Fatigue Failure Prediction of U-Notched ZK60 Magnesium Samples Using the Strain Energy Density Approach

Abstract

The light weight of magnesium alloys makes them a promising material in different potential industries, such as aerospace and automobile. In addition, magnesium alloys are attractive materials for biomedical applications due to their biocompatibility with the human body. The applications of these alloys in structural parts require an understanding of their fatigue behavior because they are usually subjected to time-varying loading. Furthermore, notches are inevitable in structural parts. Geometrical discontinuities weaken structures because they act as stress raisers. Localized cyclic plasticity around notches leads to crack formation and final failure. The main objective of this research was to investigate the fatigue failure of ZK60-T5 extrusion in the presence of a notch. U-notched specimens with a diameter of 16 mm, notch radius of 1.5 mm, and notch depth of 1.5 mm were machined along the extrusion direction. Cyclic tests were performed under completely reversed cyclic loading and ambient conditions. The results obtained from the cyclic tests of the U-notched specimens were compared with those of unnotched and V-notched specimens to assess the effects of both the presence and the geometry of a notch on fatigue life. The strain energy density approach was successfully used to analyze the fatigue behavior of the U-notch specimens.

Estimation of mixed-mode I/II fracture of U-notched polycarbonate specimens using the TCD and SED methods

“…Он основан на критерии плотности энергии деформации (SED), который был разработан Lazzarin и Zambardi [19]. Критерий SED также широко используется для анализа разрушения образцов с надрезом из различных материалов: сталь [20], алюминий [21], титан [22], магний [23][24][25], ПЭЭК [26], ПММА [17,27]. Третий подход основан на использовании коэффициента интенсивности напряжений в вершине надреза (NSIF) [28][29][30].…”

Estimation of Mode I Fracture of U-Notched Polycarbonate Specimens Using the Equivalent Material Concept and Strain Energy Density

“…However, such models require extensive computational effort. Engineering design models such as the strain energy density (SED) [23] and the theory of critical distance (TCD) [24] have been successfully used to analyze the failure of notched members with different notch geometries and materials, and under both static and cyclic loading [25][26][27][28][29]. A key advantage of these models is that they do not require elastic-plastic or complex computational analyses and yet provide accurate predictions.…”