応用機械工学ジャーナル

概要

Design and Optimization of Screwed Fasteners to Reduce Stress Concentration Factor

Govindu N, Jayanand Kumar T and Venkatesh S

The bolt and nuts are used for temporary fastening in the machines and structural assembly; they play an important role to restrict the movement of individual parts in the assembly. Around 10 to 20% of fasteners are used in various designs, sizes, strength levels and materials in complex mechanical systems for diverse applications. The unequal load distribution in the threaded fasteners causes the fatigue failure due to stress concentration In this paper stress distribution in Buttress and ACME threads, for various symmetrical models such as groove added to bolt and nut, a step is added to nut, with or without groove on the bolt, and to the reduced diameter, a taper is added to the nut and a groove on the bolt are designed in 3D and analyzed and validated from 2D models developed to reduce stress concentration. The objective of this study is to show the quantitative comparison between the Buttress and ACME bolt and nut design modifications to improve the design methods efficiently to reduce the stress concentration. In this study various geometrical designs are proposing to reduce the stress concentration factor.