Bond evaluation method and bond evaluation device

Abstract

To evaluate a joint part suitably even when shapes of the joint part vary.SOLUTION: A joint part evaluation method measuring and evaluating a joint state between a first body to be joined and a second body to be joined at a joint part includes: a step which acquires as reference value as capacitance value of the joint part in a reference measurement state that becomes a reference of a measurement condition; a step which acquires as measured value capacitance value of the joint part in a changed measurement state that changes the measurement state from the reference measurement state and causes a changed state; a step which derives as measurement evaluation value a value that has referred the measured value by the reference value; and a step which performs evaluation based on the derived measurement evaluation value.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present disclosure relates to a bond evaluation method and a bond evaluation device for evaluating a bond. [Background technology]

[0002] Conventionally, a bond evaluation method for evaluating a bond by inspecting weak bond adhesion by a non-destructive technique and evaluating the bonding state of the bond is known (see, for example, Patent Document 1). In this bond evaluation method, an AC signal is applied to the bond, and an evaluation value for a predetermined electrical characteristic is derived from the current value and voltage value obtained by measuring while changing the frequency of the AC signal. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2017-83300 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the joint evaluation method of Patent Document 1, the frequency of the applied AC signal is high, which means that error factors resulting from differences in the shape of the joint are large. For example, shape errors such as a difference in the thickness of the joint of several tens of μm or changes in the shape dimensions in the order of mm can adversely affect the signal-to-noise ratio (S / N), making it difficult to detect an appropriate evaluation value.

[0005] Therefore, an object of the present disclosure is to provide a bond evaluation method and a bond evaluation device that can appropriately evaluate a bond even when there is a difference in the shape of the bond. [Means for solving the problem]

[0006] The bond evaluation method disclosed herein is a bond evaluation method for measuring and evaluating the bonded state at the bond between a first bonded body and a second bonded body, and includes the steps of: acquiring, as a reference value, a capacitance value of the bond in a reference measurement state that serves as a reference for measurement conditions; changing the measurement state from the reference measurement state, and acquiring, as a measured value, a capacitance value of the bond in a post-change measurement state that is the result of the state change; deriving a value obtained by referencing the measured value with the reference value as a measurement evaluation value; and performing an evaluation based on the derived measurement evaluation value.

[0007] The bond evaluation device disclosed herein is a bond evaluation device that measures and evaluates the bonded state at the bond between a first bonded body and a second bonded body, and includes a pair of electrodes arranged to form a capacitor at the bond, and a control unit that measures a capacitance value of the bond and performs an evaluation of the bond based on the measured capacitance value, wherein the control unit executes the following steps: acquiring the capacitance value of the bond in a reference measurement state that serves as a reference for measurement conditions, as a reference value; changing the measurement state from the reference measurement state, and acquiring the capacitance value of the bond in a post-change measurement state after the state change, as a measured value; deriving a value obtained by referencing the measured value with the reference value as a measurement evaluation value; and performing an evaluation based on the derived measurement evaluation value. Effect of the Invention

[0008] According to the present disclosure, even when there is a difference in the shape of the joint, it is possible to appropriately evaluate the joint. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic diagram showing the structure of a bond evaluation device according to the first embodiment. [Diagram 2] FIG. 2 is a flowchart of an example of a bond evaluation method according to the first embodiment. [Diagram 3]FIG. 3 is a flowchart of an example of a bond evaluation method according to the first embodiment. [Figure 4] FIG. 4 is a graph relating to the health evaluation value and the measurement evaluation value. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, the embodiments of the present disclosure will be described in detail with reference to the drawings. Note that the present invention is not limited to these embodiments. In addition, the components in the following embodiments include those that are easily replaceable by those skilled in the art, or those that are substantially the same. Furthermore, the components described below can be appropriately combined, and when there are multiple embodiments, the respective embodiments can be combined.

[0011] [Embodiment 1] The bond evaluation method and bond evaluation device 1 according to the first embodiment are a method and device for measuring and evaluating the bonded state of a bonded portion 5. In the bond evaluation method, the bonded state of the bonded portion 5 immediately after bonding is evaluated, and the bonded state of the bonded portion 5 after aging is evaluated. FIG. 1 is a schematic diagram showing the bond evaluation device according to the first embodiment. FIG. 2 is a flowchart of an example of the bond evaluation method according to the first embodiment. FIG. 3 is a flowchart of an example of the bond evaluation method according to the first embodiment. FIG. 4 is a graph relating to soundness evaluation values ​​and measurement evaluation values. First, before describing the bond evaluation method and the bond evaluation device 1, the bonded portion 5 will be described.

[0012] (joint part) The joint 5 is a portion formed in the joined body 4 in which a first joined body 7 and a second joined body 8 are joined, and is a portion in the joining portion between the first joined body 7 and the second joined body 8. The joint 5 may be, for example, an adhesive portion bonded via an adhesive 9, or a fusion portion bonded by melting. In the first embodiment, the joint 5 is described as being applied to an adhesive portion, but may also be a fusion portion.

[0013] Each of the first and second objects 7 and 8 to be joined is a composite material, and is a laminate in which composite layers containing carbon fiber and resin are laminated. The stacking direction of the laminate is the direction in which the first and second objects 7 and 8 to be joined face to face. Note that the first and second objects 7 and 8 to be joined are made of composite materials using carbon fiber, but there is no particular limitation, and any reinforcing fiber may be used. In addition, in the first embodiment, the first and second objects 7 and 8 to be joined are made of composite materials, but they may be made of metal materials, or a combination of a composite material and a metal material.

[0014] In the first embodiment, when the joint 5 is an adhesive joint, there is a possibility that a weak bond adhesion occurs in which the adhesive strength is reduced due to contamination of the joint surface or the like. For this reason, the joint evaluation method using the joint evaluation device 1 evaluates whether the joint state of the joint 5 is a weak bond adhesion or not. Note that even when the joint 5 is a fused joint, the joint evaluation method using the joint evaluation device 1 makes it possible to evaluate a joint state in which the adhesive strength of the joint 5 is reduced.

[0015] (Joint evaluation device) As shown in FIG. 1, the bond evaluation device 1 includes a heating furnace 10, a pair of electrodes 11, an AC power supply unit 12, and a control unit 15.

[0016] The heating furnace 10 is capable of housing the bonded body 4 therein, and heats the inside of the furnace to a predetermined temperature, thereby heating the bonded body 4 to a predetermined temperature. The heating furnace 10 is connected to a control unit 15, which controls the temperature inside the furnace to be the predetermined temperature.

[0017] The pair of electrodes 11 are disposed to sandwich the joint portion 5 of the joint body 4 from both sides in the stacking direction (opposing direction), thereby forming a capacitor. Therefore, the joint portion 5 is disposed between the pair of electrodes 11 as a dielectric.

[0018] The AC power supply unit 12 applies an AC signal between the pair of electrodes 11. The AC signal is an AC current or an AC voltage. The AC power supply unit 12 is, for example, an LCR meter. The AC power supply unit 12 is capable of changing the frequency of the AC signal and applying it between the pair of electrodes 11. The AC power supply unit 12 is connected to the control unit 15, which controls the applied AC signal so that the frequency becomes a predetermined frequency. The AC power supply unit 12 may superimpose a DC signal on the AC signal and apply it between the pair of electrodes 11. By superimposing the DC signal, the AC power supply unit 12 can reduce adverse effects on the signal-to-noise ratio (S / N), and therefore can accurately measure the capacitance value of the capacitor formed by the pair of electrodes 11.

[0019] The control unit 15 includes an integrated circuit such as a CPU (Central Processing Unit). The control unit 15 executes a bond evaluation process for evaluating the bonded state of the bonded portion 5. In the bond evaluation process, the control unit 15 controls the heating furnace 10 and the AC power supply unit 12 to change the temperature inside the heating furnace 10 and to change the frequency of the AC signal.

[0020] (Joint evaluation method) Next, an example of a bond evaluation method executed in the bond evaluation device 1 will be described with reference to FIGS.

[0021] In the joint evaluation method, a soundness evaluation value, which is an evaluation value of a specimen having a sound joint 5, is obtained in advance, and then a measurement evaluation value, which is an evaluation value of the joint 5 of the joint 4 to be evaluated, is obtained, and the joint condition of the joint 5 is evaluated based on the soundness evaluation value and the measurement evaluation value. At this time, the shape of the sound joint 5 of the specimen and the shape of the joint 5 of the joint 4 to be measured are identical.

[0022] A process flow for acquiring a soundness evaluation value will be described with reference to FIG. 2. As shown in FIG. 2, in the joint evaluation method, first, the control unit 15 executes step S11 for acquiring a soundness reference value, which is a reference value of a sound joint 5. Here, the reference value is a capacitance value of the joint 5 in a reference measurement state that is a reference of the measurement conditions. The reference measurement state is a reference temperature that is a reference for the joint 5, and the reference temperature is the room temperature. The room temperature is 1° C. to 35° C., and the reference temperature is, for example, 30° C. In addition, the measurement frequency of the AC signal applied when measuring the capacitance value may be in a band of 100 Hz to 100 MHz, and in the first embodiment, the band is in a band of 100 Hz to 100 kHz, and the capacitance value is measured in a state where it is fixed at a predetermined frequency. That is, in step S11, the temperature inside the heating furnace 10 is the room temperature, and the control unit 15 applies an AC signal of a predetermined frequency to the pair of electrodes 11 using this temperature as the reference temperature to acquire the capacitance value of the joint 5 as the reference value.

[0023] Next, in the joint evaluation method, the control unit 15 executes step S12 to acquire a sound measurement value, which is a measurement value of a sound joint 5. Here, the measurement value is a capacitance value of the joint 5 in a post-change measurement state after the state change, which is obtained by changing the measurement state from the reference measurement state. The post-change measurement state is a post-change temperature of the joint 5, and the post-change temperature is a temperature higher than the reference temperature. The post-change temperature is, for example, 80°C or higher. In step S12, the sound measurement value is acquired at a predetermined temperature interval. Also, the measurement frequency of the AC signal applied when measuring the capacitance value is the same as that in step S11. That is, in step S12, the temperature inside the heating furnace 10 is the post-change temperature, and the control unit 15 applies an AC signal having a predetermined frequency to the pair of electrodes 11 to acquire the capacitance value of the joint 5 as a measurement value.

[0024] Next, in the joint evaluation method, the control unit 15 executes step S13 in which the control unit 15 derives a value obtained by referencing the sound measurement value with the sound reference value as a sound evaluation value. The term "referencing" refers to making the sound measurement value dimensionless with the sound reference value. Here, the capacitance value C is given as the product of the dielectric constant ε and the shape factor f(r), "C=ε×f(r)". For example, when the pair of electrodes 11 are a parallel plate capacitor, the shape factor f(r) is given as the formula "f(r)=S / d" in which the parallel plate area S is divided by the distance d between the parallel plates. The sound reference value is C0, the dielectric constant in the sound reference value is ε0, the sound measurement value (sound capacitance value) is C, and the dielectric constant in the sound measurement value is ε. The sound evaluation value, which is the value obtained by referencing (C / C0) the sound measurement value C with the sound reference value C0, is "C / C0=ε / ε0" because the shape factor f(r) is canceled. That is, in step S13, "ε / ε0 (dielectric constant ratio)" is derived as the soundness evaluation value.

[0025] Fig. 4 is a graph of the dielectric constant ratio that changes with temperature, with the horizontal axis being the temperature and the vertical axis being the dielectric constant ratio. The black triangle marks shown in Fig. 4 are soundness evaluation values ​​that change with temperature. The soundness evaluation values ​​are acquired by the control unit 15 as the dielectric constant ratio gradually increases from 1 to about 1.4 when the temperature changes from 30°C to 150°C by executing the process flow for acquiring the soundness evaluation value shown in Fig. 2.

[0026] Next, with reference to Fig. 3, a process flow for acquiring a measurement evaluation value and evaluating the bonding state of the bonded joint 5 to be measured will be described. As shown in Fig. 3, in the bond evaluation method, first, the control unit 15 executes step S21 for acquiring a reference value of the bonded joint 5 to be measured. The reference measurement state in step S21 is the same as in step S11. That is, in step S21, the temperature inside the heating furnace 10 is the room temperature, and with this temperature as the reference temperature, the control unit 15 applies an AC signal of a predetermined frequency to the pair of electrodes 11 to acquire the capacitance value of the bonded joint 5 as the reference value.

[0027] Next, in the bond evaluation method, the control unit 15 executes step S22 to acquire a measurement value of the bond 5 to be measured. The post-change measurement state in step S22 is the same as in step S12. That is, in step S22, the temperature inside the heating furnace 10 is the post-change temperature, and the control unit 15 applies an AC signal with a predetermined frequency to the pair of electrodes 11 to acquire the capacitance value of the bond 5 as a measurement value.

[0028] Next, in the bond evaluation method, the control unit 15 executes step S23 in which it derives a value obtained by referencing the measurement value with a reference value as a measurement evaluation value. That is, in step S23, "ε / ε0 (dielectric constant ratio)" is derived as the measurement evaluation value. The black circle marks in FIG. 4 are measurement evaluation values ​​that change according to temperature. The measurement evaluation value shown in FIG. 4 is a value when the bonding state of the bonded portion 5 is poor (Weak Bond adhesion). The measurement evaluation value is acquired by the control unit 15 as a value at which the dielectric constant ratio increases from 1 to about 2.3 when the temperature changes from 30° to 150° by executing the process flow for acquiring the measurement evaluation value shown in FIG. 3.

[0029] Thereafter, in the bond evaluation method, the control unit 15 executes step S24 of acquiring the difference between the acquired soundness evaluation value and the measured evaluation value. The control unit 15 executes step S25 of judging whether the acquired difference is within a sound range or not. The larger the difference is, the more impaired the soundness is. If the control unit 15 judges in step S25 that the difference is within the sound range (step S25: Yes), it evaluates the bond 5 to be sound (step S26) and ends the process flow of evaluating the bonded state of the bond 5. On the other hand, if the control unit 15 judges in step S25 that the difference is not within the sound range (step S25: No), it evaluates the bond 5 to be defective (Weak Bond adhesion) (step S27) and ends the process flow of evaluating the bonded state of the bond 5.

[0030] In the bond evaluation method of the first embodiment, the evaluation of the bonded state of the bonded portion 5 is performed based on the difference between the soundness evaluation value and the measurement evaluation value as in the process flow shown in Fig. 3, but the present invention is not limited to this configuration. The bond evaluation method may also evaluate the bonded portion 5 using only the measurement evaluation value.

[0031] Furthermore, the evaluation of the joint 5 using the measurement evaluation value may be performed by taking into consideration the slope of the measurement evaluation value. For example, the slope of the soundness evaluation value and the slope of the measurement evaluation value may be compared to evaluate the soundness of the joint state of the joint 5, or the soundness of the joint state of the joint 5 may be evaluated from the slope of only the measurement evaluation value.

[0032] In the first embodiment, a pair of electrodes 11 is provided on both sides of the joint 5, but the present invention is not particularly limited to this configuration. A laminate in which composite layers containing carbon fiber and resin are laminated may be applied as the first joined body 7 and the second joined body 8, and a predetermined composite layer of the first joined body 7 may be used as one side of the pair of electrodes 11, and a predetermined composite layer of the second joined body 8 may be used as the other side of the pair of electrodes 11.

[0033] [Embodiment 2] Next, a description will be given of embodiment 2. In embodiment 2, in order to avoid repetitive description, only the parts different from embodiment 1 will be described, and parts having the same configuration as embodiment 1 will be described with the same reference numerals.

[0034] In the bond evaluation method of the first embodiment, a reference temperature is used as a reference measurement state, and a post-change temperature is used as a post-change measurement state. In the bond evaluation method of the second embodiment, a reference measurement frequency is used as a reference measurement state instead of the reference temperature of the first embodiment, and a post-change frequency is used as a post-change measurement state instead of the post-change temperature of the first embodiment. In the second embodiment, the temperature inside the heating furnace 10 is fixed to a predetermined temperature.

[0035] Specifically, in the joint evaluation method of the second embodiment, when acquiring the soundness reference value and the reference value in steps S11 and S21, the frequency of the AC signal applied between the pair of electrodes 11 by the AC power supply unit 12 is set as the reference measurement frequency. Then, the control unit 15 applies the AC signal having the reference measurement frequency to the pair of electrodes 11, and acquires the capacitance value of the joint 5 as the soundness reference value and the reference value, respectively.

[0036] In the joint evaluation method, when acquiring the healthy measurement value and the measurement value in steps S12 and S22, the frequency of the AC signal applied between the pair of electrodes 11 by the AC power supply unit 12 is a post-change frequency that is higher than the reference measurement frequency. Then, the control unit 15 applies the AC signal having the post-change frequency to the pair of electrodes 11 to acquire the capacitance values ​​of the joint 5 as the healthy measurement value and the measurement value, respectively. Here, the reference measurement frequency is a frequency of 1 kHz or more and 100 kHz or less, and the post-change frequency is a frequency of 10 MHz or more and 100 MHz or less.

[0037] In the joint evaluation method, in steps S13 and S23, the soundness measurement value and the measured value are referenced to the soundness reference value and the reference value, respectively, to derive the soundness evaluation value and the measured evaluation value, respectively.

[0038] [Embodiment 3] Next, a description will be given of embodiment 3. In embodiment 3, in order to avoid repetitive description, only the parts different from embodiments 1 and 2 will be described, and the parts having the same configuration as embodiments 1 and 2 will be denoted by the same reference numerals.

[0039] In the bond evaluation method of the first embodiment, the reference temperature is used as the reference measurement state, and the post-change temperature is used as the post-change measurement state. In the bond evaluation method of the third embodiment, the reference temperature and the reference measurement frequency are used as the reference measurement state, and the post-change temperature and the post-change frequency are used as the post-change measurement state. In the third embodiment, the bond 5 is evaluated using a measurement evaluation value based on the reference temperature and a measurement evaluation value based on the reference measurement frequency.

[0040] That is, in the bond evaluation method of the third embodiment, in step S21, a reference value based on a reference temperature and a reference value based on a reference measurement frequency are obtained. Next, in step S22, the bond evaluation method obtains a measurement value based on the reference temperature and a measurement value based on the reference measurement frequency. Then, in step S23, the bond evaluation method obtains a measurement evaluation value based on the reference temperature from the reference value and the measurement value based on the reference temperature, and obtains a measurement evaluation value based on the reference measurement frequency from the reference value and the measurement value based on the reference measurement frequency.

[0041] Thereafter, in the joint evaluation method of the third embodiment, the correlation between the measurement evaluation value based on the reference temperature and the measurement evaluation value based on the reference measurement frequency is obtained, and an evaluation based on the correlation is performed. For example, the evaluation based on the correlation is performed by previously obtaining the correlation of a specimen having a sound joint 5, and comparing the correlation of the sound joint 5 with the correlation of the joint 5 to be measured, thereby making it possible to evaluate the joint condition of the joint 5 to be measured.

[0042] In addition, in embodiment 3, when evaluating the joint 5, similarly to embodiments 1 and 2, a soundness evaluation value based on a reference temperature and a soundness evaluation value based on a reference measurement frequency may be obtained, the difference between the two may be taken, and the bonding condition of the joint 5 may be evaluated based on the difference.

[0043] As described above, the bond evaluation method and the bond evaluation device 1 according to the embodiment can be understood, for example, as follows.

[0044] The bond evaluation method according to the first aspect is a bond evaluation method for measuring and evaluating the bonded state at the bond 5 between a first bonded body 7 and a second bonded body 8, and includes step S21 of acquiring, as a reference value, a capacitance value of the bond 5 in a reference measurement state that is the basis for the measurement conditions, step S22 of changing the measurement state from the reference measurement state and acquiring, as a measured value, a capacitance value of the bond in a post-change measurement state that is the state change state, step S23 of deriving a value obtained by referencing the measured value with the reference value as a measurement evaluation value, and steps S24 to S27 of performing an evaluation based on the derived measurement evaluation value.

[0045] According to this configuration, by referencing the measurement value with the reference value, it is possible to obtain a measurement evaluation value that cancels the influence due to the shape of the joint 5. Therefore, even if there is a difference in the shape of the joint 5, the joint 5 can be suitably evaluated by using the measurement evaluation value.

[0046] In a second embodiment, the joint 5 is a bonding portion in which the first object to be joined 7 and the second object to be joined 8 are bonded together via an adhesive.

[0047] According to this configuration, the adhesive joint can be appropriately evaluated using the measurement evaluation value.

[0048] In a third embodiment, the joint portion 5 is a fused portion in which the first object to be joined 7 and the second object to be joined 8 are fused together.

[0049] According to this configuration, the fused portion can be appropriately evaluated using the measurement evaluation value.

[0050] As a fourth aspect, the reference measurement state includes a reference temperature that serves as a reference for the junction 5, and in step S22 of acquiring the measurement value, the temperature of the junction 5 is changed from the reference temperature, and the capacitance value of the junction 5 at a post-change temperature, which is the post-change measurement state after the temperature change, is acquired as the measurement value.

[0051] According to this configuration, a measurement evaluation value that changes depending on the temperature is obtained, and by using this measurement evaluation value, it is possible to evaluate the bonding state of the bonding portion 5 taking into account the temperature dependency.

[0052] In a fifth embodiment, the reference temperature is a room temperature.

[0053] According to this configuration, by setting the reference temperature to the room temperature, the work relating to measuring the capacitance value can be made easier.

[0054] In a sixth embodiment, the changed temperature is higher than the reference temperature.

[0055] According to this configuration, it is possible to suitably acquire the change in the measurement evaluation value accompanying the temperature change.

[0056] In a seventh aspect, the capacitance value of the junction is obtained by applying an AC signal having a predetermined measurement frequency, and the measurement frequency is in a band of 100 Hz or more and 100 MHz or less.

[0057] According to this configuration, when changing the temperature of the joint, for example, by setting the measurement frequency to a band of 100 Hz or more and 100 kHz or less, the device configuration configured according to the measurement frequency band can be simplified, thereby enabling reduction in device costs.

[0058] As an eighth aspect, the reference measurement state includes a reference measurement frequency that is the reference for the AC signal applied when acquiring the capacitance value of the junction 5, and in step S22 of acquiring the measurement value, the frequency is changed from the reference measurement frequency, and the capacitance value of the junction 5 at a post-change frequency, which is the post-change measurement state after the frequency change, is acquired as the measurement value.

[0059] According to this configuration, a measurement evaluation value that changes depending on the frequency is obtained, and by using this measurement evaluation value, it is possible to evaluate the bonding state of the bonding portion 5 taking frequency dependency into consideration.

[0060] As a ninth aspect, the reference measurement frequency is not less than 1 kHz and not more than 100 kHz, and the changed frequency is not less than 10 MHz and not more than 100 MHz.

[0061] According to this configuration, it is possible to suitably obtain the change in the measurement evaluation value accompanying the change in frequency.

[0062] As a tenth aspect, in step S22 of acquiring the measurement value, if the measurement evaluation value based on the reference temperature and the measurement evaluation value based on the reference measurement frequency are acquired, in the step of performing evaluation, a correlation between the measurement evaluation value based on the reference temperature and the measurement evaluation value based on the reference measurement frequency is acquired, and an evaluation based on the correlation is performed.

[0063] According to this configuration, the bonding condition of the bonding portion 5 can be evaluated from the correlation between the measurement evaluation value based on the reference temperature and the measurement evaluation value based on the reference measurement frequency.

[0064] As an eleventh aspect, the method further includes step S11 of acquiring a soundness reference value, which is the reference value for the sound joint 5, step S12 of acquiring a soundness measurement value, which is the measurement value of the sound joint 5, and step S13 of deriving a value obtained by referencing the soundness measurement value with the soundness reference value as a soundness evaluation value, and in steps S24 to S27 of performing evaluation, an evaluation is performed based on the difference between the soundness evaluation value and the measurement evaluation value.

[0065] According to this configuration, the soundness of the joint 5 can be evaluated from the difference between the soundness evaluation value and the measurement evaluation value, so that the joint 5 can be evaluated with high accuracy.

[0066] As a twelfth aspect, in steps S24 to S27 for performing the evaluation, when the difference between the soundness evaluation value and the measurement evaluation value is within a predefined range for soundness, the joint 5 is evaluated as sound.

[0067] According to this configuration, the soundness of the joint 5 can be easily evaluated.

[0068] The bond evaluation device 1 of the thirteenth aspect is a bond evaluation device 1 that measures and evaluates the bonded state at the bond 5 between a first bonded body 7 and a second bonded body 8, and includes a pair of electrodes 11 arranged to form a capacitor at the bond 5, and a control unit 15 that measures a capacitance value of the bond 5 and performs an evaluation of the bond 5 based on the measured capacitance value. The control unit 15 executes the following steps: step S21: acquiring, as a reference value, the capacitance value of the bond 5 in a reference measurement state that is the basis for the measurement conditions; step S22: changing the measurement state from the reference measurement state, and acquiring, as a measured value, the capacitance value of the bond 5 in a post-change measurement state after the state change; step S23: deriving a value obtained by referencing the measured value with the reference value as a measurement evaluation value; and steps S24 to S27: performing an evaluation based on the derived measurement evaluation value.

[0069] According to this configuration, by referencing the measurement value with the reference value, it is possible to obtain a measurement evaluation value that cancels the influence due to the shape of the joint 5. Therefore, even if there is a difference in the shape of the joint 5, the joint 5 can be suitably evaluated by using the measurement evaluation value.

[0070] In a fourteenth aspect, the first joined body 7 and the second joined body 8 are laminates of composite layers containing carbon fiber and resin, and the pair of electrodes 11 are composed of a predetermined composite layer of the first joined body 7 that is on one side of the joint 5 and a predetermined composite layer of the second joined body 8 that is on the other side of the joint 5.

[0071] According to this configuration, a predetermined composite layer of the joint 5 can be used as a pair of electrodes 11, so that the device configuration can be simplified.

[0072] As a fifteenth aspect, the device further includes an AC power supply unit 12 that applies an AC signal to the pair of electrodes 11, and the AC power supply unit 12 superimposes a DC signal on the AC signal to obtain a capacitance value of the joint 5.

[0073] According to this configuration, by superimposing a DC signal, adverse effects on the signal-to-noise ratio (S / N) can be reduced, so that the capacitance value can be measured with high accuracy. [Explanation of symbols]

[0074] 1. Joint evaluation device 4 zygote 5 Joint 7 First conjugate 8 Second transconjugant 9. Adhesive 10 Furnace 11 Pair of electrodes 12 AC power supply section 15 Control section

Claims

1. A bond evaluation method for measuring and evaluating a bonded state at a bonded portion between a first bonded body and a second bonded body, comprising the steps of: acquiring a capacitance value of the junction in a reference measurement state that is a reference for a measurement condition as a reference value; changing a measurement state from the reference measurement state, and acquiring, as a measurement value, a capacitance value of the junction in a post-change measurement state after the state change; a step of deriving a value obtained by referencing the measurement value with the reference value as a measurement evaluation value; and performing an evaluation based on the derived measurement evaluation value; the reference measurement condition includes a reference temperature at the junction; A junction evaluation method in which, in the step of acquiring the measurement value, the temperature of the junction is changed from a reference temperature, and the capacitance value of the junction at a post-change temperature, which is the post-change measurement state after the temperature change, is acquired as the measurement value.

2. 2. The bond evaluation method according to claim 1, wherein the bond is a bonded portion in which the first bonded body and the second bonded body are bonded together via an adhesive.

3. 2. The bond evaluation method according to claim 1, wherein the bond is a fusion bond between the first bonded body and the second bonded body.

4. The bonded portion evaluation method according to claim 1 , wherein the reference temperature is an indoor temperature.

5. The bond evaluation method according to claim 1 , wherein the changed temperature is higher than the reference temperature.

6. The capacitance value of the junction is obtained by applying an AC signal having a predetermined measurement frequency, The joint evaluation method according to claim 1 , wherein the measurement frequency is in a band of 100 Hz to 100 MHz.

7. the reference measurement condition includes a reference measurement frequency that is a reference for an AC signal to be applied when acquiring a capacitance value of the junction; A joint evaluation method according to any one of claims 1 to 6, wherein in the step of acquiring the measurement value, the frequency is changed from the reference measurement frequency, and the capacitance value of the joint at a post-change frequency, which is the post-change measurement state after the frequency change, is acquired as the measurement value.

8. The reference measurement frequency is 1 kHz or more and 100 kHz or less, The bonded portion evaluation method according to claim 7 , wherein the changed frequency is equal to or higher than 10 MHz and equal to or lower than 100 MHz.

9. In the step of acquiring the measurement values, when the measurement evaluation value is based on a reference temperature serving as a reference for the junction and the measurement evaluation value is based on the reference measurement frequency, The joint evaluation method according to claim 7 or 8, wherein in the step of performing the evaluation, a correlation between the measurement evaluation value based on the reference temperature and the measurement evaluation value based on the reference measurement frequency is obtained, and an evaluation is performed based on the correlation.

10. acquiring a soundness reference value which is the reference value of the sound joint; obtaining a soundness measurement value which is the measurement value of the sound joint; and deriving a value obtained by referencing the health measurement value with the health reference value as a health evaluation value, The bonded portion evaluation method according to claim 1 , wherein in the step of performing evaluation, evaluation is performed based on a difference between the soundness evaluation value and the measurement evaluation value.

11. The joint evaluation method according to claim 10 , wherein in the step of performing the evaluation, the joint is evaluated as being sound if a difference between the soundness evaluation value and the measurement evaluation value is within a predefined range for soundness.

12. A bond evaluation method for measuring and evaluating a bonded state at a bond between a first bonded body and a second bonded body, comprising: acquiring a capacitance value of the junction in a reference measurement state that is a reference for a measurement condition as a reference value; changing a measurement state from the reference measurement state, and acquiring, as a measurement value, a capacitance value of the junction in a post-change measurement state after the state change; A step of deriving a value obtained by referencing the measurement value with the reference value as a measurement evaluation value; and performing an evaluation based on the derived measurement evaluation value; the reference measurement condition includes a reference measurement frequency that is a reference for an AC signal to be applied when acquiring a capacitance value of the junction; A joint evaluation method in which, in the step of acquiring the measurement value, the frequency is changed from the reference measurement frequency, and the capacitance value of the joint at a post-change frequency, which is the post-change measurement state after the frequency change, is acquired as the measurement value.

13. A bond evaluation device that measures and evaluates a bonded state at a bonded portion between a first bonded body and a second bonded body, comprising: a pair of electrodes arranged to form a capacitor at the junction; a control unit that measures a capacitance value of the joint and performs an evaluation of the joint based on the measured capacitance value; The control unit is acquiring a capacitance value of the junction in a reference measurement state that is a reference for a measurement condition as a reference value; changing a measurement state from the reference measurement state, and acquiring, as a measurement value, a capacitance value of the junction in a post-change measurement state after the state change; A step of deriving a value obtained by referencing the measurement value with the reference value as a measurement evaluation value; performing an evaluation based on the derived measurement evaluation value; the reference measurement condition includes a reference temperature at the junction; In the step of acquiring the measured value, the joint evaluation device changes the temperature of the joint from a reference temperature, and acquires, as the measured value, the capacitance value of the joint at a post-change temperature, which is the post-change measurement state after the temperature change.

14. A bond evaluation device for measuring and evaluating a bond condition at a bond between a first bonded body and a second bonded body, comprising: a pair of electrodes arranged to form a capacitor at the junction; a control unit that measures a capacitance value of the joint and performs an evaluation of the joint based on the measured capacitance value; The control unit is acquiring a capacitance value of the junction in a reference measurement state that is a reference for a measurement condition as a reference value; changing a measurement state from the reference measurement state, and acquiring, as a measurement value, a capacitance value of the junction in a post-change measurement state after the state change; A step of deriving a value obtained by referencing the measurement value with the reference value as a measurement evaluation value; performing an evaluation based on the derived measurement evaluation value; the reference measurement condition includes a reference measurement frequency that is a reference for an AC signal to be applied when acquiring a capacitance value of the junction; In the step of acquiring the measurement value, the joint evaluation device changes the frequency from the reference measurement frequency, and acquires, as the measurement value, the capacitance value of the joint at a post-change frequency, which is the post-change measurement state after the frequency change.

15. the first and second objects to be joined are laminates of composite layers containing carbon fibers and resin, 15. The bond evaluation device according to claim 13 or 14, wherein the pair of electrodes comprises a predetermined composite layer of the first bonded body which is one side of the bonded body, and a predetermined composite layer of the second bonded body which is the other side of the bonded body.

16. Further comprising an AC power supply unit that applies an AC signal to the pair of electrodes, 16. The bond evaluation device according to claim 13, wherein the AC power supply unit superimposes a DC signal on the AC signal to obtain a capacitance value of the bond.

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