Systems and methods for assessing bonds

Abstract

A system for evaluating a bond includes a first electrode and a second electrode. A dielectric material layer is at least partially disposed between the first electrode and the second electrode. A power source is connected to the first electrode and the second electrode. The power source is configured to generate an electric arc between the first electrode and the second electrode. The electric arc is configured to at least partially melt the sacrificial material layer and generate a plasma.

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to U.S. patent application Ser. No. 16 / 670,857, filed Oct. 31, 2019, the entire contents of which are incorporated herein by reference.

[0002] The present disclosure is directed to a system and method for evaluating a bond between two components. In particular, the present disclosure is directed to a system and method for evaluating an adhesive bond between two components using a plasma actuator. [Background technology]

[0003]

[0003] Laser bond inspection (LBI) is a process used to evaluate adhesive bonds in bonded structures. LBI uses a laser pulse to generate a plasma that creates stress waves in the bonded structure. In one embodiment, the bonded structure includes carbon fiber reinforced polymer (CFRP) and CFRP, or CFRP and metal. The stress waves mechanically generate a tensile load on the adhesive bond. During exposure to this load, weak bonds break and strong bonds do not break. Thus, bonded structures with weak bonds can be identified and repaired or discarded. However, current LBI systems are large and expensive. Thus, there is a need for improved systems and methods for evaluating bonds. Summary of the Invention

[0004]

[0004] A system for evaluating a bond is disclosed. The system includes a first electrode and a second electrode. A dielectric material layer is at least partially disposed between the first electrode and the second electrode. A power source is connected to the first electrode and a second electrode. The power source is configured to generate an electric arc between the first electrode and the second electrode. The electric arc is configured to at least partially melt the sacrificial material layer to generate a plasma.

[0005]

[0005] In another embodiment, a system includes a support. The system also includes a first electrode in contact with the support. The system also includes a second electrode spaced apart from the support and the first electrode. The system also includes a dielectric material layer in contact with the support. The dielectric material layer is at least partially disposed between the support and the second electrode and at least partially disposed between the first electrode and the second electrode, whereby the second electrode is not in contact with the support or the first electrode. The system also includes a power source connected to the first electrode and the second electrode. The power source is configured to transmit an alternating current pulse to the first electrode and the second electrode. The alternating current pulse creates an electric arc between the first electrode and the second electrode. The electric arc at least partially melts a sacrificial material layer on the joined structures to create a plasma. The creation of the plasma creates a compression wave that is directed into the joined structures. The compression wave is reflected as a tension wave from the joints in the joined structures.

[0006]

[0006] A method for evaluating a bond is also disclosed. The method includes disposing a sacrificial material layer on a surface of a bonded structure. The method also includes transmitting an electrical pulse to a first electrode and a second electrode. The electrical pulse creates an electrical arc between the first electrode and a second electrode. The electrical arc at least partially melts the sacrificial material layer to create a plasma. The creation of the plasma creates a compression wave that is directed into the bonded structure. The compression wave is reflected as a tension wave from the bond within the bonded structure.

[0007]

[0007] It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present disclosure, as claimed.

[0008]

[0008] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate aspects of the present teachings and, together with the description, serve to explain the principles of the present teachings. [Brief description of the drawings]

[0009] [Figure 1]

[0009] A schematic diagram of a system for evaluating bonds in bonded structures according to one embodiment is shown. [Diagram 2]

[0010] 1 illustrates a flowchart of a method for evaluating bonds in bonded structures, according to one embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010]

[0011] It should be noted that some details of the drawings have been illustrated in a simplified manner to facilitate understanding, rather than to maintain strict structural accuracy, detail, and scale.

[0011]

[0012] Reference will now be made in detail to the present teachings, examples of which are illustrated in the accompanying drawings, in which like reference numerals are used throughout to refer to identical elements. In the following description, reference is made to the accompanying drawings, which form a part hereof, and in which is shown by way of illustration specific embodiments in which the present teachings may be practiced. Accordingly, the following description is by way of example only.

[0012]

[0013] The present disclosure is directed to a plasma actuator that represents a smaller, less expensive alternative to LBI systems. The plasma actuator includes a support, one or more electrodes, and a dielectric material layer. The plasma actuator is configured to generate an electric arc that at least partially melts a sacrificial material layer to generate a plasma. As described in more detail below, the plasma generates waves that travel into the bonded structures to assess the quality of the bond.

[0013]

[0014] FIG. 1 shows a schematic diagram of a system 100 for evaluating bonds in a bonded structure 110, according to one embodiment. The system 100 includes a plasma actuator that provides an alternative to LBI systems. Thus, the system 100 evaluates bonds in a bonded structure 110 (e.g., aids in determining the quality of the bonds) without the use of a laser. The evaluation of the bonds may be performed according to ASTM STP1455-Mechanism of Adhesion in Secondary Bonds of Fiberglass Composites and Peel Ply Surface Treatments. In particular, the system 100 applies a predetermined force to the bond. The predetermined force is about 30% to about 70% (e.g., about 50%) of the force required to break an ideal bond (or 30% to 70% (e.g., 50%) of the force required to break an ideal bond). The bond is then inspected. If the bond is not fractured or broken, the bond is passed / satisfactory. If the bond is fractured or broken, the bond is rejected / unsatisfactory.

[0014]

[0015] The bonded structure 110 includes a first component 112 and a second component 114 bonded together by a bonding material 116 (e.g., a bond). As will be appreciated, there may be more components bonded together, but for clarity, only two components are shown. In some embodiments, the first component 112 and the second component 114 are made at least in part from CFRP. In other embodiments, the first component 112 is made at least in part from CFRP and the second component 114 is made at least in part from a metal. The bonding material 116 can be a resin, adhesive, or epoxy (e.g., boron epoxy or carbon epoxy).

[0015]

[0016] The system 100 includes a support 120. The support 120 may also be referred to as a support surface or substrate. The support 120 may be or include a polyimide material, a polyamide material, or both. In some embodiments, the support 120 is at least partially made from a polyamide tape, such as KAPTON® tape. The support 120 provides high heat resistance and high dielectric strength. The support 120 also prevents unintentional dielectric arcs.

[0016]

[0017] The system 100 also includes one or more electrodes (two are shown, namely, a first electrode 130A and a second electrode 130B). As described in more detail below, the first electrode 130A and the second electrode 130B are configured to generate an electric arc.

[0017]

[0018] The first electrode 130A and the second electrode 130B are at least partially made from copper or other metal. The electric arc depends at least in part on the material(s) in the first electrode 130A and the second electrode 130B. For example, the material(s) can affect the magnitude, direction, and / or temperature of the electric arc.

[0018]

[0019] In some embodiments, the first electrode 130A and the second electrode 130B are the same size (e.g., length, width, and / or height). However, in some embodiments, similar to that shown in FIG. 1, the first electrode 130A has a different size (e.g., different length) than the second electrode 130B. For example, the first electrode 130A can have a length of about 10 mm to about 30 mm, e.g., about 20 mm (or 10 mm to 30 mm, e.g., 20 mm), and the second electrode 130B can have a length of about 1 mm to about 10 mm, e.g., about 5 mm (or 1 mm to 10 mm, e.g., 5 mm). The electric arc depends at least in part on the size of the first electrode 130A and the second electrode 130B. Their size (e.g., length) affects the magnitude, direction, and / or temperature of the electric arc. As the size(s) of the electrode(s) 130A, 130B increases, the amount of current required to generate the electric arc also increases. A larger electric arc has a higher temperature.

[0019]

[0020] The first electrode 130A and the second electrode 130B are spaced apart from each other. As shown, the first electrode 130A and the second electrode 130B can be spaced apart from each other by a first distance 132 in a first direction parallel or substantially parallel to the surface 118 of the joined structure 110. The first electrode 130A and the second electrode 130B can also be spaced apart from each other by a second distance 134 in a second direction perpendicular or substantially perpendicular to the surface 118 of the joined structure 110. The first distance 132 can be from about 2 mm to about 10 mm, such as about 5 mm (or from 2 mm to 10 mm, such as 5 mm), and the second distance 134 can be from about 0.5 mm to about 2 mm, such as about 1 mm (or from 0.5 mm to 2 mm, such as 1 mm). Thus, as shown, the first electrode 130A is positioned farther from the joined structure 110 than the second electrode 130B. The electric arc depends on the spacing / positioning of the first electrode 130A and the second electrode 130B relative to one another. For example, the spacing / positioning affects the size, direction, and / or temperature of the electric arc. By moving the first electrode 130A and the second electrode 130B closer together, the size of the electric arc is reduced, which reduces the temperature of the electric arc. Conversely, by moving the first electrode 130A and the second electrode 130B farther apart, the size of the electric arc is increased, which increases the temperature of the electric arc.

[0020]

[0021] The system 100 also includes a dielectric material layer 140 disposed at least partially between the first electrode 130A and the second electrode 130B. The first direction (see above) may be parallel or substantially parallel to a plane 142 passing through the dielectric material layer 140, and the second direction may be perpendicular or substantially perpendicular to the plane 142. The plane 142 may also be parallel or substantially parallel to the surface 118 of the joined structure 110. The dielectric material layer 140 may have a thickness of about 0.5 mm to about 3 mm, such as about 1 mm (or 0.5 mm to 3 mm, such as 1 mm). The dielectric material layer 140 may be or may include a polyimide film with a silicone adhesive, such as KAPTON® tape. In other embodiments, the dielectric material layer 140 is at least partially made of polytetrafluoroethylene (PTFE). For example, the dielectric material layer 140 may be made of TEFLON®. The dielectric material layer 140 is configured to provide an electrical barrier between the first electrode 130A and the second electrode 130B. As the thickness and / or resistance of the dielectric barrier increases, more current is required to create an electric arc. Conversely, as the thickness and / or resistance of the dielectric barrier decreases, less current is required to create an electric arc.

[0021]

[0022] As shown, the first electrode 130A is in contact with and / or coupled to the support 120 and / or the dielectric material layer 140. The second electrode 130B is in contact with and / or coupled to the dielectric material layer 140 but not in contact with and / or coupled to the support 120. The dielectric material layer 140 is in contact with and / or coupled to the support 120, the first electrode 130A, the second electrode 130B, or a combination thereof.

[0022]

[0023] The system 100 includes a power source 150 connected to the first electrode 130A and the second electrode 130B. The power source 150 may have a voltage of about 40 kilovolts (kV) to about 60 kV (or 40 kV to 60 kV). The power source 150 generates alternating current (AC) pulses having a duration of about 10 nanoseconds (ns) to about 1 millisecond (ms), about 25 ns to about 500 ns, or about 50 ns to about 200 ns (or 10 ns to 1 ms, 25 ns to 500 ns, or 50 ns to 200 ns). For example, the pulses may have a duration of 100 ns or about 100 ns. The pulses cause the first electrode 130A and the second electrode 130B to generate an electric arc.

[0023]

[0024] A sacrificial material layer 160 is bonded to and / or in contact with the surface 118 of the bonded structure 110. The sacrificial material layer 160 is made from a material configured to be at least partially melted by an electric arc to generate a plasma. For example, the sacrificial material layer 160 may be made at least in part from polyvinyl chloride tape.

[0024]

[0025] A liquid (e.g., water or FLUORINERT®) 170 is disposed at least partially between the surface 118 of the bonded structures 110 and the dielectric material layer 140. As shown, the liquid 170 is disposed on the sacrificial material layer 160. As described in more detail below, a compression wave is generated by melting the sacrificial material layer 160, and the liquid 170 directs at least a portion of the compression wave into the bonded structures 110 (e.g., towards the bonding material 116).

[0025]

[0026] 2 illustrates a flow chart of a method 200 for evaluating bonds in a bonded structure 110, according to one embodiment. Method 200 may be performed using system 100. An exemplary order of method 200 is described below, although it is understood that one or more steps of method 200 may be performed in a different order and / or omitted.

[0026]

[0027] The method 200 includes, at 202, disposing a sacrificial material layer 160 on the surface 118 of the bonded structure 110. In some embodiments, the sacrificial material layer 160 is adhered to the surface 118. The method 200 also includes, at 204, disposing a liquid 170 between the system 100 and the sacrificial material layer 160. In some embodiments, the liquid is disposed on the sacrificial material layer 160.

[0027]

[0028] The method 200 includes, at 206, generating an electrical pulse using the system 100. In particular, a power source 150 is connected to the electrodes 130A, 130B and transmits an electrical (e.g., AC) pulse to the electrodes 130A, 130B. The electrical pulse causes the electrodes 130A, 130B to generate an electrical arc. The electrical arc at least partially melts at least a portion of the sacrificial material layer 160 to generate a plasma 180 (see FIG. 1). Thus, the plasma 180 can be generated without the use of a laser, which allows the system 100 to have a smaller footprint and be less expensive than conventional LBI.

[0028]

[0029] In response to melting the sacrificial material layer 160 and / or generating the plasma 180, a first wave is generated. The first wave is a compression wave. The first wave is guided toward the surface 118 of the bonded structure 110 (e.g., toward the bonding material 116) at least in part by the liquid 170. The first wave is additionally or alternatively guided toward the surface 118 of the bonded structure 110 (e.g., toward the bonding material 116) at least in part depending on the material of the electrodes 130A, 130B, the size of the electrodes 130A, 130B, the arrangement of the electrodes 130A, 130B, the arrangement of the dielectric material layer 140, or a combination thereof. The first wave is reflected from the bonded structure 110. In particular, the first wave is reflected from the bonding material 116 and / or the surface 118 as a second wave. The second wave is a tension wave.

[0029]

[0030] The first wave and / or the second wave may apply a predetermined force to the bond (e.g., the bond material 116), the predetermined force being about 30% to about 70%, e.g., about 50%, of the force required to break an ideal bond (or about 30% to about 70%, e.g., 50% of the force required to break an ideal bond).

[0030]

[0031] The method 200 also includes inspecting the bonded structure 110 at 208. For example, the bond (e.g., the bonding material 116) may be inspected using a non-destructive inspection (NDI) system 190 (see FIG. 1), such as an ultrasonic imaging system or an ultrasonic inspection system, after the first wave reflects off the bonding material 116 to generate the second wave. The inspection detects inconsistencies and / or damage to the bond that occurs in response to contact with the first wave and / or the second wave. If the inspection reveals that the bond (e.g., the bonding material 116) is shattered or broken, the quality of the bond is determined to be poor (i.e., the bond does not pass the inspection). If the inspection reveals that the bond (e.g., the bonding material 116) is not shattered or broken, the quality of the bond is determined to be good (i.e., the bond passes the inspection). Such inspection of the bond is sufficient to meet the requirements of ASTM D5528-13-Standard Test Method for Interlaminar Fracture Toughness of Unidirectional Fiber Reinforced Polymer Matrix Composites (Mode 1). Alternative or additional steps may also be performed.

[0031]

[0032] In other embodiments, one or more portions of the system 100 may be replaced or modified to generate a different pulse width, an electric arc with different characteristics, a wave with different characteristics, or a combination thereof. For example, one or both of the electrodes 130A, 130B may be replaced by a different electrode(s) made of a different material and / or having a different size / shape. Furthermore, the arrangement of the electrodes 130A, 130B (e.g., the spacing of the electrodes 130A, 130B) may be changed. In other examples, the dielectric material layer 140 may be replaced by a different dielectric material layer made of a different material and / or having a different shape / size. Furthermore, the arrangement of the dielectric material layer 140 may be changed. By replacing or modifying the electrodes 130A, 130B and / or the dielectric material layer 140 as described above, the magnitude, direction, and / or temperature of the electric arc are affected. For example, the dielectric material layer 140 may be replaced by a second dielectric material layer having a different thickness and / or resistivity. It affects the amount of current required to generate the electric arc and / or the temperature of the electric arc.

[0032]

[0033] In at least one embodiment, system 100 may not include / use a test tape with copper wiring, as is often used by LBI systems, because system 100 does not include an electromagnetic transducer (EMAT) for converting compressional and / or tensional waves. In fact, the system does not receive compressional waves.

[0033]

[0034] The above-described system 100 and method 200 can replace peel ply testing, which uses mechanically applied stress to pull a bond apart. The above-described system 100 and method 200 can also replace LBI testing, which uses a laser to generate a plasma and a compression wave.

[0034]

[0035] The tensile force required to damage or destroy a bond with satisfactory / passing quality may be known prior to performing method 200. Thus, the waves generated during testing may have a force less than that required to destroy the bond (e.g., between 50% and 70% of that force, or between about 50% and about 70% of that force). If inspection shows that the bond is still intact after the wave(s) contact the bond, the bond is considered to have the desired quality (the bond passes the test). If inspection shows that the bond is damaged or destroyed after the wave(s) contact the bond, the bond is considered not to have the desired quality (the bond does not pass the test).

[0035]

[0036] Additionally, the disclosure includes embodiments according to the following provisions:

[0036]

[0037] Article 1. 1. A system for evaluating a bond, comprising: a first electrode, a second electrode, a dielectric material layer at least partially disposed between the first electrode and the second electrode, and a power source connected to the first electrode and the second electrode, the power source configured to generate an electric arc between the first electrode and the second electrode, the electric arc configured to at least partially melt a sacrificial material layer to generate a plasma.

[0037]

[0038] Article 2. 11. The system of any one of clauses 1 or 3 to 10, wherein the first electrode, the second electrode, or both, are made of copper.

[0038]

[0039] Article 3. 11. The system of any one of clauses 1, 2, or 4-10, wherein the first electrode is spaced a first distance from the second electrode in a first direction, the first distance being 0.5 mm to 2 mm or about 0.5 mm to about 2 mm, and the first direction being parallel or substantially parallel to a plane through the dielectric material layer.

[0039]

[0040] Article 4. The system of any one of clauses 1 to 3 or 5 to 10, wherein the first electrode is spaced a second distance from the second electrode in a second direction, the second distance being about 2 mm to about 10 mm or 2 mm to 10 mm, and the second direction being perpendicular or substantially perpendicular to a plane through the dielectric material layer.

[0040]

[0041] Article 5. The system of any one of clauses 1 to 4 or 6 to 10, wherein the first electrode is positioned farther from the sacrificial material layer than the second electrode.

[0041]

[0042] Article 6. The system of any one of clauses 1 to 5 or 7 to 10, wherein the first electrode has a different size than the second electrode.

[0042]

[0043] Article 7. The system of any one of clauses 1 to 6 or 8 to 10, wherein the first electrode is longer in a first direction than the second electrode, and the first direction is parallel or substantially parallel to a plane through the dielectric material layer.

[0043]

[0044] Article 8. The system of any one of clauses 1 to 7, 9, or 10, wherein the power source is configured to transmit alternating current pulses having a duration of 50 ns to 200 ns or about 50 ns to about 200 ns to the first electrode and the second electrode, the alternating current pulses causing the electric arc to be generated in the first electrode and the second electrode.

[0044]

[0045] Article 9. The system of any one of clauses 1 to 8 or 10, further comprising a support comprising a polyimide material, a polyamide material, or both, wherein the first electrode is in contact with the support, the dielectric material layer is in contact with the support, and the second electrode is not in contact with the support.

[0045]

[0046] Article 10. 10. The system of any one of clauses 1 to 9, wherein the plasma is generated at least partially between the dielectric material layer and the sacrificial material layer.

[0046]

[0047] Article 11. 1. A system for evaluating bonds comprising: a support; a first electrode in contact with the support; a second electrode spaced from the support and the first electrode; a dielectric material layer in contact with the support, the dielectric material layer being at least partially disposed between the support and the second electrode and at least partially disposed between the first electrode and the second electrode such that the second electrode is not in contact with the support or the first electrode; and a power source connected to the first electrode and the second electrode, the power source configured to transmit alternating current pulses to the first electrode and the second electrode, the alternating current pulses causing an electric arc to be generated between the first electrode and the second electrode, the electric arc at least partially melting a sacrificial material layer on a bonded structure to generate a plasma, the generation of the plasma generating a compression wave that is directed into the bonded structures, the compression wave reflecting as a tension wave from a bond within the bonded structures.

[0047]

[0048] Article 12. 12. The system of claim 11, wherein the first electrode is spaced a first distance from the second electrode in a first direction, the first distance being about 0.5 mm to about 2 mm or 0.5 mm to 2 mm, the first direction being parallel or substantially parallel to a plane through the dielectric material layer, the first electrode is spaced a second distance from the second electrode in a second direction, the second distance being about 2 mm to about 10 mm or 2 mm to 10 mm, the second direction being perpendicular or substantially perpendicular to the plane through the dielectric material layer, and the first electrode is positioned farther from the sacrificial material layer than the second electrode.

[0048]

[0049] Article 13. 16. The system of any one of clauses 11, 12, 14, or 15, wherein the first electrode has a length in the first direction of about 10 mm to about 20 mm or 10 mm to 20 mm, and the second electrode has a length in the first direction of about 1 mm to about 10 mm or 1 mm to 10 mm.

[0049]

[0050] Article 14. 16. The system of any one of clauses 11 to 13 or 15, wherein water is disposed between the dielectric material layer and the sacrificial material layer, the water directing a portion of the compression wave toward the bond within the bonded structure.

[0050]

[0051] Article 15. 15. The system of any one of clauses 11 to 14, wherein the system is capable of generating the plasma and the compressional wave without the use of a laser.

[0051]

[0052] Article 16. 1. A method for evaluating a bond, comprising: disposing a sacrificial material layer on a surface of a bonded structure; and transmitting an electrical pulse to a first electrode and a second electrode, the electrical pulse causing an electrical arc to be generated between the first electrode and the second electrode, the electrical arc at least partially melting the sacrificial material layer and generating a plasma, the generation of the plasma generating a compression wave that is directed into the bonded structure, the compression wave being reflected as a tension wave from the bond within the bonded structure.

[0052]

[0053] Article 17. 21. The method of any one of clauses 16 or 18-20, further comprising disposing a liquid adjacent to the sacrificial material layer, the liquid directing at least a portion of the compression wave into the bonded structure.

[0053]

[0054] Article 18. 18. The method of claim 17, wherein a dielectric material layer is disposed at least partially between the first electrode and the second electrode, and the liquid and the plasma are disposed between the sacrificial material layer and the dielectric material layer.

[0054]

[0055] Article 19. 19. The method of any one of clauses 16 to 18, further comprising inspecting the bond using an ultrasonic imaging system after the compression wave is reflected from the bond.

[0055]

[0056] Article 20. 20. The method of any one of clauses 16-19, wherein the first electrode is spaced a first distance in a first direction from the second electrode, the first distance being about 0.5 mm to about 2 mm or 0.5 mm to 2 mm, the first direction being parallel or substantially parallel to a plane through the dielectric material layer, the first electrode is spaced a second distance in a second direction from the second electrode, the second distance being about 2 mm to about 10 mm or 2 mm to 10 mm, the second direction being perpendicular or substantially perpendicular to the plane through the dielectric material layer, and the first electrode is positioned further from the sacrificial material layer than the second electrode.

[0056]

[0057] Article 21. 1. A system for evaluating a bond, comprising: a first electrode, a second electrode, a dielectric material layer at least partially disposed between the first electrode and the second electrode, and a power source connected to the first electrode and the second electrode, the power source configured to provide an electric current to the first electrode and the second electrode to generate an electric arc between the first electrode and the second electrode, the electric arc at least partially melting a sacrificial material layer to generate a plasma.

[0057]

[0058] Article 22. 22. The system of claim 21, wherein the first electrode and / or the second electrode are made of copper.

[0058]

[0059] Article 23. 23. The system of claim 21 or 22, wherein the first electrode is spaced a first distance from the second electrode in a first direction, the first distance being 0.5 mm to 2 mm or about 0.5 mm to about 2 mm, and the first direction being parallel or substantially parallel to a plane through the dielectric material layer.

[0059]

[0060] Article 24. 24. The system of claim 23, wherein the first electrode is spaced a second distance from the second electrode in a second direction, the second distance being about 2 mm to about 10 mm or 2 mm to 10 mm, and the second direction being perpendicular or substantially perpendicular to a plane through the dielectric material layer.

[0060]

[0061] Article 25. 25. The system of claim 24, wherein the first electrode is positioned farther from the sacrificial material layer than the second electrode.

[0061]

[0062] Article 26. 26. The system of any one of clauses 21 to 25, wherein the first electrode has a different size than the second electrode.

[0062]

[0063] Article 27. 27. The system of any one of clauses 21 to 26, wherein the first electrode is longer than the second electrode in a first direction, the first direction being parallel or substantially parallel to a plane through the dielectric material layer.

[0063]

[0064] Article 28. 28. The system of any one of clauses 21 to 27, wherein the power supply is configured to provide an alternating current pulse having a duration of 50 ns to 200 ns or about 50 ns to about 200 ns to the first electrode and the second electrode, the alternating current pulse causing the first electrode and the second electrode to generate the electric arc.

[0064]

[0065] Article 29. 29. The system of any one of clauses 21 to 28, further comprising a support comprising a polyimide material and / or a polyamide material, the first electrode in contact with the support, the dielectric material layer in contact with the support, and the second electrode spaced apart from the support.

[0065]

[0066] Article 30. 30. The system of any one of clauses 21 to 29, wherein the plasma is generated at least partially between the dielectric material layer and the sacrificial material layer.

[0066]

[0067] Article 31. 31. The system of clauses 21 to 30, wherein the system is suitable for evaluating bonds in bonded structures, such as CFRP to CFRP or CFRP to metal bonded structures.

[0067]

[0068] Article 32. 32. The system of claim 31, further comprising a bonded structure, such as a CFRP to CFRP or a CFRP to metal bonded structure.

[0068]

[0069] Article 33. 1. A system for evaluating bonds comprising: a support; a first electrode in contact with the support; a second electrode spaced from the support and the first electrode; a dielectric material layer in contact with the support, the dielectric material layer being at least partially disposed between the support and the second electrode such that the second electrode is spaced from the support and the first electrode; and a power source connected to the first electrode and the second electrode, the power source configured to provide alternating current pulses to the first electrode and the second electrode, the alternating current pulses causing an electric arc to be generated between the first electrode and the second electrode, the electric arc at least partially melting a sacrificial material layer on a bonded structure to generate a plasma, the generation of the plasma generating a compression wave that is directed into the bonded structures, the compression wave reflecting as a tension wave from a bond within the bonded structures.

[0069]

[0070] Clause 34. The system of clause 33, wherein the first electrode is spaced a first distance in a first direction from the second electrode, the first distance being about 0.5 mm to about 2 mm or 0.5 mm to 2 mm, the first direction being parallel or substantially parallel to a plane through the dielectric material layer, the first electrode is spaced a second distance in a second direction from the second electrode, the second distance being about 2 mm to about 10 mm or 2 mm to 10 mm, the second direction being perpendicular or substantially perpendicular to the plane through the dielectric material layer, and the first electrode is positioned farther from the sacrificial material layer than the second electrode.

[0070]

[0071] Article 35. The system described in clause 34, wherein the first electrode has a length in the first direction of about 10 mm to about 20 mm or 10 mm to 20 mm, and the second electrode has a length in the first direction of about 1 mm to about 10 mm or 1 mm to 10 mm.

[0071]

[0072] Article 36. 36. The system of claim 35, wherein water is disposed between the dielectric material layer and the sacrificial material layer to direct a portion of the compression wave toward the bond within the bonded structure.

[0072]

[0073] Article 37. 37. The system of claim 36, wherein the system is capable of generating the plasma and the compressional wave without the use of a laser.

[0073]

[0074] Article 38. 38. The system of any one of clauses 33 to 37, wherein the system is suitable for evaluating bonds in bonded structures, such as CFRP to CFRP or CFRP to metal bonded structures.

[0074]

[0075] Article 39. 39. The system of claim 38, further comprising a bonded structure, such as a CFRP to CFRP or a CFRP to metal bonded structure.

[0075]

[0076] Article 40. 1. A method for evaluating a bond, comprising: disposing a sacrificial material layer on a surface of a bonded structure; and transmitting an electric pulse to a first electrode and a second electrode, the electric pulse causing an electric arc to be generated between the first electrode and the second electrode, the electric arc at least partially melting the sacrificial material layer and generating a plasma, the generation of the plasma generating a compression wave that is directed into the bonded structure, the compression wave being reflected as a tension wave from the bond within the bonded structure.

[0076]

[0077] Article 41. 41. The method of claim 40, further comprising disposing a liquid adjacent to the sacrificial material layer, the liquid directing at least a portion of the compression wave into the bonded structure.

[0077]

[0078] Article 42. 42. The method of claim 41, wherein a dielectric material layer is disposed at least partially between the first electrode and the second electrode, and the liquid and the plasma are disposed between the sacrificial material layer and the dielectric material layer.

[0078]

[0079] Article 43. 43. The method of any one of clauses 40 to 42, further comprising inspecting the bond using an ultrasonic imaging system after the compression wave has reflected from the bond.

[0079]

[0080] Article 44. 44. The method of any one of clauses 40 to 43, wherein the first electrode is spaced a first distance in a first direction from the second electrode, the first distance being about 0.5 mm to about 2 mm or 0.5 mm to 2 mm, the first direction being parallel or substantially parallel to a plane through the dielectric material layer, the first electrode is spaced a second distance in a second direction from the second electrode, the second distance being about 2 mm to about 10 mm or 2 mm to 10 mm, the second direction being perpendicular or substantially perpendicular to the plane through the dielectric material layer, and the first electrode is positioned further from the sacrificial material layer than the second electrode.

[0080]

[0081] Article 45. 45. The method of any one of clauses 40 to 44, wherein the system is suitable for assessing bonds in bonded structures, such as CFRP to CFRP or CFRP to metal bonded structures.

[0081]

[0082] Article 46. A method for evaluating a bond using the system described in any one of clauses 1 to 39, comprising: disposing a sacrificial material layer on a surface of a bonded structure; and transmitting an electric pulse to a first electrode and a second electrode, the electric pulse causing an electric arc to be generated between the first electrode and the second electrode, the electric arc at least partially melting the sacrificial material layer and generating a plasma, the generation of the plasma generating a compression wave that is directed into the bonded structure, the compression wave being reflected as a tension wave from the bond within the bonded structure.

[0082]

[0083] Article 47. 47. The method of claim 46, further comprising disposing a liquid adjacent to the sacrificial material layer, the liquid directing at least a portion of the compression wave into the bonded structure.

[0083]

[0084] Article 48. 48. The method of claim 46 or 47, further comprising inspecting the bond using an ultrasonic imaging system after the compression wave has reflected from the bond.

[0084]

[0085] Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the present disclosure are approximations, the numerical values ​​set forth in the specific examples are reported as precisely as possible. However, any numerical value inherently contains certain errors necessarily resulting from the standard deviation found in their respective testing measurements. Moreover, all ranges disclosed herein should be understood to include any and all subranges subsumed therein.

[0085]

[0086] Although the teachings herein have been illustrated with respect to one or more embodiments, changes and / or modifications may be made to the examples without departing from the spirit and scope of the appended claims. Also, while a particular feature of the teachings may have been disclosed with respect to only one of several embodiments, such feature may be combined with one or more other features of other embodiments, where such feature is desirable and advantageous for any given or particular function. As used herein, the terms "a," "an," and "the" may refer to one or more elements or parts of an element. As used herein, the terms "first" and "second" may refer to two different elements or parts of an element. As used herein, for example, the term "at least one of A and B" with respect to a list of items such as A and B means A only, B only, or A and B. Those skilled in the art will appreciate that these and other variations are possible. Additionally, the words "including / includes," "having / has," "with," or variations thereon, wherever used in the specification and claims, are intended to be inclusive in the same sense as the word "comprising." Additionally, in the discussion and claims herein, the term "about" indicates that the recited value may be somewhat modified as long as such modification does not cause non-suitability of the process or structure for the intended purpose described herein. Finally, "exemplary" indicates that the description is used as an example, rather than implying ideality.

[0086]

[0087] It will be appreciated that the above-disclosed and other features and functions, or alternatives thereof, may be combined into many other different systems or applications. Various presently unforeseen or unanticipated alternatives, modifications, variations or improvements thereon may be subsequently made by those skilled in the art, but are encompassed by the following claims.

Claims

1. 1. A system for evaluating a bond, comprising: support, a first electrode in contact with the support; a second electrode spaced apart from the support and the first electrode; a dielectric material layer in contact with the support, the dielectric material layer being at least partially disposed between the support and the second electrode and at least partially disposed between the first electrode and the second electrode such that the second electrode is not in contact with the support or the first electrode; and 11. A system comprising: a power source connected to the first electrode and the second electrode, the power source configured to transmit alternating current pulses to the first electrode and the second electrode, the alternating current pulses causing an electric arc to be generated between the first electrode and the second electrode, the electric arc at least partially melting a sacrificial material layer on a bonded structure to generate a plasma, the generation of the plasma generating a compression wave that is directed into the bonded structures, the compression wave being reflected as a tension wave from a bond within the bonded structures.

2. 2. The system of claim 1 , wherein the first electrode is spaced a first distance from the second electrode in a first direction, the first distance being about 0.5 mm to about 2 mm, the first direction being substantially parallel to a plane through the dielectric material layer, the first electrode is spaced a second distance from the second electrode in a second direction, the second distance being about 2 mm to about 10 mm, the second direction being substantially perpendicular to the plane through the dielectric material layer, and the first electrode is positioned further from the sacrificial material layer than the second electrode.

3. 3. The system of claim 2, wherein the first electrode has a length in the first direction of about 10 mm to about 20 mm and the second electrode has a length in the first direction of about 1 mm to about 10 mm.

4. 4. The system of claim 1, wherein water is disposed between the dielectric material layer and the sacrificial material layer, the water directing a portion of the compression wave toward the bond in the bonded structure.

5. 5. The system of claim 1, wherein the system is capable of generating the plasma and the compressional wave without the use of a laser.

6. 1. A method for assessing adhesion, comprising: disposing a layer of sacrificial material on a surface of the bonded structure; and 1. A method comprising: transmitting an electrical pulse to a first electrode and a second electrode, the electrical pulse causing an electrical arc to be generated between the first electrode and the second electrode, the electrical arc at least partially melting the sacrificial material layer to generate a plasma, the generation of the plasma generating a compression wave that is directed into the bonded structures, the compression wave being reflected from the bond within the bonded structures as a tension wave.

7. The method of claim 6 , further comprising disposing a liquid proximate to the sacrificial material layer, the liquid directing at least a portion of the compression wave into the bonded structure.

8. 8. The method of claim 7, wherein a dielectric material layer is disposed at least partially between the first electrode and the second electrode, and the liquid and the plasma are disposed between the sacrificial material layer and the dielectric material layer.

9. 9. The method of claim 6, further comprising inspecting the bond using an ultrasonic imaging system after the compression wave is reflected from the bond.

10. 10. The method of claim 6, wherein the first electrode is spaced a first distance from the second electrode in a first direction, the first distance being about 0.5 mm to about 2 mm, the first direction being substantially parallel to a plane through the dielectric material layer, the first electrode is spaced a second distance from the second electrode in a second direction, the second distance being about 2 mm to about 10 mm, the second direction being substantially perpendicular to the plane through the dielectric material layer, and the first electrode is positioned further from the sacrificial material layer than the second electrode.

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