Mo Shing Cheung

Static and dynamic analysis of thin and thick sectorial plates by the finite strip method

Abstract Two and three-dimensional finite strips are developed for the analysis of thin and thick sectorial plates. The plates can be isotropic or orthotropic, of constant or variable thickness, and can have different combinations of boundary conditions. The displacement functions for the finite strips are made up of polynomial shape functions and beam eigenfunctions. The 2- D finite strips are derived based on plate bending theory and have as nodal degrees of freedom, the out-of-plane displacement and the slope. The 3- D finite strips are formulated using three-dimensional elasticity constitutive equations, and the three displacement components in a cylindrical co-ordinate system are chosen as the nodal degrees of freedom. Numerical results involving various boundary conditions, radii and subtended angles are presented. Comparisons are made with existing solutions whenever available. Close agreements are noted.

Finite strip analysis of anisotropic laminated composite plates using higher-order shear deformation theory

Abstract In the present study, a finite strip method for the elastic analysis of anisotropic laminated composite plates is developed according to higher-order shear deformation theory. This theory accounts for the parabolic distribution of the transverse shear strains through the thickness of the plate and for zero transverse shear stresses on the plate surfaces. In comparison with the finite strip method based on first-order shear deformation theory, the present method gives improved results while using approximately the same number of degrees of freedom. It also eliminates the need for shear correction factors in calculating the transverse shear stiffness.

Natural vibrations of thin, flat-walled structures with different boundary conditions

Abstract The natural frequencies of thin, flat-walled structures with different boundary conditions are analyzed by the finite strip method. This class of structures includes plates with eccentric stiffeners, thin multi-celled box girder bridges, and folded plate roofs, etc. The method is simple and at the same time very powerful and versatile, and can treat problems with variably-spaced stiffeners, and with orthotropic and variable thickness plates without any difficulty. The finite strip method is an extension of the now well-known finite element method. This method is, however, semi-analytical in nature, since the displacement functions chosen are always of the form φ ( x ) ψ ( y ), in which φ ( x ) is a polynomial with undetermined parameters, and ψ ( y ) a function series satisfying a priori the two end conditions. Thus a two-dimensional strip is reduced to a one-dimensional problem, with a corresponding reduction in computational efforts.

Finite Strip Analysis of Bridges

Preface. Notation. Mathematical approach. Introduction Basic concepts of numerical method. The finite strip method. Finite strip method. Higher order finite strips. Spline finite strip method. Compound strip method. Finite layer method and finite prism method. Vibration and stability analyses. Nonlinear analysis. Combined analysis. Finite strip analysis of bridges. Slab and slab-on-girder bridges. Curved and skew bridges. Box girder bridges. Continuous haunched bridges. Cable-stayed bridges. Finite strip modeling of bridges. References. Index.

Static and dynamic behaviour of rectangular plates using higher order finite strips

Abstract A higher order finite strip using basic function series in the longitudinal direction and a quintic polynomial in the other direction is developed in this paper and applied to various static and dynamic problems in plates. Excellent results have been obtained for all cases. In the finite strip method, the basic function series satisfy the end conditions in the longitudinal direction of the plate a priori , and a two-dimensional plate bending problem can thus be reduced to a one-dimensional ‘equivalent’ beam problem. As a result, the size as well as the band width of the stiffness matrix has been greatly reduced, and the whole procedure can be programmed on small computers. Also little input data is required for such a program.

A combined boundary element and finite element solution of slab and slab-on-girder bridges

Abstract The boundary element method (BEM) has been shown by many researchers to be an efficient numerical tool with which to analyse various engineering structures. In particular, the method has been extensively applied to a large number of plate bending problems. The distinct advantage of the method is in the reduction in dimensionality of the problem and, as a consequence of this, both computer time and data preparation are significantly reduced. In this paper, the suitability of a new method combining the advantages of both the BEM and the finite element method (FEM) is studied. The method is first applied to investigate the conventional plate bending problems. After the validity of the method is established it is then extended to analyse the more complicated problems of slabs and slab-on-girder bridges. Through a series of slab-on-girder bridge calculations, it is demonstrated that the method is not only accurate and fast converging but its ease of application and data preparation is not attainable by the ordinary FEM.

DSC Analysis and Mechanical Properties of Wood—Plastic Composites:

Wood fiber-reinforced recycled plastic composites (WRPCs) manufactured from sawdust and post-consumer high density polyethylene (HDPE) were studied in this article. The thermal, flexural properties and impact strength of the manufactured WRPCs were determined according to the relevant standard specifications. Effects of mix ratio, wood fiber length, type, and content of coupling agent on the mechanical properties of WRPCs were investigated. The fracture surfaces of WRPCs after impact test were examined and the fracture mechanism of WRPCs due to impact was also analyzed in this article. The results indicated that incorporation of wood fibers resulted in higher melting and slower crystallization rate of WRPCs. A linear relationship between cooling rate and crystallization rate was observed. With the increasing of the wood fiber weight fraction, the flexural strength of WRPCs increases. The longer the wood fiber length, the less the flexural strength of WRPCs under the conditions of this study. The Charpy impact strength decreases with the increasing of wood fibers content in WRPCs. It appears that the optimum compatibilizer content for wood and recycled HDPE mixing is 5% in weight fraction.

Analysis of slab and girder bridges by the finite strip method

Abstract The finite strip method is used for the analysis of simply-supported and continuous slab girder bridge decks of constant width. New features presented herein include the derivation of the stiffness matrix of a beam and its coupling with strips, the derivation of the stiffness matrix of a strip with longitudinal variation in thickness, and the analysis of bridges with discrete internal column supports. The finite strip method requires the operation on narrow-band matrices of small order which can be easily carried out on a small capacity computer, and the computations involved are remarkably less than in other methods. Some of the results obtained by this method are verified by model testing while other results are compared with “exact” or approximate solutions. Good agreement has been observed for all cases.

Progressive Failure Analysis of Composite Plates by the Finite Strip Method

Abstract In the present study, a finite strip method for the progressive failure of anisotropic composite laminates is developed based on the higher-order shear deformation theory and Lees strength criterion. This method produces results in a good agreement with existing analytical and numerical solutions. The effects of fibre orientation and the number of plies on the load-carrying capacity are also investigated in numerical examples.

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.