Advanced Materials Research Vols. 838-841

Abstract: This paper uses numerical simulation to simulate wind field for closed two-span double-pitch light steel roof under different pitches. Simple computing methods are given for local shape coefficient of wind load through comparing and analyzing the results of numerical simulation and standard values, which can provide some reference for the design.

Abstract: Saddle-shaped cable structure is a new form of prestressed structure. Its reliability need to be analyzed for a new type structure. According to the different failure modes, the finite element model of prestressed steel structure is established. By using APDL language, the program is created. Finally, the reliability index of the model for different failure modes is got by reliability analysis. The results Provides reference basis for mechanics performance evaluation of prestressed structure.

Abstract: The methodologies used to calculate piled raft foundations are normally more complex than conventional foundations due to the large number of variables involved in the problem. In the conventional block, the interaction variables considered are only between the pile and the soil. In the piled raft, all the interaction effects must be considered, as follows: plate-soil, plate-piles and piles-soil, simultaneously. The Finite Element Method (FEM) has proven to be a useful tool in analyzing these types of problems. This study aims at assessing the behavior of piled rafts using the Cesar-LCPC numerical tool, version 4.0, which is based on the finite element method. Literature cases of rafts supported by 9, 15 and 16 piles were analyzed. The results obtained were compared with analysis methods presented in the bibliography. The following parameters were assessed: relative spacing (S/D), relative length (L/D), relative stiffness between piles and the soil (K_PS), and settlement of piles and the raft. The spacing between piles has a significant influence on load distribution between piles and the raft. Very small spacing provides stiffness to the foundation, which then functions as a conventional pile foundation, in which only the piles absorb the load from the superstructure. The larger the L/D ratio, the lower the settlement and for a given modulus of elasticity of the pile, the increase in relative stiffness (K_PS) causes an increase in settlement. In all analyses, the data obtained corroborated the results presented by other methods published in the literature.

Abstract: Compared to the vertical impact, horizontal impact load is closer to real life. For example, external objector collision, debris flow hazards, terrorist attacks, etc. In this paper, a K6 single-layer reticulated shell structure model was established with ANSYS/LS-DYNA, and the influence of material strain rate was considered. Firstly, the basic theory of finite element method and the model parameters which were used in the analysis were introduced. Then changed the mass and velocity of impact body to analyze the dynamic response of the structure. Analysis results show that failure mode of the structure can be divided into five kinds under horizontal impact load; Horizontal deformation, the force of the main bar and impact force continued to increase as the increased of mass and velocity of impact matter; When the mass and the velocity increased to a certain value, the three of all were no longer change.

Abstract: Based on the mechanical analysis of the plate formed under pure bending, we developed the theoretical model of residual stress distribution pattern under single curvature cold-forming. The numerical method is used to simulate the forming procedure of The 3-d surface ship CNC bending machine, which help us acquire the stress and strain distribution of cold formed component and the relationship between steel plate thickness and its peak value of residual stress. The results show that the simulation model makes accurate prediction of the residual stress. The peak value of residual stress increases with the increase of plate thickness, and it decreases with the increase of bend radius.

Abstract: The box-culvert jacking of highway constructions crossing the existing railway is construction difficult and technically complex. If there are safe accidents, it will bring great loss. According to this situation, a new method based on WBS-RBS is presented in this paper to comprehensively identify the risk factors of safety accident with the fault tree, and then the fuzzy probability of basic events are described to triangle fuzzy numbers. Furthermore the happening fuzzy probability of the top event can be calculated. The proposed method provides a scientific method for the safety risk analysis of similar engineering.

Abstract: In order to predict the failure probability of a complicated structure, the structural responses usually need to be predicted by a numerical procedure, such as FEM method. The response surface method could be used to reduce the computational effort required for reliability analysis. However the conventional response surface method is still time consuming when the number of random variables is large. In this paper, a Fourier orthogonal neural network (FONN)-based response surface method is proposed. In this method, the relationship between the random variables and structural responses is established using FONN models. Then the FONN model is connected to the first order and second moment method (FORM) to predict the failure probability. Numerical example result shows that the proposed approach is efficient and accurate, and is applicable to structural reliability analysis.

Abstract: The matrix representation of space point group is used in transferring the elastic matrix of the braided yarn based on the symmetries of braided composites representative volume element (RVE) meso-geometrical structure. The off-axis elastic matrixes of the whole braided yarns of the RVE are deduced. With a use of meso-mechanical model based on the mixture rule, the yarn segments off-axis elastic matrixes in the RVE and matrixs one are summed with weight; Equivalent elastic matrix of 3D braided composites was deduced. Equivalent engineering elastic constants are achieved in the end. The model can be applied in 2D braided composites mechanical analysis if its geometry is satisfied to the symmetries corresponding to plain point group.

Abstract: Large span transmission tower is the lifeline of electricity transmission，Its collapse destroyed will causes adverse to the social and economic effects，The mechanism of the power transmission tower collapsed caused people's attention.The analysis is based on LS-DYNA program，explicit beam161 beam element is adopted to establish the finite element model for transmission towers，Analyses the collapse process of transmission tower and its failure mode with downburst load.

Abstract: In the paper the experiment results of deformation in foundation slab segment in interaction with subsoil are presented. Pilot measurement is carried out on original subsoil with characteristics which were tested in cooperation with geotechnics specialists. Concrete precast slab with square dimensions 500 mm and with thickness 48 mm made of plain concrete is exposed to vertical load. The tests results are compared with bending moments and deformations analysed according to subsoil models given in Eurocodes using FEM analysis.