Web crippling design of Cold-Formed sigma sections - IOF load case

Sigma sections are one of the innovative sections modified from the conventional section to improve its bending and shear capacity. However, web crippling behaviour of Cold-Formed (CF) sections is considered as crucial aspect considering its higher slender values. Hence, web crippling behaviour of CF sigma sections must be scrutinized. Limited studies have been conducted on sigma sections. Therefore, this research paper intends to numerically analyse the web crippling behaviour of sigma sections made of CF carbon steel, aluminium, and stainless steel under IOF load case. The numerical approach was opted based on the numerical verification study and comprehensive parametric plan consisting of 756 models was selected. The parametric plan accommodates the key parameters of CF sections based on the literature available. Accordingly, numerical models were developed, and numerical analysis was conducted with the aid of ABAQUS/CAE 2020. The results from the numerical analysis are presented for all three material sigma sections. Detailed analysis regarding the effect of parameters on the web crippling capacity is provided. In addition, the existing design equations were checked for their applicability to predict the web crippling capacity of sigma section under IOF load case. As they were found inapplicable, new modified design provisions were developed and presented to accurately predict the web crippling capacity of sigma sections.