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.

抽象的细胞固体是一类轻重量材料，具有独特的特性，例如高刚度和强度重量比和出色的能量吸收特征。现代泡沫由聚合物，金属，陶瓷和其他材料制成。它们被用作结构组件作为三明治结构中的核心，以及在大气和太空车辆，汽车组件，船舶结构，土木工程结构，大众运输车辆，大众运输工具，体育用品等中的降低，缓冲和其他能源吸收应用中的影响。为了使这项技术发挥其全部潜力，基本材料的细胞大小，密度和特性必须与感兴趣的泡沫特性有关。该项目的主要目的是使用实验和分析来了解微观结构如何控制开放式泡沫的所有相关机械性能。各种密度和细胞大小的聚氨酯和铝泡沫将用作代表性材料系统。 典型的泡沫压缩响应由几乎线性的弹性状态组成，该弹性机制终止于极限载荷，然后是广泛的负载高原。极限载荷代表不稳定性和本地化的开始。对于聚氨酯泡沫，不稳定性是微结构的弹性屈曲，而对于铝泡沫，这是由于塑料崩溃所致。代表吸收能力的高原与粉碎在材料中的逐渐扩散有关。该项目旨在了解管理这些行为的微观力学，并开发能够复制它们的模型。该问题将通过实验以及几个级别的建模来解决。实验将涉及：（a）测量泡沫的弹性和“非弹性”机械性能； （b）泡沫微结构的表征； （c）测量原位泡沫支柱的机械性能。该建模将涉及：（a）弹性特性的梁型模型； （b）弹性特性和不稳定性发作的数值特征细胞类型模型； （c）可以重现压缩响应的所有方面的大型模型，包括大变形粉碎。首先，微结构将表示为常规开尔文细胞，但具有逼真的支撑物几何特征。其他更多代表性的微观结构将被视为所需的。