Compressive Response and Crushing of Cellular Solids

多孔固体的压缩响应和破碎

• 批准号: 0245485
• 负责人: Stelios Kyriakides
• 金额: --
• 依托单位: University of Texas at Austin
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-05-01 至 2007-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0245485&HistoricalAwards=false
• 关键词: Compressive; Response; Crushing; Cellular; Solids

Abstract Cellular solids are a class of light-weight materials with unique properties such as high stiffness- and strength-to-weight ratios and excellent energy absorption characteristics. Modern foams are made from polymers, metals, ceramics and other materials. They are used as structural components as cores in sandwich structures and in impact mitigation, cushioning and other energy absorption applications in atmospheric and space vehicles, automotive components, ship structures, civil engineering structures, mass transit vehicles, sporting goods, etc. Advances in foaming processes enable their manufacture to prescribed cell sizes and densities. For this technology to reach its full potential, the cell size, density and properties of the base material must be related to the foam properties of interest. The main objective of this project is to use experiment and analysis to understand how the microstructure governs all relevant mechanical properties of open cell foams. Polyurethane and aluminum foams of various densities and cell sizes will be used as representative material systems. A typical foam compressive response consists of a nearly linear elastic regime terminating into a limit load which is followed by an extensive load plateau. The limit load represents the onset of instability and localization. For polyurethane foams the instability is elastic buckling of the microstructure while for aluminum foams it is due to plastic collapse. The plateau, which represents the energy absorbing capacity, is related to progressive spreading of the crushing through the material. The project aims to understand the micromechanisms governing these behaviors and to develop models which are able to reproduce them. The problem will be tackled through experiments coupled with several levels of modeling. The experiments will involve: (a) Measurement of the elastic and "inelastic" mechanical properties of the foams; (b) characterization of the foam microstructure; and (c) measurement of the mechanical properties of the foam struts in situ. The modeling will involve: (a) beam-type models for the elastic properties; (b) numerical characteristic cell-type models for the elastic properties and the onset of instability; and (c) large-scale models which can reproduce all aspects of the compressive response including the large deformation crushing. At first the microstructure will be represented as regular Kelvin cells but with realistic strut geometric characteristics. Other more representative microstructures will be considered as deemed required.

摘要多孔固体是一类轻质材料，具有高刚度、高强度比和优良的能量吸收特性。现代泡沫由聚合物、金属、陶瓷和其他材料制成。它们用作夹层结构中的结构部件，以及大气和空间车辆、汽车部件、船舶结构、土木工程结构、公共交通车辆、体育用品等中的冲击缓解、缓冲和其他能量吸收应用。为了使该技术充分发挥其潜力，基础材料的泡孔尺寸、密度和性能必须与所关注的泡沫性能相关。该项目的主要目标是使用实验和分析来了解微观结构如何控制开孔泡沫的所有相关机械性能。各种密度和孔尺寸的聚氨酯和铝泡沫将被用作代表性材料系统。 一个典型的泡沫压缩响应包括一个接近线性的弹性状态终止到一个极限载荷，随后是一个广泛的载荷平台。极限载荷表示失稳和局部化的开始。对于聚氨酯泡沫，失稳是微结构的弹性屈曲，而对于铝泡沫，失稳是由于塑性塌陷。表示能量吸收能力的平台与破碎通过材料的逐渐扩展有关。该项目旨在了解这些行为的微观机制，并开发能够重现这些行为的模型。这个问题将通过实验结合几个层次的建模来解决。这些实验将涉及：（a）测量泡沫的弹性和“非弹性”机械性能;（B）表征泡沫微结构;和（c）原位测量泡沫支柱的机械性能。建模将涉及：（a）弹性特性的梁型模型;（B）弹性特性和失稳起始的数值特征单元型模型;（c）能够再现压缩响应的所有方面（包括大变形破碎）的大尺度模型。首先，微观结构将被表示为规则的开尔文单元，但具有真实的支柱几何特征。其他更具代表性的微观结构将视需要予以考虑。