Papers by Keyword: Strip Bending Test

Abstract: In this study, we use the strip-bending test to measure the residual stress of a thin film structure. The principle of the strip bending test and the test procedures are described and the analysis of the strip deformation is presented. The explicit formula for estimating the residual stress is given, which requires the initial stress as an input. As an example, the E-beam evaporated Au thin film is chosen, and the residual stress is measured by the present method. The Au thin film structure has a tensile or compressive residual stress depending on the film thickness. The tensile and the compressive residual stresses of Au thin film are successfully measured by the present method.

Abstract: To measure the micro-mechanical properties for micro/nano materials, out-of-plane ESPI system and micro-strip bend testing system were developed. For the bending system, PZT actuator was controlled with the stroke resolution of 0.6 nm and out-of-plane ESPI system was developed in compact and portable type. To quantitatively analyze the out-of-plane ESPI fringe patterns, 4-bucket technique was used and unwrapped phase map was obtained. Electrolytic copper foil with the thickness of 18 μm was used for preparation of the strip bend specimen with length of 8 mm and three different widths of 2, 3 and 5 mm. The strip bending tests showed that the out-of-plane deflection in the bend specimen was measured with a maximum of 8 % in error. Furthermore, from the experiment, the variation of the deflection along the supporting span could be determined and significant region was linear.