Finite element-assisted fatigue life evaluation of notched Aisi 316l: Comparative insights into v-notch and rectangular notch geometries

The present work illustrates a comprehensive fatigue life assessment methodology for notched AISI 316L stainless-steel specimens employing a hybrid experimental-FEM framework. V-shaped and rectangular notches were introduced into fatigue specimens designed as per ASTM E606 standard to represent real-world geometric discontinuities. Tensile strength was evaluated from experimentation and used as input to in ANSYS Workbench 18.1 to simulate fatigue behaviour under cyclic axial loading. A Taguchi L9 orthogonal design was used to vary notch width, depth, and central angle to quantify their effect on the fatigue response. Results showed a drastic reduction in fatigue life due to notches in all cases. V-notches yielded higher stress concentrations and lower fatigue lives than rectangular notches in most of the cases. The un-notched specimen under the same loading experienced a maximum stress of 228.91 MPa and infinite fatigue life whereas the notched specimens experienced an extreme decrease in fatigue life with values between 68 to 17720 cycles. The rectangular notches promoted broader plastic zone development and favourable stress redistribution, whereas V-notches localized strain energy, expediting crack initiation. Central angle and depth were found to be the most critical parameters for V- and rectangular notches respectively. Quantified insights about fatigue life degradation due to notch profiles is attained by this work and it is critical for biomedical, marine, and structural applications.