EFFECT OF THERMO-ELECTRO-MECHANICAL COUPLING AND NON-LINEARITIES ON DYNAMIC PROCESSES IN INELASTIC LAYERED STRUCTURES

结构及其构件的受迫振动分析在可变形系统动力学中占有重要地位。结构及其构件的动态和准静态响应的准确预测是一个巨大的挑战，因为结构的材料在强烈载荷下可能变得塑性和/或表现出粘性。在设计风荷载和地震荷载下建筑结构振动的金属阻尼器、管道振动抑制装置、低周疲劳试验中的试样等时，应研究可变粘弹塑性行为。众所周知，材料的非弹性变形伴随着由于机械能耗散而释放的热量。当这种热效应总是要考虑的时候，我们至少可以区分两类过程。第一类包括强烈的单调或循环塑性变形。在某些条件下，例如冲击载荷或共振，耗散加热可能达到显著水平。例如，在评估阻尼系统元件的适用性或开发材料低周疲劳加速分析技术时，应考虑到这一点。在高速加载条件下，粘塑性体中的耗散加热对绝热剪切带的形成起着关键作用。第二类包括热电机械材料模型，检测缺陷的热成像技术，裂纹扩展的非等温模型，主动振动控制的不同方法等加热可能会改变结构的强度，恶化其性能，并在不利条件下，甚至导致故障。几何非线性和非均匀性是额外的复杂因素。动态特性、非线性（非弹性和几何非线性）以及热-电-机械耦合的综合影响涉及复杂的行为模型。因此，精确模拟薄壁非弹性被动和主动构件的复杂动态和准静态过程需要开发新的方法，以成功地解决这个问题。提出的工作是非常及时的，因为在层状结构中的机械，电气和热场之间的相互作用是目前的强烈学术和工业兴趣的主题。上述相互关系和耦合的探索有望发现新的有趣的和工业上有价值的effects.The拟议的研究的总体目标是提高我们的理解复杂的耦合过程中的薄壁非弹性结构，可以包含主动和被动层，可以经历密集的循环或冲击载荷。我们打算澄清的作用，如固有的动态特性，材料和几何非线性，应力应变状态的异质性和耦合的机械，电气和热场可以发挥在定义结构响应，与发展的一般设计准则，以实现必要的生产力和可靠性的结构的长期目标。

The forced-vibration analysis of structures and their members occupies a significant place in the dynamics of deformable systems. An accurate prediction of the dynamic and quasi-static response of structures and their members is a huge challenge, since the material of a structure may become plastic under intensive loading and/or exhibit viscous properties. Variable viscoelastoplastic behaviour should be studied when designing metal dampers for the vibrations of building structures under wind and seismic loads, devices for suppressing vibrations of pipelines, test specimens in low-cycle fatigue tests, etc.It is well known that the inelastic deformation of a material is accompanied by release of heat due to dissipation of mechanical energy. We may distinguish at least two classes of processes when such thermal effects should be always taken into account. The first class includes intensive monotonic or cyclic plastic deformation. Under certain conditions such as impact load or resonant vibrations, the dissipative heating may reach a significant level. This should be taken into account, for example, in evaluating the serviceability of elements of damping systems or when developing the techniques for accelerated analysis of the low-cycle fatigue of materials. The dissipative heating plays a key role in the formation of adiabatic shear bands in viscoplastic bodies under the high-speed loading. The second class includes thermo-electro-mechanical material models, thermographic techniques for detection of defects, non-isothermal models of crack propagation, different approaches to active vibration control, etc. The heating may change the strength of the structure, deteriorate its performance, and, under adverse conditions, even cause failure. Geometrical nonlinearity and heterogeneity are the additional complicating factors.The combined effect of the dynamic properties, nonlinearity (both inelasticity and geometrical nonlinearity) as well as the thermo-electro-mechanical coupling involves complex behavioural models. Therefore, an accurate simulation of complex dynamic and quasi-static processes in thin-wall inelastic passive and active members demands new approaches to be developed in order to successfully attack the problem. The proposed work is very timely because the interaction between mechanical, electric and thermal fields in layered structures is currently the subject of strong academic and industrial interest. Exploration of the said interrelations and couplings promises the discovery of new interesting and industrially valuable effects.The overall aim of the proposed research is to improve our understanding of the complex coupled processes in thin-wall inelastic structures that can contain both active and passive layers and can experience intensive cyclic or impact loading. We intend to clarify the role that such factors as the inherent dynamic properties, the material and geometrical nonlinearities, heterogeneity of the stress-strain state and the coupling of the mechanical, electrical and thermal fields can play in defining the structure response, with a long-term goal of development of general design guidelines to achieve the necessary productivity and reliability of structures.