Wave-motion propagation speed measurement method, wave-motion propagation speed measurement device, and program

Abstract

In the present invention, an acoustic wave is transmitted to a first surface S1 of an object S having acoustic anisotropy by a transmission unit 11a disposed on the first surface S1. A plurality of acoustic waves propagating through the inside of the object S at different angles are received by a reception unit 11b disposed on the first surface S1 of the object S or a second surface S2 opposing the first surface S1, and thereby a plurality of pieces of reception information are acquired. A plurality of propagation speed vectors are calculated on the basis of the plurality of pieces of reception information. A propagation wavefront shape model corresponding to the acoustic anisotropy of the object S is determined on the basis of the plurality of propagation speed vectors. A horizontal propagation speed parallel to the first surface S1 is calculated on the basis of the propagation wavefront shape model.

Description

Wave propagation velocity measurement method, wave propagation velocity measurement device, and program

[0001] The present invention relates to a wave propagation velocity measuring method, a wave propagation velocity measuring device, and a program.

[0002] Conventionally, a method for evaluating the mechanical properties of an object is known in terms of the degree of freedom of the object and operational safety, by measuring the propagation velocity of elastic waves, which have a high correlation with the mechanical properties.

[0003] For example, Patent Document 1 describes an elastic wave inspection system that irradiates an object with elastic waves and measures the propagation velocity of the elastic waves from the propagation time. Also, Patent Document 2 describes an elastic constant measurement device that propagates elastic waves from each direction to a plate to be measured, calculates multiple propagation velocities, and calculates the elastic constant of the plate to be measured based on the multiple propagation velocities.

[0004] JP 2008-286622 A JP 2007-127547 A

[0005] Because the propagation velocity of an elastic wave has a unique relationship with the elastic modulus of the object serving as the propagation medium, a method for nondestructively testing the elastic strength characteristics of an object is known that utilizes this phenomenon. Meanwhile, composite materials such as fiber-reinforced resins and some metals exhibit "anisotropy," meaning that their strength characteristics vary depending on the direction of applied stress. Such materials exhibit "acoustic anisotropy," meaning that the propagation velocity of elastic waves varies depending on the direction of applied stress. Therefore, to test elastic strength based on the propagation velocity of elastic waves as described above, the propagation direction of the elastic waves must be aligned with the expected direction of applied stress. For example, when testing the longitudinal elastic strength of a long object, the elastic waves must be propagated in that direction. However, if the propagation attenuation of elastic waves in the object is large, sufficient reception quality cannot be ensured, making it impossible to measure the propagation velocity. Furthermore, the invention of Patent Document 1 measures the propagation velocity in multiple directions to reduce measurement variability, but because it arithmetically averages the propagation velocities measured in multiple directions, it is unable to evaluate materials with acoustic anisotropy. Furthermore, the invention of Patent Document 2 makes it possible to measure the elastic modulus in each direction for materials with acoustic anisotropy, but it has the problem that it requires elastic waves with different properties, such as longitudinal waves and transverse waves, to propagate in different directions, making measurement time-consuming.

[0006] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a wave propagation velocity measuring method, a wave propagation velocity measuring device, and a program that can more easily measure the propagation velocity of an elastic wave in a predetermined direction in an object having acoustic anisotropy.

[0007] In order to solve the above problem, the invention described in claim 1 is a wave propagation velocity measuring method, comprising: transmitting elastic waves to a first surface of an object having acoustic anisotropy using a transmitting unit arranged on the first surface; receiving a plurality of the elastic waves propagating at different angles within the object using a receiving unit arranged on the first surface or a second surface opposite the first surface of the object, thereby obtaining a plurality of pieces of received information; calculating a plurality of propagation velocity vectors based on the plurality of pieces of received information; determining a propagation wavefront shape model corresponding to the acoustic anisotropy of the object based on the plurality of propagation velocity vectors; and calculating a horizontal propagation velocity parallel to the first surface based on the propagation wavefront shape model.

[0008] The invention described in claim 2 is a wave propagation velocity measuring method described in claim 1, wherein each of the multiple pieces of reception information includes information on the propagation time of the elastic wave propagating within the object, and the multiple propagation velocity vectors are calculated based on the multiple pieces of reception information, information on multiple arrangement intervals between the transmitter and the receiver in a direction parallel to the first surface, and thickness information of the object.

[0009] A third aspect of the present invention is the wave propagation velocity measuring method according to the first aspect, further comprising the step of calculating the propagation wavefront shape model based on the plurality of propagation velocity vectors.

[0010] A fourth aspect of the present invention is the wave propagation velocity measuring method according to the first aspect, wherein the propagation wavefront shape model is selected from a plurality of propagation wavefront shape model candidates based on the plurality of propagation velocity vectors.

[0011] The invention described in claim 5 is the wave propagation velocity measuring method described in claim 2, wherein the thickness information of the object is a provisional thickness value which is a provisional length in the thickness direction of the object, or a true thickness value which is a true length in the thickness direction of the object.

[0012] The invention described in claim 6 is the wave propagation velocity measuring method described in claim 5, wherein when the thickness information of the object is the true thickness value, a vertical propagation velocity perpendicular to the first surface is calculated in addition to the horizontal propagation velocity.

[0013] A seventh aspect of the present invention is the wave propagation velocity measuring method according to the second aspect, wherein the plurality of pieces of reception information are acquired by adjusting an arrangement interval between the transmitting unit and the receiving unit.

[0014] The invention described in claim 8 is a wave propagation velocity measuring method described in claim 7, in which the spacing between the transmitter and receiver is adjusted by selecting from a plurality of transmitting and / or receiving sensor elements arranged in advance at predetermined positions and / or shapes.

[0015] The invention of claim 9 is the wave propagation velocity measuring method of claim 1, comprising: arranging the transmitter and the receiver in a direction within an acoustic isotropy plane in which an object having uniaxial acoustic anisotropy exhibits acoustic isotropy, and calculating a first propagation velocity vector; calculating a vertical propagation velocity perpendicular to the first plane based on the first propagation velocity vector; arranging the transmitter and the receiver in a direction within an acoustic anisotropy plane in which the object exhibits acoustic anisotropy, and calculating a second propagation velocity vector; and calculating a horizontal propagation velocity within the acoustic anisotropy plane based on the vertical propagation velocity, the second propagation velocity vector, and a propagation wavefront shape model corresponding to the acoustic anisotropy of the object.

[0016] The invention described in claim 10 is a wave propagation velocity measuring method described in claim 1, wherein the arrangement positions and / or arrangement directions of the transmitter and receiver are changed, and the horizontal propagation velocity is measured for each of the arrangement positions and / or arrangement directions.

[0017] An eleventh aspect of the present invention is the wave propagation velocity measuring method according to the tenth aspect, further comprising analyzing a horizontal propagation velocity corresponding to the installation position and / or the installation direction.

[0018] The invention described in claim 12 is the wave propagation velocity measuring method described in claim 11, wherein statistical data including at least one of the maximum value, minimum value, average value, variance value, and principal component analysis result of the horizontal propagation velocity corresponding to the installation direction is obtained for each installation position.

[0019] A thirteenth aspect of the present invention is the wave propagation velocity measuring method according to the twelfth aspect, further comprising deriving an arrangement direction in which the horizontal propagation velocity exhibits a maximum value and / or a minimum value for each of the arrangement positions.

[0020] A fourteenth aspect of the present invention provides the wave propagation velocity measuring method according to the tenth aspect, wherein the installation position and / or the installation direction are displayed in association with the magnitude of the horizontal propagation velocity.

[0021] The invention described in claim 15 is a wave propagation velocity measuring method described in any one of claims 1 to 14, wherein the transmitting unit and / or the receiving unit are arranged by integrating multiple acoustic elements in a line or matrix.

[0022] A sixteenth aspect of the present invention is the wave propagation velocity measuring method according to any one of the first to fourteenth aspects, wherein the propagation wavefront shape model has an elliptical shape within an acoustic anisotropy plane of the object.

[0023] The invention described in claim 17 is a wave propagation velocity measuring device comprising: a transmitting unit disposed on a first surface of an object having acoustic anisotropy and inputting elastic waves to the first surface; a receiving unit disposed on the first surface of the object or on a second surface opposite the first surface and receiving a plurality of the elastic waves propagating within the object at different angles and outputting a plurality of pieces of received information; a propagation velocity vector calculating unit calculating a plurality of propagation velocity vectors based on the plurality of pieces of received information; a propagation wavefront shape model determining unit determining a propagation wavefront shape model corresponding to the acoustic anisotropy of the object based on the plurality of propagation velocity vectors; and a propagation velocity calculating unit calculating a horizontal propagation velocity parallel to the first surface based on the propagation wavefront shape model.

[0024] The invention described in claim 18 is a program that causes a computer of a wave propagation velocity measuring device to function as: a transmitting unit that is arranged on a first surface of an object having acoustic anisotropy and inputs elastic waves to the first surface; and a receiving unit that is arranged on the first surface of the object or a second surface opposite the first surface and receives a plurality of the elastic waves propagating within the object at different angles and outputs a plurality of pieces of reception information; a propagation velocity vector calculating unit that calculates a plurality of propagation velocity vectors based on the plurality of pieces of reception information; a propagation wavefront shape model determining unit that determines a propagation wavefront shape model corresponding to the acoustic anisotropy of the object based on the plurality of propagation velocity vectors; and a propagation velocity calculating unit that calculates a horizontal propagation velocity parallel to the first surface based on the propagation wavefront shape model.

[0025] According to the present invention, the propagation velocity of an elastic wave in a predetermined direction in an object having acoustic anisotropy can be measured more simply.

[0026] 1 is a block diagram showing the configuration of a wave propagation velocity measuring device. FIG. 1 is a schematic perspective view showing the arrangement of a sensor element of the wave propagation velocity measuring device and an object. FIG. 2 is a flowchart showing a horizontal propagation velocity calculation method according to the first embodiment. FIG. 3 is a conceptual perspective view showing the acoustic anisotropy axis of an object according to the first embodiment. FIG. 4 is a conceptual side view showing the arrangement of a sensor element of the wave propagation velocity measuring device and an object. FIG. 5 is a conceptual diagram of a propagation wavefront shape model of an elastic wave in a plane showing acoustic anisotropy. FIG. 1 is a block diagram showing another configuration of a wave propagation velocity measuring device. FIG. 2 is a flowchart showing a horizontal propagation velocity calculation method according to a modified example of the first embodiment. FIG. 3 is a flowchart showing a horizontal propagation velocity calculation method according to the second embodiment. FIG. 4 is a schematic perspective view showing the arrangement of a sensor element and an object according to the modified examples of the first to fourth embodiments. FIG. 5 is a schematic perspective view showing the arrangement of a sensor element and an object whose arrangement direction is set in a first direction according to a fifth embodiment. FIG. 6 is a schematic perspective view showing the arrangement of a sensor element and an object whose arrangement direction is changed to a second direction according to the fifth embodiment. FIG. 7 is a flowchart showing a horizontal propagation velocity calculation method according to the fifth embodiment. FIG. 8 is a conceptual diagram of a propagation wavefront shape model of an elastic wave in a plane showing acoustic isotropy. 10 is a flowchart showing a horizontal propagation velocity calculation method according to a sixth embodiment. FIG. 11 is a flowchart showing a horizontal propagation velocity calculation method according to a modified example of the sixth embodiment. FIG. 12 is a conceptual perspective view of an object whose acoustic anisotropy axis is not parallel to the first surface. FIG. 13 is a conceptual side view of an object whose acoustic anisotropy axis is not parallel to the first surface. FIG. 14 is a schematic perspective view showing an arrangement of sensor elements and an object according to a modified example of the sixth embodiment. FIG. 15 is an example of a velocity map showing velocity data corresponding to the placement position of an array-type sensor. FIG. 16 is another example of a velocity map showing velocity data corresponding to the placement position of an array-type sensor. FIG. 17 is an example of a velocity map showing velocity data corresponding to the placement direction of an array-type sensor.

[0027] A wave propagation velocity measuring device for realizing a wave propagation velocity measuring method according to an embodiment of the present invention will be described in detail below with reference to the drawings. However, the scope of the invention is not limited to the illustrated examples. In the following description, components having the same functions and configurations are given the same reference numerals, and their description will be omitted, with the focus being on the differences.

[0028] [Overall Configuration of Wave Propagation Velocity Measuring Device] Fig. 1 is a block diagram showing the functional configuration of a wave propagation velocity measuring device 100. The wave propagation velocity measuring device 100 includes a sensor unit 10 and a processing device 20, and measures the propagation velocity of an elastic wave in an object S. Fig. 2 is a perspective view showing the arrangement of sensor elements 11 that constitute the sensor unit 10 that propagates an elastic wave in the object S.

[0029] Here, elastic waves are waves that propagate through an elastic body, and include, for example, sound waves, seismic waves, etc. In the following, an example will be given in which ultrasonic waves are used as elastic waves. In addition, in the following, the x direction, y direction, and z direction represent the directions shown in Figure 2. In addition, in the following, the object S is a material that exhibits acoustic anisotropy.

[0030] Acoustic anisotropy is the property of elastic waves whose propagation speed varies depending on the direction of propagation. Materials that may exhibit acoustic anisotropy include, for example, metals or metal alloys such as titanium (Ti) that contain a crystalline structure or are stretched in a specific direction, and composites in which various fillers are blended into a resin matrix, such as carbon fiber reinforced plastics (CFRP), carbon fiber reinforced thermoplastics (CFRTP), or glass fiber reinforced plastics (GFRP).

[0031] 2 illustrates an example in which the object S is flat, but is not limited to this. However, it is preferable that the first surface S1 (yz plane) and the opposing second surface S2 of the object S are substantially parallel to each other, and the object S may be cylindrical, for example.

[0032] (Sensor Unit) The sensor unit 10 transmits and receives ultrasonic waves while in contact with the first surface S1 of the object S. The sensor unit 10 includes a sensor element 11 and a drive unit 12.

[0033] {Sensor Element} The sensor element 11 is an array-type sensor consisting of a plurality of piezoelectric elements arranged one-dimensionally in a predetermined direction, as shown in Fig. 2, for example. The transmitter 11a is selected from the sensor element 11 and transmits ultrasonic waves by vibrating in accordance with a transmission signal output from a signal generator 22 (described later) of the processing device 20. The receiver 11b is selected from the sensor element 11 and receives the ultrasonic waves transmitted by the transmitter 11a, converts them into an electrical signal, and generates a received signal, which is input to the processing device 20.

[0034] {Drive Unit} The drive unit 12 changes the arrangement position and arrangement direction of the sensor element 11. Specifically, the drive unit 12 is a two-dimensional movement mechanism that moves the sensor element 11 to an arbitrary position on the first surface S1 of the object S, and a rotation mechanism that rotates the sensor element 11 in an arbitrary direction on the first surface S1.

[0035] (Processing Device) The processing device 20 is connected to the sensor unit 10 and controls the sensor unit 10. The sensor unit 10 and the processing device 20 may be connected by wire, for example, a cable and a connector, or may be connected wirelessly by wireless communication. The processing device 20 includes a control unit 21, a signal generating unit 22, a display unit 23, an operation input unit 24, a memory unit 25, etc.

[0036] {Control Unit} The control unit 21 includes a central processing unit (CPU), a random access memory (RAM), and a read only memory (ROM). The control unit 21 controls the overall operation of the wave propagation velocity measuring device 100.

[0037] The CPU controls each part of the wave propagation velocity measuring device 100. The RAM is a volatile memory that temporarily stores various pieces of information in a writable and readable manner. The ROM is a non-volatile memory that stores various pieces of information and programs in a readable manner. More specifically, the control unit 21 reads a specified program from the various programs stored in the ROM using the CPU and expands it into the RAM. The control unit 21 then executes various processes in cooperation with the expanded program.

[0038] The control unit 21 functions as a propagation time measurement unit 21a that measures, as reception information, the propagation time, which is the time from when the transmitter 11a transmits ultrasonic waves to when the receiver 11b receives the ultrasonic waves. The control unit 21 also functions as a transmission / reception interval adjustment unit 21b that selects the transmitter 11a and the receiver 11b from the sensor element 11 by supplying a signal to the sensor unit 10 and adjusts the spacing between the transmitter 11a and the receiver 11b. The control unit 21 also functions as a propagation velocity vector calculation unit 21c that calculates a propagation velocity vector based on the propagation time of the ultrasonic waves, the spacing between the transmitter 11a and the receiver 11b, and information about the thickness of the object S. The control unit 21 also functions as a propagation wavefront shape model determination unit 21d that determines a propagation wavefront shape model of the ultrasonic waves in the object S based on the calculated propagation velocity vector. The control unit 21 also functions as a propagation velocity calculation unit 21e that calculates the propagation velocity of the ultrasonic waves in a predetermined direction of the object S based on the propagation wavefront shape model. The control unit 21 also functions as an analysis unit 21f that analyzes the propagation speed of ultrasonic waves corresponding to the arrangement positions and / or arrangement directions of the transmission unit 11a and the reception unit 11b.

[0039] {Signal Generator} The signal generator 22 inputs a transmission signal, which is an electrical signal, to the transmitter 11a of the sensor unit 10 under the control of the controller 21, thereby transmitting ultrasonic waves to the target S from the transmitter 11a.

[0040] {Display Unit} The display unit 23 displays various information in the propagation velocity calculation process described below. In particular, the display unit 23 displays a velocity map described below. The display unit 23 includes a display panel such as an LCD (Liquid Crystal Display) or an organic EL (Electro-Luminescence) display.

[0041] {Operation Input Unit} The operation input unit 24 is operated by a user of the processing device 20. In response to the operation, the operation input unit 24 inputs various information and instructions to the processing device 20. The operation input unit 24 is, for example, a mouse, a keyboard, or a push button.

[0042] {Storage Unit} The storage unit 25 is configured by a hard disk drive (HDD) or a solid state drive (SSD), and stores various types of information in a readable and writable manner.

[0043] [First Embodiment] [One-Direction Horizontal Propagation Velocity Calculation Process; Change in Arrangement Interval → Acquire Two Vectors (Thickness Known)] Next, the propagation velocity calculation process according to the first embodiment, performed by the wave propagation velocity measuring device 100, will be described with reference to Fig. 3 to Fig. 5. Note that, hereinafter, as shown in Fig. 4A, the propagation velocity calculation process will be described assuming that the target object S is a material having uniaxial acoustic anisotropy, and more specifically, when two anisotropy axes are parallel to the first surface S1 (yz-plane), and one of the axes is in the y direction.

[0044] The control unit 21, which has received an operation input from the user via the operation input unit 24, acquires thickness information D relating to the thickness value of the object S (step S100). In this embodiment, the control unit 21 acquires the true thickness value, which is an actually measured value, as the thickness information D from data previously stored in the storage unit 25 or from an operation input by the user via the operation input unit 24.

[0045] After acquiring the thickness information D, the control unit 21, which is the transmission / reception interval adjustment unit 21b, sets the placement interval L1 in the y direction between the transmission unit 11a and the reception unit 11b (step S102). Specifically, the control unit 21 sets the placement interval L1 by selecting the sensor elements 11 that function as the transmission unit 11a and the reception unit 11b.

[0046] Installation interval L １ After setting the above, the control unit 21 inputs a transmission signal from the signal generating unit 22 to the transmitting unit 11a, causing the transmitting unit 11a to transmit an ultrasonic wave, and the receiving unit 11b receives the ultrasonic wave and outputs a received signal (step S103).The control unit 21, which is the propagation velocity vector calculating unit 21c, then calculates the propagation velocity vector of the ultrasonic wave (step S104).

[0047] Here, the oblique propagation time from when an ultrasonic wave is transmitted from the transmitting unit 11a on the first surface S1 of the object S, reflected by the second surface S2, to when the ultrasonic wave is received by the receiving unit 11b on the first surface S1, which is located L1 away from the transmitting unit 11a, is defined as t1. １ is calculated from FIG. 4B using the following formula (1).

[0048]

[0049] Furthermore, the input angle of the ultrasonic wave transmitted from the transmitting unit 11a and input to the first surface S1, i.e., the angle θ1 that the first propagation velocity vector makes with respect to the y-axis, is calculated from FIG. 4B using the following equation (2).

[0050]

[0051] The control unit 21 determines whether multiple propagation velocity vectors have been calculated (step S105). If multiple propagation velocity vectors have not been calculated (step S105; No), the control unit 21 proceeds to step S102 and changes the placement interval to L2, which is different from L1. Here, the oblique propagation time from when an ultrasonic wave is transmitted from the transmitter 11a until the ultrasonic wave is received by the receiver 11b (11b') that is L2 away from the transmitter 11a is defined as t2. The control unit 21 calculates the magnitude Vc2 of the second propagation velocity vector of the ultrasonic wave that enters the first surface S1 at an angle different from the first propagation velocity vector and propagates through the object S, using the following formula (3), similar to formula (1).

[0052]

[0053] Similarly to equation (2), the angle θ 2 that the second propagation velocity vector makes with respect to the y-axis is calculated using equation (4) below.

[0054]

[0055] If multiple propagation velocity vectors have been calculated (Step S105; Yes), the control unit 21, which is the propagation wavefront shape model determination unit 21d, determines a propagation wavefront shape model of the ultrasonic waves propagating within the object S from the multiple propagation velocity vectors (Step S106). The control unit 21, which is the propagation velocity calculation unit 21e, calculates a horizontal propagation velocity (propagation velocity in the y direction) Vb from the propagation wavefront shape model (Step S107).

[0056] As described above, the object S is an acoustically anisotropic material with one axis of anisotropy in the y direction. Here, as shown in FIG. 5 , the wavefront of the ultrasonic waves propagating within the xy plane of the object S exhibits an elliptical shape or a shape similar thereto. Therefore, if the vertical propagation velocity (propagation velocity in the x direction) of the object S is Va and the horizontal propagation velocity is Vb, the multiple propagation velocity vectors calculated in steps S102 to S105 can be mapped onto the same propagation wavefront shape model expressed as an ellipse, as shown in FIG. 5 . That is, based on the first and second propagation velocity vectors, the propagation wavefront shape models expressed by the following mathematical expressions (5) and (6) are simultaneously established.

[0057]

[0058]

[0059] Among the variables included in Equations (1) to (4), the placement intervals L1 and L2, the thickness information D, and the oblique propagation times t1 and t2 are all values ​​obtained by actual measurement. Substituting Equations (1) and (2) into Equation (5) and Equations (3) and (4) into Equation (6), the only unknown variables included in Equations (5) and (6) are the vertical propagation velocity Va and the horizontal propagation velocity Vb. Therefore, by simultaneously solving Equations (5) and (6), the horizontal propagation velocity Vb and the vertical propagation velocity Va can be calculated.

[0060] [Effects of the First Embodiment] As described above, in the propagation velocity calculation process according to the first embodiment, the transmitter 11a disposed on the first surface S1 of the object S having acoustic anisotropy transmits elastic waves to the first surface S1, and the receiver 11b disposed on the first surface S1 of the object S receives multiple elastic waves propagating at different angles within the object S, thereby acquiring multiple pieces of reception information. Then, multiple propagation velocity vectors are calculated based on the multiple pieces of reception information, a propagation wavefront shape model corresponding to the acoustic anisotropy of the object S is determined based on the multiple propagation velocity vectors, and a horizontal propagation velocity Vb parallel to the first surface S1 is calculated based on the propagation wavefront shape model. With this configuration, the horizontal propagation velocity Vb in the y direction can be calculated without arranging the transmitter 11a and the receiver 11b opposite each other on both end surfaces parallel to the zx plane of the object S and propagating ultrasound in the y direction. In other words, according to the wave propagation velocity measurement method of this embodiment, the propagation velocity of elastic waves in a specified direction can be measured more easily even for an object S with an elongated shape where it is physically difficult to arrange a sensor on the end surface.

[0061] [Variation 1 of the First Embodiment] (Storage of Propagation Wavefront Shape Model Candidates) In the above configuration, the propagation wavefront shape model is arithmetically determined by substituting multiple propagation velocity vectors into Equations (5) and (6), but this is not limited to this. That is, as shown in FIG. 6 , multiple candidates for the propagation wavefront shape model (hereinafter referred to as propagation wavefront shape model candidates) corresponding to the object S are calculated in advance and stored in the storage unit 25. Then, an optimal propagation wavefront shape model may be selected based on the multiple propagation velocity vectors expressed by Equations (1) and (2) and Equations (3) and (4). This eliminates the effort and cost of sequentially calculating the propagation wavefront shape model using the propagation velocity vectors, and allows for more efficient calculation of the horizontal propagation velocity Vb.

[0062] [Variation 2 of the First Embodiment] (Simultaneous Acquisition of Multiple Propagation Velocity Vectors) In the above embodiment, after the placement interval is set by the transmission / reception interval adjuster 21b, the transmitter 11a and the receiver 11b transmit and receive ultrasonic waves, and this process is repeated multiple times to calculate multiple propagation velocity vectors. However, this is not limited to this. That is, as shown in FIG. 2 , when the transmitter 11a and the receiver 11b are selected from multiple sensor elements 11, for example, multiple sensor elements 11 may be simultaneously selected as the receiver 11b, and multiple reception signals may be acquired in a single transmission / reception of ultrasonic waves, thereby calculating multiple propagation velocity vectors. Conversely, multiple sensor elements 11 may be simultaneously selected as the transmitter 11a, and multiple ultrasonic waves may be simultaneously transmitted and received by a single receiver 11b, thereby calculating multiple reception signals. This eliminates the need to set the placement interval multiple times and transmit and receive ultrasonic waves multiple times, thereby more efficiently calculating the horizontal propagation velocity Vb.

[0063] The propagation velocity calculation process according to this embodiment will be described with reference to the flowchart of Fig. 7. In the following, detailed description of the content common to Fig. 3 will be omitted and differences will be mainly described.

[0064] The control unit 21 acquires thickness information D relating to the thickness value of the object S (step S1000). The control unit 21, which functions as the transmission / reception interval adjustment unit 21b, sets multiple intervals L1 and L2 as the y-direction interval L between the transmission unit 11a and the reception unit 11b (step S1002). The control unit 21 transmits ultrasonic waves from the transmission unit 11a, receives the ultrasonic waves at the reception unit 11b, which is L1 away from the transmission unit 11a, and at the reception unit 11b (11b'), which is L2 away from the transmission unit 11a, and outputs multiple received signals (step S1003). The control unit 21, which functions as the propagation velocity vector calculation unit 21c, then calculates multiple propagation velocity vectors based on the multiple received signals (step S1004). The control unit 21, which functions as the propagation wavefront shape model determination unit 21d, determines a propagation wavefront shape model of the ultrasonic waves propagating within the object S from the multiple propagation velocity vectors (step S1006). The control unit 21, which is the propagation velocity calculation unit 21e, calculates the horizontal propagation velocity Vb from the propagation wavefront shape model (step S1007).

[0065] [Third Modification of the First Embodiment] (Use of Vertical Propagation Velocity) In the above embodiment, the propagation velocity vectors are all propagation velocity vectors of ultrasonic waves propagating obliquely through the target object S, but this is not limiting. That is, one of the propagation velocity vectors may be the vertical propagation velocity Va (input angle θ=0°).

[0066] Specifically, the control unit 21 transmits ultrasonic waves from the transmission unit 11a, receives the ultrasonic waves at the reception unit 11b, which is disposed at the same position as the transmission unit 11a and at a position L away from the transmission unit 11a, and measures the vertical propagation time ta and the diagonal propagation time tc. Then, by acquiring the thickness information D, the control unit 21 calculates the magnitude Vc of the propagation velocity vector and the input angle θ using the following equations (7) and (8) based on equations (1) and (2).

[0067]

[0068]

[0069] Furthermore, the thickness information D and the vertical propagation time ta are used to calculate the vertical propagation speed Va according to the following equation (9).

[0070] As described above, the propagation velocity vector, the vertical propagation velocity Va, and the horizontal propagation velocity Vb can be mapped onto one propagation wavefront shape model. Therefore, the following equation (10) holds.

[0071]

[0072] Among the variables included in formulas (7) to (9), the placement interval L, thickness information D, vertical propagation time ta, and diagonal propagation time tc are all values ​​obtained by actual measurement. Therefore, when formulas (7) to (9) are substituted into formula (10), the only unknown variable included in formula (10) is the horizontal propagation velocity Vb, and by solving this, the horizontal propagation velocity Vb can be calculated.

[0073] [Second Embodiment] [One-way horizontal propagation velocity calculation process; change in installation interval → obtain three vectors (unknown thickness)] Next, the propagation velocity calculation process according to the second embodiment will be described using the flowchart in Fig. 8. In the first embodiment, the thickness information D was an actually measured value, but in the second embodiment, the thickness information D is an unknown value. Note that, in the following, detailed description of the content common to Fig. 3 will be omitted and the differences will be mainly described.

[0074] The control unit 21 receives an operation input from the user via the operation input unit 24 and acquires the thickness information D of the object S by setting a tentative thickness value (step S200).

[0075] Steps S202 to S206 are substantially the same as steps S102 to S106 in Fig. 3, and therefore will not be described further. After calculating the multiple propagation velocity vectors and determining the propagation wavefront shape model, the control unit 21, which is the propagation velocity calculation unit 21e, calculates the horizontal propagation velocity Vb (step S207).

[0076] In this embodiment, the thickness information D is an unknown value. Therefore, even if formulas (1) and (2) and the values ​​of L and t are substituted into formula (5), and formulas (3) and (4) and the values ​​of L and t are substituted into formula (6), the unknown values ​​among the variables included in formulas (5) and (6) are three: Va, Vb, and D. Therefore, even if formulas (5) and (6) are solved simultaneously, the horizontal propagation velocity Vb cannot be calculated.

[0077] In this embodiment, the vertical propagation time ta until the receiving unit 11b, which is disposed at the same position as the transmitting unit 11a, receives the ultrasonic wave is further acquired, and the vertical propagation velocity Va is calculated using equation (9).

[0078] Then, by further substituting the formula (9) into the formulas (5) and (6), the unknown variables included in the formulas (5) and (6) are the horizontal propagation velocity Vb and the thickness information D. Therefore, similar to the case where the thickness information D is known, the horizontal propagation velocity Vb can be calculated by simultaneously solving the formulas (5) and (6).

[0079] In the above embodiment, the vertical propagation velocity Va is used as the new third propagation velocity vector, but this is not limiting. As with the first and second propagation velocity vectors, the new third propagation velocity vector may be a propagation velocity vector of an ultrasonic wave having a predetermined input angle.

[0080] [Effects of the Second Embodiment] As described above, according to the propagation velocity calculation process of the second embodiment, the propagation velocity of an elastic wave in a predetermined direction of the object S can be measured even if the thickness of the object S is unknown.

[0081] Third Embodiment One-Way Horizontal Propagation Velocity Calculation Process: Changing the Disposition Spacing → Obtaining Two Vectors (Changing the Temporary Thickness Value) Next, a propagation velocity calculation process according to a third embodiment will be described. In the first and second embodiments, multiple ultrasonic waves are received at different placement intervals to obtain the same number of propagation velocity vectors as the number of unknown variables. That is, when the thickness information D of the object S is known, two propagation velocity vectors are obtained, and when the thickness information D is unknown, one additional propagation velocity vector is obtained to derive the horizontal propagation velocity Vb. However, even when the thickness information D is unknown, the horizontal propagation velocity Vb can be calculated from only two propagation velocity vectors, assuming that the propagation wavefront shape model is elliptical.

[0082] Specifically, the control unit 21 measures the vertical propagation time ta and the diagonal propagation time tc. Then, the control unit 21 calculates a predetermined provisional thickness value D ｐ By setting D, the following equations (11) to (13) based on the equations (1), (2), and (9) are used. ｐ The magnitude of the propagation velocity vector Vc corresponding to ｐ , the input angle θ ｐ and vertical propagation velocity Va ｐ Calculate.

[0083]

[0084]

[0085]

[0086] Next, the control unit 21 sets the thickness information D ｐ A predetermined provisional thickness value D different from ｑ By setting D, the following equations (14) to (16) based on the equations (3), (4), and (9) are obtained. ｑ The magnitude of the propagation velocity vector Vc corresponding to ｑ , the input angle θ ｑ and vertical propagation velocity Va ｑ Calculate.

[0087]

[0088]

[0089]

[0090] As mentioned above, D ｐ The propagation velocity vector (Vc ｐ , θ ｐ ), vertical propagation velocity Va ｐ and the horizontal propagation velocity Vb can be mapped onto the first propagation wavefront shape model. ｑ The propagation velocity vector (Vc ｑ , θ ｑ ), vertical propagation velocity Va ｑ and the horizontal propagation velocity Vb can be mapped onto the second propagation wavefront shape model. Therefore, the following equations (17) and (18) are simultaneously established.

[0091]

[0092]

[0093] Here, the only unknown variable among the variables included in the formulas (17) and (18) is the horizontal propagation velocity Vb. Therefore, the horizontal propagation velocity Vb can be calculated by finding a value for Vb that simultaneously satisfies the formulas (17) and (18).

[0094] Effect of Third Embodiment As described above, according to the propagation velocity calculation process according to the third embodiment, even when the thickness of the object S is unknown, the horizontal propagation velocity can be measured more easily.

[0095] [Fourth Embodiment] [One-way horizontal propagation velocity calculation; thickness value change → two vector acquisition (thickness known)] Next, a propagation velocity calculation process according to a fourth embodiment will be described. In the first to third embodiments, a plurality of ultrasonic waves are received at different intervals. In contrast, in the fourth embodiment, the horizontal propagation velocity Vb is calculated by a configuration in which a plurality of ultrasonic waves are transmitted and received while the thickness value of the target object S is changed, while the interval L between the transmitter 11 a and the receiver 11 b is fixed.

[0096] Specifically, the control unit 21 sets thickness information of the object to a predetermined value D, transmits ultrasonic waves from the transmission unit 11a, and receives the ultrasonic waves with the reception unit 11b disposed at a position L away from the transmission unit 11a, thereby measuring the oblique propagation time t. Then, the control unit 21 calculates the magnitude Vc of the first propagation velocity vector and the input angle θ by the following equations (19) and (20) based on equations (1) and (2).

[0097]

[0098]

[0099] Next, the control unit 21 sets the thickness information to a predetermined value D different from D, and measures the oblique propagation time t by transmitting ultrasonic waves from the transmitter 11 a and receiving them with the receiver 11 b. The control unit 21 then calculates the magnitude Vc of the second propagation velocity vector and the input angle θ using the following equations (21) and (22) based on equations (3) and (4).

[0100]

[0101]

[0102] As described above, the first and second propagation velocity vectors can be mapped onto the same propagation wavefront shape model together with the vertical propagation velocity Va and the horizontal propagation velocity Vb. Therefore, the following equations (23) and (24) are simultaneously established.

[0103]

[0104]

[0105] Here, among the variables included in the equations (23) and (24), there are two unknown values: the vertical propagation velocity Va and the horizontal propagation velocity Vb. Therefore, by simultaneously solving the equations (23) and (24), the horizontal propagation velocity Vb and the vertical propagation velocity Va can be calculated.

[0106] As mentioned above, conditions under which the thickness information of the object S can be changed include when the object S is a deformable material such as a liquid, or when samples of different thicknesses can be prepared even if the object S is a solid material such as metal.

[0107] Effect of Fourth Embodiment As described above, according to the propagation velocity calculation process of the fourth embodiment, the horizontal propagation velocity of the object S can be measured without changing the distance between the transmitter and receiver of the ultrasonic wave.

[0108] [Other Modifications of the First to Fourth Embodiments] In Figures 2 and 4B, the sensor unit 10 is an array-type sensor configured by arranging a plurality of sensor elements 11 in a one-dimensional array, and the transmitter 11a and receiver 11b are selected from the plurality of sensor elements 11, but this is not limiting.

[0109] 9A , the sensor unit 10 may include a plurality of independent sensor elements 11, with a first sensor element 11 serving as a transmitter 11a and a second sensor element 11 serving as a receiver 11b. In this configuration, the control unit 21 sets the spacing and / or orientation of the transmitters 11a and receivers 11b by moving the sensor element 11 corresponding to either or both of the transmitters 11a and receivers 11b using the two-dimensional movement mechanism of the drive unit 12.

[0110] 9A shows a configuration in which ultrasonic waves are transmitted from the transmitting unit 11a disposed on the first surface S1 and ultrasonic waves reflected by the second surface S2 are received by the receiving unit 11b, but this is not limiting. That is, as shown in FIG. 9B, a configuration in which the receiving unit 11b is disposed on the second surface S2 and receives ultrasonic waves that have passed through the target S may also be used.

[0111] Fifth Embodiment Multidirectional Horizontal Propagation Velocity Calculation Process; Axial Direction Known (Thickness Unknown and Known) Next, a propagation velocity calculation process according to a fifth embodiment will be described. In the first to fourth embodiments, for a uniaxial acoustically anisotropic material in which two anisotropy axes are parallel to the first surface S1, the transmitter 11a and the receiver 11b are disposed in the uniaxial direction on the first surface S1 of the object S, and the horizontal propagation velocity Vb in that direction is calculated based on the acquired propagation velocity vector. In the fifth embodiment, similarly, the object S has uniaxial acoustic anisotropy, the two acoustic anisotropy axes are parallel to the first surface S1, and the axial direction is known. Then, as shown in FIGS. 10A and 10B , the horizontal propagation velocity Vb is calculated while changing the arrangement direction Φ of the transmitter 11a and the receiver 11b (sensor element 11) on the first surface S1 of the object S.

[0112] The propagation velocity calculation process according to the fifth embodiment will be described with reference to the flowchart of Fig. 11. In this embodiment, the thickness of the object S is assumed to be unknown. In the following, detailed description of the content common to Fig. 8 will be omitted, and differences will be mainly described.

[0113] The control unit 21 acquires a tentative thickness value as thickness information D of the object S (step S300). The control unit 21 controls the drive unit 12 to set the arrangement direction Φ of the sensor elements 11 (step S301). Specifically, as shown in FIG. 10A , the control unit 21 sets the arrangement direction Φ of the sensor elements 11 to an in-plane direction (z direction) in which the object S exhibits acoustic isotropy.

[0114] The subsequent steps S302 to S305 are substantially the same as steps S202 to S205 in Fig. 8, and therefore detailed description thereof will be omitted. That is, by receiving a plurality of ultrasonic waves at different arrangement intervals L1 and L2 in one direction, the control unit 21 calculates the magnitudes Vc1 and Vc2 of a plurality of propagation velocity vectors in a cross section including that direction using the formulas (1) and (3).

[0115] After calculating the multiple propagation velocity vectors (step S305; Yes), the control unit 21 calculates the true thickness value of the object S (step S306). In a plane where the object S exhibits acoustic isotropy, the wavefront shape of the ultrasonic waves propagating within the object S is a perfect circle, as shown in Fig. 12. Therefore, the magnitudes Vc1 and Vc2 of the multiple propagation velocity vectors calculated by arranging the sensor elements 11 in the in-plane direction are all equal.

[0116] Therefore, the thickness information D of the object S can be expressed by the following formula (25) based on formulas (1) and (3). The true thickness value D can be calculated by substituting the arrangement intervals L and L set in the isotropic in-plane direction of the object S and the oblique propagation times t and t, which are actual measured values, into formula (25).

[0117]

[0118] Then, the control unit 21 measures the vertical propagation time ta and substitutes it into the equation (9) together with the true thickness value D calculated in step S306, thereby calculating the vertical propagation speed Va (step S307).

[0119] Next, the control unit 21 changes the arrangement direction Φ of the sensor element 11 by 90° using the drive unit 12 (step S308). That is, as shown in Fig. 10B, the control unit 21 sets the arrangement direction Φ of the sensor element 11 to the in-plane direction (y direction) in which the object S exhibits acoustic anisotropy.

[0120] The subsequent steps S309 to S311 are substantially the same as steps S302 to S304, and therefore detailed description thereof will be omitted. That is, the control unit 21 sets the placement interval L and transmits and receives ultrasonic waves, thereby calculating the magnitude Vc and the input angle θ of one propagation velocity vector in a cross section including the direction in question using equations (7) and (8). The control unit 21 determines a propagation wavefront shape model expressed by equation (10) (step S312). The control unit 21 calculates the horizontal propagation velocity Vb by substituting the magnitude Vc and the input angle θ of the propagation velocity vector and the vertical propagation velocity Va calculated in step S307 into equation (10) (step S313).

[0121] Effect of Fifth Embodiment As described above, in the propagation velocity calculation process according to the fifth embodiment, the transmitter 11a and the receiver 11b are arranged in the acoustic isotropy plane direction of the object S having uniaxial acoustic anisotropy to calculate multiple propagation velocity vectors, and the true thickness value of the object S and the vertical propagation velocity Va perpendicular to the first surface S1 are calculated based on the propagation velocity vectors. Also, the transmitter 11a and the receiver 11b are arranged in the acoustic anisotropy plane direction of the object S to calculate a propagation velocity vector, and the horizontal propagation velocity Vb in the acoustic anisotropy plane is calculated based on the propagation velocity vector, the vertical propagation velocity Va, and a propagation wavefront shape model corresponding to the acoustic anisotropy of the object S. With this configuration, not only the horizontal propagation velocity Vb of a uniaxial anisotropic material but also the thickness information D and the vertical propagation velocity Va can be measured.

[0122] [Modification of the Fifth Embodiment] In the above, since the thickness of the object S is unknown, in steps S302 to S305, a plurality of ultrasonic waves are received at different intervals in the in-plane direction of the acoustic isotropy. In contrast, if the thickness information D of the object S is known, only the vertical propagation time ta in that direction can be obtained, and the vertical propagation velocity Va can be calculated from Equation (9). In other words, if the thickness of the object S is known, the sensor elements 11 can be arranged in the in-plane direction of the acoustic isotropy of the object S, and the receiving unit 11b, which is arranged in the same position as the transmitting unit 11a, can receive an ultrasonic wave once to measure the propagation time and calculate the vertical propagation velocity Va.

[0123] [Sixth Embodiment] [Multi-directional horizontal propagation velocity calculation process; axial direction unknown / thickness unknown] Next, a propagation velocity calculation process according to a sixth embodiment will be described. In the fifth embodiment, the object S is a material having uniaxial acoustic anisotropy, and the two axes of the acoustic anisotropy are parallel to the first surface S1 and the directions of the axes are known, i.e., the surface direction exhibiting acoustic isotropy is known. In contrast, in this embodiment, the direction of the acoustic anisotropy axes of the object S is unknown, i.e., the surface direction exhibiting acoustic isotropy is unknown.

[0124] The propagation velocity calculation process according to the sixth embodiment will be described with reference to the flowchart of Fig. 13. In this embodiment, the thickness information of the object S is assumed to be unknown. In the following, detailed description of the content common to Fig. 8 will be omitted, and differences will be mainly described.

[0125] The control unit 21 acquires a tentative thickness value as thickness information D of the object S (step S400). The control unit 21 controls the drive unit 12 to set the arrangement direction Φ of the sensor element 11 to a predetermined direction (step S401).

[0126] The subsequent steps S402 to S407 are substantially the same as steps S202 to S207 in Fig. 8, and therefore detailed description thereof will be omitted. That is, the control unit 21 receives a plurality of ultrasonic waves at different placement intervals in a predetermined direction Φ, thereby calculating a plurality of propagation velocity vectors in a cross section including the direction Φ. Then, based on the plurality of propagation velocity vectors, it calculates a horizontal propagation velocity Vh(Φ) in the placement direction Φ. Here, one of the plurality of propagation velocity vectors includes a provisional value Va' of the vertical propagation velocity (input angle θ = 0°) based on the provisional thickness value (step S404).

[0127] After step S407, the control unit 21 determines whether or not the horizontal propagation velocities Vh(Φ) in all directions within the desired measurement range have been calculated (step S408).

[0128] If the horizontal propagation velocity Vh(Φ) in all directions in the desired measurement range has not been calculated (step S408; No), the process proceeds to step S401, the installation direction Φ is changed, and the horizontal propagation velocity Vh(Φ) is calculated again.

[0129] When the horizontal propagation velocities Vh(Φ) in all directions within the desired measurement range have been calculated (step S408; Yes), the control unit 21 analyzes the relationship between the multiple horizontal propagation velocities Vh(Φ) and the installation position and installation direction Φ of the sensor element 11 corresponding to each horizontal propagation velocity Vh(Φ).

[0130] Specifically, the control unit 21, which is the analysis unit 21f, acquires statistical data of the horizontal propagation velocity Vh(Φ) corresponding to the installation direction Φ for each installation position of the sensor element 11 (step S409). The statistical data includes at least one of the maximum value, minimum value, average value, variance value, and principal component analysis result of the horizontal propagation velocity Vh(Φ).

[0131] After acquiring the statistical data of the horizontal propagation velocity Vh(Φ), the control unit 21 determines the vertical propagation velocity Va and the horizontal propagation velocity Vb based on the statistical data. When two of the acoustic anisotropy axes of the object S are parallel to the first surface S1, for example, the propagation wavefront shape model in the cross section of the object S is elliptical, and the horizontal propagation velocity Vh(Φ) relative to the installation direction Φ also changes in an elliptical shape. In this case, the vertical propagation velocity Va coincides with either the maximum or minimum value of the horizontal propagation velocity Vh(Φ), and the horizontal propagation velocity Vb coincides with either the maximum or minimum value of the horizontal propagation velocity Vh(Φ) that is different from the vertical propagation velocity Va. Therefore, the maximum or minimum value of the horizontal propagation velocity Vh(Φ) closest to the virtual value Va' of the vertical propagation velocity calculated in step S404 is determined as the vertical propagation velocity Va (true value) (step S410). Furthermore, the value that differs most from Va' is determined as the horizontal propagation velocity Vb (step S411).

[0132] After determining the vertical propagation velocity Va, the control unit 21 calculates the true thickness value based on the determined vertical propagation velocity Va and Equation (9) (step S412).

[0133] [Effects of the Sixth Embodiment] For example, when the object S is a composite material such as CFRP, the direction of the acoustic anisotropy axis may change depending on the blending state of the contained filler. In other words, by knowing the direction of the acoustic anisotropy axis, it is possible to know the blending state of the contained filler, and thereby estimate the strength characteristics of the object S. As described above, according to the configuration of the sixth embodiment, the dependency of the horizontal propagation velocity Vb on the arrangement direction can be obtained, and the strength characteristics of the object S can be evaluated based on this.

[0134] [Modification of Sixth Embodiment] In the above, since the thickness of the object S is unknown, the vertical propagation velocity Va and the horizontal propagation velocity Vb are determined based on statistical data and the tentative value Va' of the vertical propagation velocity. In contrast to this, the propagation velocity calculation process when the thickness information D of the object S is known will be described using the flowchart of Fig. 14. Note that, in the following, steps S501 to S503 and steps S505 to S509 are substantially similar to steps S401 to S403 and steps S405 to S409 in Fig. 13, and therefore detailed description thereof will be omitted and the description will focus on the differences.

[0135] The control unit 21 acquires a true thickness value as thickness information D of the object S (step S500). When the thickness information D is known, if the vertical propagation time ta is acquired, the vertical propagation speed Va can be directly calculated using Equation (9) (step S504). Accordingly, the horizontal propagation speed Vb can be calculated more simply by selecting statistical data that is different from the vertical propagation speed Va (step 510).

[0136] [Other Modifications of the Fifth and Sixth Embodiments] In the above, the case where two of the acoustic anisotropy axes of the object S are parallel to the first surface S1 has been described, but this is not limited to this. As shown in Figures 15A and 15B, when the acoustic anisotropy axes are not parallel to the first surface S1, it is not possible to quantitatively determine the horizontal propagation velocity Vb and the vertical propagation velocity Va. However, by calculating the horizontal propagation velocity Vh(Φ), which depends on the installation direction, it is possible to qualitatively grasp the approximate axial direction of the acoustic anisotropy of the object S, and thereby predict the strength characteristics.

[0137] 10A and 10B illustrate an example in which the sensor element 11 is an array-type sensor, but as shown in Fig. 16, the sensor element 11 may be composed of a plurality of independent sensor elements, similar to Fig. 9A. In this configuration, the control unit 21 sets the arrangement direction Φ of the transmitter 11a and the receiver 11b by moving one or both of the sensor elements using the two-dimensional movement mechanism of the drive unit 12.

[0138] In addition, in FIG. 16, the transmitting unit 11a and the receiving unit 11b are arranged on the first surface S1, but in the fifth and sixth embodiments, either one may be arranged on the second surface S2, as in FIG. 9B.

[0139] In addition, based on the analysis results of the analysis unit 21f, the control unit 21 may display on the display unit 23 a velocity map or the like that visualizes the position dependence and directional dependence of the horizontal propagation velocity in the object S, as shown in Figures 17A to 17C.

[0140] FIG. 17A is an example of a two-dimensional map of the horizontal propagation velocity in the z direction, and FIG. 17B is an example of a two-dimensional map of the horizontal propagation velocity in the y direction. FIG. 17C is an example of a two-dimensional map showing the directional dependency of the horizontal propagation velocity. In FIGS. 17A to 17C, areas where the horizontal propagation velocity of ultrasound is relatively fast are shown dark, while areas where the horizontal propagation velocity of ultrasound is relatively slow are shown light. These maps reveal that the horizontal propagation velocity is not constant with respect to position or direction, but is faster in some areas, indicating variations in elastic strength in the velocity measurement direction. In particular, FIG. 17C reveals that the horizontal propagation velocity is faster in the 135° direction, indicating an increase in elastic strength in that direction. Such information is known to be closely related to the orientation state of the contained filler in fiber-reinforced resins such as CFRTP, and provides useful information for considering filler formulations and shaping methods.

[0141] In addition, Figures 17A to 17C illustrate velocity maps that display the orientation in the object S in two dimensions, but in cases where the object S does not have an acoustic anisotropy axis on the first surface S1, a velocity map that is displayed in three dimensions may also be displayed.

[0142] [Other Configurations] While the present invention has been specifically described above based on the embodiments thereof, the present invention is not limited to the above-described embodiments. Of course, the present invention can be modified in various ways within the scope of the invention described in the claims and their equivalents.

[0143] For example, in Figures 2, 4B, 10A and 10B, an array-type sensor in which sensor elements 11 including transmitters 11a and receivers 11b are arranged in a one-dimensional array is shown as an example, but this is not limited to this.

[0144] For example, it may be a matrix-type sensor in which a plurality of sensor elements 11 are arranged in a two-dimensional array (matrix). In this configuration, ultrasonic waves can be transmitted and received by disposing the transmitter 11a and receiver 11b at any position and / or direction of the target S by electronically selecting the sensor elements, without physically moving the sensor elements by the drive unit 12.

[0145] In the above description, an example has been disclosed in which a ROM is used as a computer-readable medium for the program according to the present invention, but this is not limiting. Other computer-readable media include non-volatile memory such as a flash memory and portable recording media such as a CD-ROM. Furthermore, a carrier wave is also applicable to the present invention as a medium for providing the program data according to the present invention via a communication line.

[0146] INDUSTRIAL APPLICABILITY The present invention can be used in a wave propagation velocity measuring method, a wave propagation velocity measuring device, and a program that can more easily measure the propagation velocity of an elastic wave in a predetermined direction in an object having acoustic anisotropy.

[0147] 100 Wave propagation velocity measuring device 10 Sensor unit 11 Sensor element 11a Transmitter 11b Receiver 12 Driver 20 Processing device 21 Control unit 21a Propagation time measuring unit 21b Transmission / reception interval adjuster 21c Propagation velocity vector calculator 21d Propagation wavefront shape model determiner 21e Propagation velocity calculator 21f Analysis unit 22 Signal generator 23 Display unit 24 Operation input unit 25 Memory unit D Thickness information L Arrangement interval t Propagation time of ultrasonic wave Va Vertical propagation velocity Vb Horizontal propagation velocity Vc Propagation velocity vector (magnitude) θ Input angle of ultrasonic wave S Object S1 First surface S2 Second surface

Claims

1. A wave propagation velocity measuring method comprising: transmitting elastic waves to a first surface of an object having acoustic anisotropy using a transmitting unit disposed on the first surface; receiving a plurality of the elastic waves propagating at different angles within the object using a receiving unit disposed on the first surface of the object or a second surface opposite the first surface, thereby obtaining a plurality of pieces of reception information; calculating a plurality of propagation velocity vectors based on the plurality of reception information; determining a propagation wavefront shape model corresponding to the acoustic anisotropy of the object based on the plurality of propagation velocity vectors; and calculating a horizontal propagation velocity parallel to the first surface based on the propagation wavefront shape model.

2. A wave propagation velocity measuring method as described in claim 1, wherein each of the multiple reception information includes information on the propagation time of the elastic wave propagating within the object, and the multiple propagation velocity vectors are calculated based on the multiple reception information, information on multiple arrangement distances between the transmitter and the receiver in a direction parallel to the first surface, and thickness information of the object.

3. The wave propagation velocity measuring method according to claim 1, further comprising the step of calculating the propagation wavefront shape model based on the plurality of propagation velocity vectors.

4. The wave propagation velocity measuring method according to claim 1, further comprising the step of selecting the propagation wavefront shape model from a plurality of propagation wavefront shape model candidates based on the plurality of propagation velocity vectors.

5. A wave propagation velocity measuring method as described in claim 2, wherein the thickness information of the object is a provisional thickness value which is a provisional length in the thickness direction of the object, or a true thickness value which is the true length in the thickness direction of the object.

6. A wave propagation velocity measuring method as described in claim 5, further comprising the steps of: calculating a vertical propagation velocity perpendicular to the first surface in addition to the horizontal propagation velocity when the thickness information of the object is the true thickness value.

7. A method for measuring wave propagation velocity according to claim 2, wherein the plurality of pieces of reception information are obtained by adjusting the spacing between the transmitting unit and the receiving unit.

8. A method for measuring wave propagation velocity as described in claim 7, in which the spacing between the transmitting unit and the receiving unit is adjusted by selecting from a plurality of transmitting and / or receiving sensor elements arranged in advance at predetermined positions and / or shapes.

9. A wave propagation velocity measuring method as described in claim 1, further comprising the steps of: arranging the transmitting unit and the receiving unit in an acoustic isotropy plane direction in which an object having uniaxial acoustic anisotropy exhibits acoustic isotropy, calculating a first propagation velocity vector; calculating a vertical propagation velocity perpendicular to the first plane based on the first propagation velocity vector; arranging the transmitting unit and the receiving unit in an acoustic anisotropy plane direction in which the object exhibits acoustic anisotropy, calculating a second propagation velocity vector; and calculating a horizontal propagation velocity in the acoustic anisotropy plane based on the vertical propagation velocity, the second propagation velocity vector, and a propagation wavefront shape model corresponding to the acoustic anisotropy of the object.

10. A wave propagation velocity measuring method as described in claim 1, wherein the position and / or direction of the transmitting unit and the receiving unit are changed, and the horizontal propagation velocity is measured for each of the position and / or direction.

11. The method for measuring wave propagation velocity according to claim 10, further comprising analyzing a horizontal propagation velocity corresponding to the installation position and / or the installation direction.

12. A wave propagation velocity measuring method as described in claim 11, wherein statistical data including at least one of the maximum value, minimum value, average value, variance value, and principal component analysis result of the horizontal propagation velocity corresponding to the installation direction is obtained for each installation position.

13. The wave propagation velocity measuring method according to claim 12, further comprising deriving an arrangement direction in which the horizontal propagation velocity exhibits a maximum value and / or a minimum value for each of the arrangement positions.

14. The wave propagation velocity measuring method according to claim 10, wherein the installation position and / or installation direction is displayed in association with the magnitude of the horizontal propagation velocity.

15. A method for measuring wave propagation velocity according to any one of claims 1 to 14, wherein the transmitting section and / or the receiving section are configured by integrating a plurality of acoustic elements into a line or matrix.

16. A wave propagation velocity measuring method according to any one of claims 1 to 14, wherein the propagation wavefront shape model has an elliptical shape within the acoustic anisotropic plane of the object.

17. A wave propagation velocity measuring device comprising: a transmitting unit disposed on a first surface of an object having acoustic anisotropy and inputting elastic waves to the first surface; a receiving unit disposed on the first surface of the object or on a second surface opposite the first surface and receiving a plurality of the elastic waves propagating within the object at different angles and outputting a plurality of pieces of reception information; a propagation velocity vector calculation unit calculating a plurality of propagation velocity vectors based on the plurality of pieces of reception information; a propagation wavefront shape model determination unit determining a propagation wavefront shape model corresponding to the acoustic anisotropy of the object based on the plurality of propagation velocity vectors; and a propagation velocity calculation unit calculating a horizontal propagation velocity parallel to the first surface based on the propagation wavefront shape model.

18. A program that causes a computer of a wave propagation velocity measuring device comprising: a transmitting unit disposed on a first surface of an object having acoustic anisotropy and inputting elastic waves to the first surface; and a receiving unit disposed on the first surface of the object or on a second surface opposite the first surface and receiving a plurality of the elastic waves propagating within the object at different angles and outputting a plurality of pieces of reception information to function as: a propagation velocity vector calculation unit that calculates a plurality of propagation velocity vectors based on the plurality of pieces of reception information; a propagation wavefront shape model determination unit that determines a propagation wavefront shape model corresponding to the acoustic anisotropy of the object based on the plurality of propagation velocity vectors; and a propagation velocity calculation unit that calculates a horizontal propagation velocity parallel to the first surface based on the propagation wavefront shape model.

Images