Simulation of Dissipation in Solids

派的名字，机构：卡内基梅隆大学的阿德南·阿凯建议数字建议标题：固体中耗散的模拟项目摘要这个项目涉及固体中耗散的建模和模拟。虽然常见的耗散形式，如内耗散和接触耗散在动力学中起着非常重要的作用，但耗散仍然被视为一种经验现象，没有基于第一原理的描述。固体中的耗散通常描述动能到热的转换，例如，声波通过固体激发原子，并提高它们的能级。原子振动增加的动能定义了固体的热容，假设它们是不热平衡的。对固体中耗散的模拟涉及一个由振荡器组成的3-D晶格，这些振荡器表示通过弹簧相互连接的原子。弹簧代表与位移有关的力，这种力是由原子之间的非线性势产生的。实现这一目标的具体研究任务从非线性连接振子的一维阵列开始，数值地研究不可逆性和等分条件。然后，模拟将扩展到包含杂质的非理想晶格，以描述真实固体，以研究它们在波数(和频率)转换中的作用。这项工作的一个重要方面将是确定模拟的下限，以正确地描述固体中的耗散，并确定量化固体耗散特性的方法。拟议的研究还将通过将模糊阻尼置于关于能量均分和不可逆能量吸收的更基本的基础上，从而有助于澄清模糊阻尼所固有的理论要求。

PI's Name, Institution : Adnan Akay, Carnegie Mellon UniversityProposal NumberProposal Title: Simulation of Dissipation in SolidsProject Abstract This project concerns modeling and simulating dissipation in solids. Although common forms of dissipation such as internal damping and contact damping have a very important role in dynamics, dissipation is still treated as an empiricalphenomenon without a description based on first principles. Dissipation in solids often describes conversion of kinetic energy to heat as in, for example, a sound wave passing through a solid exciting its atoms, and raising their energy level. The increased kinetic energy of the oscillations of atoms define the heat capacity of a solid with the assumption that they are inthermal equilibrium. Simulation of dissipation in a solid involves a 3-D lattice of oscillators that represent atoms connected to each other with springs. Springs represent displacement-dependent forces thatresult from the nonlinear potential between the atoms. The specific research tasks to accomplish this goal begin with a one-dimensional array of nonlinearly connected oscillators to investigate numerically the conditions of irreversibility and equipartitioning. The simulations will then be extended to nonideal lattices that include impurities to describe real solids to investigate their role in wavenumber (and frequency)conversion. An important aspect of this effort will be to determine the lower limit of the size of simulations to correctlydescribe dissipation in a solid and determine means to quantify dissipation characteristics of solids. The proposed investigation will also help clarify the theoretical requirements inherent in fuzzy damping by putting them on a more fundamental footing regarding energy equipartition and irreversible absorption of energy.