考虑热力耦合的橡胶减振器阻尼特性

针对橡胶减振器在热力耦合减振过程中的温度和阻尼特性的变化进行分析,引入大应变黏弹性本构模型描述橡胶材料的非线性变形和黏弹性行为。对橡胶材料进行静态试验拟合得到超弹性本构模型系数,进行动态机械分析获得材料的储能模量时程曲线和损耗因子时程曲线并拟合得到Prony级数系数。假设生热率为非弹性变形产生的能量,对模型施加边界条件和热对流边界,基于热力耦合理论对有限元模型进行分析。结果显示:模型中心温度最高,并由中心向边缘逐渐降低;不同频率下的表面温度与试验值较为接近。由于非弹性效应橡胶减振器结构动刚度和损耗因子均有损失。初始耗散能随频率增大而明显增大,随温度升高缓慢减小;最终耗散能对频率和温度变化不敏感,趋于稳定。

Damping Properties of Rubber Isolator Considering Thermomechanical Coupling

The change of temperature distributions and damping properties of rubber isolator are analyzed considering thermomechanical coupling process. Large strain constitutive model is introduced to describe non-linear deform and viscoelasticity simultaneously. The parameters of strain energy function are fitted by static tensile test of the material specimen. The time history curves of storage modulus and loss factor are tested by dynamic mechanical analysis (DMA). According to the DMA results the coefficients of Prony series are obtained by optimization. Assumed that the heat generation is equal to the energy produced by the inelastic deformation, thermomechanical coupled problem is computed by finite element method with proper mechanical boundary and heat convection boundary. The result shows that the heat built-up appears in the center of the model and the temperature declines from inside to outside. The simulated temperatures on the surface are close to the experiment. The stiffness and loss factor decline because of the inelastic effect. The initial dissipated energy obviously increases with the increase of frequency and decreases slowly with the temperature rising. The finial dissipated energy is insensitive to frequency and temperature, which is stable at different frequencies.