宽带随机应力损伤计算误差分析及改进措施

CALCULATION ERROR ANALYSIS OF WIDE-BAND RANDOM STRESS DAMAGE AND IMPROVEMENT

基于疲劳损伤理论,研究信号分段影响宽带随机应力疲劳损伤计算精度的机理。研究表明,信号分段时将长周期大应力循环截断成小应力循环,以及峰谷值信号重组时将最大应力循环放大,是造成损伤计算偏差的主要原因。提出分段提取峰谷值,再将一定数量的分段峰谷值对接重组进行应力循环提取的信号处理方法。以某混凝土泵车为对象,测试实际工作状态下的应力历程,并采取不同信号分段方案验证该信号处理方法的可行性。研究对其他长周期应力循环占主导地位的宽带随机应力过程的损伤计算也有借鉴作用。

Based on fatigue damage theory, the influence mechanism of signal segment on the damage calculation accuracy was studied. The study shows that the phenomenon of long period large stress cycles be cut into small stress cycles and the amplification of the maximum stress cycle due to signal reorganization is the main reason affecting the damage calculation. The signal processing strategy was improved, which extracts Peak-Valley data from subsection signal at first, then connects and reorganizes a certain number of subsection signal Peak-Valley data, at last extracts the stress cycles. Taking one concrete pump as object, the strain history in practical working condition was tested. Taking different signal segment scheme, the feasibility of the signal processing method was validated. This research can also be used to the damage calculations of other wide random stress process in which long-period stress cycle dominated.