A Probability Distribution Model for the Degree of Bending In Tubular KT-Joints of Offshore Jacket-Type Platforms Subjected To IPB Moment Loadings

Abstract

Article History: Received: 5 Mar. 2019 Accepted: 1 Sep. 2019 The objective of present research was the derivation of probability density functions (PDFs) for the degree of bending (DoB) in tubular KT-joints commonly found in jacket-type platforms. A total of 243 finite element (FE) analyses were carried out on 81 FE models of KT-joints subjected to three types of in-plane bending (IPB) moment loading. Generated FE models were validated using experimental data, previous FE results, and available parametric equations. Based on the results of parametric FE study, a sample database was prepared for the DoB values and density histograms were generated for respective samples based on the Freedman-Diaconis rule. Thirteen theoretical PDFs were fitted to the developed histograms and the maximum likelihood (ML) method was applied to evaluate the parameters of fitted PDFs. In each case, the Kolmogorov-Smirnov test was used to evaluate the goodness of fit. Finally, the Generalized Extreme Value model was proposed as the governing probability distribution function for the DoB. After substituting the values of estimated parameters, nine fully defined PDFs were presented for the DoB at the crown, toe, and heel positions of the central and outer braces in tubular KT-joints subjected to three types of IPB moment loading.