Applied Mechanics and Materials Vols. 325-326

Abstract: In this paper is presented an evaluation study regarding the manipulation of 3D CAD models using multimodal Virtual Reality (VR) interface and traditional desktop environment. A multimodal interface based on VR technologies that offers direct access to the space model by using several sensorial channels (visual, tactile, verbal) is described. Users can manipulate 3D objects using 6DOF tracking device, gestures and visualize the design status in an immersive CAVE - like system. The results of the evaluation study illustrate that using VR technologies as an alternative to replace WIMP CAD software interface is viable and brings more advantages.

Abstract: First establish a dynamic model of tower crane in the load lifting process, the lifting load is solved under two work conditions.Then establish the FEM(finite element analysis) model of the tower crane under the normal and the damage condition. Get the dynamic displacement of the normal and the damage status under the lifting dynamic load. With wavelet packet decomposition and SVM(Support vector machines) multi-classification algorithm, a multi-fault classifier is constructed, and applied to the fault diagnosis of tower body. The results of the study show that the multi-fault classifier has such advantages as simple algorithm and excellent capability of fault classification, and it can not only diagnose the structural damage status, but also determine the positions of structural damage. This will be a new search on tower crane structural health diagnosis.

Abstract: The paper deals with the kinematics and automated calculation of intermittent mechanisms with radial cams. Currently, electronic cams are increasingly applied in the drives of working link mechanisms. Despite a huge advantage of electronic cams in their re-programmability or instantaneous change of displacement diagrams, conventional cam mechanisms have an irreplaceable role in production and handling machines. With high frequency of working cycle periods, the dynamic load of the proper servomotor rotor increases and efficiency of electronic cams strongly decreases. Though conventional intermittent mechanisms with radial cams are representatives of fixed automation, they have distinct advantages in their high speed (high dynamics), positional accuracy and relatively easy manufacture. We try to remove the disadvantage of firm displacement diagram by reducing costs for simple design and automated calculation that leads reliably to high-quality and inexpensive manufacture.

Abstract: The self centering grasping mechanisms aim to improve the positioning accuracy of the object movement. The paper presents the FEM method applied to such mechanism using compliant joints with elastic properties. We have studied the tensions and displacements for the three dimensional model and the experimental results achieved the goal of our work.

Abstract: Jet fans are widely used in ventilation systems of road tunnels, railway tunnels and subways etc. It was demonstrated that the static pressure generated by jet fan impeller is merely useful for overcoming its own internal flow resistance and can not improve the ventilation state of tunnel. It was pointed out that in the aerodynamic design process, the static pressure of jet fan should be made as small as possible. The effective way to reduce static pressure produced by impeller is the rational design of jet fan passage components.

Abstract: In this paper, we deal with a two-unit standby redundant electronic equipment system under human failure. In reliability study, it is ordinary to substitute the steady-state reliability indices for dynamic ones because the time-dependent solution is difficult to get. But this replacement should be based on some conditions in general. Therefore it is important to study the unique existence and the expression of the dynamic solution and it is the same with its stability.

Abstract: Fuzzy robust design will be applied to optimal design of cycloid pin wheel reducer, and it is established that fuzzy robust optimal design mathematical model of cycloid pin wheel reducer in order to achieve the goal of the small size and high efficiency. Genetic algorithms correlation functions in MATLAB is used to solve the model, and optimal methods and calculation examples is given.

Abstract: The connections between the thermoelectric modules are crucial importance for the performance of the thermoelectric power system. Many studies have been done to improve the output of thermoelectric system, but very little specific to the connections between the modules. A mathematical model of a module has been established, and based on this model, the performance of two systems composed of 6 pieces of thermoelectric modules, one in series connection and the other in parallel connection, is simulated with MATLAB software and then compared. The results can be used as reference for the design and prediction of thermoelectric system.

Abstract: The development of infrared optical materials is always closely related to the research and exploration of material science. The infrared optical domes bears shock and produces stress when the infrared optical domes mounted on the missile moving at a high speed is shocked by high temperature. According to aerodynamics theory and thermo shock theory, the surge current will be transferred to optical parts through holding up layer and warms the surface of optical parts when infrared optical parts are shocked by high temperature. A compress stress is formed on the hot external surface of optical parts forms and a tension stress is formed on the internal surface or optical parts under the circumstance of the edge of optical parts being fixed. The windows of optical parts become curvature radius of lens with the function of pressure difference which can cause aberration change. The brittle fracture of material will be caused if peak stress is beyond the strength which is permitted for infrared materials. Therefore, limits to design of windows thickness is proposed in this paper.

Abstract: The creep deformation of the cast copper cooling staves was researched based on the steady temperature field by using thermal - mechanical coupling finite element transient analysis method and ABAQUS software. The results show that the creep deformation only under the effect of thermal stress is slight and negligible compared to the deformation generated by thermal expansion. The total tress is not adequate to crack the stave body. Therefore, the cast copper stave can meet the requirements of blast furnace longevity.