Investigation on mechanical behaviors for bolted connections in carbon steel and in stainless steel using FEM

Abstract

A finite element (FE) analysis with three-dimensional solid elements has been performed for estimating the structural behaviors of single shear bolted connections fabricated with cold-formed austenitic stainless steel by utilizing the existing test data for calibration. Failure and curling (out-of-plane deformation perpendicular to the direction of loading) criteria were proposed. Therefore, the failure mode and ultimate strength, predicted by FE analysis method, showed good agreements with those of experimental results. In this study, FE analyses for 10 test specimens fabricated with cold-formed carbon steel as well as stainless steel including failure mode of bolt shear fracture are carried out and the validity of numerical prediction for ultimate behaviors in cold-formed carbon steel bolted connections is also verified, based on the applicability of FE method for predicting the mechanical behaviors of bolted connections in cold-formed stainless steel. It is known from the coupon test results of steel materials that austenitic stainless (SUS304) steel has a higher tensile strength of material due to the effect of strength enhancements (considerable strain hardening) by means of cold-working process and much lower yield stress when compared to carbon steel. The influence of curling on the strength reduction of bolted connections is estimated quantitatively. In addition, characteristics of mechanical behaviors and the influence of curling in bolted connections between two different steel materials are compared through detailed investigation of FE analysis results.