Evaluation of SCFs for stiffened tubular joints

Abstract

In this thesis the field of stress concentration factors for use in fatigue analysis is explored. The focus is on stiffened tubular joints, which are common on offshore structures. An analysis methodology is established following a literature study of the subject. Shell and solid analysis is performed for different joint geometries, as well as determination of SCFs by use of parametric flume. Verification of the analysis methodology was performed on two types of joints. One of the joints is a verification specimen from DNVGL-RP-0005 [1]. The other is a simple tubular T-joint from a flare tower. Two case studies are then performed, to compare performance between a simple tubular joints and a stiffened tubular joint. The first case study compares two types of T-joints, one which is simple and one which is stiffened. The second case study is for tubular KT-joints. The first joint geometry is simple and the second is a stiffened joint. SCFs obtained through solid and shell FEM analysis are compared, as well as SCFs determined from parametric formulae.