2018 年 2018 巻 63 号 p. 53-62
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.