Applied Mechanics and Materials Vols. 117-119

Abstract: The solidification pressure is one of the most important factors in the counter-gravity casting process. Through testing and analyzing the microstructures of aluminum alloy castings under different solidification pressure, the effect of different solidification pressure on the secondary dendrite arm spacing and grain size is studied. The results show that with the increase of the solidification pressure, the secondary dendrite arm spacing and the grain size of aluminum alloy decreases. When the solidification pressure is 250 KPa, the secondary dendrite arm of aluminum alloy is thick, the SDAS is 37.9μm, but when the solidification pressure increases to 450 KPa, the refinement of grain is obviously, and the SDAS is 20.7μm, which is reduced by 45.3% comparing to solidification under 250 KPa. Moreover, when solidification pressure higher, the effect of feeding force becomes more evident, and the dendrite is broken when the feeding force higher than the strength of dendrite. Therefore, the grain size becomes more and more uniform and thin, and the (SDAS) of aluminum alloy are more and more small.

Abstract: In this paper, ASCE Benchmark Finite Element Model was established and analyzed. Also, The MLI(the max Lyapunov Index) and LISE(Lyapunov Index Spectrum Entropy) has made to recognize state of the FEM using non-linear theory and chaos time sequence. The results show that MLI and LISE are sensitive with the structure state, and the structure system is chaotic.

Abstract: 7075 aluminum alloy ingot with the diameters of 100 mm was produced by Horizontal Direct-Chill (HDC). The temperature in the melt was measured and the ingots were examined in detail with the aim to reveal the floating grains in the HDC ingot. Experimental results show that very large floating grains with coarse dendrite arm spacing (DAS) mainly concentrate in the half-moon area near bottom surface of the HDC casting ingot, under the function of gravity. The floating grains in the HDC casting process is much bigger than that founded in Vertical Direct-Chill (VDC) casting process.

Abstract: In this paper, the clamping unit of a two-platen injection molding machine was modeled by Pro/ENGINEER, and was imported to Altair HyperWorks. In HyperMesh module, the finite element model was set up, ANSYS has been used in the finite element analysis of the clamping unit and the deformation and stress results were obtained. Based on the topology optimization of HyperWorks/OptiStruct, recommendations to improve the structure of the clamping mechanism are presented; the results showed that less material was used while its performance was maintained.

Abstract: Based on the principle of thermal expansion and theory of virtual work, a class of equations for in-plane displacements at three freedom direction and internal forces in the cross-section of statically indeterminate curved beams under thermo load are derived explicitly. In the case of infinite limit of radius, these equations coincide with that of the straight beams. Compared with the results of FEM, the analytical solutions by the proposed formulae are accurate. The analytical solutions obtained in this paper would provide a scientific base for further study and design of the curved bridges.

Abstract: Real estate price has been one of the hottest discussion topics, especially in recent years, it becomes the focus of attention. In this paper, we aim to study the impact of economic factors on real estate price. By multiple linear regression model and SPSS software, we analyze four economic indicators affecting the real estate price of Jilin city, and make some amendments and testings, the conclusions show the consumption level and housing construction area are important factors affecting the price trend. On this basis, we further to give the corresponding countermeasures and suggestions.

Abstract: Shaft tower has the characteristics of long service time and once the damage will affect the normal production, thus ensuring the normal use is particularly important. Vibration made by the Multi rope friction hoist operation will lead to floor resonance, thus" card tank" and" rolls over" loads determining the hoist layer structure arrangement become very critical. Through the analysis of existing data, the shaft tower vibration characteristics and seismic behavior research is analysed and forecasted.

Abstract: With the development of long life pavement concept, asphalt treated permeable base (ATPB) has become the typical structure of asphalt pavement in more rain and wet area. In order to effectively analysis and prediction of pavement performance, and targeted design, pavement materials parameters research seems more and more important. This paper uses MTS system to do the dynamic modulus test for ATPB-25 and ATPB-30. During the test, different measuring temperature and load frequency are set according to the working environment of ATPB type asphalt mixture. With the dynamic modulus test results, full time domain dynamic modulus master curve and corresponding master curve equation of ATPB type asphalt mixture are created. These experimental studies can provide high quality parameters for the optimization design and performance analysis of asphalt pavement structure with ATPB and are important to extend the service life of the asphalt pavement.

Abstract: This paper describes effect of cutting parameters on surface roughness for turning of aluminium alloy 7050 using carbide cutting tool with dry cutting condition. The model is developed based on cutting speed, feed rate and depth of cut as the parameters of cutting process. The selection of cutting process was based on the design of experiments Response Surface Methodology (RSM). The objective of this research is finding the optimum cutting parameters based on surface roughness. The relation between cutting parameters and surface roughness were discussed.

Abstract: The numerical simulation of the fillet-welded joint which is welded with the four kind of clamped methods by laser-MIG hybrid welding is researched by the SYSWELD software. The results of the numerical simulation are compared with the results of the experienced welding. The results of research show: The joint of the laser-MIG hybrid welding was simulated well by the SYSWELD software. The simulating result is deviated 10% from the result of the actual deformation. The laser-MIG hybrid welding deformation of the aluminum structure is least when the holding position is in the near weld zone and the clamps are unloaded near the room temperature.