木材横纹压缩应力-应变关系及其影响因素研究进展

Research Development of Influencing Factors of Stress-Strain Relationship under Wood Transverse Compression

木材横向压缩下应力-应变关系对压缩材料热压工艺的设计和最终产品的物理力学性能有着重要的影响。从木材横纹压缩应力-应变关系和屈服点的确定入手,重点阐述从微观到宏观角度的木材自身组织构造特性,以及压缩工艺参数中温度、含水率等因素对木材横纹压缩应力-应变关系的影响,并对今后木材横纹压缩技术研究方向提出了建议。目前木材横纹压缩变形机制的研究多是围绕木材整体压缩开展,缺乏木材应力-应变关系随木材自身特性及含水率、温度交互作用变化规律的系统研究,以及湿热状态下层状压缩木材内部屈服应力差形成机制的研究。要实现层状压缩木材压缩层位置和厚度的可控性,需要在准确确定木材屈服点和掌握木材应力-应变关系的湿热响应规律的前提下,科学构建适用于湿热条件下木材层状压缩应力-应变关系模型。

The stress-strain relationship of wood under transverse compression has an important influence on the design of the hot pressing process and the physical and mechanical properties of the final product.In this paper,the effects of wood properties on the transverse compressive stress-strain relationship were analyzed from the microscopic scale to the macroscopic scale,as well as the effects of temperature and moisture.Suggestions and opinions on the research direction of wood transverse compression technology in the future were pointed out.At present,the study of the compression mechanism of wood is carried out around the overall compression of wood,lacking of the systematic research of wood softening and yield stress change with moisture content and temperature variation,and the law of yield stress difference response to wood anisotropy.In order to acquire the controllability of the sandwich compression,it is necessary to control the hydro-thermal response of the wood softening and plastic deformation,and scientifically construct stress-strain model which is suitable for sandwich compression under the hydro-thermal condition.