轻型木桁架体系系统效应分析

摘要

In order to quantitatively recognize the phenomenon that the properties of light wood trass assembly are better than those of individual trass, the system effect and its influential factors for light wood truss assembly were analyzed with a random sampling simulation method. The analysis was performed on the basis of a 3D finite element model for light wood trass assembly. With considering the property statistic characteristics of different dimension lumber and trass plate joints, the repeated sampling was conducted on the ANSYS-PDS platform for the light wood trass assemblies with three structural arrangements. The system effect coefficients were quantitatively calculated with taking stress ratio and overall deformation as indexes. The obtained stress ratio system effect coefficients are between 1. 05 and 1. 27, and the deformation system effect coefficients are between 1.12 and 1. 29. The analysis on the parameters of influencing the system effect shows that the system effect of light wood trass assembly is mainly influenced by the failure mode, system volume, boundary supporting condition as well as the correlation between elastic modulus and strength of dimension lumber. The analysis conclusion can provide the references for the design standard in light wood trass.%为了定量认识轻型木桁架体系性能优于单榀桁架性能这一现象,采用随机抽样模拟的方法对轻型木桁架体系的系统效应及其影响因素进行了分析.分析过程以轻型木桁架体系的三维有限单元模型为基础,在ANSYS-PDS平台中对3种结构布置的桁架体系考虑不同的规格材及齿板节点性能统计特征后进行反复抽样,以应力比及整体变形为指标对系统效应系数进行定量计算,得出的应力比系统效应系数在1.05～1.27之间,变形系统效应系数在1.12～1.29之间.通过对影响系统效应的参数进行分析表明,轻型木桁架体系的系统效应主要受破坏模式、体系体量大小、边界支承条件和规格材弹性模量及强度相关性的影响,分析结论为编制轻型木桁架设计标准提供了参考.