円リングにおける自重大たわみ変形を利用した薄肉積層材料の新ヤング率測定法 （自重大変形積層円リング法）

In application of thin flexible multi-layered materials, it is very important to evaluate mechanical properties of these materials in both analytical and technological interests. In this study, a new and convenient mechanical testing method (Own-weight Multi-layered Circular Ring Method) is developed for measuring Young’s modulus of each layer in a flexible multi-layered material (thin plate, or rod/wire), especially, as a useful technique to overcome the difficulty in measuring Young’s modulus of a curled/curved flexible multi-layered material. The method is based on a nonlinear theory that takes into account large deformation behaviors of flexible multi-layered materials. By just measuring a maximum horizontal displacement or a maximum vertical displacement in a flexible circular ring, Young’s modulus of each layer can be easily obtained for various thin multi-layered materials (plate and rod/wire). As an example, measurements were carried out on a thin curled/curved two-layered wire consisting of a thin steel wire (a piano wire: SWP-B) and a thin plating layer (an electrodeposited nickel layer: Ni). The results elucidate that the innovative new method could be applied to measure Young’s modulus of thin flexible multi-layered materials. In the meantime, the new method “Own-weight Multi-layered Circular Ring Method” proposed in this paper is quite a promising method and can be applied widely to measure Young’s modulus of every thin layer in a flexible multi-layered material formed by PVD, CVD, Coating, Paint, Cladding, Lamination and others besides electrodeposited thin layers.