5. Fabrication of composite specimens incorporated with sensor

Standard specimens of composites for tensile test were prepared and a full integration of sensors into the composite structure was achieved, Figure 4. Silicon

Figure 4. Fabrication of composite specimen with sensor wire.

tests were performed to confirm the reproducibility of the results. Paper frame was used specifically to provide support to such a small specimen in the tensile machine; however, it was cut from the sides before starting the test so it could not affect the behavior of sensor during the test. In addition, electrodes were attached at both ends of the specimen to provide better connection. Then, the specimen was placed in the tensile machine and test was performed at low strain rate, that is 5 mm/min, Figure 1. As a result, the stress-strain behavior with resistance profile was obtained.

Coupled field analysis in commercial Abaqus/standard software was used to model the electromechanical behavior and verify experimental results. The sample geometry of conductive thin film-coated monofilament was developed at the microscale to avoid aspect ratio problems during meshing and reduce the computational time, Figure 2a and b. Before performing the finite element analysis, it was

Schematic representation of the coated yarn: (a) front view, (b) side view, and (c) mesh of the yarn.

4. Numerical modeling of sensor wire

Advances in Structural Health Monitoring

Figure 2.

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molds were used for the preparation of samples and glass fiber fabric was used as reinforcement. The glass fabric was cut into segments and placed into a mold and a sensor (nylon yarn coated with silver) was inserted between the plies of fiberglass. Then, resin mixed with hardener with a ratio of 1:4 was poured into the mold. Once the molds were filled, one could no longer see the fiberglass layers, the samples were completely transparent. Now, one could view all of the sensors easily. After that, samples were left to cure for 48 hours at room temperature.
