中红外固体激光器的振动可靠性

Vibration reliability of mid-infrared solid laser

基于ANSYS建立了中红外固体激光器的有限元仿真计算模型,通过模态分析获取了固体激光器的各阶固有频率、振型等模态参数。结合非接触测振技术搭建了振动模态试验平台,通过试验与仿真对比,验证了模态仿真模型的可靠性。然后,在模态仿真的基础上,通过谐响应分析,重点研究了激光器光学晶体组件在车载正弦扫频振动下的振动特性,获得了等效应力、总机械应变以及位移与激振频率的关系。最后,分析了影响激光器振动可靠性的关键位置,为改进设计提供了有益的参考。结果表明,2 000 Hz以内,底面固定约束的中红外固体激光器共有4阶固有频率与振型,试验与模态仿真得到的振型描述一致,且固有频率误差小于8%,车载扫频振动条件下,最大总机械应变和等效应力均出现在扩束器的输入镜边缘,沿光学晶体组件轴向的位移最大,其值约为0.14 mm。

Based on ANSYS, finite element simulation calculation model of mid-infrared solid laser was established, and modal parameters, such as natural frequency and vibration mode were gained through modal analysis. Combined with non-contact vibration measurement technology, the vibration modal test platform was set up, and the reliability of the modal simulation model was verified by the comparison with the test. Then, on the basis of modal simulation, the vibration characteristics of laser optical crystal assembly was studied emphasisly under condition of sinusoidal frequency sweeping vibration of vehicle through response analysis, and equivalent stress, total mechanical strain, relation between displacement and excitation frequency can also be obtained. Last,the key positions that affecting the vibration reliability of laser were analyzed and the results provide useful reference for improving design. The results indicate that there are four natural frequencies and modes in middle infrared solid laser using bottom fixed constraint, within 2 000 Hz and the experimental results of the modal agree with simulation results, and the natural frequency error is less than 8%. The maximum total mechanical strain and equivalent stress appeared at the edge of the input mirror under the condition of vehicle frequency sweeping vibration. The axial displacement along the optical crystal assembly is the largest and its value is about 0.14 mm.