y NbO 3+(x+y-1) / 2+Σ(zk*Lk / 2) :M1 z1 ,M2 z2 ,M3 z3(wherein M1 is any one metal ion selected from rare earth ions and transition metal ions, M2 or M3 is none or any one metal ion selected from rare earth ions and transition metal ions, zk is a generalized expression of z1 to z3, Lk is a generalized expression of the valence L1 of the M1 ion, the valence L2 of the M2 ion, and the valence L3 of the M3 ion, and when M2 is none, z2 is 0, and when M3 is none, z3 is 0), and x = 0.02 to 2, preferably x = 0.1 to 0.9, y = 0.01 to 1, preferably y = 0.1 to 0.95, and z1 + z2 + z3 = 0.0001 to 0.2, preferably z1 + z2 + z3 = 0.0001 to 0.1.

[0047] Here, rare earth ions are ions of rare earths (rare earth metal elements) and can be understood as ions of, for example, Sc (scandium), Y (yttrium), La (lanthanum), Ce (cerium), Pr (praseodymium), Nd (neodymium), Pm (promethium), Sm (samarium), Eu (europium), Gd (gadolinium), Tb (terbium), Dy (dysprosium), Ho (holmium), Er (erbium), Tm (thulium), Yb (ytterbium), and Lu (lutetium).

[0048] A transition metal ion is an ion of a transition metal element, and can be understood as an ion of a transition metal element present between the elements of Groups 3 and 11.

[0049] By placing such a stress recording material in a predetermined region of an object, it becomes possible to know after the fact that stress has been applied to that region. In other words, the stress recording material according to this embodiment can be said to be a material that, by placing it in a predetermined region of an object, makes it possible to know after the fact that stress has been applied to that region.

[0050] Here, "presence in a predetermined region" means that the stress recording material is present in a predetermined region of the object in a state where stress applied to the object can be transmitted, and the manner of presence is not particularly limited. For example, the stress recording material may be present by coating, spraying, mixing, or the like, such as by forming a coating film containing the stress recording material on the surface of the object, or by distributing the stress-luminescent material over all or part of the object.

[0051] Furthermore, to aid in understanding the stress recording material according to this embodiment, an example of a usage mode of the stress recording material will be further explained. The object to which the stress recording material is placed is not particularly limited as long as it is an object to which the applied stress is to be measured, and may be, for example, a structure such as a vehicle or furniture, a building such as a tunnel or a bridge, or even an instrument applied to a living body such as a bone, tooth, or implant.

[0052] The predetermined area of ​​the object where the stress recording material is present is not particularly limited, and may be the entire object or a part of the object. In the following description, the predetermined area of ​​the object where the stress recording material is present is also referred to as a (stress) recordable area.

[0053] The recordable area may be a dot-like, linear, or planar area, or may be a three-dimensional area.

[0054] Although it is difficult to read out the recorded stress distribution in the dot-like recordable area, it is useful because it is possible to read out the recorded stress distribution. Note that the dot-like here does not mean a point in the strict sense that does not have an area or volume, but rather something like a dot, and the same applies to the line-like shape described below.

[0055] It is also useful in that it is possible to record whether or not a stress is applied to a linear region, and to read out the record of stress propagation in the linear direction.

[0056] The planar region is not limited to the surface of an object, but may also be a surface in the direction of cutting the object. Furthermore, the surface may be a curved surface, not just a flat surface, and may be continuous or discontinuous. Planar refers to an area that is realistically treated as a curved or flat surface, such as a coating, sheet, or film, in addition to the surface of an object with irregularities, and is not limited to a strictly two-dimensional area.

[0057] The three-dimensional area may be a three-dimensional area having a portion exposed on the surface of the object, or the entire recordable area may be formed inside the object. However, in order to facilitate reading, it is desirable that the recordable area and the object have a configuration in which at least the portion of the recordable area where the stress recording is to be observed can be irradiated with readout light from a readout light irradiating unit described later and information on the afterglow intensity can be acquired by an afterglow intensity acquiring unit, or in a simpler example, a configuration in which the recordable area and the object have sufficient transparency to the readout light and afterglow (to the extent that excitation for afterglow light emission and readout are possible).

[0058] Furthermore, the recordable area may be provided in only one location on the object, or may be provided in multiple locations.

[0059] In this way, the present application can be said to also provide a stress recording structure that is characterized by having a recordable area in which the stress recording material of this embodiment is present in a predetermined area of ​​the object to be measured, and is configured so that it is possible to know after the fact that stress has been applied to the recordable area.

[0060] The present application also provides a stress recording medium in which the stress recording material according to the present embodiment is present, for example, dispersed, in a predetermined matrix material. For example, by using a curable resin as the matrix material and dispersing the powdered stress recording material in the uncured resin and then curing it, a stress recording medium of a desired shape capable of recording applied stress can be easily formed. The matrix material used should be one that is at least transmissive to the readout light for generating the afterglow of the stress recording material mixed in the matrix material, and the afterglow emitted from the stress recording material.

[0061] The present application also provides a stress recording body forming agent that contains the stress recording material of this embodiment in a liquid, viscous, or viscoelastic base, and that forms a stress recording body by solidifying the base.

[0062] Here, the liquid base can be understood as, for example, paint, adhesive, or ultraviolet curing resin before solidification, the viscous base as putty or clay, and the viscoelastic base as slime.

[0063] Furthermore, the solidification is not limited to a degree that allows the stress applied to the measurement object or the recordable area to be transmitted to the stress recording material, and includes solidification reactions such as evaporation of the solvent (dispersion medium) or crosslinking.

[0064] In other words, in the above example, the matrix material in which the stress recording material is dispersed before solidification corresponds to the stress recording material forming agent according to this embodiment.

[0065] Furthermore, as a specific embodiment of the stress recording material forming agent, the present application also provides a stress recording coating film forming paint containing a stress recording material in a base paint. Note that the form of use of the paint is not particularly limited, and it may be applied or sprayed.

[0066] Furthermore, with this type of stress recording coating paint, a recordable area can be easily formed by forming a stress recording coating on the surface of the measurement object. This stress recording coating can also be considered as a stress recording medium.

[0067] The present application also provides a method for recording stress applied to a predetermined area of ​​an object, in which the stress recording material according to this embodiment is present in the predetermined area, in other words, a stress recording method in which the predetermined area of ​​an object in which the presence or absence and strength of stress applied is to be recorded is made into a recordable area by having the stress recording material present.

[0068] In particular, in the case of the stress recording method according to this embodiment, if stress is applied multiple times, the record that is read out is an accumulated record of the repeatedly applied stress, which is useful for grasping the total amount of applied stress.

[0069] The present application also provides a stress recording system capable of recording and reading stress. The stress recording system according to this embodiment is characterized by including a recordable area, a readout light irradiating unit, an afterglow intensity acquiring unit, and an afterglow intensity notifying unit.

[0070] As explained above, the recordable area is a predetermined area of ​​an object to be measured in which the mechanoluminescent material according to this embodiment is present. In the stress recording system according to this embodiment, the recordable area may be a recordable area placed in an environment where stress can be applied, or a recordable area placed in an environment where stress cannot be applied. For example, when recording stress at a certain portion of a bridge, even if the bridge is sound and no load is applied to the recordable area, resulting in no record of stress application being left, that is, even if the recordable area is placed in an environment where stress cannot be applied, the stress recording system according to this embodiment is still useful for indicating the soundness of the bridge, and such an embodiment is also included in the stress recording system according to this embodiment.

[0071] The read light irradiation unit is a part that irradiates the recordable area with excitation light for afterglow emission. The excitation light to be irradiated is not particularly limited as long as it has a wavelength and intensity that can cause the stress recording material present in the recordable area to emit afterglow, and the type of light source can be appropriately selected as long as it does not contradict the purpose.

[0072] The afterglow intensity acquisition unit is a component that acquires information about the afterglow intensity of the recordable area. As a specific example, it can be configured with an imaging unit equipped with an image sensor and an afterglow intensity information generation unit that generates afterglow intensity information from an image signal obtained by the imaging unit. The imaging unit and the afterglow intensity information generation unit may be integrated into one unit like an imaging camera, or the imaging unit may be configured specifically for generating image signals, while the afterglow intensity information generation unit may be configured with a predetermined circuit or computer capable of generating afterglow intensity information.

[0073] In a simpler example, for example, when the recordable area is in the form of a dot and it is only necessary to confirm the presence or absence of stress and its intensity, and it is not necessary to record the stress distribution, it is also possible to configure it by a light-receiving element arranged opposite the dot-shaped recordable area, and a predetermined circuit or computer that generates information on the afterglow intensity based on a signal generated by receiving light. Note that it goes without saying that the image pickup unit such as the above-mentioned image pickup element or image pickup camera, or the light-receiving element, etc., that can respond to the afterglow wavelength, should be used.

[0074] The afterglow intensity notification unit is a component for notifying information on the afterglow intensity acquired (generated) by the afterglow intensity acquisition unit. This notification mode can be appropriately selected according to the situation, such as when it is sufficient to know only whether or not stress is applied as described above, when it is also desired to know the intensity of the stress, or when it is also desired to know the stress distribution.

[0075] In other words, if you only need to know whether stress is being applied, you can use any means that humans can perceive with their five senses, such as whether an LED is lit, whether there is a sound, whether there is printing, or whether there is a display on a display. If you want to know the strength of stress as well as whether it is being applied, you can use any means, such as the intensity of light or sound, the magnitude of printed values, or differences in values ​​or colors displayed on a display. If you also want to know the stress distribution, you can express it using differences in brightness or color on a displayed image, print it, or in some cases express it numerically.

[0076] Such a stress recording system is free from the influence of dark reactions due to chemical reactions, has excellent quantitative properties and long-term record retention, and can provide a stress recording system that allows the application of stress to be known after the fact simply by observing the afterglow.

[0077] Furthermore, the stress recording system according to this embodiment may further include a storage unit and a difference information generator, which may store data before and after the application of stress and generate and report the difference. When stress is applied multiple times, the system may store data before and after the application of the first stress (before the application of the second stress) and generate and report the difference, or may store data before and after the application of the second stress (before the application of the third stress) and generate and report the difference, and repeat this process. This configuration may eliminate noise and background signals present before and after the application of stress, allowing information on the afterglow intensity generated in response to the stress to be obtained.

[0078] Here, the storage unit is a part that stores information on the afterglow intensity in the recordable area before and after the stress to be measured, which are obtained from the afterglow intensity acquisition unit. The term "information on the afterglow intensity before being subjected to the stress to be measured" refers to the case where stress is applied only once or multiple times. If the stress to be measured is a first stress, the term refers to information on the afterglow intensity before being subjected to the first stress, i.e., information on the afterglow intensity in a state where substantial stress (to be measured) has not yet been applied since irradiation with the reset light described below (hereinafter, also referred to as the reset state). However, if the stress to be measured is applied for the second time (when it is a second stress), the term does not refer to information on the afterglow intensity in the reset state, but rather to information on the afterglow intensity after the application of the first stress (before the application of the second stress). The same applies to "information on the afterglow intensity after being subjected to the stress to be measured."

[0079] The storage unit is not particularly limited as long as it can store information on the afterglow intensity before and after the stress of the measurement target is applied in a format that allows the difference information generating unit (described below) to generate difference information. For example, any storage medium can be used, such as a random access memory (RAM), an electrically erasable programmable read-only memory (EEPROM), a hard disk drive (HDD), a solid state drive (SSD), an optical disk, or a magnetic disk.

[0080] The difference information generating unit generates difference information between information on the afterglow intensity before the measurement target is subjected to stress and information on the afterglow intensity after the measurement target is subjected to stress. The difference information can be generated by a known method according to the form of the afterglow intensity information, such as by subtraction if the information is numerical information, or by subtraction of brightness information if the information is image information.

[0081] Furthermore, in a configuration further comprising such a memory unit and a difference information generation unit, if the aforementioned afterglow intensity notification unit is capable of reporting the difference information generated by the difference information generation unit, it becomes possible to remove noise and background that exist before and after the application of stress, and to provide information on the afterglow intensity that occurs in response to the stress.

[0082] Furthermore, in the stress recording system according to this embodiment, as a further configuration, the difference information generated by the difference information generating unit may be stored in a memory unit, and the afterglow intensity reporting unit may be configured to report predetermined afterglow intensity information or difference information stored in the memory unit.

[0083] With this configuration, the afterglow intensity information and difference information can be stored as a history, and the information can be displayed from this history. In particular, when stress is applied multiple times, it becomes possible to refer to the afterglow intensity information and difference information of a predetermined stress. If necessary, a search and extraction unit that searches for and extracts desired information from the stored afterglow intensity information and difference information of stress may be realized by a program or the like.

[0084] Furthermore, as mentioned above, if the information on the afterglow intensity is image information on the afterglow, the information on the afterglow intensity can be notified in a manner that is easy to view.

[0085] Furthermore, the stress recording system according to this embodiment may further include a reset light irradiation unit that irradiates the recordable area with high-intensity reset light having approximately the same wavelength as the excitation light for afterglow emission.

[0086] One interesting feature of the stress recording material according to this embodiment is that the recorded stress traces can be erased by irradiating the material with high-intensity light (reset light) at approximately the same wavelength as the excitation light for afterglow. This allows the recordable area to be reset. The intensity of the reset light must be adjusted according to various conditions, such as the composition of the stress recording material and the distance between the reset light irradiation area and the recordable area, but a rough guideline is approximately 100 to 1000 times the intensity of the read light.

[0087] The stress recording material, stress recording structure, stress recording body, stress recording body forming agent, stress recording coating film forming paint, stress recording method and stress recording system according to the present embodiment will be further described below with reference to the drawings.

[0088] 1. Preparation of stress recording material The stress recording material according to this embodiment, Li, was produced by a solid-state reaction method. 0.35 Na 0.80 NbO 4.168 :Pr 0.01 ,Nd 0.005 ,Cr 0.003 was prepared.

[0089] First, Na2CO3, Li2CO3, and Nb2O5 as the raw materials for the base material, and Pr2O3, Nd2O3, and Cr2O3 as metal ion supply compounds to be added to the base material were weighed out according to the above composition (based on a non-stoichiometric ratio), and then thoroughly mixed and ground in an agate mortar.

[0090] Next, the pulverized mixture was pre-fired in an electric furnace at 850° C. for a predetermined time (for example, 3 to 10 hours, more specifically 4 to 6 hours) in an air atmosphere, and the pre-fired product was pulverized.

[0091] Next, the pre-sintered and pulverized material was sintered at 1100°C for a predetermined time (for example, 3 to 100 hours, more specifically, 20 hours) in an O2 atmosphere (100% O2), and the sintered material was pulverized. If necessary, the sintered and pulverized material can be sintered and pulverized again (sometimes more than once) to prepare a more reliable stress recording material.

[0092] Next, the sintered and pulverized product that has been subjected to one or more sintering and pulverization steps is sized as necessary to obtain Li 2 O 3 as the stress recording material according to this embodiment. 0.35 Na 0.80 NbO 3.102 :Pr 0.01 ,Nd 0.005 ,Cr 0.003 A powder sample of the above (hereinafter referred to as stress recording material A1) was obtained. Figure 1 shows an SEM image of the prepared stress recording material A1.

[0093] [2. Creation of stress recorder] Next, stress recording pellet B1 was prepared as a stress recording medium using stress recording material A1.

[0094] 0.5 g of the stress recording material A1 was mixed with 4.5 g of an epoxy resin base, and the epoxy resin was solidified to prepare a stress recording material forming agent C1 for forming stress recording pellets B1.

[0095] Next, the stress recording material forming agent C1 was placed in a predetermined mold and solidified to produce a composite resin pellet (diameter 25 mm, thickness 10 mm), which is the stress recording pellet B1 according to this embodiment. The produced stress recording pellet B1 is shown in Figure 2. This stress recording pellet B1 has a stress recordable area formed all over it, and the stress recording pellet B1 itself is used as the measurement object in the tests described below.

[0096] 3. Construction of test equipment Next, a test device D was constructed to perform stress recording tests using the stress recording pellet B1. Figure 3 is a conceptual diagram showing the configuration of the constructed test device D.

[0097] As shown in FIG. 3, the test device D includes a load tester 10, a light source unit 11, an image capturing unit 12, and a computer 13.

[0098] The load testing machine 10 is a device for applying a predetermined stress to a stress recording pellet B1, which is a measurement object placed on a test stage 10a. The load testing machine 10 is electrically connected to a computer 13 via a cable (not shown), enabling control of the load and acquisition of various data.

[0099] The light source unit 11 is a component for irradiating the stress recording pellet B1, more specifically, the recordable area E1 of the stress recording pellet B1, with excitation light and reset light for afterglow. The light source unit 11 is electrically connected to the computer 13, for example, via a communication cable 14 or other wired or wireless means, and is configured to be able to change the intensity of the light emitted from the light source unit 11 under the control of the computer 13 to emit the excitation light and reset light. In other words, the light source unit 11 functions as part of the read light irradiation unit and reset light irradiation unit in cooperation with the computer 13.

[0100] The imaging unit 12 is a part that captures the afterglow emitted from the stress recording pellet B1 (recordable area E1), and is equipped with an optical system for capturing the afterglow, an imaging element that electrically converts the light incident through the optical system, and an image information generation unit that generates image information based on the electrical signal from the imaging element.

[0101] The optical system is directed toward the stress-recording pellet B1 (recordable area E1) through the gap 11a of the light source unit 11. The imaging unit 12 is also electrically connected to a computer 13 via a communication cable 14 or the like, enabling control of the imaging unit 12 and acquisition of information. The imaging unit 12 must be sensitive to at least the afterglow emitted from the recordable area E1, but may also be configured to be sensitive to mechanoluminescence as needed.

[0102] The computer 13 is a part that transmits and receives data between the load testing machine 10, the light source unit 11, and the imaging unit 12, performs control, acquires information, and displays information, and is composed of a computer main body unit 13a and a display 13b.

[0103] The computer main unit 13a incorporates a CPU, ROM, RAM, etc., and is capable of performing the aforementioned control and acquiring and displaying information in accordance with a predetermined program. The computer main unit 13a also incorporates a HDD as a storage unit, which can store afterglow intensity information supplied from connected peripheral devices, such as information on the afterglow intensity before the stress to be measured and information on the afterglow intensity after the stress to be measured, and information on the difference between these (along with, if necessary, chronological information such as the date and time when the afterglow intensity was acquired and the date and time when the difference information was generated). The difference information is generated by the CPU or the like executing predetermined processing in accordance with a program to acquire the difference between the afterglow intensity information before the stress to be measured and the afterglow intensity information after the stress to be measured. In this embodiment, the afterglow intensity information and the difference information are image information, but as mentioned above, this is not necessarily limited to this.

[0104] The computer main body 13a is also configured so that the user can select the desired information from the afterglow intensity information and difference information stored in the memory unit via a specified input means such as a keyboard or mouse, and extract it together with time-series information as needed.

[0105] The display 13b is a part for displaying information on the afterglow intensity and information on the difference together with time-varying information as necessary, and in this embodiment, the display is configured to notify by displaying an image of the afterglow based on image information supplied from the imaging unit 12 or stored in the memory unit of the computer main body unit 13a.

[0106] Thus, the test device D includes a stress recording system F1 according to this embodiment, which includes a stress recordable area E1 formed in the stress recording pellet B1, which is the object to be measured, a readout light irradiation unit constituted by a computer 13 and a light source unit 11 for irradiating the recordable area E1 with excitation light for afterglow emission, an afterglow intensity acquisition unit constituted by a computer 13 and an imaging unit 12 for acquiring information on the afterglow intensity of the recordable area E1, and an afterglow intensity notification unit constituted by a computer 13 (particularly, a display 13b) for reporting information on the afterglow intensity.

[0107] [4. Verification of stress records] Next, the stress recording was verified using the above-mentioned test device D. That is, as shown in Figure 4, the ML / MR characteristics were evaluated using a material testing machine and a camera system with LED illumination. In addition, the MR function was evaluated using optical readout images (afterglow images) after light irradiation before and after stress application. The wavelengths of the readout light and reset light were 200 to 480 nm, and the readout light was 0.1 to 3 mW / cm. 2 , 100-1000mW / cm for reset light 2 The irradiation was carried out at .

[0108] As a result, applying a load produced a luminescence image proportional to the dynamic stress distribution, as shown in Figure 5. After the load was applied, the mechanoluminescence disappeared, but the stress history record could be read out by irradiating the light source 11 with readout light and observing the afterglow image. Comparing the MR images before and after the load test, it was found that the recorded image was proportional to the stress distribution history. Figure 6(a) shows an image generated based on the afterglow intensity information (image information) before the measurement target was subjected to stress, and Figure 6(b) shows an image generated based on the difference between the afterglow intensity information before the measurement target was subjected to stress and the afterglow intensity information after the measurement target was subjected to stress.

[0109] Thus, it was demonstrated that the stress recording material according to this embodiment is capable of recording stress. Furthermore, it was demonstrated that the stress recording material, stress recording structure, stress recording body, stress recording method, and stress recording system according to this embodiment make it possible to know the application of stress after the fact simply by observing the afterglow. Furthermore, it was demonstrated that the stress recording body according to this embodiment is a stress recording body capable of expressing the presence or absence of stress and its strength as differences in afterglow intensity. Furthermore, it was demonstrated that the stress recording body forming agent according to this embodiment is a stress recording body forming agent capable of forming the stress recording body described above.

[0110] [5. Verification of stress distribution and MR strength distribution] Next, we examined the stress distribution and MR intensity distribution. Figure 7 shows the results of the FEM analysis. As can be seen from a comparison of Figures 5 and 7, the results of the FEM analysis are in good agreement with the mechanoluminescence observation results.

[0111] Furthermore, as can be seen by comparing FIG. 6(b) with FIG. 7, the MR intensity distribution shown in the stress recording image is in good agreement with the stress distribution shown by the FEM analysis results.

[0112] Figure 8 is a graph showing the relationship between the stress distribution and the MR intensity between the black arrows in Figure 6(b). Note that the stress distribution is shown in absolute values. As can be seen from Figure 8, the stress distribution and the MR intensity distribution are in good agreement.

[0113] These results show that the stress recording material, stress recording structure, stress recording body, stress recording body forming agent, stress recording coating film forming paint, stress recording method, and stress recording system according to the present embodiment are capable of quantitatively recording and reading out stress, in particular, recording and reading out stress that matches the stress distribution.

[0114] [6. Verification of long-term retention of stress records] Next, we investigated how long the stress record could be maintained. As a result, as shown in Figure 9, it was shown that the stress record could be maintained for at least six months. This indicates that the stress recording material according to this embodiment can maintain the stress record for a long period of at least six months or more.

[0115] [7. Examination of the relationship between the number of weightings and MR] Next, we investigated the relationship between the number of loads and MR. Specifically, as shown in Figure 10(a), we applied the same load for 1 degree from 12 o'clock to 6 o'clock, 5 degrees from 10-11 o'clock to 4-5 o'clock, and 10 degrees from 9 o'clock to 3 o'clock while moving the stress-recording pellet B1 around its axis, and measured the afterglow intensity, which is the difference from before the load.

[0116] Figure 10(b) shows the afterglow image after loading from three directions, and Figure 10(c) shows the afterglow recording intensity. As can be seen from Figures 10(b) and 10(c), it was shown that the cumulative stress has no effect on the MR intensity.

[0117] [8. Examination of stress record strength under maximum load] Next, we investigated the stress recording intensity under maximum load. Specifically, to examine the relationship between load and MR intensity, loads of 500 N were applied from 1-2 o'clock to the 7-8 o'clock direction, 750 N from 12 o'clock to the 6 o'clock direction, and 1000 N from 9 o'clock to the 3 o'clock direction, as shown in Figure 11(a), while moving the stress recording pellet B1 around its axis. MR intensity was evaluated from the afterglow images. The afterglow intensity after load application was defined as I, and the afterglow intensity before load application was defined as I0. The stress recording intensity (MRI) was calculated as MRI = |I - I0|.

[0118] Figure 11(b) shows the afterglow images after loading from three directions, and Figure 11(c) shows the calculated results of the afterglow recording intensity. As can be seen from Figures 11(b) and 11(c), an increase in MR intensity was confirmed as the load increased, demonstrating that MR is quantitative over a wide range.

[0119] 11(d) is a graph showing the relationship between stress-stimulated luminescence intensity and stress-recording intensity. As shown by the dashed line in FIG. 11(d), conventional stress-stimulated luminescent materials exhibit luminescence in response to stress, but are unable to perform stress recording, and therefore no stress-recording intensity has been confirmed. In contrast, the stress-recording material A1 (stress-recording pellet B1) according to this embodiment has been confirmed to exhibit stress-recording intensity that is highly correlated with stress-stimulated luminescence.

[0120] [9. Investigation of the resolution of stress records] Next, using the stress recording pellet B1, we investigated how fine an area recording is possible, that is, the resolution of stress recording.

[0121] Figure 12 shows a load application jig and the state of the experiment to examine the spatial resolution of stress history using this jig. Tests were conducted using various jigs shown in Figure 12(a), but here we will explain the test using jig 30 shown as number 3 in Figure 12(a) (see Figure 12(b)) as a representative example.

[0122] For the test, as shown in Figure 12(c), the flat part of the stress recording pellet B1 was placed upside down, and the protrusion-forming surface 30a of the jig 30 was placed facing the top surface 31a of the stress recording pellet B1, and a load was applied from above the jig 30.

[0123] 13(a) and 13(b) show the MR images after the load was applied. Six cylindrical protrusions were formed on the jig 30, designated as areas 1 to 6.

[0124] The MR image shown in Figure 13(b) shows the record of the stress history up to area 6. To examine the spatial resolution, we calculated the pixel size. Because the pellet diameter is constant, we calculated it from the proportion of the pellet in the MR image. Based on the calculation results, we performed a 3D surface analysis centered on area 6.

[0125] The analysis results of the fitted surface are shown in Figure 13(c). The analysis results showed that load application information of approximately 600 μm could be detected with high spatial resolution. The results of the line distribution analysis are shown in Figure 14.

[0126] In compression tests using a materials testing machine, we discovered that it was possible to record the stress history of LNNO. Starting from this, we attempted to examine the quantitativeness, strength, and resolution of MR. The strength of MR matched the stress distribution obtained by FEM analysis, and we succeeded in reading out the past history from the afterglow. Furthermore, experiments using a jig enabled us to read out the spatial distribution of the stress history record with a diameter of sub-millimeter size, and in this study, we were able to observe the history at approximately 600 μm.

[0127] [10. Other stress recording materials] So far, the stress recording material A1 according to this embodiment, i.e., Li 0.35 Na 0.80 NbO 3.102 :Pr 0.01 ,Nd 0.005 ,Cr 0.003 Although the stress recording structure, stress recording body, stress recording body forming agent, stress recording method, and stress recording system using the same have been described, it goes without saying that the present invention is not limited to the same composition. Therefore, here, other stress recording materials will be mentioned.

[0128] Two stress recording materials A2 and A3 according to other embodiments were prepared in the same manner as in the solid-state reaction method described in [1. Preparation of stress recording material]. Stress recording material A2 was prepared using Li 0.14 Na 0.89 NbO 3.017 :Pr 0.002 and stress recording material A3 is Li 0.21 Na 0.80 NbO3.095 :Nd 0.05 ,Cr 0.01 is.

[0129] Further, by the method explained in [2. Preparation of stress recording medium], stress recording pellet B2 containing stress recording material A2 and stress recording pellet B3 containing stress recording material A3 were prepared.

[0130] Then, in the same manner as in [4. Verification of stress recording], it was confirmed whether stress recording was possible. In the test of stress recording pellet B2, the wavelengths of the read light and reset light were 250 to 400 nm, and the read light was 0.1 to 1 mW / cm. 2 , 100-500mW / cm for reset light 2 In the test of the stress recording pellet B3, the wavelength of the read light and the reset light was set to 200 to 300 nm, and the read light was set to 0.8 to 3 mW / cm 2 , and 300-800mW / cm for reset light. 2 The irradiation was carried out at .

[0131] As a result, it was confirmed that stress could be recorded and read out in both stress-recording pellets B2 and B3, just as in stress-recording pellet B1. The afterglow of stress-recording pellet B2 was red visible light centered at 605 nm and near-infrared light centered at 1050 nm, while the afterglow of stress-recording pellet B3 was green visible light centered at 500 nm and near-infrared light centered at 1100 nm.

[0132] As described above, the stress recording material according to this embodiment is a compound represented by the general formula Li x Na y NbO 3+(x+y-1) / 2+Σ(zk*Lk / 2) :M1 z1 ,M2 z2 ,M3 z3(wherein M1 is any one metal ion selected from rare earth ions and transition metal ions, M2 or M3 is none or any one metal ion selected from rare earth ions and transition metal ions, zk is a generalized expression of z1 to z3, Lk is a generalized expression of the valence L1 of the M1 ion, the valence L2 of the M2 ion, and the valence L3 of the M3 ion, and when M2 is none, z2 is 0, and when M3 is none, z3 is 0), and x = 0.02 to 2, y = 0.01 to 1, and z1 + z2 + z3 = 0.0001 to 0.2, it is possible to provide a stress recording material that is not affected by dark reactions due to chemical reactions, has excellent quantitative properties and long-term record retention, and allows the application of stress to be known after the fact simply by observing the afterglow.

[0133] Finally, the above-described embodiments are merely examples of the present invention, and the present invention is not limited to the above-described embodiments. Therefore, even if the embodiments are different from those described above, various modifications can be made depending on the design, etc., as long as they do not deviate from the technical concept of the present invention. [Explanation of symbols]

[0134] 10 Load testing machine 11 Light source section 12 Imaging unit 13. Computer 13a Computer main body 13b Display A1, A2, A3 Stress recording material B1, B2, B3 stress recording pellets C1 Stress record forming agent D. Test equipment E1 Recordable area F1 Stress Recording System

Claims

1. General formula Li x Na y NbO 3+（x+y-1） / 2＋Σ(zk*Lk / 2) :M1 z1 ,M2 z2 ,M3 z3 (wherein M1 is any one metal ion selected from rare earth ions and transition metal ions, M2 or M3 is none or any one metal ion selected from rare earth ions and transition metal ions, zk is a generalized expression of z1 to z3, Lk is a generalized expression of the valence L1 of the M1 ion, the valence L2 of the M2 ion, and the valence L3 of the M3 ion, and when M2 is none, z2 is 0, and when M3 is none, z3 is 0), x = 0.02 to 2, y = 0.01 to 1, and z1 + z2 + z3 = 0.0001 to 0.2, and a measurement By placing the stress recording material in a recordable area formed in a predetermined region of the object to be measured, it is possible to know after the fact information about the stress experienced by the object to be measured by irradiating the recordable area with readout light of a wavelength of 200-480 nm and observing the difference between the afterglow observed before the stress is applied, which has a peak in the 500-1100 nm band, and the afterglow observed after the stress is applied, which has a peak in the 500-1100 nm band that changes depending on the past load history of the object to be measured; and further, the traces of the recorded stress can be erased by irradiating reset light of approximately the same wavelength as the readout light and 100 to 1000 times the intensity of the readout light.

2. General formula Li x Na y NbO 3+（x+y-1） / 2＋Σ(zk*Lk / 2) :M1 z1 ,M2 z2 ,M3 z3 (wherein M1 is any one metal ion selected from rare earth ions and transition metal ions, M2 or M3 is none or any one metal ion selected from rare earth ions and transition metal ions, zk is a generalized expression of z1 to z3, Lk is a generalized expression of the valence L1 of the M1 ion, the valence L2 of the M2 ion, and the valence L3 of the M3 ion, and when M2 is none, z2 is 0, and when M3 is none, z3 is 0), and the stress recording material (wherein the general formula is Li(1-P)(1+α)NaPNbO3:QR) is satisfied, where x=0.02 to 2, y=0.01 to 1, and z1+z2+z3=0.0001 to 0.

2. (However, materials in which Q is represented by the formula (where Q is at least one metal ion selected from transition metal ions), P is in the range of 0.10 to 0.98, R is in the range of 0.0001 to 0.2, and α is 0 or more are excluded.)

3. A stress recording structure comprising a recordable area formed as a coating layer or sheet layer in a predetermined area of ​​an object to be measured, in which powder of the stress recording material described in claim 1 or claim 2 is dispersed in a light-transmitting resin matrix, and the recordable area is configured so that after stress is applied, an afterglow is generated by irradiating a readout light, thereby making it possible to know after the fact that stress has been applied to the object to be measured.

4. a region where stress formed on the measurement object can be recorded; a read light irradiation unit that irradiates the recordable area with excitation light for afterglow emission; an afterglow intensity acquisition unit that acquires information about the afterglow intensity of the recordable area; an afterglow intensity reporting unit that reports information about the afterglow intensity, The recordable area has a general formula Li x Na y NbO 3+ (x+y-1) / 2 + Σ(zk*Lk / 2): M1 z1 , M2 z2 , M3 z3 (wherein M1 is any one metal ion selected from rare earth ions and transition metal ions, M2 or M3 is none or any one metal ion selected from rare earth ions and transition metal ions, zk is a generalized expression of z1 to z3, Lk is a generalized expression of the valence L1 of the M1 ion, the valence L2 of the M2 ion, and the valence L3 of the M3 ion, and when M2 is none, z2 is 0, and when M3 is none, z3 is 0), and x=0.02 to 2, y=0.01 to 1, and z1+z2+z3=0.0001 to 0.2, is present in a predetermined region of the measurement object, A stress recording system comprising a reset light irradiation unit that irradiates the recordable area with high-intensity reset light having substantially the same wavelength as the excitation light for afterglow emission.

5. a storage unit that stores information on the afterglow intensity in the recordable area before the stress to be measured is applied and information on the afterglow intensity after the stress to be measured, the information being obtained from the afterglow intensity acquisition unit; a difference information generating unit that generates difference information between information on afterglow intensity before the measurement object is subjected to stress and information on afterglow intensity after the measurement object is subjected to stress, 5. The stress recording system according to claim 4, wherein the afterglow intensity notifying unit is capable of notifying information on the difference.

6. the storage unit is capable of storing information about the difference; 6. The stress recording system according to claim 5, wherein the afterglow intensity notifying unit is capable of notifying information on a predetermined afterglow intensity or information on a difference stored in the storage unit.

7. 7. The stress recording system according to claim 4, wherein the information on the afterglow intensity is image information on the afterglow.

8. General formula Li x Na y NbO 3+（x+y-1） / 2＋Σ(zk*Lk / 2) :M1 z1 ,M2 z2 ,M3 z3 (wherein M1 is any one metal ion selected from rare earth ions and transition metal ions, M2 or M3 is none or any one metal ion selected from rare earth ions and transition metal ions, zk is a generalized expression of z1 to z3, Lk is a generalized expression of the valence L1 of the ion of M1, the valence L2 of the ion of M2, and the valence L3 of the ion of M3, and when M2 is none, z2 is 0, and when M3 is none, z 3 is 0.) where x = 0.02 to 2, y = 0.01 to 1, and z1 + z2 + z3 = 0.0001 to 0.2, is placed in a recordable area formed in a predetermined area of ​​an object to be measured, and readout light of a predetermined wavelength is irradiated onto the recordable area, and the difference between an afterglow image before stress application and an afterglow image after stress application is observed. This method of use is as a stress recording material for emitting afterglow, which allows information about the stress received by the object to be measured to be obtained after the fact.

Images