被締結物がクリープするねじ締結体の変形解析とボルト軸力低下について

抄録

Reducing the car weight is very important for the development of automobiles to, since it is one of the solutions for the environmental issues. Adoption of materials with high specific tensile strength such as Magnesium and CFRP is under investigation. Those materials have the creep characteristic under high temperature atmosphere. Therefore, the combination of the temperature and clamping force potentially causes decreases in the bolt axial tensions for the bolted joints.

The purpose of this study is to propose the precise prediction method for the reductions of the bolt axial tension in case that material of clamped parts has the creep characteristics. The experiments and elasto-plastic FEM analyses with creep characteristic are conducted on the bolted joints with two hollow disc specimens made of Magnesium alloy AZ80-F. The FEM analyses show good correspondence with experimental results by using compressive creep characteristic of AZ80-F which is under the yield point.