一种新的LTFCPR微机测试系统

 介绍微机辅助低温疲劳裂纹扩展速率测试系统,采用温度补偿翻转电位法,可以消除零点漂移、热电势及电阻率的温度效应等所引起的测试误差。对控温信号采用了锁存技术,可以消除电机起动与停止导致电网波动所引起的采样误差。采用低通滤波加数值补偿数据平滑技术,可以减小数据不平滑度且又避免了裂纹长度显示值滞后于实际值的现象。求da/dN的数值求导采用座标变换旋转放大卷积割线法。可提高求导精度。

A NEW LTFCPR MEASUREMENT SYSTEM BY USING MICROCOMPUTER

A new microcomputer aided system for measuring LTFCPR in near-threshold region is developed in our laboratory, having the following five special features: (1) By using the temperature compensation technique, the measurement error caused by temperature effect of resistivity can be eliminated. (2) By using reversal electrical technique, the zero drift and thermal eiectrical potential effect can be eliminated. (3) By using signal latching technique on temperature contrcller, the measurement error caused by electric network fluctuation induced by start-up and shut-off motor can be eliminated. (4) By using data smoothing technique of low-pass filtering and numerical compensation, the degree of smoothness of numerical data can be conspicuously increased, and the phenomenon of crack length displaying value lagging behind actual value can be eliminated. (5) By using the coordination rotation and amplification convolution secant method, the derivative (da / dN) accuracy is effectively improved.