Applied Mechanics and Materials Vols. 37-38

Abstract: Nickel-based super alloy GH4169 has been widely used in aerospace industry because of its good mechanical properties under high temperature. However, it is difficult to machine for its high strength, poor thermal conductivity and serious work-hardening. The effects of tool geometric parameters on tool life are studied by machining experiments using YG8 tools with different cutting edge angle in this paper. The tool with cutting edge angle 45°has longer tool life than 75°. The cutting experiments have been carried out using TiAlN (PVD) coated tools (AC520U) with different rake angle. It shows that the tool life with rake angle 9° were increased by 50% and 25% compared to tool with rake angle 3°and 6° when cutting speed is 30m/min. The tool with rake angle 9° is not suitable for cutting GH4169 when cutting speed is more than 35m/min. The results show that geometric parameter of cutting tool is one of the important factors affecting tool life.

Abstract: The effects of cooling gallery position on the piston temperature field and thermal stress are studied. A finite element model of 1015 engine piston is developed using Pro/E software and finite element analyses are achieved through ANSYS code. Numerical simulations are performed to find the temperature and thermal stress change rules with regard to the cooling gallery position. The results demonstrate that the axial direction position of cooling gallery has obvious effects on the piston temperature while the radial direction position of cooling gallery affects the piston thermal stress a lot. The highest position of cooling gallery should be as the same line as the top of the first ring groove. The distance between cooling gallery and piston radial edge should be more than a certain value to decrease the temperature gradient and thermal stress concentration.

Abstract: In order to evaluate the resources and environment attributes of manufacturing process, an IPO model and an evaluation index system are presented first. And then scatter degree combination evaluation method is proposed to solve the inconsistency produced by different evaluation methods. The evaluation results are more accurate by integration of several evaluation results and evaluation information of other evaluation methods. In the end, the validity of the method is confirmed by an example, evaluating a valve body’s resources and environment attributes of manufacturing process.

Abstract: In powder compaction, the great influence of the drive structure upon the electromagnetic force is a key problem to be addressed. A simulation is carried out to analyze the parameters of electromagnetic compaction drive structure by using ANSYS software. And in the two-dimensional model, the study focuses on the effects on electromagnetic pressure, which are produced by the bore and height of the coil, the radius and resistivity of the driver slice, and interval between coil and driver slice. The final results show that electromagnetic pressure of inverse correlates with other parameters of different forms and will grow slowly if the radius is increasing. On the basis of simulation, we draw the general rules of plane coil and driver slice parameter selection.

Abstract: The titanium and its alloys are getting used more and more as for human implant in recent years. In this paper, the broken titanium palmer-bone implant was investigated with field emission scanning electron microscopy (SEM) and X-ray spectrometer and then the reasons of implant fracture was researched. The material composite analysis result shows that the implant is made of industrially pure titanium in which the microelements aluminum, calcium and vanadium are on the high sides. The macro analysis result indicates that the implant did not deform remarkably before cracking. The micro analysis result indicates that there is coarse crystalloid fracture in the SEM macrograph, suggesting that the implant material has low fracture strength. The implant fails in mixed cleavage fracture and intergranular fracture accompanied by fatigue fracture in part region, suggesting that the main fracture type was brittle fracture.

Abstract: Multi-wedge synchronous rolling by cross-wedge rolling is one of the most advanced methods that can form rolling railway axis. Its rolling quality mainly lies on inner transversal stress and shearing stress of rolling workpiece. In this paper, based on the rotated theory of multi-wedge rolling, through using Ansys/Ls-Dyna FEM software, multi-wedge synchronous rolling railway axis by cross-wedge rolling is simulated. It has been systemically researched that technical parameters effect transversal stress and shearing stress. In the meantime, the calculating model is verified by experiment. Through this study, It is obtained that the law of technical parameters effect on rolling railway axis by multi-wedge synchronous cross-wedge rolling. These research conclusions can provide scientific basis for rolling railway axis by multi-wedge synchronous cross-wedge rolling and rolling better quality.

Abstract: Based on the research of non-circular gear Continuously Variable Transmission (CVT), firstly the working principle of the heart-shaped gear is introduced, and then the kinematic characteristics are analyzed, lastly the feature of the heart-shaped gear CVT is obtained.

Abstract: A new process method called multi-unit-lapping plate process is proposed in this paper. This technique could reduce change of cutting depth owing to difference of grain size and protrusion height of surface abrasive of grinding plate, and near equal-cutting-depth processing is realized. For characteristics and machining performance of multi-unit-lapping, this paper reports the following studies: A new experiment was carried out with the optimal parameters and compared with the traditional plate, under the same processing conditions. The results showed that the abrasive grains cutting depth changed obviously with multi-unit-lapping plate.

Abstract: A matching pursuit method based on Dual-Tree Complex Wavelet Transform (DT-CWT) is proposed for extracting feature. Many new orthogonal wavelet bases formed Hilbert transform pairs is constructed by the method which is based on the sufficient and necessary condition on constructing wavelet, via the flat delay filter, and translated the problem into resolving algebraic equations. And taking these wavelets as choice object, a matching pursuit method based on DT-CWT is used for extracting feature. The matching pursuit method is based on series expansion of the signal by a set of elementary functions of orthogonal wavelets formed Hilbert transform pairs to match feature more effectively. Simulation testing and field experiments confirm that the proposed method is effective especially in extracting impulsive feature on high intensity noise, which matching pursuit method based on Discrete Wavelet Transform and other wavelet de-noising methods based on threshold and frequency-band, etc cannot do it completely.

Abstract: The paper is to simulate and analyze the mechanical behavior of the clamp system of an injection molding machine. Different commercial simulation tools are combined to create complete model of the system. The flexibility of several components is included by importing a FE model generated in ANSYS. Then the dynamic characters are presented in MBS software ADAMS. The mechanical behavior of connecting bars, tie bars were analyzed and quantified in order to work out improvements. The results show that the rear link and tie bar were the weakest parts in terms of safety.