结构动力弹塑性和倒塌分析(Ⅲ)——地震差动作用下输电塔—线体系的弹塑性与倒塌分析

Elasto-plasticity and Collapse Analysis for Large-span and High Structure(Ⅲ)——Elasto-plastic and Collapse Analysis of Transmission-lines System under Multi-point Seismic Motions

首先,建立SAP2000有限元模型,采用接口程序SAP2ABAQUS生成为ABAQUS有限元模型。然后,明确给出长周期显式动力加载法实现重力作用下静力效果的加载过程,以完成的重力作用下索找形和初始刚度施加,最终实现重力分析与后续地震激励下动力加载的续接。进而,分别计算四类边界条件的结构体系的动力特性,并通过对转化前后模型的构件与结构模态分别进行对比,从而考察SAP2ABAQUS接口程序的转化精度。此外,更新升级自主开发的MEMS_b V2012.8至MEMS_b V2013.5,并生成多点地震动。最后,通过ABAQUS主程序中开发的子程序进行弹塑性和倒塌分析,考虑大变形和差动输入。结果表明:(1)从实际工程角度验证了所开发接口程序SAP2ABAQUS的转化准确性与高效性;(2)从实际工程角度验证了所开发子程序的可行性与现实可靠性;(3)长周期动力加载法实现静力重力加载过程,理论严格合理、现实可行,克服了隐式静力重力方式加载与显式动力分析不续接问题;(4)从模态与理论分析两方面说明以四塔三线体系作为研究对象的必要性和可信性;(5)地震动的一致与差动输入对于构件塑性铰的出现与发展分布有显著影响,进一步说明多点地震动对于此类结构体系的地震弹塑性反应的必要性。

Firstly,the 3D finite element model of a large-span transmission tower lines system with main tower height of 375m and main span of 2 756m is established using software SAP2000,and is transformed to ABAQUS finite element model by the developed interface program SAP2ABAQUS.Then,the approach for achieving the loading process of static effect under the gravity action is given explicitly by using long-period explicit dynamic loading method.By the approach,the shape finding of cable and its initial stiffness are finished under the gravity action,which further realized that gravity analysis could be performed subsequently with dynamic loading excited by the subsequent earthquake.Besides,the dynamic characters of four types of model with different boundary conditions are analyzed and compared,and from the comparison of model component before and after the transformation and their corresponding modal analysis results,the transformation accuracy through program SAP2ABAQUS is verified.Further,the program MEMS_ b V2012.5 is updated to MEMS_ b V2013.5 and the multi-point earthquake motions of target field are simulated.At last,considering geometric large deformation and differential input,the developed subroutine given by ABAQUS main program is used to analyze the elastoplastic and collapse of tower-lines system.The actual engineering analysis results show that：（1） The developed interface program SAP2ABAQUS is further verified to have reliable accuracy and high efficiency transformation from the aspect of actual engineering.（2） The developed subroutine is feasible and reliable for analyzing actual engineering.（3） The static gravity loading process realized by the long-period dynamic loading method which is reasonable in theory and feasible in real,and overcome the difficulty that implicit static gravity mode loading cannot be performed subsequently with explicit dynamic analysis.（4） From modal and theory analysis,it shows that the necessity and reliability of selecting the system of four towers with three lines as analysis object.（5） The consistency of multi-point earthquake motion and differential input have the significant influence on occurrence and developing distribution of plastic hinges.So,it is very necessary to consider the multipoint earthquake motions as input while analyzing the elasto-plastic responses of the similar structural system.