Advanced Materials Research Vols. 671-674

Abstract: A coupled elastoplastic-damage constitutive model with consideration of chemo-induced material elastoplastic-damage effects due to heating concrete is proposed. A consistent return mapping algorithm for the integration of the rate coupled constitutive equations is developed. Consistent tangent modulus matrices for coupled chemo-thermo-hygro-mechanical analysis are derived to preserve the quadratic rate of convergence of the global Newton iterative procedure. Numerical results demonstrate the validity of the presented algorithm and illustrate the performance of the proposed constitutive model in reproducing coupled chemo-thermo-hygro-mechanical behavior in concretes subjected to fire.

Abstract: Three kinds of numerical methods (Lagrange, ALE, SPH-FEM) were used to analyze the response of an fully buried underground structure under blast loading, the differences of these three methods and factors which affect calculation accuracy were analyzed and compared. The results show that the Lagrange method can give more accurate results, but it should be taken into account that the shape of the ammunition may influence the calculation of impact stress in soil.

Abstract: Empirical formula can be used to get ground shock parameters produced by conventional weapons buried in soil medium. With the development of finite element technology, ground shock parameters can be obtained by numerical simulation. However, sometimes the numerical simulation results were not consistent with the empirical formula results. A two-dimensional axial symmetry model and a three-dimensional model were set up to calculate the ground shock from a fully buried spherical charge, numerical results and empirical formula results were compared and the causes of the calculation error were analyzed.

Abstract: By using Quasi-Shannon wavelet, we develop a wavelet collocation method for the Hamilton canonical equation of elastic bodies, and get the Hamilton canonical equation which is discrete in the plane of the rectangular laminated plate and continuum along its thickness. The approximate solution expressed by Quasi-Shannon wavelet satisfies the clamped boundary conditions of the plate easily. Hence, it is convenient to establish the wavelet collocation precise integration method for the static problem of the rectangular laminated plate with four sides clamped. Numerical results show that the current approach offers excellent predictive capability for rectangular composite laminated plate with clamped boundary conditions.

Abstract: Numerical simulations for tests of thin metal plate against explosion were performed by using models with and without taking into account shock wave around-flow. The results show that the center deflections of plates from numerical simulations are in good agreement with those from experiments, and that the shock wave around-flow can reach the back surface of plate during the shock wave acting on the front surface of plate and interact with the plate response. It is found that the shock wave around-flow has significant effect on the plate response when the scale distance and the size of the plate are small.

Abstract: The equilibrium problem includes many fundamental mathematical problems, e.g., optimization problems, saddle point problems, fixed point problems, economics problems, comple- mentarity problems, variational inequality problems, mechanics, engineering, and others as special cases. In this paper, properties of the solution set for generalized equilibrium problems with lower and upper bounds in FC-metric spaces are studied. In noncompact setting, we obtain that the solution set for generalized equilibrium problems with lower and upper bounds is nonempty and compact. Our results improve and generalize some recent results in the reference therein.

Abstract: Firstly, based on the theory of state-vector equation, the semi-analysis finite element formulation for the stability of the plates under various boundary conditions was derived by modified Hellinger-Reissner (H-R) variation principle for the elastic material. Secondly, the three-dimensional models for the stability of stiffened plates were established. The semi-analytical solution of state equation for the stability of stiffened plates are proved to be efficient and accurate by comparing with the exact solutions of references and the numerical solutions of the finite element software through several examples.

Abstract: This paper further points out mistakes about testfying unit weight mean square error of no-equal precision independent surveying values in literatures[1-2],and further supports literature[3].So,this paper has some positive meaning.

Abstract: The traditional constraint model employed in Interface Stress Element Method is cumbersome due to the using of additional virtual elements. To remedy this, a new constraint model without virtual elements was proposed, based on the introductions of constrained interface, formula for stress mode on bound boundary and governing equations considering geometric boundary conditions. With the elimination of virtual elements, constraints can be treated more naturally and simply. Programs based on this model were developed and numerical examples were provided to demonstrate the validity and convenience of the presented technique.

Abstract: Wind field calculation is a research focus for wind disaster prevention in Civil Engineering. A new finite element procedure using flow-condition-based interpolation method combined with splitting algorithm is proposed in the paper. It used the analytical solution of one-dimensional advection–diffusion equation, and naturally introduced upwind effect in element interpolation functions. Further, combined with splitting algorithm, the element interpolation functions of velocity and pressure have concise format without meet Babuska-Brezzi condition. A two dimension four-node bilateral fluid element was constructed using flow-condition-based interpolation method and a corresponding program was developed. The solution procedure was discussed in detail and the numerical example solution was given to illustrate the capabilities of the procedure