Modeling of acoustic field dependent tensile property for metal materials

Abstract

Acoustic softening is a physical phenomenon with important application significance. Whether for ultrasonic-assisted metal processing or metal materials serving in the acoustic field environment, quantitative characterization of the impact of the acoustic field on material strength have important technological and engineering values. However, there are few reports on theoretical characterization models that can reveal the evolution of metal material strength with acoustic field. Based on the Force-Heat Equivalence Energy Density Principle, considering the equivalent relationship between acoustic energy and elastic deformation energy, the acoustic field dependent yield strength model of metal materials without fitting parameters is developed; considering the equivalent relationship between acoustic energy and elastoplastic strain energy, the acoustic field dependent ultimate tensile strength model considering strain hardening behavior is developed, and only the fitting parameters introduced in the constitutive equation are included in this model. The predicted results of both models are in good agreement with the experimental results. The quantitative effects of strength coefficient and strain hardening index on ultimate tensile strength under different acoustic fields is analyzed. The critical acoustic energy density is proposed to describe the point of abrupt change of ultimate tensile strength. Further, quantitative comparison of the influence on strain hardening effect and yield strength in different acoustic fields is conducted to explain the rapid decline of ultimate tensile strength. Finally, based on the above conclusions, some useful suggestions for safe use of metal materials under acoustic fields and ultrasonic-assisted machining are put forward.