混合非线性黏弹性阻尼器非线性特征与力学模型研究

随着黏弹性材料的不断发展，出现了具有更大耗能能力和变形能力的新型黏弹性阻尼器，但同时不可避免的丧失了其线性特征。该文基于一种混合非线性黏弹性阻尼器，揭示了其多种非线性特征的来源及规律，并基于此提出和验证了能够全面考虑其非线性特征的力学模型。结果表明，该种混合非线性黏弹性阻尼器的非线性来源主要包括五方面:相位差非线性引起滞回曲线形状的改变、初次加载大应变速率引起的初始刚度、升温效应和疲劳性能引起的软化、马林斯效应导致的大应变幅值下的软化和捏拢效应导致的大应变幅值下的硬化。提出的力学模型数学表达简洁，能够呈现其多种非线性因素和规律，无需在不同工况下分别进行参数识别，与试验结果吻合良好，能够精确模拟其滞回行为。

STUDY ON NONLINEAR CHARACTERISTICS AND MECHANICAL MODEL OF HYBRID NONLINEAR VISCOLEASTIC DAMPER

With the continuous development of viscoelastic material, new types of viscoelastic dampers with improved dissipating performance and deformation performance have been put forward. But inevitably, they also loses linear characteristics at the same time. This paper introduces one type of hybrid nonlinear viscoelastic damper, and explores the characteristics of its nonlinearity. Then an accurate mechanical model, which considers its nonlinearity, is proposed and verified. The results indicate that there are five sources of nonlinearity, including the nonlinearity of phase difference which induces shape change of hysteretic curve, initial stiffness caused by large strain rate during the first loading, softening caused by temperature rise and fatigue performance, softening and hardening under large strain amplitude. The mathematical expression of the proposed mechanical model is concise with less parameters need to be identified. It can present a lot of nonlinear factors and features, such as heating-fatigue softening, ambient temperature dependency, softening and hardening under large strain. Therefore, the parameters are not need to be identified respectively under various cases. The hysteretic loops defined by the model agree well with the testing ones, so the model can simulate the nonlinear behavior of the hybrid nonlinear viscoelastic damper.