杨木静动态压缩本构模型研究

Static and Dynamic Compression Constitutive Model of Poplar Wood

中文关键词: 杨木  静动态压缩加载试验  多孔材料特征  应变率  本构模型

英文关键词: poplar wood  static and dynamic compression loading experiments  porous material characteristics  strain rate  constitutive model

中文摘要:

      目的 以杨木为研究对象，研究其静动态压缩载荷作用下应力-应变曲线的变化特征，建立适合的本构模型，并对其进行描述。方法 对杨木试件进行静动态压缩加载试验，分析静动态压缩载荷作用下杨木应力-应变曲线的变化特征，构建适用于静动态压缩载荷作用下杨木的本构模型。结果 静态压缩加载杨木的应力-应变曲线分为线弹性阶段、屈服阶段和密实化阶段等3个部分，动态压缩加载杨木的应力-应变曲线分为线弹性阶段和屈服阶段等2个部分；静态压缩加载时，杨木轴向屈服应力最大，分别是径向和弦向的5.70倍和7.75倍；动态压缩加载时，当应变率从400 s-1增加到1000 s-1时，径向、弦向和轴向的屈服应力分别增加了1.51，1.59，3.12倍，杨木的屈服应力具有应变率敏感性；采用包含应变率影响的本构方程来描述杨木在静动态压缩载荷作用下的本构关系是比较合适的。结论 杨木是一种应变率敏感材料，静动态压缩载荷作用下杨木的应力-应变曲线均表现出多孔材料的特征，将多孔材料本构模型应用于木材是可行的。

英文摘要:

      The work aims to study the stress-strain variation characteristics of the poplar under the static and dynamic compression loading with the poplar as the research object, and build proper constitutive model to describe it. Through static and dynamic compression loading test on poplar specimen, the stress-strain variation characteristics of the poplar were analyzed, and the constitutive model suitable for the poplar under static and dynamic compression load was built. The study found that under static compression loading of poplar wood from the stress-strain curve was divided into three parts: linear elastic stages, yield stages and densification stage. The dynamic compression loading of poplar wood from the stress-strain curve was divided into two parts: stages of linear elastic and yield. During static compression loading, the axial yield stress of poplar was the largest, and it was 5.70 times and 7.75 times of radial and tangential yield stress respectively. During dynamic compression loading, when the strain rate was increased to 1000 s-1 from 400 s-1, radial, tangential to yield stress and axial was respectively increased by 1.51 times, 1.59 times and 3.12 times; the yield stress of poplar wood had strong strain rate sensitivity. It is more appropriate to describe the constitutive relation under static and dynamic compression loading with constitutive equation containing the influence of strain rate. Poplar is a strain rate sensitive material. Under static and dynamic compression loading, poplar wood from the stress-strain curve shows the characteristics of the porous materials. It is feasible to apply the constitutive model of porous materials to the wood.