Application of the compound strip method for the analysis of slab-girder bridges

The compound strip method is illustrated for the analysis of slab-girder bridges modeled as a linear elastic plate continuous over deflecting supports. This approach incorporates the effects of support elements in a direct stiffness methodology by creating a substructure composed of plate. beam. and column elements which is termed a “compound strip.” The theory and application of the compound strip method is presented. The finite element and compound strip methods are compared in an illustrative analysis for a slab-girder bridge. The results of the compound strip analysis compare well with the finite element method. The methodology presented herein can be used to efficiently model any slab-girder bridge configuration. Typically, the compound strip method requires significantly less computational resources than does the finite element method and is well suited for use on today's microcomputers.     

Three-dimensional finite strip analysis of laminated panels

In this paper, a combined finite strip and state space approach is introduced to obtain three-dimensional solutions of laminated composite plates with simply supported ends. The finite strip method is used to present in-plane displacement and stress components, while the through-thickness components are obtained by using the method of state equation. The method can replace the traditional three-dimensional finite element solutions for structures that have regular geometric plans and simple boundary conditions, where a full three-dimensional finite element analysis is very often both extravagant and unnecessary. The new method provides results that show good agreement with available benchmark problems having different material compositions, thickness and boundary conditions. The new method provides a three-dimensional solution for laminated plates, while the advantages of using the traditional finite strip method are fully taken. This solution also yields a continuous transverse stress field across material interfaces that normally is not achievable by other numerical modelling of laminates, such as the traditional finite element method.     

Geometric non-linear analysis of channel sections under end shortening,using different versions of the finite strip method

Two finite strip methods, namely the full-energy and the semi-energy FSM, are developed for predicting the geometrically non-linear response of channel sections with simply supported ends when subjected to uniform end shortening in their plane. The developed finite strip methods are then applied to analyze the post-local-buckling behaviour of some representative channel sections. The comparison of results revealed the fact that for the channel sections under study, the full-energy finite strip method is capable of predicting results with a greater degree of accuracy than that of the results obtained by the semi-energy finite strip method. This is due to the fact that a lower level of compressional stiffness is experienced in the case of the full-energy FSM results as compared to those observed in the case of semi-energy FSM. It is however worth noting that at the expense of slightly less accurate results, the current semi-energy analysis is benefiting from considerably less computer CPU time, due to the implementation of a fairly small number of degrees of freedom, as compared to the CPU time elapsed by the computer when the full-energy method is applied. It is noted that in the current semi-energy approach only one term is utilized, whereas several terms are implemented in the formulation of the full-energy method. Therefore, it is expected that the accuracy of the semi-energy approach will improve and correspondingly the required computer CPU time will increase if more than one term is utilized in its formulation.     

Refined three-dimensional finite strip model for analysis of thick composite sandwich plates

A refined three-dimensional finite strip model for stress analysis of thick hybrid composite sandwich plates is presented in the present article. The new model is based on a combination of two different strip elements: quadratic linear skin strip (QLSS), and modified quadratic cubic core strip (MQCCS). The applications of the proposed model for sandwich plates containing a local damage under membrane or bending loading are illustrated. Numerical results are compared to independent solutions and measured data and found to be in excellent agreement. A comprehensive discussion of the numerical aspects of the method is conducted to test the strips' characteristics regarding the spectral accuracy, finite element convergence and accuracy of numerical integrations.     

The performance of Mindlin plate finite strips in geometrically nonlinear analysis

The finite strip method is used in the geometrically nonlinear analysis of laterally loaded isotropic plates within the context of Mindlin plate theory wherein the effects of transverse shear deformation are included. The analysis is of the Lagrangian type with the nonlinearity introduced by the inclusion of certain nonlinear terms in the strain-displacement equations. Following on from a related earlier investigation which dealt with a particular finite strip model, the performance of a range of different models is investigated. Linear, quadratic, cubic, and quartic polynomial interpolation is used in the different models in representing the variation of the five relevant displacement type quantities across a strip: also, both analytical (exact) and numerical (reduced, selective) schemes of integration are used in the crosswise direction in evaluating the stiffness properties of the various models. The ends of the finite strips are simply supported for out-of-plane behaviour and immovable for inplane behaviour. Detailed results are presented of the application of seven types of finite strip model to a range of plate problems, all involving uniformly loaded, square plates but with thin or moderately thick geometry and with simply supported or clamped longitudinal edges.     

智能多Agent技术在样条有限条法中的应用研究

样条有限条法是一种有效的分析冷弯成形过程的方法,将多Agent技术应用于样条有限条法中不仅增强了各有限条的智能化描述,而且优化了孔型设计和轧辊设计。介绍了多Agent技术在样条有限条法中的应用,论述了如何利用多Agent技术建立多Agent系统的体系结构,内容包括Agent与多Agent系统的相关介绍、样条有限条法的基本理论以及多Agent系统的体系结构。     

Buckling of initially stressed mindlin plates using a finite strip method

The buckling of initially stressed Mindlin plates is considered using a thick finite strip method. The method is compared with a wide variety of published results and for both thin and moderately thick plates excellent accuracy is obtained. Some further results are obtained for initially stressed rectangular plates with two opposite edges simply supported and various support conditions on the remaining sides. In general, it is found that for moderately thick plates, Mindlin's plate theory gives lower buckling loads than those obtained using classical thin plate theory.     

Stability analysis of anisotropic laminated composite plates by finite strip method

The finite strip method has been applied to the stability analysis of rectangular shear-deformable composite laminates. However, for the plates with two opposite simply supported sides, the existing analysis was restricted to the symmetrical cross-ply laminates under compression loading.In the present study, by selecting proper displacement functions and including the coupling between different series terms, the finite strip method is extended to the stability analysis of any anisotropic laminated plates under arbitrary in-plane loading. Furthermore, a number of numerical results are presented to show the effects of thickness, fibre orientation and stacking sequence on the buckling loads.     

Radiation characteristics of strip‐loaded dielectric‐coated conducting cylinder

The radiation characteristics of strip‐loaded dielectric‐coated conducting cylinder are investigated theoretically for the infinite and finite periodic structures. For the infinite case, the strip electric current expansion satisfying edge condition and the field expression with a summation of space harmonics are applied to solve a homogeneous matrix equation. The integral equation is derived for the finite structure by using the inverse Fourier transform and the strip current expansion. The influences of the strip width, cylinder radius, and finite strip number on the radiation characteristics (leakage constant, phase constant, radiation pattern, and beam scanning) are investigated. The results of the finite periodic strips are compared with those of the infinite extent structure and good agreement is found. © 2007 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2008.     

Thermal behavior of formed sandwich plate by finite-prism-strip method

In this paper, the thermal analysis for prefabricated architectural sandwich panels is carried out. The core of the sandwich panel is approximated by the finite prism, and the thin faces are handled by the finite strip. The finite-prism-strip method is simple to program and saves considerable computing effort compared with the finite element method. The results are compared with the Chong's approximate solution.     

Continuum damage mechanics analysis of strip tearing in a tandem cold rolling process

Strip tearing during tandem cold rolling is one of the manufacturing issues in the rolling industry that can significantly increase production costs. In this paper, an explicit finite element code coupled with the improved Lemaitre damage model is developed to predict strip tearing in a five-stand tandem rolling mill. The simulation results are validated using experimental data from an industrial rolling mill, and there is good agreement between the numerical and experimental results. Some factors related to strip tearing, such as friction coefficient variations, thickness difference between two welded strips and reduction schedule, are introduced, and their influence on the damage evolution through the strip during the process is investigated by using damage-coupled finite element simulations.     

Geometric nonlinear analysis of stiffened plates by the spline finite strip method

Geometric nonlinear analysis of stiffened plates is investigated by the spline finite strip method. von Karman’s nonlinear plate theory is adopted and the formulation is made in total Lagrangian coordinate system. The resulting nonlinear equations are solved by the Newton–Raphson iteration technique. To analyse plates having any arbitrary shapes, the whole plate is mapped into a square domain. The mapped domain is discretised into a number of strips. In this method, the displacement interpolation functions used are: the spline functions in the longitudinal direction of the strip and the finite element shape functions in the other direction. The stiffener is elegantly modelled so that it can be placed anywhere within the plate strip. The arbitrary orientation of the stiffener and its eccentricity are incorporated in the formulation. All these aspects have ultimately made the proposed approach a most versatile tool of analysis. Plates and stiffened plates are analysed and the results are presented along with those of other investigators for necessary comparison and discussion.     

Assumed stress hybrid model in X-spline finite strip method

The X-spline finite strip method (XFSM) developed in another paper by the first author and K. P. Chong enabled the finite strip method to apply to problems defined in some irregular-shaped region and may be regarded as the compatibility model in XFSM. In this paper an assumed stress hybrid model (ASHM) for XFSM is obtained so that the strong points of ASHM in finite element method and that of the XFSM are combined together. Furthermore, calculations for finding the inverse of matrix [H] in ASHM are considerably simplified by employing a theorem which is developed.     

Comparison of numerical techniques for 3D flutter analysis of cable-stayed bridges

This paper presents the results of a comparison study of the numerical techniques of structural and aerodynamic force models developed based on the spline finite strip method with the conventional finite element approach in three-dimensional flutter analysis of cable-stayed bridges. In the new formulation, the bridge girder is modelled by spline finite strips. The mass and stiffness properties of the torsional behaviour of complex bridge girder, which have a significant influence on the wind stability of long-span bridges, are modelled accurately in the formulation. The effects of the spatial variation of the aerodynamic forces can be taken into account in the proposed numerical model by distributing the loads to the finite strips modelling the bridge deck. The numerical example of a 423 m long-span cable-stayed bridge is presented in the comparison study. The accuracy and effectiveness of the proposed finite strip model are compared to the results obtained from the equivalent beam finite element models. The advantages and disadvantages of these different modelling schemes are discussed.     

Finite strip analysis of curved composite girders with incomplete interaction

This paper presents a finite strip analysis of curved composite girders with incomplete interaction. In the present analysis curved composite girder bridges are modelled by curved strip elements for the concrete slab and steel girder and spring elements for the shear connectors. The shear connectors are assumed as a two-dimensional spring element along the nodal line. The proposed method is applied to the analysis of curved box girders, curved plates and curved composite girder bridges with complete and incomplete interaction. Some analytical results obtained by this method are compared with the test results and theoretical values obtained by other methods, and they are in good agreement. Slip behavior of curved composite box girders is also discussed based on the results by the proposed method.     

Geometrically nonlinear analysis of rectangular mindlin plates using the finite strip method

A general finite strip method of analysis is presented for the geometrically nonlinear analysis of laterally loaded, rectangular, isotropic plates. The analysis is based on the use of Mindlin plate theory and therefore includes the effects of transverse shear deformation. The nonlinearity is introduced via the strain-displacement equations and correspondingly the analysis pertains to problems involving moderate displacements but small rotations. The principle of minimum potential energy is used in the development of the strip and the complete plate stiffness equations and the latter equations are solved using the Newton-Raphson method. In numerical applications a particular type of finite strip is used in which all five reference quantities (three displacements and two rotations) are represented by cubic polynomial interpolation across the strip whilst the ends of the strip are simply supported for bending/shearing behaviour and immovable for membrane behaviour. These applications are concerned with uniformly loaded plates of both thin and moderately-thick geometry and detailed presentation is given of both displacement- and force-type quantities.     

Dynamic analysis of structures using a Reissner-Mindlin finite strip formulation

In this paper a finite strip formulation based on Reissner-Mindlin plate theory for dynamic analysis of prismatic shell type structure is presented. Detailed expressions of the relevant strip matrices for a variety of structures using the simple two node linear strip element are given. Examples of the good performance of the linear strip element for free and forced vibration analysis of plates, bridges and axisymmetric shells are presented.     

The mixed strip method using combination splines for plate bending

Based on the Hellinger–Reissner principle, a new mixed combination spline finite strip method is proposed. Not only the deflections of a plate, but also the moments can be simultaneously obtained with the same order of accuracy. The advantage of this method over the conventional finite strip method and the spline finite strip method is that the real values of the field variables, not parameters, can be directly obtained and the boundary conditions can be treated more easily. Numerical examples indicate that this method is effiecient and accurate.