变温场中热应力测试技术研究

变温场中非金属材料因温度变化所受到的拉压应力，可利用金属丝的应变－电阻效应把构件表面的应变量直接变换为电阻相对变化量的原理，通过电阻应变片进行其应变测量。已知主应力方向的单向应力状态时，沿主应力方向贴1 片应变片可测得主应变。已知主应力方向的二向应力状态时，粘贴相互垂直的2 片应变片可测得主应变。未知主应力方向时，应粘贴相互成45°的3 个应变片测其应变分量并换算成主应变。由铜－康铜T 型热电偶测温传感器、BE120- 2BA 双向应变片测应变传感器、FLUKE 2285B 数据采集器、计算机及其应用程序构成的变温场中热应力测量系统，实现了应变和温度的同时测量及其数据采集、处理、显示等。
关 键 词 ： 热应力； 温度测量； 应变测量； 变温场
Abstract: The expanding and contracting strain of nonmetal material in change temperature field varies with temperature. Using strain resistance effect of metal wire, the strain variable of surface of component is changed into relative variable of resistance, the strain variable is measured with resistance strain chip. When the state of single -way stress to main stress direction was known, a strain chip is attached along main stress direction, the strain variable can be measured. When the state of double-way stress to main stress direction was known, two strain chips each other are attached perpendicularly, the strain variable can be measured. When the main stress direction was not known, three strain chips each other are attached in 45°angle , the local strain variable can be measured and is converted into the main strain variable. The test system for the heat strain in change temperature field is composed of copper T thermocouple temperature sensor, sensor with BE120-2BA double-way strain chip, FLUKE 2285B data acquisition device, computer and application program. The strain and the temperature measured at one time, and the stress test, data acquisition, data processing and displaying are realized.
Key Word: Heat strain; Temperature measure; Strain measure; Change temperature field