T.-L. Zhu¹

The International Conference on Computational & Experimental Engineering and Sciences, Vol.7, No.3, pp. 107-112, 2008, DOI:10.3970/icces.2008.007.107

Abstract A modeling method for flapwise and chordwise bending vibration analysis for rotating Timoshenko beams is introduced. For the modeling method shear and the rotary inertia effects are correctly judged based on \textit {Timoshenko beam theory}. Equations of motion of continuous models are derived from a modeling method which employs hybrid deformation variables. The equations thus derived are transmitted into dimensionless forms. The effects of dimensionless parameters on the modal characteristics of the Timoshenko beams are successfully examined through numerical study. In particular, eigenvalue loci veering phenomena and integrated mode shape critical deviations are contemplated and More >

B.K. Raghu Prasad¹, T.V.R.L. Rao¹, A.R.Gopalakrishnan¹

The International Conference on Computational & Experimental Engineering and Sciences, Vol.6, No.2, pp. 99-112, 2008, DOI:10.3970/icces.2008.006.099

Abstract A modified lattice model using finite element method has been developed to study the mode-I fracture analysis of heterogeneous materials like concrete. In this model, the truss members always join at points where aggregates are located which are modeled as plane stress triangular elements. The truss members are given the properties of cement mortar matrix randomly, so as to represent the randomness of strength in concrete. It is widely accepted that the fracture of concrete structures should not be based on strength criterion alone, but should be coupled with energy criterion. Here, by incorporating the More >

Alireza Fereidooni¹, Kamran Behdinan¹, Zouheir Fawaz¹

The International Conference on Computational & Experimental Engineering and Sciences, Vol.5, No.3, pp. 157-162, 2008, DOI:10.3970/icces.2008.005.157

Abstract In this paper, dynamics instability of laminated composite beams subjected to axial and harmonically varying time loads are studied. The equations of motion are derived in integral form using the principle of virtual work and the first order shear deformation theory. A five node twenty-two degrees of freedom beam element has been developed to discretize these equations. The regions of dynamic instability of the beam are determined by solving the obtained Mathieu form differential equations. The effects of non-conservative loads and shear stiffness parameters on dynamic instability of the beam are studied. More >

C. Wielgosz¹, J. C. Thomas¹, A. Le Van¹

The International Conference on Computational & Experimental Engineering and Sciences, Vol.5, No.2, pp. 93-98, 2008, DOI:10.3970/icces.2008.005.093

Abstract In this paper we present a summary of the behaviour of inflatable fabric beams. Analytical studies on inflatable fabric beams are presented and inflatable fabric beam finite elements are described. The stiffness matrixes take into account the inflation pressure. Shakedown analysis is used to calculate limit loads of inflatable fabric beams. Results on the dynamic behaviour of inflatable beams are finally displayed. More >

J.-M. Battini¹

CMES-Computer Modeling in Engineering & Sciences, Vol.33, No.1, pp. 1-16, 2008, DOI:10.3970/cmes.2008.033.001

Abstract This paper deals with the parameterisation of large rotations in corotational beam and shell elements. Several alternatives, presented in previous articles, are summarised, completed and compared to each other. The implementation of applied external moments and eccentric forces, consistent with the different parameterisations, is also considered. More >

X.Y. Cui^1,2, G. R. Liu^2,3, G. Y. Li^1,4, G. Zheng¹

CMES-Computer Modeling in Engineering & Sciences, Vol.38, No.3, pp. 217-230, 2008, DOI:10.3970/cmes.2008.038.217

Abstract In this paper, a gradient smoothed formulation is proposed to deal with a fourth-order differential equation of Bernoulli-Euler beam problems for static and dynamic analysis. Through the smoothing operation, the C¹ continuity requirement for fourth-order boundary value and initial value problems can be easily relaxed, and C⁰ interpolating function can be employed to solve C¹ problems. In present thin beam problems, linear shape functions are employed to approximate the displacement field, and smoothing domains are further formed for computing the smoothed curvature and bending moment field. Numerical examples indicate that very accurate results can be yielded when More >

Hsin-Yi Lai¹, C. K. Chen^1,2, Jung-Chang Hsu¹

CMES-Computer Modeling in Engineering & Sciences, Vol.34, No.1, pp. 87-116, 2008, DOI:10.3970/cmes.2008.034.087

Abstract An innovative solver for the free vibration of an elastically restrained non-uniform Euler-Bernoulli beam with tip mass of rotatory inertia and eccentricity resting on an elastic foundation and subjected to an axial load is proposed. The technique we have used is based on applying the Adomian modified decomposition method (AMDM) to our vibration problems. By using this method, any$i$th natural frequencies can be obtained one at a time and some numerical results are given to illustrate the influence of the physical parameters on the natural frequencies of the dynamic system. The computed results agree well More >

Sen Yung Lee¹, Shin Yi Lu², Yen Tse Liu², Hui Chen Huang²

CMES-Computer Modeling in Engineering & Sciences, Vol.33, No.3, pp. 293-312, 2008, DOI:10.3970/cmes.2008.033.293

Abstract A new analytic solution method is developed to find the exact static deflection of a Timoshenko beam with nonlinear elastic boundary conditions for the first time. The associated mathematic system is shifted and decomposed into six linear differential equations and at most four algebra equations. After finding the roots of the algebra equations, the exact solution of the nonlinear beam system can be reconstructed. It is shown that the proposed method is valid for the problem with strong nonlinearity. Examples, limiting studies and numerical analysis are given to illustrate the analysis. The exact solutions are More >

Sen Yung Lee¹, Sheei Muh Lin², Chien Shien Lee³, Shin Yi Lu³, Yen Tse Liu³

CMES-Computer Modeling in Engineering & Sciences, Vol.30, No.1, pp. 27-36, 2008, DOI:10.3970/cmes.2008.030.027

Abstract An analytic solution method, namely the shifting function method, is developed to find the exact large static deflection of a beam with nonlinear elastic springs supports at ends for the first time. The associated mathematic system is a fourth order ordinary differential equation with nonlinear boundary conditions. It is shifted and decomposed into five linear differential equations and at most four algebra equations. After finding the roots of the algebra equations, the exact solution of the nonlinear beam system can be reconstructed. It is shown that the proposed method is valid for the problem with More >

H.M. Lee¹, H.S. Park^1,2

CMES-Computer Modeling in Engineering & Sciences, Vol.29, No.1, pp. 29-44, 2008, DOI:10.3970/cmes.2008.029.029

Abstract This paper presents a computational model to estimate deformed shapes of beam structures using 3D coordinate information from terrestrial laser scanning (TLS). The model is composed of five components: 1) formulation of polynomial shape function, 2) application of boundary condition, 3) inducement of compatibility condition, 4) application of the least square method and 5) evaluation of error vector and determination of reasonable polynomial shape function. In the proposed model, the optimal degree of polynomial function is selected based on the complexity of beam structures, instead of using a specific degree of polynomial function. The chosen More >