Entropy generation approach for evaluating energy dissipation and temperature rise to predict the fatigue life behaviour in magnesium alloy

Abstract

The objective of this present study is to use entropy generation to predict the fatigue life behaviour of magnesium alloy. As the energy dissipation rate directly correlates with material degradation and increases in temperature, the entropy generation was developed while considering the thermodynamic framework. By performing the compact tension test, the effect of different stress ratios and compaction loads was examined to determine the correlation between energy dissipation rate and increase in temperature. An empirical model to predict the amount of entropy change has been developed by using descriptive statistics as the statistical method. Therefore, the degree of dispersion should be a good indicator to describe the actual characteristics of a data set. The amount of entropy generated increased as the number of cycles to failure increased. The data sets of the temperatures were also collected and analysed to determine the amount of entropy generated. The lowest amount of entropy (2.536 MJm−3 K−1) was generated when the magnesium alloy was subjected to a load of 3000 N at R = 0.7. The entropy generation of magnesium alloy ranged between 2.536 MJm−3 K−1 and 3.454 MJm−3 K−1. Therefore, examining fatigue life with entropy generation provides a better understanding of the fatigue life determination measure for the fatigue failure mechanism.

Keywords

• Temperature change
• Energy dissipation
• Entropy generation