Papers by Author: Xing Ma

Abstract: This paper provides a comprehensive review of various methods used for skin buckling analysis in composite components. The skin buckling phenomenon is one of the governing criteria in composite design. It is a kind of contact buckling in which partial sections of skin buckle away from the filler material. In general, the problem can be modelled as a thin plate (skin) in unilateral contact with elastic medium (filler material). The theoretical analysis of contact buckling is complicated due to the nonlinearity arising from changing contact regions. To simplify the calculations, the filler material was usually modelled as a tensionless elastic foundation. The skin buckling coefficient varies in terms of the relative foundation stiffness factors. Because the Eigen-value method is not applicable to nonlinear systems, the finite element (FE) method was usually employed for post-buckling analysis, while initial buckling performance was investigated through analytical or semi-analytical methods such as rigid foundation model, infinite plate model and finite plate model. The compressive buckling and shear buckling problems for thin plates resting on tensionless foundations have been solved successfully. However, there are still urgent needs for future research on the topic. For example, the load carrying capacity of the buckling plates needs to be formulated for practical application. Complicated problems with complex loadings and/or corrugated skins need further investigation as well.

Abstract: In this paper, transmission line systems are modeled as multi-span cable structures. A force method model is proposed for analysing the static response of the multi-span cables with small sags. The accepted cable model reduces to two groups of differential equations (the equilibrium equations in y, z directions) and an integral equation (the compatibility equation). Substituting the differential equation solutions into the compatibility condition, the governing equation is obtained in terms of the tension component in chord direction. This equation has been named the force method equation (FME). In this way the infinite-degree-of-freedom dynamic system is effectively simplified to a system with only one unknown. Finally, one example is presented to illustrate the application of the proposed force method.

Abstract: A nonlinear force method model is proposed to study the dynamic behavior of cable trusses. In the paper, travelling wave method is employed to solve the governing equation of motion. After support reaction forces are considered as excitations, cable trusses are extended to infinitude, and D’Alembert solution to the partial differential equation (PDE) is achieved. Substituting the solution into compatibility condition and boundary conditions, the governing equation expressed by dynamic tension is derived, which is named force method dynamic equation (FMDE). Hence the dynamic system of infinite-degree-of-freedom is simplified as a system with only one unknown without any loss of precision. Nonlinear governing equations are developed through considering the effect of quadratic terms of displacements. At last, an example is given to verify the force method model presented in the paper.