摘要
重组竹力学性能优于木材,非常适用于装配式梁柱结构。重组竹抗压强度高于普通混凝土材料,受压应力-应变关系非线性特征明显,但其弹性模量仅为混凝土弹性模量的1/2左右。采用碳纤维(CFRP)增强重组竹梁可充分利用重组竹的抗压性能,提高梁的承载能力,但其非线性变形更加显著。考虑重组竹的受压非线性本构关系,提出计算梁极限挠度的弹性理论修正计算方法。该方法将梁简化为带塑性铰的杆件,假设非线性变形仅发生在塑性铰区域,杆件其余部分始终处于弹性工作状态,将梁的变形分为弹性变形与塑性变形。通过截面应变分析,得到塑性变形的计算公式,进而得到CFRP增强重组竹梁的非线性变形计算公式。CFRP增强重组竹梁的四点弯曲试验表明,所提出的计算方法具有足够的精度。
With good mechanical properties, parallel strand bamboo （PSB） is superior to wood and increasingly used to be beams and columns in building constructions. The compressive strength of PSB is higher than the commonly used concrete materials, and the compressive stress-strain relationship exhibits pronounced nonlinear deformation, while the elastic modulus of PSB is lower than half of the C30 concrete modulus. Carbon fiber reinforced polymer （CFRP） reinforced PSB beams could fully develop the compressive nonlinearity of PSB, and increase the load-carry- ing capacity and show more significant ductility than those of the unreinforced one. Thus, PSB beams exhibit pro- nounced nonlinear deformation under the ultimate state. In this study, we proposed a modified calculating method based on the elastic theory of the ultimate deformation of the beam by considering the nonlinear constitutive relation- ship of PSB. The method simplified the beam to be a bar with a plastic hinge, presumed that the nonlinear deformation only occurred in the plastic hinge region, and the rest of the bar was always in elastic state. The deformation of the beam was divided into the elastic deformation and plastic deformation. The calculation formula of the plastic deforma- tion was developed through the analysis of the cross-section strain, and the formula of the nonlinear deformation of CFRP reinforced PSB beams was put forward. The calculated method proposed in this study was validated through four-point bending experiments of CFRP reinforced PSB beams. The results showed that the model results well agreed with the test ones.
出处
《林业工程学报》
北大核心
2017年第5期115-119,共5页
Journal of Forestry Engineering
基金
"十三五"国家质量基础的共性技术研究与应用专项(2017YFF0207200)
国家自然科学基金(51578291)
林业科学技术成果国家级推广项目([2015]21)
江苏高校优势学科建设工程资助项目(PAPD)
江苏省大学生创新创业训练计划项目(201510298049Z)
关键词
碳纤维
重组竹
非线性变形
力学模型
carbon fiber reinforced polymer （CFRP）
parallel strand bamboo （ PSB ）
nonlinear deformation
mechan- ical model
