一种基于复模量的粘弹减摆器非线性VKS改进模型

根据粘弹减摆器单频、对称激振实验获得的复模量数据,对粘弹减摆器的非线性VKS模型进行了参数识别;为了使模型适用于单频及双频条件,提出了一种考虑频率修正的非线性VKS改进模型,并用单频及双频条件下的复模量实验数据对分析模型进行了验证。改进模型可以正确地反映出粘弹减摆器复模量的非线性特性,可用来预估其单频及双频条件下的复模量特性。应用该模型进行了直升机空中共振分析,发现某直升机从悬停到前飞,其摆振后退型模态阻尼下降了37%左右。

AN IMPROVED NONLINEAR VKS MODEL OF ELASTOMERIC LAG DAMPER BASED ON ITS COMPLEX MODULUS

Based on complex modulus of elastomeric lag dampers obtained from bench mark test undergoing symmetrical and single frequency excitations, nonlinear Voigt-Kelvin Solid (VKS) model parameters are identified. An improved nonlinear VKS model is presented accounting for frequency modifications so as to be appropriate for both single and dual frequency cases. The improved model is then verified by correlating with test data. The updated model can capture the nonlinear characteristics of complex modulus of elastomeric lag dampers. Hence the model is applicable to the predictions of complex modulus for single and dual frequency situations. The improved model is applied in helicopter air resonance stability analysis. Result shows that the regressive lag modal damping decreases by about 37% as helicopter flies from hovering to forward flight.