Optimal Design of Cap Screw Thread Runout for Transversal and Axial LoadsKedziora S*
Faculty of Science, Technology and Communication, University of Luxembourg, Campus Kirchberg, 6 rue Coudenhove-Kalergi, L-1359 Luxembourg, Luxembourg
- *Corresponding Author:
- Kedziora S
Faculty of Science, Technology and Communication
University of Luxembourg, Campus Kirchberg
6 rue Coudenhove-Kalergi, L-1359 Luxembourg, Luxembourg
Tel: +352 46 66 44 1
E-mail: [email protected]
Received date: January 13, 2017; Accepted date: February 04, 2017; Published date: February 08, 2017
Citation: Kedziora S (2017) Optimal Design of Cap Screw Thread Runout for Transversal and Axial Loads. J Appl Mech Eng 6:250. doi: 10.4172/2168-9873.1000250
Copyright: © 2017 Kedziora S. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
The presented work is focused on a design of a new thread runout of screws and bolts subjected by transversal loads. These types of loads can occur in a normal service of bolt connection and they can lead to a failure. Two failure modes of the screw could occur: self-loosening of the screw or fatigue failure of the screw. The latter failure mode is analysed in the presented project focusing on an improvement of the existing design of the screws in terms of fatigue failure. The fatigue fracture of the screws, which are loaded by the transversal load, occurs normally in a groove of a first thread run of an engagement. A shape of the thread runout has some influence on stress in the thread therefore that shape can optimize to minimize the thread stress. Considering this, free shape optimisation was employed to find the best runout shape. As results of the presented work, the optimum design of the thread runout is proposed for the analysed conditions. The elaborated design of the cap screw brings significant improvement of the lifetime when the cycling tangential load occurs. In addition, the new design gives the better structural performance than the existing designs also for the cycling normal loads.