Advanced Materials Research Vols. 314-316

Abstract: This paper proposes a new type of piezoelectric peristaltic pump driven by circumferential traveling-wave. The disk drive stator consists of an annular metal elastic base and a piezoelectric ceramic ring bonded to the metal elastic base with special welding adhesive. The vibration displacement function of composite vibrator was built. One end of the drive stator is divided into four sections. And it will generate mechanical deformation in circumferential direction to extrude the fluid in the tube when two-phase voltages with 90º difference and amplitude of 120V are added to each group consist of two relative sections and voltage of 0 is added to the other end of the drive stator. The actuation sequences can affect the flowing direction of the fluid. This pump has the advantages of simple structure, small size, light weight, low energy consumption and no electromagnetic interference. In this paper,the finite element model of the drive stator was also built by using ANSYS software, and relevant ANSYS harmonic response analysis was carried out. The results demonstrate that the positive and negative displacement of the maximal displacement node can satisfy the extrusion of silicon tube to the fluid and siphonage, and the corresponding resonance frequency can be operated. According to the simulation results the structure of the drive stator was determined.

Abstract: In this paper, the process of solid pellets being molten in the liquid melt in a co-rotating twin screw extruder is studied. Melting sequence of multiple pellets in the melt is calculated to find out the location where pellet is molten finally, and then a theoretical model is set up in which a cylindrical pellet is placed here. Further research is carried out to study how orientation of pellet and processing variables influence the melting time. FEM software, FLUENT is adopted to simulate the cases. It could be concluded that melting mechanisms of solid pellets are mainly convection; Pellets in the pushing zones would be molten at first and pellets in the middle channel and trailing zones at last. The orientation of pellets, temperature of melt and screw speed affect the melting time of the solid significantly.

Abstract: End concavity controlled effectively is one of important factors to achieve no material loss end of workpiece in cross wedge rolling (CWR). In the paper, nonlinear finite element modeling(FEM) for the process of CWR is presented with the aid of DEFORM software. The production mechanism of concavity on the end of rolled-piece is analyzed by displacement method, grid method and axial strain method. The reason of concavity is obtained that the surface metal flows faster than the center and the metal deformation in axle is uneven. The study is significant to avoid end concavity and realize no material loss end for rolled-piece.

Abstract: In this paper, in order to make the simulation of the whole process of electrochemical machining(ECM), the characteristic of electric field and flow field is made detailed analysis in the gap of ECM. Mathematical-physical models of ECM simulation is set up based on the basic theories of electrochemistry, electric field and flow field. And the method of model solution is discussed and researched. So the theoretical base is established of the full process of ECM simulation.

Abstract: 3D model of 6006 gulley ball bearing inner ring is established in this paper. Based on the study of finite element numerical simulation on the cold rolling process of inner ring by Deform-3D software, the paper shows the influence of the feed rate of idle roller, rotational rate of driving roller as well as wide-diameter ratio on the rules of rolling forming of bearing inner ring. Through the research of numerical simulation, it is discovered that feed rate of idle roller and wide diameter ratio have a greater impact on the ring end surface quality larger than rotational rate of driving roller does. Thus, process parameters should be chosen reasonably according to mold parameters and material parameters, which will help improve the stability of the cold rolling process and the rolling production efficiency.

Abstract: Aircraft components are mostly made by aluminum alloy as thin wall types. These parts are usually end milled to required thicknesses and tight tolerances in specific areas. The thin wall parts are difficult to machine because they are easy to vibrate and deformed due to their lower rigidity. This paper proposes a new elastic-plastic deformation model which is suitable for prediction of machining deformations of end milled thin wall parts. The theoretical deformation model is established on the basis of the equations of Von Kármán. The effect of bending springback is also taken into account. The part deformations are simulated using FE analysis and Matlab. Milling experiments on a CNC machining center are performed. The experimental results show that the deformations for the peripheral milling of thin wall parts can be captured with very high accuracy using the proposed elastic-plastic deformation prediction model.

Abstract: The influence brought by the granularity of task decomposition on the key factors of enterprise aliance was studied based on system dynamics method. These factors includs inter-restriction, product manufacturing time, collaboration fee, Alliance leader benefit, capability and compatibility. Causality diagram and system dynamics model were established for these factors. This paper also developed a simulation program for the granularity of task decomposition based on the system dynamics model and validated the effectiveness of the proposed model by a qualitative analysis. The results show that it is a workable method to research the granularity of task decomposition in enterprise aliance using system dynamics theory.

Abstract: To study the effect of different sample materials on the nano dynamic ploughing process in the AFM tapping mode, the spring-oscillator model is employed to simulate the vibrating AFM tip to deform the sample surface. On the surface of different samples with the Young’s modulus of 0.2 GPa, 80 GPa and 180 Gpa, the interaction between the tip and the sample is simulated with different driven amplitudes, spring constants, tip radius and original tip-sample distances. These effects are studied. Results show that the sample with a smaller Young’s modulus is suitable for being used as the sample machined by the dynamic ploughing technique. When the Young’s modulus is greater than 80 GPa, the machine depth is so small that the machining process can not be controlled as we required.

Abstract: In this paper, firstly, the common equation of involute gear profile was derived with the slotting tool, based on the principle of Envelope Method & Coordinate Transform. Secondly, different equqtions of the involute and transition curve were solved with different gear profiles of slotting tool through some mathmatical substitution. Finally, the model of gear profile equation was bulit with the software Pro/E. After verification, it proved that all derived equations, which can be used to establish the accurate 3D model of gear, are correct.

Abstract: Propose a collision and interference inspection algorithm based on bounding box, which can divide the collision and interference detection into rough, careful and precise inspection three steps. Rough inspection uses AABB bounding box, which can preclude the object that the interference wasn’t occurred obviously quickly and find out the potential intersectant object and area; careful inspection constructs the FDH bounding box to the object that has been confirmed interaction in the AABB bounding box; precise inspection detects and judges that the object occurs interference or not through the intersectant test of the triangular surfaces in the bounding box. This algorithm can simplify the calculating difficulty, improve the inspecting efficiency and meet the requirement to the inspecting speed and real-time in NC machining simulation.