Design of a defense hole system for a uniaxial loaded plate

• Main Author: Song, Xuehong.
• Other Authors: Ang Hock Eng
• Format: Theses and Dissertations
• Language: English
• Published: 2013
• Subjects: DRNTU::Engineering
• Online Access: http://hdl.handle.net/10356/54886
• Institution: Nanyang Technological University

Minimizing stress concentration in the vicinity of geometrical discontinuity in stress fields is an important issue in engineering design, especially in ship structure design. Stress concentration areas are potential site for crack initiation which would lead to abrupt failure of structure by fast fracture. This report studied the optimum position and size of defense hole in reducing stress concentration around the circular main holes and oblong shaped main hole in structure plate using the boundary element method (BEM). It was observed that reduction of stress concentration around the circular main hole or oblong shaped main hole could be achieved by introducing defense hole on either side of circular main hole or oblong main hole. The defense hole helps to smooth the flow of tensile principal stress flow on the side of circular main hole or oblong main hole. It was observed that by making the hole oblong by 20 per cent of its diameter in the direction of loading, a reduction in the stress concentration of the order of 10-11% cent is achieved. It also was noticed that a further reduction of the stress concentration around the oblong shaped main hole could be achieved by introducing the defense hole system (DRS). The defense holes effects of parametric variation of size and its distance from the oblong shaped main hole was investigated. Generally, stress concentration around the oblong shaped main hole can be further reduced by 14-15% with introducing the defense hole on either side of the main hole which is oblong shaped.