Advanced Materials Research Vols. 255-260

Abstract: In order to model the mechanical behavior of joints efficiently, a thin-layer tri-node joint element is constructed. The stiffness matrix of the element is derived in the paper. For it shares the common nodes with the original tri-node triangle element, the tri-node joint element can be applied to model the crack propagation without remeshing or mesh adjustment. Another advantage is that the cracked body is meshed without consideration of its geometry integrity and existence of the joints or pre-existed crack in the procedure of mesh generation, and then the triangular element intersected by the crack or joint is automatically transformed into the tri-node joint element to represent pre-existed cracks. These make the numerical simulation of crack propagation highly convenient and efficient. After CZM is chosen to model the crack tip, the mixed- energy simple criterion is used to determine whether the element is intersected by the extended crack or not, the extended crack is located in the model. By modeling the marble plates with two edge cracks subjected to the uniaxial compressive loads, it is shown that the numerical results are in good agreement with the experimental results, which suggests that the present method is valid and feasible in modeling rock crack propagation.

Abstract: Steel cofferdam is an advanced technology for high pile cap construction in deepwater foundation. Using Xiangjiang river bridge of Changsha-Xiangtan expressway as engineering background, we use software ANSYS to analyze the stress states of sealing bottom concrete layer of steel cofferdam of this bridge, and obtain some results of deformation, direct stress, principal stress, shear stress and equivalent stress. At the same time, a fixed-ends beam under uniform pressure is used to simplify the analytical model, and results show that this model can give relatively correct stress state with proper precision, but give poor deformation state. As for the design of steel cofferdam, engineers are mainly interested in the stress results. So the simplified model can be used in the design and analysis procedure.

Abstract: Using the steel cofferdam of Xinzhao Pearl River Bridge in Guangzhou City as the engineering background, structural designing and size proposing of steel cofferdam are introduced briefly. To ensure structural safety, general purpose finite element software Ansys was used to analyze structural strength and stability. Load styles and boundary conditions were also discussed. 6 load cases with calculating model were presented.

Abstract: In this paper, based on the principle of heat balance, the computing equation of temperature field which used the thermal coefficient, surface coefficient, and heat as the basic parameters of the heat conduction equation is derived, and thereafter the FEM computation procedure about temperature field named RCTS which used the thermal diffusivity as basic parameter is modified. The modified procedure can reasonably reflect the temperature field of composite construction which is made of a great variety of material with different thermal property, and also can simulate the effect of surface heat preservation at arbitrary periods and arbitrary parts of the bulk concrete structure. According to the calculation example, the similarities and differences of the heat preservation effect on the heated board calculation by using different methods: the equivalent surface coefficient method, the equivalent thickness method, the thermal conductivity method and the thermal diffusivity method are analyzed. The calculation results show that the computing results of the thermal conductivity method are closed to the result of the equivalent surface coefficient method, the results of the equivalent thickness method have certain differences but not quite because it is the approximation process of the equivalent surface coefficient method, and the reasonable result is often missed by using the thermal diffusivity method.

Abstract: This paper examines the validity of the Crack3D FEA Code method to solve the crack cylinder of the Saint-Venant’s torsion problem. To finish it, a useful comparison was obtained between the numerical results calculated by two different methods on the crack cylinder.

Abstract: This paper provides a simple and effective modeling method for complicated geological bodies in numerical software. By means of the most common tool software, the high quality 3d numerical model of the complicated geological body in the geotechnical engineering was built quickly and easily in the numerical software, ANSYS. Furthermore, this numerical model was reproduced in other numerical software, FLAC^3D and ABAQUS. It is achieved that the 3d numerical model is shared among the numerical software, ANSYS, FLAC^3D and ABAQUS and a basis is supplied for numerical calculation. The modeling method in this paper is of practical significance.

Abstract: When a RC structure is laterally restrained, the load resistance is enhanced due to the membrane effects. A simplified membrane action theory was proposed by modifying the Maximum Membrane Force Design Method (MMFM) to predict the resistance-deflection curves of restrained slab RC structures, in which the total strain plastic theory and strain rate plastic theory were combined and a serial of explicit formulae were derived. A better agreement was observed between the test data and the analytical results predicted by the proposed theoretical method, comparing with MMFM and numerical results conducted by ABAQUS. It is demonstrated that the proposed theory is validated and the steel bar at compressive zone has definite influence on the load carrying capacity, and cannot be neglected in the case of high compressive reinforcement ratio.

Abstract: For hollow but high bridge piers, single side sun exposure causes great temperature stress. Currently, the bridge specifications of each countries have different regulations on hollow pier’s temperature load, partly can only reference to the temperature gradient curve of box girders, but the errors might be large sometimes. This paper gives a method to calculate the hollow pier’s temperature field and stress that caused by solar radiation, a method which can consider any region, any season and any time. A secondary development is also applied to reinforce ANSYS software, and the aforementioned functions is embedded in the ANSYS GUI.

Abstract: In this paper, computer aided engineering of some innovative sheet metal forming processes is reviewed. Because of the complexity of this process, numerical simulation becomes necessary for its analysis. The deformation behavior of sheet metal in forming process is numerically simulated using quasi-static implicit and explicit finite element codes. The main advantages of the finite element method are: the capability of obtaining detailed solutions of the mechanics in a deforming body, namely, stresses, shapes, strains or contact pressure distributions; and the computer codes, can be used for a large variety of problems by simply changing the input data.

Abstract: For concrete bridge, creep effect throughout the whole process that from construction to the entire service life, and it has large effect on internal force and deformation of the bridge, therefore, accurate calculation of the effect is very meaningful. In this paper, we put up the detailed implementation calculation in the ANSYS based on “Age-Adjusted Effective Modulus Method (AEMM)”. Finally the author verified by the example.