宽应变率加载下云杉微结构演化与失效机制研究

项目名称： 宽应变率加载下云杉微结构演化与失效机制研究

项目编号： No.11302211

项目类型： 青年科学基金项目

立项/批准年度： 2014

项目学科： 数理科学和化学

项目作者： 钟卫洲

作者单位： 中国工程物理研究院总体工程研究所

项目金额： 28万元

中文摘要： 云杉木材因其比强度高、压缩平台区域宽、高温碳化吸热等优良性能被逐步应用于武器产品缓冲结构设计。本课题拟在0.01/s-1000/s应变率范围内开展云杉沿顺纹、横纹径（弦）向预定变形的压缩行为研究，借助扫描电镜对材料阶段变形行为进行观察，分析云杉微观胞元沿不同方向压缩下的变形演化机制，建立胞元微观失效模式与加载方向的数学关系；获得宏观力学性能空间分布规律，并分析能量耗散的应变率效应和各向异性特征。同时基于微观结构排列分析，创建能反映云杉三维微观结构的代表体积单元，开展不同方向加载下云杉变形失效行为数值分析，再现木材顺纹压缩发生屈曲、横纹压缩产生滑移褶皱的典型失效模式。本课题研究可以较为系统认识云杉微观结构变形演化失效机制和宽应变率范围内的力学行为，研究成果可作为木材类包装箱结构设计中材料方向布局、结构尺寸参量选取的依据，对木材变形失效机理认识和大变形行为数值模拟具有重要的理论意义和应用价值。

中文关键词： 云杉；微结构；各向异性；失效机制；宽应变率

英文摘要： As high specific strength, wide compression plateau stress and carbonizing absorption material, spruce is applied widely in weapon product cushioning design field. Spruce comppression mechanical properties parallel to grain and across grain ,from 0.01/s to 1000/s, are investigated in the project. Spruce microscopic cell stepped deformation along different compression condition is observed by scan electron microscope. Microstructure deformation evolutionby mechanism along different loading direction is analyzed. And mathematics expression is established to describe the relationship of cell structure and loading style. Spatial distributing rule of spruce macroscopic mechanics property is obtained. Energy dissipation variation with strain rate and loading direction is studied. According to microstructure-based alignment, representative volume elment of spruce is established. Numerical simulation on spruce under different direction loading is implemented. And typical failure modes of buckling along grain loading and slippage folding across grain loading are simulated. Based on the corresponding studies, spruce deformation evolutionby mechanism and spatial mechanical property distribution under wide strain rate loading can be obtained. The research findings can be applied to guide wood arrangement and structure dimen

英文关键词： spruce；microstructure；anisotropy；failure mechanism；wide strain rate