 | | |
| | |
|
Spaces home  陆新征的共享空间PhotosProfileFriendsMore |  Tools   |
|
陆新征的共享空间August 20 新上载论文：钢板筒仓侧壁压力的非线性有限元分析张炎圣 杨晓蒙 陆新征 摘要：钢板筒仓已有超过70年的使用历史。Janssen公式的提出，使钢板筒仓的设计有了理论基础，但难以适应各种复杂的筒仓结构和形状。本文基于大型有限元软件MSC.MARC，通过借助MARC提供的用户自定义材料功能，开发了关联流动和非关联流动弹塑性本构模型，利用MARC自带的接触功能，对筒仓侧壁的应力进行了分析，并将结果与Janssen公式进行了对比。分析结果表明，非线性有限元计算可以准确获得筒仓侧壁的压力分布且具有较好的灵活性。 Nonlinear finite element analysis for the wall pressure in a steel silo Zhang Yan-sheng Yang Xiao-meng Lu Xin-zheng Abstract: It has been 70 years since people started using steel silos for the storage of grain. The proposal of Janssen’s Formula makes a theoretical foundation for the study of steel silos, but it is difficult to adapt the formula to complex silo structures and shapes. This paper is based on finite element software MSC.MARC. By using user-defined material function provided by MARC, associated and non-associated flow of elastic-plasticity constitutive models are developed. Wall stress of the silo is analyzed by the contact function in MARC, and the results are compared with Janssen’s Formula. The results show that the non-linear finite element calculation can be accurate to the silo wall pressure distribution and of better flexibility. August 04 新上载论文：结构抗连续倒塌的拉接强度设计方法李 易1,2，陆新征1,2，叶列平1,2，马一飞1,2，梁 益1,2 摘要：拉结强度法是国外抗连续倒塌设计规范采用的主要设计方法之一，我国还没有这方面的相关研究。拉结强度法通过假设破坏模式，将超静定结构在局部转化为静定结构进行分析，从而对结构的拉结强度进行验算和设计。该方法无需对整个结构进行受力分析，比较简便易行，是一种适合工程设计的设计方法。但由于其计算模型过于简化，设计参数的经验性成分较多，其可靠性和适用性需要进一步的检验。本文总结了国外抗连续倒塌设计规范的拉结强度法的概念和条文，通过有限元数值仿真证明了国外拉结强度法不能明显提高我国混凝土框架结构抗连续倒塌能力的结论。最后，本文对国外拉结强度法的基本拉结强度的计算原理进行了分析，指出了该方法计算模型的不足，建议对该方法进行改进使之能够适应我国混凝土框架结构的抗连续倒塌设计。 Tie force method for progressive collapse resistance of structures Li Yi1,2，Lu Xinzheng1,2，Ye Lieping1,2，Ma Yifei1,2，Liang Yi1,2 Abstract：Tie force (TF) method is one of the major design methods proposed by foreign codes to resist progressive collapse, but the related researches are still lack in China. TF method is convenient to implement because it does not need to calculate the response of the whole structure. However, as too many assumptions have been set to build up this method, the empirical factors are needed to be carefully checked to guarantee the safety of the TF design. This paper summarized the conceptions and specifications of TF methods in foreign codes. Then foreign TF methods were proved to be not safety for Chinese concrete frames with nonlinear finite element dynamic analysis. In order to explain this phenomenon, the drawbacks in foreign TF methods were pointed out from the discussion of the fundamental principles of TF methods. And the suggestions from these discussions will be helpful to setup a feasible TF method in China. July 28 新上载论文：混凝土结构抗震非线性分析模型、方法及算例叶列平 陆新征 马千里 汪训流 缪志伟 工程力学/Engineering Mechanics, 2006, 23(sup. II). 131-140. 摘 要：结构在大震作用下会进入非线性并产生损伤，准确预测地震荷载下钢筋混凝土结构的非线性行为，对评估混凝土结构的抗震安全性具有重要意义。本文介绍了清华大学土木工程系近年来开发的适用于钢筋混凝土杆系结构的纤维模型THUFIBER程序，适用于预应力混凝土杆系结构的纤维模型NAT-PPC程序，以及适用于剪力墙结构的分层壳墙元模型的非线性分析程序。这些程序可以直接将构件的非线性节点力（轴力、剪力和弯矩）、节点变形（平动和转动）和材料的非线性应力-应变行为联系起来，可以模拟各种复杂受力构件的滞回行为和轴力－双向弯曲－剪切耦合行为，借助通用有限元程序方便的前后处理功能和非线性计算功能，该程序可以准确模拟地震作用下结构的三维非线性地震响应，也可模拟爆炸、倒塌等极端非线性行为。本文通过一系列的数值分析与试验结果的对比和工程应用算例，说明所研发程序的精度和计算能力。 关键词：钢筋混凝土，地震，非线性，杆件，纤维模型，剪力墙，分层壳单元 Seismic nonlinear analytical models, methods and examples for concrete structures Ye Lieping, Lu Xinzheng, Ma Qianli, Wang Xunliu, Miao Zhiwei Engineering Mechanics, 2006, 23(sup. II). 131-140. Abstract: Structures will enter nonlinear stage in strong earthquake, precisely prediction for the nonlinear behavior of reinforced concrete (RC) structures in earthquake is important to assess the aseismic safety of the structures. This paper presents the programs recently developed by the Civil Engineering Department of Tsinghua University, which include the fiber model based the program THUFIBER for RC frames, the program NAT-PPC for prestressed concrete (PC) frames, and multi-layer shell element based shear wall program. These programs can connect the nonlinear nodal force/nodal displacement relationship of elements directly with the nonlinear stress/strain relationship of materials. So complicated cycle behaviors and coupled axial force-biaixal bending-shear behaviors of the RC structures can be correctly simulated. And furthermore, with the convenient pre/post process and nonlinear capacity of common finite element software, these programs not only can precisely simulate the spatial structural nonlinear seismic response, but also can simulate some extreme nonlinear problems such as blast or collapse. The precision and the capacity of the programs are illustrated in this paper with a series of researches and applications. Keywords: reinforced concrete, seismic, nonlinear, fiber model, shear wall, multi-layer shell July 15 新上载论文：某钢框架偏心核心筒弹塑性分析缪志伟 陆新征 王载 黄盛楠 叶列平
四川建筑科学研究, 2008, 34(3): 5-10. 摘 要：结构在大震作用下会进入弹塑性并产生损伤，准确预测地震荷载下结构的非线性行为，对评估结构的抗震安全性具有重要意义。本文总结了现有的一些结构弹塑性分析模型，并介绍了清华大学土木工程系近年来以通用有限元程序MSC.Marc为平台所开发的一些新的结构弹塑性分析模型。这些模型可以直接将构件的非线性节点力（轴力、剪力和弯矩）、节点变形（平动和转动）和材料的非线性应力-应变行为联系起来，可以模拟各种复杂受力构件的滞回行为和轴力－双向弯曲－剪切耦合行为。同时，借助通用有限元程序方便的前后处理功能和非线性计算功能，这些模型可以准确模拟地震作用下结构的三维非线性地震响应。利用这些工具，本文对一个实际工程结构进行了静力弹塑性分析和动力弹塑性时程分析，表明这些分析模型可以较好的模拟实际工程结构中的各种弹塑性行为，供科研和工程人员参考。 关键词：弹塑性分析，结构非线性，地震，纤维模型，剪力墙，分层壳单元 Elasto-plastic Analysis for A Steel Frame-Core Wall Structure with An Eccentric Tube Miao Zhiwei, Lu Xinzheng, Wang Zai, Huang Shengnan, Ye Lieping Sichuan Building Science, 2008, 34(3): 5-10. Abstract: Structures will enter nonlinear stage during strong earthquakes. Hence accurate prediction for the structural nonlinear behaviors is important to the safety and loss assessment during earthquakes. This paper reviews the existed nonlinear analytic models for structures and presents some novel models for structural nonlinear analysis that recently developed by the Tsinghua University. With these models, the material stress-strain relationship can be connected directly with the force-displacement behavior of the structural elements. So that the complicated coupled axial force-bending moment-shear force behaviors can be properly simulated, as well as the corresponding cycle behaviors. With the secondary development user subroutines, convenient pre and post process functions and extinct nonlinear capacity of general purpose FE software of MSC.MARC, the spatial seismic responds of structures can be precisely simulated. A steel frame-core wall structure with an eccentric tube is analyzed with static pushover and dynamic time-history analysis to demonstrate the applications of the new models. Keywords: nonlinear analysis, structure, seismic, fiber model, shear wall, multi-layer shell July 03 新上载论文：论结构抗震的鲁棒性论结构抗震的鲁棒性 建筑结构, 2008, 38(6): 11-15. 摘要：本文首先介绍了结构鲁棒性的概念，及其提高结构鲁棒性对避免结构在罕遇地震下垮塌的重要意义。然后，分别从抗震结构体系、结构承载力与延性、结构破坏模式，以及赘余构件等几方面讨论了提高结构抗震鲁棒性的措施。 Introduction of Robustness for Seismic Structures Building Structures, 2008, 38(6): 11-15. Abstract:The concept of robustness of structures is firstly introduced in this paper. And importance with enough robustness for seismic structures in preventing collapse of the structures under strong intensity earthquake attack is discussed. Then the approaches to increase the robustness of seismic structures, including structural systems, strength and ductility of structure, failure modes and redundancy, are suggested. July 02 汶川地震建筑震害分析与重建研讨会在工程院等相关部门的支持下，全国建筑抗震领域的100多名专家在中国工程院召开了“汶川地震建筑震害分析与重建研讨会”。把我们灾后完成的一些工作在这里简要介绍一下吧。 汶川地震建筑震害分析, 清华大学土木结构组, 西南交通大学土木结构组, 北京交通大学土木结构组, 汶川地震建筑震害分析与重建研讨会论文集, 2008.6, 北京 砌体结构的地震倒塌模拟与分析, 林旭川, 陆新征, 叶列平, 汶川地震建筑震害分析与重建研讨会论文集, 2008.6, 北京 现浇楼板对框架结构柱梁强度比的影响研究, 马千里, 叶列平, 陆新征, 马玉虎, 汶川地震建筑震害分析与重建研讨会论文集, 2008.6, 北京 填充墙震害数值模拟与对策讨论, 张炎圣, 马千里, 陆新征, 叶列平, 汶川地震建筑震害分析与重建研讨会论文集, 2008.6, 北京 出屋面结构震害分析与设计建议, 缪志伟, 陆新征, 叶列平, 汶川地震建筑震害分析与重建研讨会论文集, 2008.6, 北京 建筑结构的抗倒塌能力——汶川地震建筑震害的教训, 叶列平, 曲哲, 陆新征, 汶川地震建筑震害分析与重建研讨会论文集, 2008.6, 北京 June 22 新上载论文：核爆冲击波作用下空心砌块墙对主体结构的作用核爆冲击波作用下空心砌块墙对主体结构的作用 工程力学/Engineering Mechanics, 2008, 25(5): 73-78. 摘 要：该文采用显式动力有限元软件LS-DYNA 对核爆冲击波作用下高层建筑混凝土小型空心砌块外墙(以下简称砌块墙)的破坏模式进行了数值模拟，计算模型考虑了材料非线性、接触非线性、大应变、大变形等主要特征。在此基础上讨论了砌块墙在破坏飞散过程中传给结构的荷载，得到了不同冲击波超压作用下砌块墙传给结构的荷载时程。计算结果表明：核爆冲击波作用下，砌块墙的破坏模式与冲击波超压的大小有关；其传给结构的荷载时程基本呈三角形分布，荷载峰值随超压的增加而增大，墙体顶部与结构构件之间接触面的允许抗剪强度对荷载峰值时间和持续作用时间起关键作用。 EFFECTS OF CONCRETE MASONRY WALLS ON STRUCTURES UNDER NUCLEAR BLAST LOADINGS Engineering Mechanics, 2008, 25(5): 73-78. Abstract: Concrete masonry walls subjected to blast loadings were analyzed with the explicit dynamic finite element method. The nonlinear material properties, nonlinear contact, large strain, large displacement were considered in the analysis model. The effects on high rise building caused by masonry wall deformation and failure under blast loadings were discussed. The loading time history on high rise building caused by masonry wall failure is presented. The numerical results show the mode of failure of masonry walls is significantly influenced by the strength of blast wave. The induced forces of structures are of triangle pattern, the larger the strength of blast wave, the higher the peak value of forces . The critical shear strength of mortar between masonry wall and the structural members played an important role on the moment of peak forces and the duration of forces. June 05 新上载论文：采用逐步增量弹塑性时程方法对RC框架结构推覆分析侧力模式的研究采用逐步增量弹塑性时程方法对RC框架结构推覆分析侧力模式的研究 马千里, 叶列平, 陆新征, 缪志伟 摘要:以两个普通六层和十层钢筋混凝土框架结构为例,采用基于纤维模型的逐步增量弹塑性时程方法得到的层间剪力-位移关系曲线,与不同侧力模式的推覆分析结果进行了对比,研究了推覆分析结果的可靠程度。通过与不同场地的大量地震记录的弹塑性时程计算结果进行比较分析,建议采用多种合理的侧力模式进行推覆分析,对结构不同楼层的抗震性能进行全面的评价,即均布侧力模式适合于底部楼层的评价;考虑高度影响分布力模式适合于结构中部楼层的评价;而对结构上部楼层特别是顶层,可以采用SRSS侧力模式或规范侧力模式进行评价。分析研究表明,采用本文建议的侧力模式进行推覆分析,可在统计意义上可对钢筋混凝土规则框架结构的抗震能力作出偏于安全的估计。 Ma QL, Ye LP, Lu XZ, Miao ZW Abstract: In this research, the nonlinear static p rocedures with different lateral load patterns were compared by using incremental dynamical analysismethod based on a six2storey and a ten2storey RC frame fibermodel. For each story of different frames, the inter2story shear force vs. drift curves computed by pushover analysis by using different lateral load patterns and time history analysis with a series of earthquake records on the design site have been compared to give a rational lateral load pattern of pushover analysis. Finally, for a whole frame structure, the lateral load pattern choice was suggested, that is, uniform load pattern was better for the stories near foundation; load pattern with the story heights taken into consideration was suitable for the mid stories and the SRSS pattern or Chinese Code pattern was suitable for upper stories. It is also shown that the nonlinear static p rocedure gives a safe estimation of the inelastic seismic response statistically for regular RC frames with good numerical stability. June 02 新上载论文：钢筋混凝土楼板火灾反应数值计算模型钢筋混凝土楼板火灾反应数值计算模型 摘 要：基于退化壳原理，考虑火灾下板壳截面的不均匀温度场分布而引入分层模型，同时在每分层上考虑材料在不同温度下的热力弹塑性本构关系，建立了火灾下钢筋混凝土板壳结构的有限元数值计算模型。另外，通过全拉格朗日方法考虑了大位移的几何非线性影响。最后通过一钢筋混凝土板在高温下的试验进行了验证，并分析了配筋率和保护层厚度的影响。结果表明：提出的火灾下钢筋混凝土壳单元数值计算模型的计算结果与试验结果吻合较好，可以用来分析火灾下钢筋混凝土框架结构楼板的反应。 NUMERICAL MODELING OF REINFORCED CONCRETE SLABS SUBJECTED TO FIRE Abstract: Based on the degenerated shell theory, a finite element numerical model is proposed to analyze the behavior of the reinforced concrete slabs exposed to fire. The non-uniform temperature distribution across the section of the slab is considered. The temperature dependent thermal-elastic plastic material model is introduced in each layer through the layered model. The geometric nonlinearity due to large displacement is taken into consideration through Total Lagrange approach. The proposed model is validated by a fire experimental test on a reinforced concrete slab and the effects of parameters including the ratio of reinforcement and the thickness of the concrete cover are analyzed. The results show that the predictions agree well with the experimental results and the proposed model can be used to analyze the response of the reinforced concrete slabs under fire.
|
|
|||||||||||||||||||||||||
|
|
Invite as friend
Profile
Blog
Photos
Lists