Microstructural Modeling and Probabilistic Prediction of Micro-Electro-Mechanical Systems Response (REU Supplement)

这是一个研究项目，旨在开发一种 更好地理解 材料和结构元件（梁，板， 膜）用于制造 微电子机械系统（MEMS）， 的基础上表现出的微观结构， 材料，目的是评估 这种系统的可靠性。 有效 （总体）物理性能，主要是弹性和 强度，以及相关的结构响应将 评估时应认识到， 许多微观结构的影响， 重要的是， MEMS，但在较长的长度上不重要 鳞片这些包括典型的线性尺寸， 材料中的微晶在同一个 膜厚度的数量级， 晶粒尺寸在整个厚度上的显著变化 和形状，存在相当大的对齐 的晶粒（纹理），导致各向异性的 响应，并产生大的残余应力水平 形成用于创建MEMS的工艺。 这种影响可能妨碍直接适用 结构元素的经典理论，因此 这就需要发展新的理论。 此外， 微观结构，这在很大程度上取决于 过程条件，需要概率 材料行为和结构描述 应对评估旨在评估 MEMS的性能可靠性 为此， 研究将解决：（1）数学建模 材料强度和有效性能，（2） 显微组织对组织的影响 MEMS的响应，以及（3）可靠性分析 微机电系统使用随机有限元方法。

This is a research project aimed at developing an improved understanding of the behavior of materials and structural elements (beams, plates, membranes) employed in the manufacture of micro-electro-mechanical systems (MEMS), on the basis of the microstructure exhibited by the materials, with the goal of assessing the performance reliability of such systems. Effective (overall) physical properties, primarily elasticity and strength, and the associated structural response will be evaluated with the recognition that there are a number of microstructural effects that are important at the length scales associated with MEMS but which are unimportant at larger length scales. These include the typical linear dimension of a crystallite within the material being on the same order of magnitude as the thickness of the film, substantial through-thickness variations in grain size and shape, the presence of considerable alignment of the grains (texture) leading to anisotropy of response, and large levels of residual stress arising form the processes used to create may MEMS. Such effects may preclude direct application of classical theories for structural elements, thus necessitating the development of new theories. Furthermore, the variability inherent in the microstructure, which depends strongly on the process conditions, requires a probabilistic description of the material behavior and structural response evaluation aimed at assessing the performance reliability of MEMS. To this end, this research will address: (1) mathematical modeling of material strength and effective properties, (2) influence of microstructure on the structural response of MEMS, and (3) reliability analysis of MEMS using stochastic finite-element methods.