导弹模拟件水下动态特性试验研究

Dynamic Characteristics of Model Missile Under Water

导弹水下发射时 ,附连水质量对结构系统的动态特性具有不同程度的影响 .基于流固耦合以及模态理论 ,分析了流体介质环境对结构系统动态特性的影响表现为结构系统模态质量的变化 .在此基础上利用实际导弹缩比模型 ,分别在空气和水两种介质环境中进行了振动模态试验 ,时域模态分析结果定量地给出了附连水质量对导弹结构系统模态特性的影响关系 .附连水质量引起的结构模态质量的增加对导弹模型结构低阶弯曲模态频率的影响比较明显 ,对高阶弯曲振动的模态频率、系统的阻尼比以及纵向振动的模态频率影响较小 .对弯曲振动的细长体导弹类结构 ,入水深度所产生的影响相对较小 .

The influences of water on the submerging structural system are theoretically analyzed using the modal theory,and the influences take the form of variation of modal mass in the system.Modal experiments have been carried out both in air and under water using a scaled model missile,and a series of quantitative effects are obtained from the analysis in time domain,the added mass impact on the dynamic behaviors of the model missile.The modal mass increase due to the added mass of water would greatly reduce the lower bend modal frequency,and have little influences on the damping ratio and the modal frequency in its lengthways.Furthermore,the depth of a structure submerged in water need not take into consideration the bend vibration of such a long and thin structure of missile.As a result,much attention should be paid to those incidences of added mass in practice for the design of structural dynamic characteristics of missiles under water.