Stability Analysis of Prestressed Space Truss Structures Based on the Imperfect Truss Element

Zhen Zhou,Shao-ping Meng,Jing Wu 한국강구조학회 2009 International Journal of Steel Structures Vol.9 No.3

Prestressed space truss structures have been widely used in various public buildings in recent years. However, because of its large span, the length of its members also increases. Therefore the member initial curvature will probably affect the stability of the structure. This paper focuses on the truss element with initial geometrical imperfection under high axial load. The relation between axial force and deformation, the expression of axial tangent stiffness, and the concept of initial curvature coefficient for truss element are established. With the example of prestressed cable-stayed arch-truss structure, the influence of member initial curvature on nonlinear stability performance of the structure under various prestress values is studied. The result indicates that member initial curvature has little influence on global stiffness of the structure before buckling, but has great influence on the performance of the structure after buckling and on limit load of the structure. Under different prestress values, the limit load–member initial curvature curves are parallel and almost linear. The proposed method in this paper can be widely applied into nonlinear stability analysis of various prestressed space truss structures with large span, so that the influence of member initial curvature on structural stability can be estimated. Prestressed space truss structures have been widely used in various public buildings in recent years. However, because of its large span, the length of its members also increases. Therefore the member initial curvature will probably affect the stability of the structure. This paper focuses on the truss element with initial geometrical imperfection under high axial load. The relation between axial force and deformation, the expression of axial tangent stiffness, and the concept of initial curvature coefficient for truss element are established. With the example of prestressed cable-stayed arch-truss structure, the influence of member initial curvature on nonlinear stability performance of the structure under various prestress values is studied. The result indicates that member initial curvature has little influence on global stiffness of the structure before buckling, but has great influence on the performance of the structure after buckling and on limit load of the structure. Under different prestress values, the limit load–member initial curvature curves are parallel and almost linear. The proposed method in this paper can be widely applied into nonlinear stability analysis of various prestressed space truss structures with large span, so that the influence of member initial curvature on structural stability can be estimated.

요소 중심의 네트워크 접근법을 이용한 부정정 트러스 구조 해석

한이철,Han, Yicheol 한국농공학회 2016 한국농공학회논문집 Vol.58 No.3

Element-focused network analysis method for truss structure is proposed. The propagation process of loads from external loads to connected other elements is similar to that of connections between nodes in accordance with attachment rule in a network. Here nodes indicate elements in a truss structure and edges represent propagated loads. Therefore, the flows of loads in a truss structure can be calculated using the network analysis method, and consequently the structure can also be analyzed. As a first step to analyze a truss structure as a network, we propose a local load transfer rule in accordance with the topology of elements, and then analyze the loads of the truss elements. Application of this method reveal that the internal loads and reactions caused by external loads can be accurately estimated. Consequently, truss structures can be considered as networks and network analysis method can be applied to further complex truss structures.

Comparison of Brazed Residual Stress and Thermal Deformation between X-Type and Pyramidal Lattice Truss Sandwich Structure: Neutron Diffraction Measurement and Simulation Study

Jiang, Wenchun,Wei, Zhiquan,Luo, Yun,Zhang, Weiya,Woo, Wanchuck De Gruyter 2016 High temperature materials and processes Vol.35 No.6

<P><B>Abstract</B></P><P>This paper uses finite element method and neutron diffraction measurement to study the residual stress in lattice truss sandwich structure. A comparison of residual stress and thermal deformation between X-type and pyramidal lattice truss sandwich structure has been carried out. The residual stresses are concentrated in the middle joint and then decreases gradually to both the ends. The residual stresses in the X-type lattice truss sandwich structure are smaller than those in pyramidal structure. The maximum longitudinal and transverse stresses of pyramidal structure are 220 and 202 MPa, respectively, but they decrease to 190 and 145 MPa for X-type lattice truss sandwich structure, respectively. The thermal deformation for lattice truss sandwich panel structure is of wave shape. The X-type has a better resistance to thermal deformation than pyramidal lattice truss sandwich structure. The maximum wave deformation of pyramidal structure (0.02 mm) is about twice as that of X-type (0.01 mm) at the same brazing condition.</P>

Progressive Collapse Behavior of Large-span Truss String Structures Subjected to Cable Failure

Haiying Zhang,JinYu Lu,Xiaolong Wu,Na Li 대한토목학회 2024 KSCE Journal of Civil Engineering Vol.28 No.4

Cables play an important role in truss string structures, and their sudden failure can lead to massive damage and even collapse of the structures. This paper studies the dynamic response of a 72 m span truss string structure, the progressive collapse numerical simulation of the structure is carried out under different load conditions, the displacement and force responses of the structure after cable failure are investigated, the dynamic amplification factor is calculated, and the collapse mechanism is revealed. The effect of individual factor changes on the structural response is analyzed and compared. Results showed that after cable failure, the stress state of the upper truss changed from an arch to a simply supported beam, when reaching collapse load, the structure collapsed within 5s instead of reaching new equilibrium positions. Moreover, the structure with stiffer elastic support exhibited higher resistance to collapse. The critical member of the truss, which first buckled under compression, shifted from the mid-span to the lower chord at the end, leading to rapid structural collapse. Increasing the cable's cross-sectional area can hardly reduce the structure's dynamic response. However, when the instantaneous failure time of the cable exceeded 0.1s, a significant alleviation of the structure's dynamic response was observed.

구조디자인 측면에서 본 트러스의 구성요소와 역학적 거동특성

이주나(Lee, Juna) 대한건축학회 2014 대한건축학회논문집 Vol.30 No.2

The design composition elements and the mechanical behaviors of trusses have been investigated in order to design more various and effective trusses in architectural and structural design. First, trusses were classified into Pratt truss, Howe truss, Warren truss with composition of web members, and the mechanical behaviors of these trusses were explained from the principle of suspension and arch structures. Also, the structural features and architectural design features of the various trusses have been determined by analyzing truss models with a variation of design elements ; composition of web members, number of web panels, chord profile, depth, double chord. This has an object to provide more useful design informations for truss in early planning stage considering various architectural design purposes and structural efficiency.

코어 및 오프셋 아웃리거-벨트 트러스 구조시스템을 구성하는 구조요소의 수평거동

김형기 대한건축학회지회연합회 2021 대한건축학회연합논문집 Vol.23 No.4

The study aimed to grasp the lateral behavior of the structure elements such as slab, exterior columns and outrigger-belt truss in core and offset outrigger-belt truss system. For this purpose, a structural design of 70 stories outrigger-belt truss building was accomplished by making the use of MIDAS-Gen. And the key variables of this analysis study were the stiffness of outrigger-belt truss system and the outrigger position in planar structure. Utilizing the results of this analysis, we analyzed the lateral behavior of structure elements in core and offset outrigger-belt truss system. This paper showed that the stiffness of outrigger-belt truss and the outrigger position in planar structure had influence on lateral behavior of structural elements in outrigger-belt truss system. Also the results of research can give help in finding out the reasonable method for structural design of outrigger-belt truss system in tall building.

Structure-Control Combined Design with Structure Intensity

Park, Jung-Hyen,Kim, Soon-Ho Korean Society of Ocean Engineers 2003 International journal of ocean engineering and tec Vol.6 No.1

This paper proposes an optimum design method of structural and control systems, using a 2-D truss structure as an example. The structure is subjected to initial static loads and disturbances. For the structure, a FEM model is formed. Using modal transformation, the equation of motion is transformed into modal coordinates, in order to decrease D.O.F. of the FEM model. To suppress the effect of the disturbances, the structure is controlled by an output feedback $H_{\infty}$ controller. The design variables of the combined optimal design of the control-structure systems are the cross sectional areas of truss members. The structural objective function is the structural weight. The control objective function is the $H_{\infty}$ norm, the performance index of control. The second structural objective function is the energy of the response related to the initial state, which is derived from the time integration of the quadratic form of the state in the closed-loop system. In a numerical example, simulations have been perform. Through the consideration of structural weight and $H_{\infty}$ norm, an advantage of the combined optimum design of structural and control systems is shown. Moreover, since the performance index of control is almost nearly optimiz, we can acquire better design of structural strength.

일반화 전달강성계수법을 이용한 트러스 구조물의 구조해석

최명수(Myung Soo CHOI),Yasuhiro Bonkobara(盆子原康博),Takahiro Kondou(近蕂,孝廣) 전남대학교 수산과학연구소 2010 수산과학연구소논문집 Vol.18 No.2

In structural analysis, the finite element method (FEM) is most widely used and powerful analytical algorithm. But the FEM requires much computational cost to solve the structural analysis problem of an analytical model with many degrees of freedom. For overcoming the drawback of the FEM, authors suggested the transfer stiffness coefficient method (TSCM) based on the transfer of the stiffness coefficient for an analytical model. However the TSCM was not suitable for analyzing truss structures of various shapes. In this study, the generalized transfer stiffness coefficient method (GTSCM) combining the graph theory and TSCM is applied to the structural analysis of a truss structure. The validity of the GTSCM in structural analysis of a truss structure is confirmed through the comparison of computational results obtained by the GTSCM and the FEM.

Structural Evaluation of Torsional Rigidity of New FRP–Aluminum Space Truss Bridge with Rigid Transverse Braces

Le Zhu,Dongdong Zhang,Fei Shao,Qian Xu,Qilin Zhao 대한토목학회 2019 KSCE JOURNAL OF CIVIL ENGINEERING Vol.23 No.7

A unique fiber-reinforced polymer (FRP)–aluminum spatial truss structure with upper I-type, transverse beam braces was developed for deployable bridging, yielding the operational advantages of bestraddled erection bridges. Experimental testing and numerical simulation were performed to evaluate the torsional rigidity of a fabricated cantilever, full-scale experimental structure. The predictions obtained based on a computational finite element model were strongly consistent with the experimental results. Moreover, a numerical decomposition and reconstruction procedure was employed to understand the load-bearing mechanism of the structure. The results demonstrated that the improved transverse braces possessed adequate capacity for providing sufficient rigidity and lateral stability to the complete twin-treadway structure under torsion. The torsional center of the improved structure was located at the axis of symmetry of the twin-treadway bridge deck. The representative torsional rigidity of the twin-treadway module was approximately 87.5 kN·m2/degree. Compared to the original construction, the improved structure exhibited only minor discrepancies regarding the torsional rigidity, and consistent characteristics in terms of the load-bearing mechanism. The torsional rigidity of the improved twin-treadway structure was primarily generated by the vertical bending rigidities of its two parallel single treadways through the rigid transverse braces. This significant finding specifically pertains to the unique twin-treadway hybrid bridge. The results presented in this work are expected to provide valuable insights, which could, in turn, lead to further the development of similar lightweight structural systems.

Structure-Control Combined Optimal Design of 3-D Truss Structure Considering Initial State and Feedback Gain

JUNG-HYEN PARK 한국해양공학회 2003 韓國海洋工學會誌 Vol.17 No.4

This paper proposes an optimum, problematic design for structural and control systems, taking a 3-D truss structure as an example. The structure is subjected to initial static loads and time-varying disturbances. The structure is controlled by a state feedback H<SUB>∞</SUB> controller which suppress the effects of disturbances. The design variables are the cross sectional areas of truss members. The structural objective function is the structural weight. For the control objective, we consider two types of performance indices. The first function represents the effect of the initial loads. The second function is the norm of the feedback gain. These objective functions are in conflict with each other but are transformed into one control objective by the weighting method. The structural objective is treated as the constraint. By introducing the second control objective which considers the magnitude of the feedback gain, we can create a design to model errors.