Session: Government Agency Student Posters

Paper Number: 173252

Shear-Dominant Ductile Fracture Under Uniaxial Tension Loading in Additively Manufactured Stainless Steel 316l 

The present study explores test specimen geometries designed to induce shear-dominant stress states in stainless steel under quasi-static uniaxial tension loading. Most existing shear-dominant test methods in the literature rely on specialized fixtures or complex loading setups, limiting their accessibility and widespread use. As a result, experimental investigation of ductile fracture under low stress triaxiality remains constrained and relatively less explored. The present work addresses this research gap by developing new geometries and evaluating existing ones that can develop such stress states through uniaxial tension tests using conventional UTM fixtures. This enables simpler testing procedures and promotes broader integration of shear-dominant fracture studies into routine material characterization. The present work is also an effort towards standardized codal provisions for shear-dominant fracture tests of ductile metals. 
The objectives of the present study are as follows: a) to design geometries capable of generating shear-dominant fracture in ductile metals under uniaxial tension loading, b) to construct a fracture locus for low to moderate stress triaxiality (below 0.5), and c) experimentally investigate the shear-dominant fracture response of additively manufactured stainless steel SS316L under such loading conditions. Six geometries were considered in total, with stress triaxiality at fracture ranging from 0.05 to 0.5 in the gauge region. Among these, four geometries were designed to simulate nearly pure shear and the rest two were designed for combined shear and tension in the gauge region. These specimens were additively manufactured using laser power bed fusion (LPBF) with SS316L powder, employing a scanning speed of 700 mm/s, hatch spacing of 0.12 mm, and a layer thickness of 0.05 mm. After fabrication, the support structures and base plate were removed, and the specimens were subjected to hot isostatic pressing (HIP) at a peak temperature of 1150 °C and pressure of 1050 bar in an argon atmosphere, with a hold time of 3 hours, to reduce porosity and improve material integrity. 
Mechanical testing was conducted under displacement-controlled quasi-static uniaxial tension and the strain fields were captured using digital image correlation (DIC). Nonlinear finite element analysis was performed using 3D brick elements with reduced integration and J₂ plasticity model to compute the strain and stress states. Subsequently, volume averaged stress triaxiality of the elements in the gauge section and the equivalent plastic strain were computed. Finally, the fracture locus was constructed using the stress-strain data obtained from the finite element simulations corresponding to the fracture displacement observed during the experiments. The results provide insight into the shear-dominated fracture behavior of LPBF SS316L and offer a robust dataset for establishing fracture criteria under low to moderate stress triaxiality. The poster will present the DIC-based strain fields, load–displacement responses, and fracture locus of SS316L, demonstrating the potential for standardized shear-dominant ductile fracture testing through uniaxial tension tests. 

Presenting Author: Surajit Dey Arizona State University

Presenting Author Biography: Surajit is a PhD student in the School of Sustainable Engineering and the Built Environment at Arizona State University. His research interests include material damage detection, characterization, and modeling with the aid of multi-scale experiments, computational mechanics, and artificial intelligence.

Authors:

Surajit Dey Arizona State University
Ravi Yellavajjala Arizona State University