火箭动态弯矩测量的频响特性分析

介绍了火箭动态弯矩测量的方法和原理,利用横向弯曲振动梁理论,首次推导了悬臂梁和自由梁的端面弯矩动态放大倍数表达式,对箭体结构偏保守地计算了不同边界条件的载荷动态放大倍数。动态弯矩测量的频响范围可达到100Hz,测量部段的壳体响应频率(约150Hz)不影响30Hz以下的截面载荷测量结果,箭体动态弯矩测量方法的频响特性满足测量要求。另外分析了箭体直径变化的影响,比较了箭体动态弯矩测量与风洞测力天平的异同。

Frequency response characteristic analysis of the measurement about dynamic bending moment for launch vehicles

The theory and method of dynamic bending moment measurement were presented in this paper. The dynamic amplification coefficients of bending moments for both a cantilever beam and a free-free beam were deduced for the first time with the transverse bending vibration theory of a beam. The load amplification coefficients of the launch vehicle structure were calculated conservatively under different boundary conditions. The range of the frequency response about the dynamic bending moment measurement was up to 100Hz. While the cross section load measurement, whose frequency spectrtLrn range is less than 30Hz, would not be affected by local shell model frequency （approximately 150Hz）. Therefore, the frequency response characteristic of the load measurement system was accuracy enough. Additionally, the effect of launch vehicle diameter to the measurement was analyzed. Also the difference between this measuring method and the forcing balances of wind tunnel was assessed too.