胶合木曲梁横纹应力及开裂研究  

Investigation of Stress Perpendicular to Grain and Cracking of Curved Glulam Beams

作　　者：周华樟[1] 祝恩淳[1] 周广春[1] 

机构地区：[1]哈尔滨工业大学土木工程学院,黑龙江哈尔滨150090

出　　处：《建筑材料学报》2013年第5期913-918,共6页Journal of Building Materials

基　　金：国家自然科学基金资助项目(50878067;51108127);哈尔滨工业大学科研创新基金资助项目(HIT.NSRIF 2013115)

摘　　要：研究了胶合木曲梁纯弯曲区横纹应力与各向同性材料曲梁纯弯曲区径向应力.结果表明:胶合木曲梁纯弯曲区横纹应力与各向同性材料曲梁纯弯曲区径向应力分布规律大致相同,都是中性轴附近大,随距中性轴距离的增大而减小;胶合木曲梁纯弯曲区横纹应力以胶缝为分界线,呈锯齿状分布,层板髓心位置对应力峰值影响较大,髓心位于层板大面的胶合木其横纹应力最大,应力峰值是简化计算式的1.5倍.根据胶合木的应力特点和脆性开裂特点,建立了胶合木开裂损伤本构模型,并编制了相应的有限元软件ABAQUS用户材料子程序UMAT,成功预测了曲梁的横纹开裂及其极限承载力,与曲梁承载力试验相比,其刚度和极限承载力吻合良好.A comparative study between the stress perpendicular to grain of curved glulam beams and radial stress Of curved beams made of isotropic material was conducted. The distribution of stress is generally similar with each other. But the stress perpendicular to grain in Glulam distributes in a saw-toothed pat- tern and is affected severely by the position of the pith in a lamina. The maximum stress perpendicular to grain is reached when the pith appears on the wider face of lamina and it is 1.5 times the result by the sim- plified formula. Based on the characteristics of stress perpendicular to grain and the fact of brittle fracture, an elastic-brittle damage constitutive model for predicting cracking of glulam was developed. The constitu- tive model consisting of the damage model and failure criteria was incorporated into the commercial FE software ABAQUS by developing a user defined subroutine-UMAT. Then FE models were developed to predict the cracking and load-carrying capacity of curved glulam beams. The load-carrying capacity and stiffness of numerical simulation are correlated well with the experimental results.

关 键 词：胶合木 曲梁 横纹应力 开裂损伤本构模型 

分 类 号：TU366.3[建筑科学—结构工程]