Numerical modelling of stainless steel bolted T-stubs in tension

Recently, a series of experimental tests and accompanying numerical studies has been conducted on austenitic and duplex stainless steel moment resisting connections which highlighted both the excellent ductility and significant overstrength exhibited by such connections as well as the severe conservatism of current design rules specified in EN 1993-1-8 when applied to stainless steel joints. This study builds upon a previous experimental research on bolted austenitic and duplex stainless steel T-stubs in tension conducted by the authors and reports in depth the development and validation of an advanced FE model able to predict the overall behaviour, failure modes and fracture mechanisms of bolted T-stubs in tension. Key simulation strategies regarding the explicit modelling of bolt geometry and overcoming numerical instabilities are discussed and recommendations on best modelling practices are made. The model is utilised thereafter to conduct parametric studies on austenitic, duplex and ferritic stainless steel T-stubs of various geometric configurations, thus investigating the effect of plate thickness, material grade, bolt spacing and bolt strength on the joint plastic resistance, ultimate capacity, ductility as well as overall response. Based on the obtained results, the design provisions of EN 1993-1-8 are assessed.