【作者】 张浩；

【导师】 肖诗云；

【作者基本信息】 大连理工大学 ， 防灾减灾工程及防护工程， 2018， 硕士

【摘要】 钢筋混凝土结构在承受荷载时可能会发生剪切破坏,构件剪切破坏发生比较突然且危害巨大。为避免因结构发生剪切破坏造成的灾难性后果,研究钢筋混凝土构件的剪切破坏机理就变得十分重要。钢筋混凝土结构在整个寿命周期内还可能受到各种形式的动态荷载的作用,由于钢筋和混凝土材料都是典型的率相关材料,动态荷载作用时材料的特性会发生改变,因此构件在动态荷载作用下的剪切特性就变得更为复杂。虽然钢筋混凝土梁(RC梁)构件的动态剪切特性已经引起了人们的兴趣,但目前的研究还很不系统,特别是缺乏定量研究加载速率、纵筋率、配箍率和剪跨比等影响因素对钢筋混土剪切梁的动态强度、变形以及破坏模式等方面的影响。在此背景下,本文主要研究了下列四方面的内容:(1)总结了目前国内外抗剪理论的研究现状和成果,介绍了已被普遍认可的抗剪模型理论,如桁架模型、统计分析法、极限平衡理论、塑性理论以及非线性有限元理论等。(2)详细阐述了混凝土损伤塑性(CDP)模型的原理,并归纳了有限元分析软件ABAQUS的隐式求解器和显示求解器的异同点。参照已有试验实例建立了有限元模型并将模拟结果同试验结果进行比对验证,证明模拟分析的可行性。(3)借助ABAQUS软件创建了有限元梁模型,考虑加载速率、纵筋率和剪跨比等影响因素,对动态荷载作用下钢筋混凝土剪切梁的力学、变形性能和损伤特性等行为进行了系统研究。进一步考虑配箍率的影响,设计新的加载方案,研究了动态加载时多种参数(剪跨比、纵筋率和配箍率)对钢筋混凝土梁极限抗剪承载力动态增大因子DIF的影响。(4)基于MSC.MARC软件,利用编写的可以考虑混凝土率相关性的子程序Uvscpl模拟了钢筋混凝土梁在承受循环荷载作用时的动力性能,研究了不同加载速率的循环荷载对RC梁的抗剪承载力和变形性能的影响。并进一步讨论了循环动态加载时,剪跨比、纵筋率和配箍率对RC梁极限抗剪承载力的影响。更多还原

【Abstract】 In order to avoid the catastrophic effect caused by shear failure of RC(reinforced concrete)structures,it is important to study the shear failure mechanism of RC members.During their service life,reinforced concrete structures may also be subjected to various types of dynamic loads.Due to the strain-rate effect of steel and concrete,the shear behaviors of reinforced concrete structures under dynamic loads behave quite differently as compared to the static load.At present,although the dynamic shear characteristics of reinforced concrete beams have been concerned by researchers,the current research is not systematic,especially lack of effect research of the loading rate,longitudinal reinforcement ratio,stirrup ratio and shear span ratio and other factors on the dynamic strength of the reinforced concrete beams,shear deformation and failure mode.This research mainly focuses the following four aspects:(1)The current research situations and obtained achievements in shear theory are described systematically.The main analysis model of shear resistance of RC beams are introduced in details,such as truss model,statistical analysis method,limit equilibrium theory,plasticity theory and nonlinear finite element theory.(2)The concrete damage plasticity model and the implicit solver and explicit solver commonly used in ABAQUS finite element software are summarized in details.A three-dimensional nonlinear finite model is carried out and the simulation results are verified with an experimental results to prove the feasibility of the simulation.(3)The RC beam FE model is established with the ABAQUS finite element software and the effects of the loading rate,shear span ratio and longitudinal reinforcement ratio on the mechanical properties,deformation and damage characteristics are systematically investigated.Further the parametric study is designed to investigate the influence of longitudinal reinforcement ratio,transverse reinforcement ratio and shear span ratio on dynamic increase factor(DIF)of ultimate resistance of RC beams under varying loading rates.(4)Based on the finite element software MSC.MARC and the user subroutine Uvscpl,the dynamic shear mechanical behaviors and deformation behaviors of reinforced concrete beams under different cyclic loading rates are simulated.Further the influences of shear span ratio,longitudinal reinforcement ratio and stirrup ratio on ultimate resistance of RC beams under varying cyclic loading rates are discussed.更多还原