Reliability approach for lifetime prediction of the aluminum extrusion dies

Abstract

This paper introduces a probabilistic approach for predicting the lifetime of extrusion dies using a structural reliability method known as stress-strength interference. In our investigation, we have integrated the assessment of the die's cycle life by following behavioral and rheological law. The approach relies on estimating the reliability index through a combination of a behavioral model and a reliability analysis of the hot extrusion process. Subsequently, the reliability analysis is conducted using a mechanical model to depict the most likely failure conditions. In this regard, the rheological law of Hansel & Spittel emerges as the most suitable choice, as it incorporates the mechanical properties of the materials employed in the fabrication of hot tools. The proposed mechano-reliability approach enables us to estimate reliability and its sensitivity by adjusting the parameters controlling the input process in die formation. Numerous scenarios involving extrusion dies were considered. The results demonstrate that temperature's impact on the die during the extrusion process is manifested through fatigue and damage parameters, as well as the first equivalent strain, which affect the evolution of the reliability index β and subsequently enhance the number of billets extruded.