Finite element analysis of ship structural connections (fracture of ships)

Abstract

The stress analysis for a right angled welded joint is characterized with some level of difficulty when assessing results from finite element analysis. Setting up the model itself and undertaking the analysis needs some skill and also takes longer time to interpret the results. This paper, reports of some work done to derive empirical equations which is to help provide a direct calculation method for fracture mechanics stress intensity factors and also provide a better understanding of the nature of the stress field when such details are under axial or bending loading conditions. The stress singularity caused by the presence of a 90° corner for ship structural connections is investigated through the means of finite element analysis
techniques and the suitability or otherwise of a formula to evaluate the characteristic size of the singularity to the corner in a 2D case is verified for a 3D case. Along with fracture mechanics elements in finite element  method, the behavior of a crack in a corner is also investigated for   different loading conditions (tension and bending) to evaluate the  parameters 'ae'(additional crack length) and 'Y'(correction function).

Keyword: finite element, fracture mechanics, fatigue, structural detail.