摘要
广义塑性铰法能够保持传统塑性铰的比例特性并据此高效求解杆系结构在多内力联合作用下的极限承载力,克服了传统塑性铰法和精细塑性铰法的局限性。但是由于未考虑前序塑性铰上轴力增量对结构平衡状态的影响,导致刚架结构在部分荷载工况下的计算结果出现较大误差。为此,该文通过建立平衡向量,提出了修正的广义塑性铰法计算格式,从而有效消除了塑性铰上轴力增量导致的不平衡状态及其对计算精度的影响。利用强度折减因子确定各构件在多内力组合作用下的修正截面强度,在此基础上利用齐次广义屈服函数定义单元承载比;根据最大单元承载比及其与外荷载之间的比例关系确定新增塑性铰的位置和荷载增量;进而利用广义屈服准则和转角位移方程建立了平衡向量,据此修正当前加载步的塑性铰位置和荷载增量,从而解决了广义塑性铰法不适用于部分荷载工况的问题;通过与不同方法对比分析,验证了该文方法具有更高的计算精度和计算效率。
Generalized plastic hinge method can maintain the proportional characteristics of traditional plastic hinge method and obtain the ultimate bearing capacity of frame structures efficiently,which overcomes the limitations of the traditional plastic hinge method and the refined plastic hinge method.However,the effect of axial force increment of the formed plastic hinges on the structure equilibrium state is not considered,which affects the calculation accuracy of the ultimate bearing capacity of partial frame structures.Therefore,the generalized plastic hinge method was modified according to the balanced vector presented,which eliminated the negative influence of the unbalance state caused by axial force increment on the calculation accuracy.Based on the modified section strength of each component under the action of multiple internal forces determined by the strength reduced factor,the element bearing ratio was defined by the homogeneous generalized yield function.The position and load increment of the new plastic hinge were determined according to the maximum element bearing ratio and its proportional relation with external load.Additionally,the balanced vector was established by using the generalized yield criterion and the slope-deflection equation;according to which the position of plastic hinge and load increment of the current loading step were modified.A comparison of different methods verified that the proposed method was much more efficient and accurate.
作者
杨绿峰
殷玉琪
柏大炼
YANG Lu-feng;YIN Yu-qi;BAI Da-lian(School of Civil Engineering&Architecture,Guangxi University,Nanning,Guangxi 530004,China;Key Laboratory of Disaster Prevention and Structural Safety of Ministry of Education,Guangxi University,Nanning,Guangxi 530004,China)
出处
《工程力学》
EI
CSCD
北大核心
2021年第12期49-56,共8页
Engineering Mechanics
基金
国家自然科学基金重点项目(51738004)。
关键词
广义塑性铰法
刚架结构
强度折减因子
平衡向量
极限承载力
generalized plastic hinge method
frame structure
strength reduced factor
balanced vector
ultimate bearing capacity
