Acoustic softening and stress superposition in ultrasonic vibration assisted uniaxial tension of copper foil: Experiments and modeling
Acoustic softening and stress superposition in ultrasonic vibration assisted uniaxial tension of copper foil: Experiments and modeling
复制标题
超声波振动辅助铜箔单轴拉伸中的声软化和应力叠加：实验和建模
DOI：
10.1016/j.matdes.2016.09.042
复制
发表时间：
2016-12-15
影响因子：
8.4
通讯作者：
Zhang, B.
中科院分区：
文献类型：
--
作者：
Wang, C. J.;Liu, Y.;Zhang, B.
超声振动在制造过程中被广泛应用，主要是因为声场可以显著影响金属塑性，从而降低应力。然而，关于影响机制的观点尚未达成共识。本文利用自行研制的超声振动辅助单向拉伸装置，对铜箔进行了超声振动辅助单向拉伸实验。结果表明，随着振动幅值的增大，应力降低的程度增大。建立的模型考虑了超声软化和应力叠加两种情况，描述了金属成形过程中超声激励引起的应力降低。考虑到超声振动为位错滑移提供能量，基于晶体塑性理论，考虑超声强度，对声软化进行了分析。考虑到附加周期应变与振动幅值的比例关系，考虑了附加周期应变引起的应力叠加。数值模型的计算结果与实验结果吻合较好。这些研究结果为深入理解超声振动辅助金属变形的应力降低机理提供了有益的参考，对主动设计超声振动辅助金属成形工艺具有重要的指导意义。(C)2016爱思唯尔有限公司版权所有。
Ultrasonic vibration is widely utilized in manufacturing processes mainly because acoustic field could significantly affect the metal plasticity leading to stress reduction. However, viewpoints on the influence mechanism have not reached a consensus yet. In this paper, an ultrasonic vibration assisted uniaxial tension experiment with copper foils is carried out using a specially-developed device. The results show that the extent of stress reduction increases with the increase of the vibration amplitude. Acoustic softening and stress superposition are both considered in a developed model to describe the stress reduction due to ultrasonic excitation during metal forming process. Considering that ultrasonic vibration provides the energy for dislocation sliding, acoustic softening is analyzed based on crystal plasticity theory considering ultrasonic intensity. Stress superposition, mostly induced by the additional periodic strain, is included by taking account of its proportional relationship with vibration amplitude. The calculation results from the numerical model show a good agreement with those from the experiment. These findings provide an instructive understanding of mechanism of stress reduction in ultrasonic vibration assisted metal deformation and are especially helpful for pro-actively designing ultrasonic vibration assisted metal forming processes. (C) 2016 Elsevier Ltd. All rights reserved.