座屈後変形を利用した積層薄板 / 細線の簡易ヤング率測定法 (回転固定軸圧縮法)

Abstract

In recent years, flexible materials with very high performance are widely used and large deformation analyses of these materials have attracted considerable attention. Therefore, it is very important to evaluate mechanical properties, especially, Young's modulus, of these flexible materials. In this study, a new and convenient mechanical testing method (Compression Column Method) is developed for measuring Young's modulus of each layer in a thin flexible multi-layered material (thin plate, rod, or wire). The method is based on a nonlinear theory under the assumptions of the geometrical nonlinearity that takes into account large deformation behavior of multi-layered materials. Exact analytical solutions for large deformation are obtained in terms of elliptic integrals. By means of measuring the horizontal displacement at the fixed end or the vertical displacement at the middle point of the buckled column, Young's modulus of each layer can be easily obtained for various thin and long multi-layered materials. Measurements were carried out on a two-layered material consisting of PVC (a high-polymer material) and SUS (a stainless steel material). As a result, it is made clear that the new method is suitable for thin flexible multi-layered materials. In the meantime, the new method proposed in this paper can be applied widely to measure Young's modulus of every thin layers formed by PVD, CVD, Electrodeposition, Coating, Paint, Cladding, Lamination, and others.