Applied Mechanics and Materials Vols. 271-272

Abstract: Engineering change is an important and complex activity for manufacturing enterprises. In order to improve the efficiency of engineering change, we proposed a method of EC propagation in collaboration environment. First, we analyzed the method of creating the knowledge database; then, studied the way knowledge sharing in collaboration; furthermore, proposed a algorithm change propagation in collaboration environment; finally, a created a system based on the method above and the experiment of managing a type of military vehicle engine was employed to validate our method and it showed the correctness of the proposed method.

Abstract: The number of special purpose vehicle increase quickly recent year, so more Program Grounds were needed to performed the durability test. Now more than one Program Ground owned the qualification to perform the test. To secure the test results were uniform in different Program Grounds, a equivalence analysis method based on fatigue theory was given in the paper. The acceleration signals on vehicle were taken as the basic parameters in the method. At last, a high mobility vehicle was used to collecting the vibration signals on two different Program Grounds.The equivalence relationship was analyzed.

Abstract: For a more reasonable evaluating method of the ergonomics performance of airplane passenger cabin interior environment, the system of related evaluation indexes was analyzed and proposed, the hierarchies and the character of grey system were clarified, the index weights were established, and three design works were evaluated by the MHGR model practically and feed back with some constructive design suggestions. The result indicates that the MHGR model used in Ergonomics evaluation can obtain accurate and scientific consequences.

Abstract: The optimization design about hybrid discrete variables synthesizing integer, discrete and continuous variables is very significant but also difficult in engineering, mathematics for programming and operational research. Aimed at shortages of existing optimum methods, in this paper, Evolutionary Cellar Automata Algorithm (ECAA) is proposed to complex optimization problem with hybrid discrete variables which has a digging operator and two learning operators (dual arithmetic crossover operator and chaos-peak-jumping operator). The computing examples of mechanical optimization design show that this algorithm has no special requirements on the characteristics of optimal designing problems, it has a fairly good universal adaptability and a reliable operation of program with a strong ability of overall convergence and high efficiency.

Abstract: This paper presents the multi-roller contact roller-gear cam reducer. It’s a special kind of the indexing roller-gear cam that changes the stopping stage of the indexing cam to zero and chooses the equal-velocity law. And with multi-roller contact the carrying capacity is greatly improved. In this paper, we created the 3D solid model of the main components of the reducer: the cam, the turntable and the rollers. After that, we used the FEA software ANSYS Workbench to calculate the static structural behavior and the results showed us the weak or dangerous part of the mechanism so that we can optimize the structural. However the static structural behavior does not always shows the working condition. Thus we calculated the flexible dynamic behavior of the reducer and it showed us vividly that which part is weak and we could see the real deformation and stress distribution of the structural while working. Then we can pay more attention to these parts.

Abstract: The loading force of the artificial bone implanted into the human body and the flowing, growth and deposition of cells were influenced by the gradient porous structure. The software of ANSYS Workbench was used in the paper for the stress and strain analysis of the gradient porous structure of the established 3D artificial bone. The variation of the maximum equivalent stress and maximum equivalent strain and elastic modulus changed through the changing of the loading force and porosity. Basis on meeting the mechanical properties, the porosity was used as the index for the optimization of the porous structure of the artificial bone. And it also laid the foundation for the subsequent laser sintering.

Abstract: The study on power steering gear is less than other auto parts at home or abroad. Compared with developed countries, the independent design and manufacture of power steering starts late, and lacks practical and effective evaluation standards. The combination of the theoretical analysis, numerical calculation and experimental verification is the key technology to optimize the design or test to evaluate the power steering gear’s function and performance. In this paper, the power steering gear’s finite element analysis(FEA) model was built to analyse the fatigue stress and fatigue life of the power steering gear’s components, such as housing, input shaft and output shaft. and the fatigue test of the power steering gear was also designed and implemented. Research showed that, the power steering gear fatigue properties of FEA and reliability test have the same results. The total damage of 4 A-B-C event cycles is less than 1, the steering gear system is judged safe after 4 event cycles per design requirements. Each component of the power steering gear has different maximum average stress. The stress of the sector shaft, the piston and the screws is very close to the yield stress, which is much larger than the other components, and needed to be treated with caution The maximum stresses of the gear housing are a little over the yield strengths at the stress of 6,118 lbs, which is more dangerous than the other components, and great attention should be paid to it.

Abstract: Empirical Mode Decomposition (EMD) is a non-stationary signal processing method developed recently. It has been applied in many engineering fields. EMD has many similarities with wavelet decomposition. But EMD Decomposition has its own characteristics, especially in accurate trend extracting. Therefore the paper firstly proposes an algorithm of extracting slow-varying trend based on EMD. Then, according to wavelet regression estimation method, a new regression function estimation method based on EMD is presented. The simulation proves the advantages of the approach with easy computation and more accurate result.

Abstract: Structural characters of gear contact have a determinative impact on gear rattle. Contrarily traditional method using average stiffness and damp coefficients which weakens the accuracy on modeling and analysis of gear rattle phenomenon, in this paper, a methodology modeling gear rattle process with transient stiffness and damp coefficients is proposed. Gear rattle process is modeled by considering the physical model of gear contact, gear pair movement, and actually geometrical meshing curve. A study of gear rattle is made by the simulation program and an experiment is also done to verify the method. Results show that this method can effectively analyze the frequency and the relative displacement of gear rattle, etc.

Abstract: In this paper, the gridless adaptive method is extended to simulate unsteady flows with moving shocks. In order to capture physical features like moving shocks with local high resolution, a technique of dynamic cloud of points is achieved by adopting clouds refinement and clouds coarsening procedures during the evolution of the unsteady flows. The regions for clouds refinement and clouds coarsening are determined at every time step by an indicator, which is defined as a function of the local pressure gradient. Once the regions of cloud of points to be adjusted are located by the indicator, the clouds refinement is carried out by introducing new points based on the existing structure of cloud of points, and the clouds coarsening procedure is also implemented simultaneously in order to control the size of the points distributed in the whole computational domain. The numerical test cases show that the gridless adaptive method presented can capture moving shocks with high resolution successfully in both inviscid and viscous test cases.