INSPECTION SYSTEM FOR REPAIRS OR JOINTS OF COMPOSITE MATERIAL APPLIED TO A STRUCTURE

Abstract

This invention is related to inspection techniques for composite joints and repairs. In this scenario, this invention provides a system for inspecting a repair or joint made of composite material applied to a structure, comprising at least one element that excites or is excited (2, 10) by a thermal and/or vibrational stimulus, with at least one exciter or excitable (2, 10) element being embedded in the repair (1) or joint.

Claims

1. System for inspecting a repair or joint made of composite material applied to a structure, wherein at least one element that excites or is excited by a thermal and/or vibrational stimulus, with at least one exciter or excitable element being built into the repair or joint.

2. System, according to claim 1, wherein a repair or a joint of composite material comprising matrix and reinforcement material.

3. System, according to claim 2, wherein the matrix material being a plastic or resin and the reinforcement material being fiberglass.

4. System, according to claim 1, wherein the exciter element being a piezoelectric actuator embedded inside the repair or joint, where the actuator is adapted to receive an external signal and to vibrate at least at a certain frequency.

5. System, according to claim 4, wherein as comprising a set of piezoelectric actuators embedded in the extremities of the repair or joint.

6. System, according to claim 5, wherein as additionally comprising at least one connector adapted to send the external signal to each one of the piezoelectric actuators.

7. System, according to claim 1, wherein the excitable element being at least one layer of material that is excited by a thermal and/or vibrational stimulus.

8. System, according to claim 7, wherein at least one layer of a material that is excited by a thermal and/or vibrational stimulus comprising at least one layer of carbon fiber.

9. System, according to claim 8, wherein comprising at least one thermal connector adapted to connect to each of the carbon fiber layers to a power source.

10. System, according to claim 2, wherein the exciter element being a piezoelectric actuator embedded inside the repair or joint, where the actuator is adapted to receive an external signal and to vibrate at least at a certain frequency.

11. System, according to claim 3, wherein the exciter element being a piezoelectric actuator embedded inside the repair or joint, where the actuator is adapted to receive an external signal and to vibrate at least at a certain frequency.

12. System, according to claim 2, wherein the excitable element being at least one layer of material that is excited by a thermal and/or vibrational stimulus.

13. System, according to claim 3, wherein the excitable element being at least one layer of material that is excited by a thermal and/or vibrational stimulus.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0017] The detailed description presented below refers to the attached figures and their respective reference numbers.

[0018] FIG. 1 is a cutaway diagram of the first embodiment of the system of this invention in a composite repair in a pipeline.

[0019] FIG. 2 is a detailed cutaway diagram of the first embodiment of this invention.

[0020] FIG. 3 is a side view of a second embodiment of the system of this invention in a composite repair in a pipeline.

[0021] FIG. 4 is a cutaway diagram of a third embodiment of the system of this invention in a composite repair in a pipeline.

[0022] FIG. 5 is the result of a thermographic inspection from the internal excitation promoted by the system in accordance with the first embodiment of this invention.

DETAILED DESCRIPTION OF THE INVENTION

[0023] Firstly, it should be emphasized that the following description is a preferred embodiment of the invention. However, as will be evident to any person skilled in the art, this invention is not limited to this specific embodiment.

[0024] The system for inspecting a repair or joint made of composite material applied to a structure, according to this invention, comprises at least one element that excites or is excited by a thermal and/or vibrational stimulus, with at least one exciter or excitable element being embedded in the repair or joint.

[0025] FIG. 1 is a cutaway diagram of a first embodiment of the system of this invention in a composite repair 1 in a pipeline 3. In this first embodiment, applied to a composite repair 1, the excitable element is at least one layer of material that is excited by a thermal and/or vibrational stimulus. More preferably, this layer excited by a thermal and/or vibrational stimulus is a layer of carbon fiber 2.

[0026] Depending on the height of the repair, the use of two or more carbon fiber layers 2 may be necessary to ensure excitation throughout the thickness of the composite repair 1. In the first embodiment, illustrated in FIG. 1, two layers of carbon fiber 2 are used.

[0027] The system of this invention may also comprise at least one thermal connector 4 adapted to connect each of the carbon fiber layers to a power source 5. Accordingly, the carbon fiber layers are thermally excited by at least one thermal connector 4.

[0028] Preferably, the first electric cable 6 connects the thermal connector 4 to the power source 5. Additionally, and also preferably, the second electric cable 7 connects the power source 5 to the electricity network (not shown).

[0029] FIG. 2 is a detailed cutaway diagram of the first embodiment of this invention. During thermal excitation (heating), the repair 1 is observed with a non-destructive inspection system 18, as illustrated in FIG. 2. Non-destructive inspection may be conducted by means of a shearographic system, a thermographic camera or both.

[0030] FIG. 2 also illustrates the bi-directional thermal flow 17 generated by the carbon fiber chambers 2 embedded in the composite repair 1. The individual heating of each layer assists in estimating the depths at which the defects are located 15, 16.

[0031] FIG. 3 is a side view of a second embodiment of the system of this invention in a composite repair 1 in a pipeline 3. In this first embodiment, applied to a composite repair 1, the excitable element is at least one piezoelectric actuator embedded in the composite repair 1, where the actuator is adapted to receive an external signal and vibrate at least at a certain frequency. More preferably, a set of piezoelectric actuators 10 are embedded in the extremities of the composite repair 1, as illustrated in FIG. 3.

[0032] The second embodiment of the system of this invention may also comprise at least one vibrational connector 11 adapted to connect and send an external signal to each of the actuators. Accordingly, each of the piezoelectric actuators 10 is connected to the adjacent actuators. Furthermore, the vibrational connector 11 receives the signal from an amplified signal generator 12 for harmonic vibration at varying frequency. The signal sent to the vibrational connector 11 is distributed to the piezoelectric actuators 10.

[0033] Optionally, as illustrated in FIG. 3, two vibrational connectors 11 are provided, where each of them distributes the signal from an amplified signal generator 12 to a certain set of piezoelectric actuators 10.

[0034] As in the first embodiment, preferably the first electric cable 6 connects the vibrational connector 11 to the amplified signal generator 12. Additionally, and also preferably, the second electric cable 7 connects the amplified signal generator 12 to the electricity network (not shown).

[0035] FIG. 4 illustrates a schematic view of the system of this invention applied to an adhesive joint in a composite pipe 19. The adhesive joint illustrated in FIG. 4 is a bell-and-spigot-type joint, where the spigot of the pipe 19 to the left inserts into the bell 20 of the pipe on the right. At the contact point between the spigot 19 and the bell 20, an adhesive layer 21 is provided, which is responsible for fastening one end to the other. Additionally, FIG. 4 illustrates a potential defect 25 in the joint, characterized by the absence of adhesive at a certain point in the union.

[0036] In the third embodiment, as in the first, at least one layer of carbon fiber 2 is provided inside the joint, so that it can receive an external thermal stimulus. Preferably, at least one layer of carbon fiber 2 is provided in the adhesive layer 21 (illustrated in the upper part of FIG. 4) and/or between the layers of the structure of the spigot of the pipe 19 (illustrated in the lower part of FIG. 4).

[0037] Just as in the first embodiment, preferably, the first electric cable 6 connects the carbon fiber layers 2 (optionally by means of a thermal connector) to the power source 5. Additionally, and also preferably, the second electric cable 7 connects the power source 5 to the electricity network (not shown).

[0038] During thermal excitation (heating), the joint is observed with a non-destructive inspection system 18, as illustrated in FIG. 4. As in the first embodiment, non-destructive inspection may be conducted by means of a shearographic system, a thermographic camera or both.

[0039] Preferably, the composite material used in the repair of this invention comprises matrix and reinforcement material. More preferably, the matrix material is a plastic or a resin, while the reinforcement material may be, for example, fiberglass.

[0040] FIG. 5 shows a result obtained from a thermographic inspection performed in a testing body containing three internal defects (continuous arrows). The dotted arrow indicates the internal source of the thermal excitation. The result clearly shows the presence of three internal defects.

[0041] Thus, this invention provides a low-cost system for inspecting repairs or joints of composite material applied to a structure (pipes, for example), which considerably improves the efficacy of thermographic or shearographic inspection methods.

[0042] Several variations on the scope of protection of this request are permitted. Accordingly, it should be emphasized that this invention is not limited to the specific configurations/embodiments described above.