甘蔗叶鞘破坏与剥离方式试验与分析

摘要

Based on an analysis of the structure , traits and mechanical strength characteristics , sheath de-struction test of individuals and overall package of stem-leaf sheath rubbing destruction test were carried out separately .The basic strength and failure modes of individual damage of leaf sheath were established . The optimal split leaf sheath methods were summarized which were in line with its growth traits and strength characteristics of sheath .Destruction of the leaf sheath was best achieved by individuals in the form of parenchyma under transverse tensile forces tear , with the maximum transverse tensile strength (σ2max ) being 0.90 MPa.After tearing the leaf sheath , the connection strength of the leaf sheath and stern (σ2max) was 0.78 MPa.The first step of splitting leaf sheath was to stretch sheath laterally to tear sheath and destroy the cover of sheaths to the stalks .Then, sheaths should be scratched axially to rip sheath from the stem .To accomplish the sheath stripping completely , the following 2 basic conditions should be met .Stress that perpendiculars to the direction of leaf sheath fibers (σ2 ) should be no less than the maximum lateral tensile strength σ2max.Axial stress (σ1) should be no less than σtmax, which is the maximum strength of resisting ripping of leaf sheath and stem .%在分析甘蔗叶鞘的结构、生长性状和强度特性的基础上，进行了叶鞘个体的破坏试验和整体包裹茎秆叶鞘的摩擦破坏试验，得出了叶鞘个体破坏的基本强度值和破坏形式，提出了符合叶鞘生长性状和强度特性的剥离方式．叶鞘个体最容易实现的破坏形式为在横向拉伸力作用下的薄壁组织撕裂，最大横向抗拉强度（σ2max ）为0.90 MPa．撕裂后的叶鞘与茎秆在轴向上的最大连接强度（σtmax ）为0.78 MPa．在剥离叶鞘的过程中应首先对叶鞘进行横向拉伸作用造成叶鞘撕裂，破坏叶鞘对茎秆的包裹性能，再进行轴向刮擦作用将叶鞘从茎秆上撕扯脱落．叶鞘剥离应该同时满足2个基本条件：1）在垂直于叶鞘纤维方向的应力（σ2）不小于σ2max；2）轴向应力（σ1）不小于σtmax ．