Advanced Materials Research Vols. 243-249

Abstract: In combination with the practice of a pumped storage hydropower station, a 3-D nonlinear finite element method on the preloading filling spiral case is carried out to compare and analyze stresses of the steel spiral case and hoop reinforcement, the stress and bearing ratio of the surrounding concrete, the contact state between the spiral case and concrete in different precast water head. The results indicate that the stress of the surrounding concrete will get better with the increasing of precast water head. But there is a distance between the spiral case and the surrounding concrete when the water head is excessive, which is unhelpful for operating of the unit. When the precast water head of the spiral case is 439m or so, it can play a greater degree of mechanical characteristics of steel and concrete under the premise of operating stably of the unit.

Abstract: A mathematic model on the optimum design of the gas station roof was established, and made an optimization to its grid structure parameters by the finite element software ANSYS.According to the actual condition of work and on the premise of meeting the need, the minimum cross section of the grid structure was determined. The results indicate that materials and cost can evidently decreased by optimum analysis method.

Abstract: In the paper, some difficulties and their solutions, about drawings, detailed drawings and CNC data output based on three-dimensional solid model for various forms of rural residence structures, are discussed. The complex spatial relationships and construction details can be shown directly, accurately and completely in drawings software system based on 3D solid model. Therefore, drawings and detailed drawings can be drawn and labeled automatically by projecting and hiding with the extracted geometric information of particular entities. Further more, in the software system, Manufacture information of components and parts in the 3D Solid model can be extracted and CNC data can be outputted with according to the required format, such as: the binary data, Excel tables, and so on.

Abstract: In this paper, different types of steel frame structure under earthquake are adopted as the analyzed object of structural collapse. Seismic waves can be applyed into the structure in form of dynamic acceleration in ANSYS/LS-DYNA. The whole process of earthquake effects on the structure is simulated truly. It is helpful to realize and understand the failure mechanism and space mechanism of the different forms of steel frame structures. This paper can also provide a reference for reinforcement and maintenance of structure and a basis of anti-seism design of structure.

Abstract: In this paper, different destruction forms of spatial grid structure are analyzed based on LS-DYNA. The key members of structure are studied and the collapsing processes of spatial grid structure caused by different failure members are simulated numerically. By comparing the results of numerical analysis, divisional design method is proposed based on the alternate path method (AP method). The divisional design method can improve resistance to progressive collapse obviously and is of certain reference value for engineering.

Abstract: A two-dimensional simulation of earth-contact heat transfer by applying the finite element method is presented. Relevant thermal properties for each material type are determined and employed in the numerical model. Initial conditions and boundary conditions are carefully defined to improve the accuracy of this numerical investigation. The results demonstrate rational connection between the measured data set and simulated result. This research provides a useful contribution and reference to the earth-contact simulation.

Abstract: The secondary development under the environment of above the version of AutoCAD 2005 is that the design norms of highway project as the custom menu are added into help document library of AutoCAD. Then project planner can quickly find what they need through searching the corresponding electronic norms, which can increase productivity. In this paper, AutoCAD2007 is implemented as an example to introduce the idea of developing help document, the detail scheme and software instructions.

Abstract: Due to the complexity of blasting demolition of building structures, it is difficult to obtain an accurate enough approach for quantitative analysis that can be applied to the constructional engineering. In this paper, dynamic simulation of the demolition blasting process is conducted with the finite element software ANSYS/LS-DYNA. By comparing the dynamic simulation with the practical result, it is found that the calculated results are very close to the practical collapse process. It is further proved that dynamic simulation can be conducted for the quantitative analysis of the collapse process.

Abstract: This paper presents a new recognition method for human motion, which is represented by Haar wavelet transform and recognized by Coupled Hidden Markov Model. We tackle the challenge of detecting the feature points by Haar wavelet transform to improve the accuracy. We extract binary silhouette after creating the background model. Then the low-level features are detected by Haar wavelet and principal vectors in two subspaces are obtained. We utilize Coupled Hidden Markov Models to model and recognize them, and demonstrate their usability. Compared with others, our approach is simple and effective in feature detection, strength in robustness. Therefore, the video surveillance based on our method is practicable in (but not limited to) many scenarios where the background is known.

Abstract: Many Literatures pay attention to the location and parameter optimization of Tuned Mass Damper (TMD). Yet there are few studies on the case where both the TMD and the main system have plastic impacts under large stroke of TMD fixed in limitation space. A two degree-of-freedom (DOF) vibratory system having symmetrically placed rigid stops and subjected to periodic excitation is considered in this paper. The equations of the vibratory system are constructed, and then for simplification the dimensionless equations are obtained. Poincaré map was used to study the relationship between the motion stability and parameters. Period-doubling bifurcation of motion was found by numerical simulations. With the gradual change in excitation frequency, the routes of quasi-periodic impact motions to chaos are observed from simulation results.