The dynamic buckling of elasto-plastic cylindrical shells under axial fluid-solid impact is investigated theoretically. A simplified liquid- gas- structure model is given to approximately imitate the problem. The basi...The dynamic buckling of elasto-plastic cylindrical shells under axial fluid-solid impact is investigated theoretically. A simplified liquid- gas- structure model is given to approximately imitate the problem. The basic equation of the structure is derived from a minimum principle in dynamics of elasto-plastic continua at finite deformation, and the flow theory of plasticity is employed. The liquid is incompressible and the gas is compressed adiabatically. A number of numerical results are presented and the characteristics of the buckling behavior under fluid-solid impact are illustrated.展开更多
In this paper, a method for the design optimization of elasto-plastic truss structures is proposed based on parametric variational principles （PVPs）. The optimization aims to find the minimum weight/volume solution ...In this paper, a method for the design optimization of elasto-plastic truss structures is proposed based on parametric variational principles （PVPs）. The optimization aims to find the minimum weight/volume solution under the constraints of allowable node displacements. The design optimization is a formulation of mathematical programming with equilibrium constraints （MPECs）. To overcome the numerical difficulties of the complementary constraints in optimization, an iteration process, comprising a quadratic programming （QP） and an updating process, is employed as the optimization method. Furthermore, the elasto-plastic buckling of truss mem- bers is considered as a constraint in design optimization. A combinational optimization strategy is proposed for the displacement constraints and the buckling constraint, which comprises the method mentioned above and an optimal criterion. Three numerical examples are presented to show the validity of the methods proposed.展开更多
The elasto-plastic buckling and postbuckling of fiber metal laminates （FML） are studied in this research. Considering the geometric nonlinearity of the structure and the elasto- plastic deformation of the metal laye...The elasto-plastic buckling and postbuckling of fiber metal laminates （FML） are studied in this research. Considering the geometric nonlinearity of the structure and the elasto- plastic deformation of the metal layers, the incremental Von Karman geometric relation of the FML with initial deflection is established. Moreover, an incremental elasto-plastic constitutive relation adopting the mixed hardening rule is introduced to depict the stress-strain relationship of the metal layers. Subsequently, the incremental nonlinear governing equations of the FML subjected to in-plane compressive loads are derived, and the whole problem is solved by the iterative method according to the finite difference method. In numerical examples, the effects of the initial deflection, the loading state, and the geometric parameters on the elasto-plastic buckling and postbuckling of FML are investigated, respectively.展开更多
The elasto-plastic postbuckling of fiber metal laminated beams with delamination and the energy release rate along the delamination front are discussed in this paper. Considering geometrical nonlinearity, thermal envi...The elasto-plastic postbuckling of fiber metal laminated beams with delamination and the energy release rate along the delamination front are discussed in this paper. Considering geometrical nonlinearity, thermal environment and geometrical initial imperfection, the incremental nonlinear equilibrium equations of delaminated fiber metal laminated beams are established, which are solved using the differential quadrature method and iterative method. Based on these, according to the J-integral theory, the elasto-plastic energy release rate is studied. The effects of some important parameters on the elasto-plastic postbuckling behavior and energy release rate of the aramid reinforced aluminum laminated beams are discussed in details.展开更多
芯筒-刚臂结构广泛应用于超高层建筑设计中,但由于其刚臂设置引起的刚度突变容易造成刚臂及附近所在楼层在地震作用下发生破坏。目前,被动耗能减震技术日趋成熟,其中屈曲约束支撑(简称BRB)在高层建筑中应用最为广泛。将BRB设置于刚臂和...芯筒-刚臂结构广泛应用于超高层建筑设计中,但由于其刚臂设置引起的刚度突变容易造成刚臂及附近所在楼层在地震作用下发生破坏。目前,被动耗能减震技术日趋成熟,其中屈曲约束支撑(简称BRB)在高层建筑中应用最为广泛。将BRB设置于刚臂和外柱连接处,作为屈曲约束柱(简称BRC),提出新的芯筒-刚臂结构减震体系(BRC between the outrigger and exterior columns of COS,简称BRCC-COS减震结构体系),并基于抗震性能设计方法完成BRC的设计。针对芯筒-刚臂结构的平面简化模型,利用弹塑性时程分析方法研究其在地震作用下的结构特性。最后,根据不同的地震损伤模型评估研究该减震结构体系的地震损伤程度,研究分析表明,该减震结构体系能够降低由于刚臂设置引起的附近楼层和核心筒在地震下的损伤程度,并为该类结构的耗能减震设计提供可靠的理论依据。展开更多
文摘The dynamic buckling of elasto-plastic cylindrical shells under axial fluid-solid impact is investigated theoretically. A simplified liquid- gas- structure model is given to approximately imitate the problem. The basic equation of the structure is derived from a minimum principle in dynamics of elasto-plastic continua at finite deformation, and the flow theory of plasticity is employed. The liquid is incompressible and the gas is compressed adiabatically. A number of numerical results are presented and the characteristics of the buckling behavior under fluid-solid impact are illustrated.
基金Project supported by the National Natural Sciences Foundation of China (Nos. 10372084 and 10572119)the Program for New Century Excellent Talents in University (No. NCET-04-0958)the Open Foundation of State Key Laboratory of Structural Analysis of Industrial Equipment and the Doctorate Foundation of Northwestern Polytechnical University.
文摘In this paper, a method for the design optimization of elasto-plastic truss structures is proposed based on parametric variational principles （PVPs）. The optimization aims to find the minimum weight/volume solution under the constraints of allowable node displacements. The design optimization is a formulation of mathematical programming with equilibrium constraints （MPECs）. To overcome the numerical difficulties of the complementary constraints in optimization, an iteration process, comprising a quadratic programming （QP） and an updating process, is employed as the optimization method. Furthermore, the elasto-plastic buckling of truss mem- bers is considered as a constraint in design optimization. A combinational optimization strategy is proposed for the displacement constraints and the buckling constraint, which comprises the method mentioned above and an optimal criterion. Three numerical examples are presented to show the validity of the methods proposed.
基金supported by the National Natural Science Foundation of China(No.11272117)
文摘The elasto-plastic buckling and postbuckling of fiber metal laminates （FML） are studied in this research. Considering the geometric nonlinearity of the structure and the elasto- plastic deformation of the metal layers, the incremental Von Karman geometric relation of the FML with initial deflection is established. Moreover, an incremental elasto-plastic constitutive relation adopting the mixed hardening rule is introduced to depict the stress-strain relationship of the metal layers. Subsequently, the incremental nonlinear governing equations of the FML subjected to in-plane compressive loads are derived, and the whole problem is solved by the iterative method according to the finite difference method. In numerical examples, the effects of the initial deflection, the loading state, and the geometric parameters on the elasto-plastic buckling and postbuckling of FML are investigated, respectively.
基金Project supported by the National Natural Science Foundation of China(No.11272117)
文摘The elasto-plastic postbuckling of fiber metal laminated beams with delamination and the energy release rate along the delamination front are discussed in this paper. Considering geometrical nonlinearity, thermal environment and geometrical initial imperfection, the incremental nonlinear equilibrium equations of delaminated fiber metal laminated beams are established, which are solved using the differential quadrature method and iterative method. Based on these, according to the J-integral theory, the elasto-plastic energy release rate is studied. The effects of some important parameters on the elasto-plastic postbuckling behavior and energy release rate of the aramid reinforced aluminum laminated beams are discussed in details.
文摘芯筒-刚臂结构广泛应用于超高层建筑设计中,但由于其刚臂设置引起的刚度突变容易造成刚臂及附近所在楼层在地震作用下发生破坏。目前,被动耗能减震技术日趋成熟,其中屈曲约束支撑(简称BRB)在高层建筑中应用最为广泛。将BRB设置于刚臂和外柱连接处,作为屈曲约束柱(简称BRC),提出新的芯筒-刚臂结构减震体系(BRC between the outrigger and exterior columns of COS,简称BRCC-COS减震结构体系),并基于抗震性能设计方法完成BRC的设计。针对芯筒-刚臂结构的平面简化模型,利用弹塑性时程分析方法研究其在地震作用下的结构特性。最后,根据不同的地震损伤模型评估研究该减震结构体系的地震损伤程度,研究分析表明,该减震结构体系能够降低由于刚臂设置引起的附近楼层和核心筒在地震下的损伤程度,并为该类结构的耗能减震设计提供可靠的理论依据。
