Evaluation of Mixed-Mode Stress Intensity Factors Using a Small Punch Specimen with a Circular Crack: Preliminary Experiment and an Estimation of Stress Intensity Factors

Cracks often develop under complex loading conditions in practical applications, frequently leading to mixed-mode fracture scenarios. Therefore, accurately predicting fracture conditions, specifically the mixed-mode stress intensity factor (SIF) values and their influences, is crucial for assessing structural integrity. Based on preliminary empirical findings from a literature review of the fracture responses of various materials during small punch (SP) tests under different environmental conditions, we propose a model featuring a circular crack positioned on the bottom surface of the SP specimen to evaluate the I/II mixed-mode SIF. Preliminary results from experimental tests using the proposed model demonstrate its feasibility for replicating fracture behavior and determining mixed-mode SIF values. An analytical estimation of the SIF equation for mode-I and mode-II loading will be conducted using elastic finite element analysis. The effects of crack geometry parameters, including the crack ratio (a/t) and the radius of the circular crack, on the mixed-mode fracture parameter were investigated.

Graphical Abstract