A Computational/Experimental Multiscale Approach to the Analysis of Structures Containing Mechanical Joints

包含机械接头的结构的计算/实验多尺度分析方法机械接头是结构的组成部分，影响着结构的性能和可靠性。节点提供子结构之间的耦合力和力矩，并引入局部柔度和耗散。尚未完全了解的关节动力学方面包括接触界面之间滑动过程的性质，远离连接元件的配合表面的局部冲击，对配合表面粗糙度的响应敏感性，以及在响应预测过程中引入不确定性的污染物和润滑剂。提出的研究工作包括尺度表示、有效的精细尺度估计和尺度间耦合的新进展。拟议工作的一个主要贡献将是系统地将空间分解为大尺度和小尺度，后者在数学上被注入到前者的计算中。另一个将是将接合界面表示为强不连续，从而导致界面通量项，为以变化一致的方式嵌入本构定律提供自然机制，以及产生所需界面本构行为的新实验。这些结果将通过课程材料、会议报告和在档案期刊上发表而广泛传播。与研究工作相结合的是一项教育和推广计划，目标是迅速接近未来职业决定形成年龄的中学生，最初是通过与尚佩恩的杰斐逊中学合作。将发展针对紧固件技术的课堂演示和实验。招收本科生和研究生；理想的是广泛的人口统计，用于研究，构建演示和实验，并在学年期间指导中学生。

A Computational/Experimental Multiscale Approach to the Analysis of Structures Containing Mechanical JointsMechanical joints are integral to structures, affecting performance and reliability. Joints provide coupling forces and moments between substructures, and introduce localized compliance and dissipation. Aspects of joint dynamics not fully understood include the nature of the slipping process between contacting interfaces, local impacts at mating surfaces away from the connecting elements, sensitivity of response to roughness of mating surfaces, and contaminants and lubricants which introduce uncertainty into the process of response prediction. The proposed research effort includes new developments in scale representation, efficient fine-scale estimation, and interscale coupling. A major contribution of the proposed work will be a systematic spatial decomposition into large and small scales, where the latter are mathematically injected into the calculations for the former. Another will be the representation of the joint interface as a strong discontinuity, leading to interfacial flux terms that provide a natural mechanism for embedding the constitutive laws in a variationally consistent fashion, and novel experiments yielding the required constitutive behavior of the interface. These results will be broadly disseminated, through course materials, conference presentations, and publication in archival journals. Integral with the research effort is a plan for education and outreach, targeting middle school students quickly approaching the age where future career decisions are formed, initially through partnership with Jefferson Middle School in Champaign. Classroom demonstrations and experiments addressing fastener technologies will be developed. Undergraduate and graduate students will be recruited; ideally a broad demographic, for research, to construct demonstrations and experiments, and to mentor middle school students during the school year.