Finite Element Analysis Of Frame Research Articles

Finite Element Analysis of Frames with Reinforced Concrete Encased Steel Composite Columns

Structural frame systems that consists of concrete-encased-steel-embedded composite columns and reinforced concrete beams are typically used in mid-rise to tall buildings. In order to understand their overall structural behavior, a total of 12 frame models with high and low ductility features were constructed and analyzed using LS-DYNA software. Two of these models were validated using the results of previously tested frames. The remaining 10 models were studied to predict the behavior of frames with varying concrete strengths, reinforcement configurations, and structural steel sections under vertical and lateral loads. The results were investigated in terms of cracks and failure patterns, load-deflection relationships, energy dissipation, and stiffness degradation. The analytical results indicated that the high ductile frame models showed slightly better lateral load carrying performances compared to low ductility frame models. Moreover, the analytical studies demonstrated that the existence of structural steel in a column, regardless of its cross-sectional shape, was the most important parameter in improving the lateral load carrying capacity of a frame.

Augmented Lagrangian method for imposing nonlinear multi freedom constraints in static analysis for frames using FEM

This paper focuses on the treatment of nonlinear multi freedom constraints using an augmented Lagrangian method in finite element analysis of frames. The process of imposing boundary constraints is developed by changing the assembly stiffness equation to produce a modified system of equation considering nonlinear multi freedom constraints. For imposing the nonlinear constraints two better methods are the penalty augmentation method and Lagrange multiplier adjunction method. But there are not free of disadvantages. Using penalty method has a disadvantage in the choice appropriate weight values that balance solution accuracy with the violation of constraint conditions. Using the Lagrange multiplier adjunction method requires additional unknowns, and more complicated storage allocation procedures. This research proposes the connection between these methods using the augmented Lagrangian method for imposing the nonlinear multi freedom constraints in finite element analysis of frame. Based on the Newton Raphson method the incremental-iterative algorithm for solving the nonlinear balanced equations is established.

A modified penalty function method for treating multi freedom constraints in finite element analysis of frames

In finite element analysis, treating boundary condition having multi freedom constraints is needed to produce modified system of equation based on master stiffness equation considering multi freedom constraint. Generally the operation of imposing multi freedom constraints can be developed using Master-Slave Elimination, Penalty Augmentation or Lagrange Multiplier Adjunction methods. The master-slave method is useful only for simple cases but exhibits serious shortcomings for treating arbitrary constraints. The Penalty Augmentation method and Lagrange Multiplier Adjunction are better in many applications. But there are not free of disadvantages. The penalty method has difficulty of choice of weight values that balance solution accuracy with the violation of constraint conditions. The multiplier method is sensitive to the degree of linear independence of the constraints, and the bordered stiffness is singular in the case of the dependent constrains. To reduce the disadvantages of these methods, this paper presents a new method for treating multi freedom constraint. Proposed method is similar to penalty function method and it is called “modified penalty function method”. The concept of the modified penalty function method is based on the constructing equivalent solver system of equations from traditional modified system using regulatory parameters. The basic of method for selecting the regulatory parameters is reducing the violation of modified system. For solving equivalent system the authors proposed an iterative algorithm for seeking the solution. The calculation programs are established based on proposed algorithm. The calculation results using the proposed method matched with the calculation results using other methods.

Deconstructable timber-concrete composite beams with panelised slabs: Finite element analysis

This paper deals with the development of efficient and accurate numerical models for the analysis of deconstructable timber-concrete composite (TCC) beams with panelised reinforced concrete (RC) slabs. Three different methods, viz. analytical, 1D frame finite element (FE) and 2D continuum-based FE models, are proposed and validated against experimentally measured data from 4-point bending tests conducted on TCC beams with precast panels. It is shown that the analytical model is the most efficient, whereas the 2D continuum-based model is the most accurate among the three different methods considered. In addition, a parametric study is carried out using 2D FE models to assess various aspects of the TCC system and to evaluate the influence of precast panelised RC slabs on the structural response of TCC beams. Lastly, the challenges of the practical FE modelling of deconstructable TCC beams are briefly discussed and accordingly, some guidance on the FE analysis of TCC beams with panelised RC slabs is provided.

Effect of masonry infill walls with openings on nonlinear response of reinforced concrete frames

Masonry infill walls are unavoidable parts of any building to create a separation between internal space and external environment. In general, there are some prevalent openings in the infill wall due to functional needs, architectural considerations or aesthetic concerns. In current design practice, the strength and stiffness contribution of infill walls is not considered. However, the presence of infill walls may decisively influence the seismic response of structures subjected to earthquake loads and cause a different behavior from that predicted for a bare frame. Furthermore, partial openings in the masonry infill wall are significant parameter affecting the seismic behavior of infilled frames thereby decreasing the lateral stiffness and strength. The possible effects of openings in the infill wall on seismic behavior of RC frames is analytically studied by means of pushover analysis of several bare, partially and fully infilled frames having different bay and story numbers. The stiffness loss due to partial opening is introduced by the stiffness reduction factors which are developed from finite element analysis of frames considering frame-infill interaction. Pushover curves of frames are plotted and the maximum base shear forces, the yield displacement, the yield base shear force coefficient, the displacement demand, interstory drift ratios and the distribution of story shear forces are determined. The comparison of parameters both in terms of seismic demand and capacity indicates that partial openings decisively influences the nonlinear behavior of RC frames and cause a different behavior from that predicted for a bare frame or fully infilled frame.

Nonlinear buckling analysis of 2-D cold-formed steel simple cross-aisle storage rack frames

Industrial storage racks are among the most important structures made from cold-formed steel sections. They are widely used due to the increasing need for rational space utilization in warehouses, and other facilities used to store goods. Pallet rack is a material handling, storage aid system designed to store materials on pallets. Although there are many varieties of pallet racking, all types allow for the storage of palletized materials in horizontal rows with multiple levels. Rack systems are widely used in warehouses where they are loaded with valuable goods. The cold-formed steel columns usually have open cross-sections and are thin walled, making them vulnerable to torsional-flexural buckling and local buckling. The loss of goods may be greater than the total cost of the rack on which the goods are stored, which can indirectly affect the owner. Therefore, understanding the stability of rack structures is very important. This paper deals with numerical linear and nonlinear buckling analysis of 2-D cold-formed steel simple cross-aisle storage rack frames. The main focus of the study is to ascertain the stability of 2-D frames of a pallet racking system. With this objective, a pallet racking system with cold-formed steel sections is simulated by three-dimensional models using shell elements in ABAQUS, a general purpose finite element analysis software. Linear and nonlinear buckling analyses are carried out on these frames. Results are obtained from finite element analysis of frames with 12 types of column sections. Spacer bars and channel stiffeners are used to improve the torsional strength of original open cross sections. Results show that spacer bars and channel stiffeners are very effective in enhancing the strength of cold-formed steel pallet rack structures.

Finite Element Analysis of one New Type Hybrid Bus Frame

The hybrid bus frame is a vehicle’s main bearing component, in which bearing stress state is very complex. In this article, the virtual prototype vehicle model is established to extract dynamic loads between each key connecting parts and the hybrid bus frame. At the same time, the hybrid bus frame finite element model is established to make strength and stiffness analysis with dynamic loads as boundary conditions. The results verify that the strength and stiffness can meet the hybrid bus frame requirement, and the largest deformation and stress area is found. The results also can provide an important basis for correcting the frame structure. What’s more, this paper makes a comparison between the method of the frame finite element analysis based on dynamic loads and the method of the frame finite element analysis based on the statics, concluded a result that the frame finite element analysis based on dynamic loads can more accurately describe the real stress state of the frame and the analysis result is more reliable.

하중기반 유한요소모델에 의한 FRP 보강 철근콘크리트 기둥의 비선형 해석

The aim of the current study is to develop a nonlinear isoparametric layered frame finite element (FE) analysis of FRP strengthened reinforced concrete (RC) beam or column members by a force-based FE formulation. In sections, concrete is modeled in the triaxial stress-strain relationship state and the FRP sheet is modeled as layered composite materials in two-dimension. The element stiffness matrix derived by the force-based FE has the force-interpolation functions without assuming the displacement shape functions. A lateral load test of RC column strengthened by GFRP sheets was analyzed by the developed force-based FE model. From comparative studies of the experimental and analysis results, it was shown to compare with the stiffness FE method that the force-based FE analysis could give more accurate predictions in the overall lateral load-deflection response as well as in nonlinear deformations and damages in the column plastic hinge region.

Finite Element Analysis of Frame on ZXZ90 Towing Machine for Cable

In this paper, structure characteristics of frame on towing machine were analyzed. Based on shell element as the meshing type, finite element surface geometry model was established. The forms of loading on towing condition were studied, it is confirmed that drum was simplified as the key point on towing condition, and then the load was transmitted by rigid connection which got key point and frame connected together; and the load was applied at centre of gravity of parts; based on the safety performance on different conditions verified by finite element analysis, the structure improvement advice was proposed for frame.

Design and Research on Micro Pure Electric Garbage Transfer Vehicle

Based on the analysis of characteristics and Application requirements, one type of micro pure electric garbage transfer vehicle was designed. The power layout program, chassis layout and hydraulic lifting mechanism were researched to meet the driving safety need and automobile ride. The McPherson independent front suspension and the coil spring integral rear suspension were selected as the suspension program. The type of motor front and front drive was the arrangement of power system. The ladder frame chassis was selected for its high strength and low cost and the finite element analysis of frame was executed to verify the strength. The lifting mechanism was the key of the vehicle, one integrated hydraulic lifting mechanism was selected and the lifting time and angle and cylinder diameter were calculated. The tests confirm the sample vehicle being of reliable design and good performance.

Refined Finite Element Analysis of Steel Frames by the Shifted Integration Technique

The finite element analysis of framed structures by the Adaptively Shifted Integration technique is improved for higher accuracy in the present study. The bending moment distribution on the cubic element based on Bernoulli-Euler hypothesis is interpolated in a cubic form by using shear forces determined by nodal forces. This treatment makes it possible to evaluate the maximum value of the bending moment and to form a plastic hinge at an arbitrary location in the element. Several numerical studies have been carried out in order to show the effectiveness of the present method.

Refined Finite Element Analysis of Steel Frames by the Shifted Integration Technique

The Shifted Integration technique, which has been developed for the efficient nonlinear finite element analysis of framed structures, is extended to the plastic collapse analysis of frames with semi-rigid joints. By using the SI technique in short cubic elements inserted at member ends, both of the nonlinear characteristic of joints and the elastoplastic property of member ends can be independently taken into account in these short elements. The highly accurate analysis of semi-rigid frames is made possible in the framework of displacement-type finite element method using only standard cubic beam elements. Several numerical studies are conducted in order to illustrate the validity of the proposed method.