基于梯度温度场的TC4板材热力耦合弹塑性参数虚场识别  

Identification of Thermal-mechanical Elastic-plastic Parameters of TC4 Sheet based on Gradient Temperature Field and Virtual Field Method

作　　者：蔡亚辉 Cai Yahui(National Key Laboratory of Strength and Structural Integrity,Aircraft Strength Research Institute of China,Xi'an.Shaanxi,710065,China)

机构地区：[1]中国飞机强度研究所强度与结构完整性全国重点实验室,陕西西安710065

出　　处：《飞行器强度研究》2024年第4期44-54,共11页Aircraft Strength Research

摘　　要：高温和非均匀应力/应变状态下,准确表征金属板材的各向异性热力耦合属性,对于工程板材零件的结构行为评估至关重要。传统测试方法依赖于状态均匀性假设,导致表征各种高温条件下材料的各向异性热力耦合属性需开展大量测试。本文通过设计双缺口异形试件,并施加中心到夹持端的温度梯度,以实现应力/温度状态的高度异质性,同时采用数字图像相关和红外热成像同步采集全场实验数据,结合虚场法处理数据以提取材料参数。结果表明,可通过单次非均匀加载实验同时准确提取TC4钛合金的各向异性屈服、应变硬化和弹塑性热软化多个参数,且计算效率高,与传统均匀实验相比,大大简化实验过程,为高温测试提供一种有效、便捷的替代识别技术。The accurate characterization of the anisotropic thermal-mechanical constitutive properties of structural sheet metals at elevated temperatures and under nonuniform stress/strain states is crucial for the structural behavior evaluation of an engineering sheet part.Traditional thermal-mechanical testing methods rely on the assumption of states homogeneity,leading to a large number of tests required for the characterization of material anisotropy thermal-mechanical properties at va-rious high temperatures.In this paper,a double-notched tensile specimen configuration is designed and impose a tempera-ture gradient from the center to the clamping end to enable the high heterogeneity of stress/temperature states.Digital im-age correlation and infrared thermography are also used to synchronize the acquisition of full-field experimental data,and the data are processed in combination with the virtual field method to identify material properties.The results show that multiple parameters of anisotropic yield,strain hardening and elasto-plastic thermal softening of TC4 titanium alloy can be extracted simultaneously and accurately by a single non-uniform loading experiment with high computational efficiency.Compared with traditional homogeneous experiments,it greatly simplifies the experimental process and provides an effective and convenient alternative identification technique for high-temperature testing.

关 键 词：梯度温度场 虚场法 全场变形/温度测量 热力耦合属性表征 TC4钛合金 

分 类 号：TG1[金属学及工艺—金属学]