A STRUCTURAL ANALYSIS OF STRESS CONCENTRATION FACTOR OF RECTANGULAR OPENINGS IN SHIPS WITH VARIOUS CORNER RADII

Abstract

Plate discontinuities are a typical occurrence in ships. Such common discontinuities include hatch openings on decks, doors, and windows on superstructures, sea inlets and bow thrusters on hull sides, lightening holes on floors, manholes, etc. Most of the time, these openings are rectangular, circular, and elliptical in shape. The stress is concentrated near the apertures because ships are always under stress during their operation. If the corners of the openings are sharp, the stress concentration increases dramatically, making it more likely for the concentrated energy to be released by crack propagation. A lot of research has been done on circular and elliptical openings. As a few studies on rectangular openings have been found, the stress concentration factor on rectangular openings for various corner radii has been chosen as the topic. Four parameters have been considered in this research: opening size, corner radius, opening orientation, and plate dimension. A lot of models, considering different corner radii for different opening size and orientation, have been assessed by renowned Finite Element software ABAQUS. The results have been shown by analyzing ABAQUS results and reports and preparing tables and graphs. The von-mises stress is analyzed mainly at nodal points for the most vulnerable regions of different openings. The maximum stress concentration for each model has been used for comparison. As an inclined opening could lead to a higher stress concentration factor, it is also investigated in this research. Finding the optimal shape of the opening for a particular geometric configuration is the target of this study which has been successfully achieved. The authors believe this study will be a guide for Naval Architects in designing ships ensuring safety more accurately.

Keywords: Rectangular Opening, Von Mises Stress, Stress Concentration Factor.