Local Joint Flexibility: A study to modelling LJF into a beam model, for fatigue design of a stinger

Master thesis (2021)

Authors

E. Wierenga Mechanical Engineering

Contributors

X. Jiang Transport Engineering and Logistics - Mechanical, Maritime and Materials Engineering (mentor)
D.L. Schott Transport Engineering and Logistics - Mechanical, Maritime and Materials Engineering (mentor)
NS Ermolaeva (mentor)
Yanrong Yu (mentor)
Faculty
Mechanical Engineering, Mechanical Engineering
Copyright: © 2021 Ezra Wierenga
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Published Date

06-09-2021

Language

English

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Faculty

Mechanical Engineering

Abstract

As part of the fatigue assessment of a stinger, member loads on tubular joints are determined with a beam model. A beam model is a simplified method of modelling complex structures out of circular hollow sections. In a standard beam model, no attention is paid to modelling the tubular joint itself. In the model, beam elements of the braces are extended from the surface of the chord to the centerline of the chord. This connection is considered as rigid. In reality, tubular joints possess considerable elastic flexibility through local deformation of the chord wall. It is suggested that modelling local joint flexibly leads to a reduction of member-loads and thereby an increase of predicted fatigue life. A method to determine and model local joint flexibility in a beam model is developed. A numerical test-case is performed to investigate the influence of modelling LJF on the predicted fatigue life of the braces in the stinger. As effect of modelling LJF, the accumulated fatigue damage in the critical hot spots of the braces has changed with factor 0.29 up to factor 2.88. This would result in a change in predicted fatigue of factor 0.35 up to 3.45 as effect of modelling LJF.

Files

Thesis.pdf
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