T型橡胶减振器非线性特性分析与预压缩量设计

Nonlinear characteristic analysis and precompression design of T-shape rubber damper

摘要:

为研究T型橡胶减振器的结构型式和材料性能对其非线性动力学特性的影响,并提高其对飞行环境的适应能力,改善其在恶劣环境下的使用性能,提出了一种含分段线性刚度及阻尼和立方刚度的双层级非线性动力学模型。首先,对T型橡胶减振器进行了简化建模,并采用等价线性化方法,推导得到了分段线性系统的等效刚度和等效阻尼。其次,利用谐波平衡法分别数值模拟了等幅值外力载荷正弦扫频激励下分段线性刚度系统和立方刚度系统的非线性频响函数,验证了构建模型的有效性。最后,进行了T型橡胶减振系统在基础位移正弦扫频条件下的传递特性试验,并与数值计算结果进行了比对。研究结果表明,针对T型橡胶减振器,较低激励载荷即可导致结构型式的渐进软化,较高激励载荷才能引发材料性能的动态软化；该模型能够较好的模拟T型橡胶减振器具有的渐软刚度和渐小阻尼的非线性特性。此外,从航天工程应用的角度出发提出了针对大过载、强振动环境进行预压缩量设计的方法。

Abstract:

T-shape rubber damper has nonlinearity in both type of construction and rubber material. The two-level nonlinear dynamic model with piecewise linear stiffness, damping and cubic stiffness is established. The equivalent stiffness and damping of the piecewise linear system are derived from the equivalent linearization method. The nonlinear frequency response functions of piecewise linear stiffness system and cubic stiffness system under sinusoidal sweep excitation of external load are simulated by harmonic balance method. The results show that lower excitation load can lead to gradual softening of structure type, while higher excitation load can lead to dynamic softening of rubber material. Through the transfer characteristic test of T-shape rubber damper system, it is verified that T-shape rubber damper has the nonlinear characteristics of asymptotic stiffness and asymptotic damping. The correctness of the model is verified by the comparison between the calculation results and the experimental results of sinusoidal sweep excitation of base displacement. From the perspective of aerospace engineering application, the method of precompression design for large overload and strong vibration environment is proposed.