Numerical studies of residual stress in cold formed steel sigma sections

Wang, Feiliang (2015). Numerical studies of residual stress in cold formed steel sigma sections. University of Birmingham. Ph.D.

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Abstract

Residual stress is a self-balanced internal stress generated in the metal component when it is loaded beyond the elastic plateau and then unloaded. The existence of residual stress will be superimposed onto the external loadings to affect the stiffness and load resistance capacity of the structures. The most common sources of residual stress in CFS sections are cold working process and heat-treating operation. The primary motivation of this thesis is to provide a numerical solution for exploring the distribution and effect of cold working and welding residual stress on CFS sigma sections. Initially, the magnitude and distribution of coiling-uncoiling, press braking, roll forming and welding residual stress in sigma sections are presented. Parametrical studies are conducted to investigate the influences of input parameters on the numerical model. Numerical prediction validity is evaluated with analytical solutions and measured result from the X-ray diffraction measurement. Moreover, for investigating the influence of residual stress on structural beam in sigma sections, comparisons are performed based on the finite element (FE) analysis between the virgin model without cold work effects and modified model incorporated the effect of residual stress and strain hardening. Finally, some conclusions and the recommendations for future works are presented.

Type of Work:

Thesis (Doctorates > Ph.D.)

Award Type:

Doctorates > Ph.D.

Supervisor(s):