薄壁结构高温随机振动疲劳分析方法有效性验证

Random Vibration Fatigue Analysis Method Valid Verification of Thin-Walled Structure under High Temperature Environment

关键词:  薄壁结构  热振疲劳  仿真分析  试验验证

Key words:  Thin-walled structures  Thermal vibration fatigue  Simulation analysis  Experimental verification

摘要:

为了研究航空薄壁结构高温随机振动疲劳破坏机理，得到可靠的疲劳寿命分析方法，针对根部固支的GH188薄壁结构进行了数值仿真。重点研究了不同温度和不同振动量级组合下，薄壁结构危险点位置轴向动应力响应规律。采用改进的雨流计数法绘制出雨流循环矩阵和雨流损伤矩阵，结合疲劳累积损伤理论估算薄壁结构的疲劳寿命。通过高温随机振动疲劳试验对上述仿真结果进行验证。结果表明:数值仿真对结构破坏位置判断准确，不同温度和随机振动载荷作用下响应的计算值与试验值获得很好的一致性，响应峰值频率误差在1%～3%，结构疲劳寿命与试验结果处于同一量级，证明了高温随机振动疲劳分析方法的有效性和精度以及仿真结果的可靠性。

Abstract:

In order to research on the fatigue failure mechanism of aeronautical thin-walled structure in random vibration and high temperature environment， and to acquire reliable analytical methods of fatigue life， targeting on the GH188 thin-walled structure which is root supported， numerical simulation was carried out. Researches were mainly focused on the X-stress response rules of structure’s dangerous position， under the combination of different temperatures and different vibration magnitudes. The improved rain-flow counting method was used to plot rain flow cycle matrix and rain flow damage matrix， the fatigue cumulative damage theory was employed to count the fatigue life of thin-walled structure. The aforementioned simulation results were validated through thermal vibration fatigue experiment， and the results showed that the numerical simulation was accurate to the position of structural damage， the calculation value and experimental value of responses had good consistency under different temperature and vibration magnitude loading， the error peak of response frequency was between 1% ～ 3%， the structural fatigue life and the experiment results were in the same order of magnitude， which proved the validity and accuracy of high temperature random vibration fatigue analysis method， as well as the reliability of simulation results.