Applied Mechanics and Materials Vols. 121-126

Abstract: By analyzing forces acting on moving scroll, a new calculation model of overturning moment is proposed, and the principle of opening the back-pressure hole is derived. The formula of crankshaft angle is given when the back-pressure hole is completely covered. The calculation results of dynamics are shown that the back pressure is almost inversely proportional to the center corner of the back-pressure hole. The results can be double-vortex ring compressor design and direct application of the study.

Abstract: The objective of product design is to meet some function demand of people and the goal of product innovation is to realize product function innovation. Based on this, the paper proposes a new mode of product function decomposition and a strategy method system facing product function innovation, which contains function conflict solved strategy, function relation established strategy, function removed strategy, function replaced strategy and potential-function inspired strategy. The six strategies can assist designers in product function innovation effectively based on analyzing the interrelationship between each sub-function of the product. Finally, a concrete example of the agricultural miniature rototiller is demonstrated the usage of the six strategies, which illustrates the effectiveness of these innovation strategies.

Abstract: This paper discussed the theoretical analysis and engineering improvement test verification of the crack problem in the back van of the vehicle. Causes that may result in the crack problem are firstly analyzed and then determined by the finite element analysis. Improvement are given and proved to be effective by the test verification of an improved vehicle. The method used in this paper will contribute to the analysis and solution of the crack problems in some parts of the vehicle and has reference value in engineering application.

Abstract: The emergency braking deceleration and braking distance of high-speed train were studied under the conditions of adhesion brake on dry and humid rail surfaces, and adhesion and non-adhesion composite brake on humid rail surface. The average emergency braking deceleration was calculated by the area-method. The results show that the braking performance is affected significantly by the wheel/rail adhesion state and the braking performance of high-speed train can be improved by applying the adhesion and non-adhesion composite brake in the state of humid rail surface.

Abstract: According to the characteristics and needs of complicated products, a method for handing assembly sequence based on improved Slope One algorithm was proposed. On the basis of that the network graph of assembly relationship was constructed, and a method for simplifying it was proposed by expressing elliptically same parts, identifying and hiding fasteners. In this paper, Slope One algorithm was initially introduced into the assembly sequence planning, and it was improved according to the problems to be resolved. In the meantime, particle swarm optimization algorithm was introduced into the feedback of the recommendation result. The method has been proved that it was not only used to obtain a good recommendation of assembly sequence but also sensitive to the individuation of designers.

Abstract: Large-scale separation terrane in bending strip upside cranny strip is brought by un-consistency of overlying strata subsidence movement due to underground mining. Different characters of movement and deformation of overlying strata and ground include periodic caving of separation terrane interspace along with work face mining. Conglomerate rock layer movement is the main power fountain of rock burst on the basis of locale observation. And rock burst moves periodically adapt to movement of deep conglomerate rock layer which had similar characters with main roof. Practice indicates this method that forecasting and prediction using correlation information of movement of strata and ground is feasible and has reference meaning for similar stope.

Abstract: Hydraulic excavator energy saving is one of the dominating problem that trouble construction machinery industry. Hybrid technology brings forward a new solution for this puzzle. In the research of hybrid hydraulic excavator, we set up a parallel hybrid excavator test bench based on modular-design method, this fills a domestic technology gap. Power-train performance test is undertaken on this bench and the power assist control strategy is proved to be significant energy saving.

Abstract: NURBS surface modeling technique is an important part of computer aided industrial design(CAID), and surface modeling has much advantage. This thesis bases on the statistics and comparison of current CAID practical application methods and techniques, concludes the common CAID techniques, the thinking methods and application process of surface categorization in surface modeling from the basic theory of NURBS surface modeling; and together with concrete cases, this thesis also proposes an solution for the common hard problems in the process of using NURBS technique to build 3D product models.

Abstract: In this paper, a new type of large-size spiral bevel gear machine is used as a model to study the structural characteristics of spiral bevel gears. Geometric and mathematical models of the machine tool are established. According to the processing principle of spiral bevel gear by forming method with disc cutter, the position and angle of cutter relative to the workpiece are researched.The tool motion is converted to the machine tool coordinate system by coordinate transformation, then the tool trajectory can be obtained to provide the basis for the processing of spiral bevel gears.

Abstract: East auxiliary roadway of Pingshuo Mine No.3 passed through coal bed washout with the roof rock crushing, which leaded to roadway support difficulty. by experimental tests on axially loaded Φ168mm STCC (steel tube confined concrete ) short columns with different steel tube wall thickness, UBC(ultimate bearing capacity) of selected Φ168 × 7 mm steel tube confined concrete short columns was 2650 kN, support pressure was 1.16 MPa., then support scheme of Φ168 × 7 mm steel tube confined concrete supports was proposed. The result of FLAC3D simulation was that the maximum displacement of surrounding rock was 55.6mm. On-site support practice also showed that the support scheme guaranteed the stability of the roadway sounding rock