FRP约束木柱轴心抗压性能的弹塑性分析方法  

Elastoplastic Approach for Studying the Behavior of FRP Confined Wood Column under Axial Compression

作　　者：邵劲松[1] 刘伟庆[1] 

机构地区：[1]南京工业大学土木工程学院,江苏南京210009

出　　处：《建筑材料学报》2007年第3期282-287,共6页Journal of Building Materials

基　　金：国家重大基础项目前期研究专项(2002CCCD1700)

摘　　要：进行了FRP(环向)约束木柱的轴心抗压性能试验,结果表明,FRP约束木柱可提高木柱的抗压承载力,改善木柱的延性,使木柱轴向极限抗压强度提高达15%左右.在Tsai-Wu强度准则的基础上,建立了三向受压木柱的屈服准则及屈服发展方程.根据内力平衡和应变相容的原理,提出了FRP约束木柱在轴心受压时的增量应力-应变计算模型;根据FRP约束木柱受压破坏机理,即达极限应力时,FRP中的拉应变远小于其极限拉应变,提出了FRP约束木柱在极限抗压强度时的应力-应变计算公式,并将之作为计算模型程序运算的结束条件;极限抗压强度之后的FRP约束木柱应力-应变曲线接近水平线,可近似为理想塑性.试验结果表明,所建计算模型精度较好.The compressive behavior of 15 cylindrical wood columns that were externally wrapped by CFRP or GFRP sheets were experimental investigated. The results show that FRP can effectively improve the compressive bearing capacity and ductility of the wood column by confining it laterally. The axial ultimate compressive strength increase by about 15%. Based on the Tsai-Wu criterion, the plastic yielding formulation and the corresponding yielding surface equation of triaxially compressed wood columns were developed. From the equilibrium of the forces and the strain compatibility, an incremental constitutive model was developed to simulate the stress-strain behavior of uniaxially compressed wood column confined by FRP. The mechanism of the specimens shows that tensile failure of fibers does not occur at the ultimate compressive strength of the confined wood columns, and the tensile strain is far less than the ultimate tensile strain of FRP. A formula to predict the stress-strain at the ultimate compressive strength of FRP confined wood column is achieved from the experimental data, and which is used as the closing condition of the calculate model procedure. The stress-strain curve of FRP confined wood column past the ultimate compressive strength is approaching the horizontal line, and it is assumed to be idealized plasticity. The predictions of the model are agreeable well to the test data.

关 键 词：FRP 约束木柱 弹塑性模型 极限应力 

分 类 号：TU531.1[建筑科学—建筑技术科学] TQ327[化学工程—合成树脂塑料工业]