SHPB中借助气动同步装置实现材料高温高应变率测试的可靠性分析

Accuracy Analysis of SHPB Experiment at High Temperatures and High Strain Rates with Pneumatically Synchronous Mechanism

对于不同环境试验温度,针对冷杆与高温试样接触时间问题,采用ABAQUS商用软件系统的模拟了在不同接触时间内高温试样、加载杆的热传导与分布,然后对SHPB中高温高应变率气动同步机构试验方法,利用激光测速技术测试了高温试样与冷加载杆在加载前和过程中可实现的接触时间,对气动同步机构的可靠性和试验测试的有效性进行了分析。结果表明,当接触时间超过约200 ms,高温试样的温度会下降超过约10%;在1 200℃时,接触时间超过500 ms,加载杆端中心温度超过金属杆允许温度约250℃;通过精细调整,本文介绍的高温高应变率SHPB试验气动同步机构可实现10 ms量级的冷杆与高温试样的接触时间,试验验证高温高应变率测试方法具有可信性。

Aiming at the time that specimen with high temperature is in contact with bars with low temperature in different temperature environments, we use ABAQUS software to simulate heat conduction and temperature distribution between specimen and bars at different contact times. Then,Laser velocimetry is used to measure achievable contact time in accordance to SHPB experiment at high temperatures and high strain rates with pneumatically synchronous mechanism. The reliability of pneumatically synchronous mechanism and the validity of experimental test are analyzed. As the results show,the temperature of specimen will drop more than 10% if the contact time exceeds about 200 ms. When the initial temperature of specimen is 1 200 ℃,the core temperature of bars ends will exceeds about 250 ℃ which is the allowable temperature of metal bar if the contact time exceeds500 ms. By means of fine-tuning,pneumatically synchronous mechanism in the present SHPB experiment at high temperatures and high strain rates introduced in order to achieve a cold-hot contact time of 10 ms. The present test method of SHPB experiment at high temperatures and high strain rates is credible verified via testing.