Framework for Strain Measurements at Cyclic Loaded Structures with Planar Elastoresistive Sensors Applying Electrical Impedance Tomography

Damage Evaluation in Plain-Woven CFRP Plate with Circular Hole under Cyclic Tensile Loading Using Electrical Impedance Tomography

“…In Figure 2 the experimental setup, including the investigated CFRP plate with centrally placed circular hole and the used clamping fixture and hydraulic cylinder, the 3D-DIC system and the EIT measurement system are illustrated. For the EIT reconstructions, an experimental framework, developed by the authors [31], is applied consisting of all components with which the EIT measurements and evaluations are performed. In this arrangement, the wiring of the elastoresistive thin-film sensor (frontside) is routed into a multiplexer, driven by an Arduino ® Mega 2560.…”

“…In this arrangement, the wiring of the elastoresistive thin-film sensor (frontside) is routed into a multiplexer, driven by an Arduino ® Mega 2560. This allows a defined current injection pattern in accordance with [31]. As current source the Keithley ® 6620 is used.…”

“…These components are also depicted in Figure 2. The principle of the framework is described in Section 2.4, whereas a more detailed description is given in [31][32][33]. As illustrated in Figure 2, the plate is positioned in the center of the clamping fixture and held in place by tightening the clamping screws to avoid slipping out.…”

“…By masking the screen beforehand, the sensor size and shape is specified. The chosen SunChemical C2130819D1 Carbon Paste has been used by the authors in a previous study, were it was successfully used as EIT sensor material on a high cycle loaded aluminum specimen [31].…”

“…In this way, systematic voltage measurements on the placed electrodes are performed throughout the experiment (see Section 2.2) and give the boundary potential to solve the inverse solution. The EIT evaluation framework for measurement data collection, preprocessing and conductivity reconstruction was developed in a previous work [31]. In this process, the Gauss-Newton one-step algorithm is utilized to solve the differential inverse EIT reconstruction using a maximum a posteriori regularization approach [41][42][43].…”