Applied Mechanics and Materials Vols. 143-144

Abstract: Most domestic automobile factories use test method to design rubber engine-mount, which wasting of time and energy. The design optimization of engine-mount is studied by virtue of ANSYS. In order to satisfying three directions stiffness requires of engine mount, the optimization math model has been established, mount material and geometry parameters have finally been calculated by selecting appropriate arithmetic.

Abstract: Physical and mechanical properties as well as microstructure of zirconia toughened alumina ceramics with different zirconia content were tested. The results show that the best physical and mechanical properties are obtained in sub-micron composite ceramic when zirconia content is 25%; while the physical and mechanical properties of nano-zirconia toughened alumina ceramics are far better than those of sub-micron zirconia toughened alumina ceramics. Therefore physical and mechanical properties of ceramics can be improved significantly by adding proper amount of zirconia into alumina matrix and refining zirconia particles.

Abstract: Hard brittle materials have been popular used in manufacture experience because of the excellent performances. However the low plasticity, frangibility and non-conduction make the machining very difficult. Therefore, ultrasonic vibration was introduced to common lapping for the purpose of higher removal rate and fine surface quality. The acoustic model of ultrasonic lapping was proposed, the track equations of ultrasonic lapping with different vibration modes were deduced, the influencing factors of lapping tracks were obtained, and the lapping tracks with different lapping parameters had been emulated. It can be concluded that ultrasonic lapping is a high efficient processing method adapting to ceramic materials.

Abstract: With finite element analysis software Moldflow, numerical simulation and studies about FM truck roof handle were conducted on gas-assisted injection molding process. The influences of melt pre-injection shot, gas pressure, delay time and melt temperature were observed by using multi-factor orthogonal experimental method. According to the analysis of the factors' impact on evaluation index, the optimized parameter combination is obtained. Therefore the optimization design of technological parameters is done. The results show that during the gas-assisted injection molding, optimum pre-injection shot is 94%,gas pressure is 15MPa,delay time is 0.5s,melt temperature is 240 oC. This study provided a more practical approach for the gas-assisted injection molding process optimization.

Abstract: The concept of Green manufacturing is mainly reflected at Green Foundry. And the greening process for product casting could be accomplished by improving the foundry technique. For example, during the production of widely used and excellent high toughness ductile iron cast QT450－15, using two times desulphurization, covered packet spheroidization, composite inoculation and the like those consist green casting system, which could reduce the usage of rare earth, improve the scarce resource efficiency and product performance. This is of great significance for green manufacturing of ductile iron.

Abstract: Fracture mechanics analysis of the Dynamic Stress Intensity Factor of a pre-cracked 3-Point Bending Specimen suffering cyclic loads has been studied. Using the theoretical equivalent system of the pre-cracked 3-Point Bending Specimen, the Dynamic Stress Intensity Factor could be obtained theoretically. The finite element method was then applied to study the dynamic behaviors of the Dynamic Stress Intensity Factor under different cyclic loads' conditions using the standard software ABAQUS. The results have also been analyzed and discussed, which provided a deeper view for the fracture characteristics of the materials and could be used to guide further researches and practical engineering design.

Abstract: Development of low-sulfur and Pb-free hypoeutectoid graphitized free cutting steel is significant because the use of S or Pb free-cutting steel can result in serious pollution. Due to graphitization process in hypoeutectoid steel is very slowly, so it is crucial to accelerate the graphitization process. The tested steel is prepared based on that graphitization can be accelerated by increasing nuclei of graphite. On the base of indirect observation on graphite particles in the sample by OM and quantitative metallography for different graphitization times, the kinetic curve was drawn the graphitization process of tested sample, it matches the Avrami eqution well.

Abstract: Several modals on Tunnel Boring Machine (TBM) in tunneling are introduced, the revolving rock tunneling simulator set-up is designed, the finite element model of cutter parts of the experimental bench is built, and free mode analysis of it is performed, and the model on system of cutter head, cutter and rock is established. It is shown that natural frequency on the cutter parts is higher, the frequency of first step is 4536Hz, and the most modes are deformations of the cutter loop, vibration acceleration of the cutter decreases with fracture tunnel width increasing, in some degree broken rock mechanics is achieved, foundation is provided for improving using life and adaptability of the cutter, and optimizing arrangement of plate cutter on the cutter head, and finally realizing high efficiency and low energy consumption.

Abstract: During many factors affect the straightening precision, the shape of roller gap affect directly the flatness and the distribution of residual stress; At the same time, roll system's stiffness, as an important part of the roller leveler's whole stiffness, affect directly the design of leveling production process. In order to draw the conclusion of deformation characteristics and rules, the equivalent FEM Model on upper rolls and its support structure and investigates on the features of stress and strain after the rollers' deformation is established, based on the structural analysis of hot roller leveler for 3800mm plate steel.

Abstract: In view of coal mine fire, this paper studies on a electric detonator Initiation explosion suppression system. The system is mainly composed of composed of UV flame sensor, controller, and explosion suppression device. According to experiments, the system can complete spurting powder in 185ms since detecting the flame signal, and can prevent fire and gas explosion, can reduce the accidents and the loss caused by the accidents greatly. The scheme of explosion suppression system, the experiment condition and procedure are presented in the article.