Advanced Materials Research Vols. 602-604

Abstract: Progressive die has been widely used in product manufacturing field. This paper proposed a NX-based computer server support design method. The equivalent stress, resilience, equivalent strain, attenuation, and forming were analyzed in detail. The key technology of confirming blank dimension and stock layout of server support were explicated clearly.

Abstract: Traditional vehicles must separate clutch during the shifting process, which will lead to clutch wear. Parallel hybrid electrical vehicles introduce a motor which makes it possible to shift without separating clutch. This paper proposes a control algorithm which combines engine control with motor control to realize shifting control without using clutch based on dynamic analysis for every shifting stage, of which the key technologies are accurate motor torque and speed control to make full use of motor rapid response ability. The simulation result shows this can significantly improve driving comfort, shift transient property and extend service life of clutch.

Abstract: Based on the analysis of molded line geometrical characteristic and boundary conditions of high-speed frigate’s hull by using differential geometry, we report a curve modeling principle to express the hull line geometry through differential geometry application. The starting point of this molded-line automatic generation method is using the planar curve to express 3D surface shape. The first problem to be solved is how to get shape functions which describe every design ship curves via the the hull type curves geometry. The second problem to be solved is how the two-dimensional function, which describe ship lines, transformed to the hull shape function designed of three-dimensional hull surface, namely “mathematic ship”.

Abstract: It is necessary to achieve high system performances in terms of throughput rate and service level in today’s business environment. This can be achieved by implementing efficient and effective production planning methods complemented with precise and fast scheduling predictions. A framework is proposed to integrate real-time production data, scheduling mechanisms and simulation for providing realistic scheduling policies that could be used for operational and tactical decision-making. The focus is on the use of discrete event simulation utilizing relevant shop floor data, provided by an ERP system. A primary objective is to evaluate and characterize scheduling policies in a discrete manufacturing environment.

Abstract: Squeeze casting is process capable to produce high integrity parts. To minimize gas porosity, melt front’s speed must be kept as minimum as possible to ensure the laminar flow pattern with adequate flow rate to be able to fill the cavity before liquid metal is solidified. In this study, the indirect squeeze casting process was adopted to cast a motorcycle’s component originally produced by a high pressure die casting (HPDC) process. Based on shape and dimension of the parts to get the real castings for the mass production, melt’s speed must be higher than the level reported by the literatures (around 1 m/sec). As a result, a fully laminar flow may not be achievable. This is confirmed by the primary study of the process parameters and tooling design using the casting process simulation. Castings from two processes were casted and then mechanically and micro-structurally compared for both as cast and heat treated conditions. Results from the experiment have shown that size of gas porosity found in squeeze casts reduced significantly, while gain size of the squeeze casts trended to be bigger than that of HPDC casts. In terms of the mechanical properties, the ultimate tensile strength of as cast from both processes was not significantly different, while the heat treated squeeze casts has shown the big improvement compared with the as casts.

Abstract: Sheet hydroforming process of one irregular box with unequal height and flat bottom was investigated by numerical simulation and experiment. The effect of blank shape and pressure loading path on the forming result was discussed. The key process parameter was optimized. The results have shown that the round blank is the best shape blank. The part can be formed with the appropriate blank shape and die cavity pressure.

Abstract: Roll forging process for automobile front axle has been simulated by using a rigid viscoplastic finite element method, force-time curve have been obtained and analyzed. On the basis of simulation result, typical characteristics of roll forging process have been explained. It concluded that simulation results could guide the development of roll forging and die design for automobile front axle.

Abstract: In the present paper, a fabrication process to roll-bonding aluminum clad copper tube(ACC) by Planet Schràge Walzwerk(PSW) has been introduced. Aluminum alloy(3003) as a outer tube layer and oxygen free copper(C12200) tube as a inner tube, were rolled to bond together using a PSW mill. Different specifications of ACC tube were selected to investigate the Al-Cu bonding layer thickness using scanning electronic microscope with EDX and bonding strength using peering test, and mechanical properties of ACC tube were also test. The experiment results indicated that Al-Cu composite layer is not only mechanical bonding but also metallurgical bonding with thickness of several micrometers. Moreover, tensile test indicated that the tensile strength of ACC was not less than 135 Mpa and elongation is about 35%, while peeling strength test showed that the two composite layers bond strength nearly arrived to 120 N/cm.

Abstract: The springback of spherical parts in both integral-gripper and discrete-gripper stretch forming processes were investigated by using explicit-implicit algorithm. The effect on springback value and shape errors of pre-stretching, thickness and materials were studied. The simulation results show that springback and shape errors in the integral-gripper stretch forming are bigger than that in the discrete-gripper stretch forming; the springback gradually decrease and shape errors reduce as pre-strecthing increases, a prior pre-stretching is 1%; the springback and shape errors are gradually reduced as sheet metal gets thicker; the greater the elastic modulus and yield strength of the material, the smaller the springback and shape errors of the formed parts.

Abstract: A 3-D thermal-mechanical model was built to simulate the hot rolling process of medium plate, with the aid of nonlinear commercial FE code MSC.SuperForm on a company's actual process parameters. The hot rolling process of single-pass which slab thickness is 180mm was simulated, and the influence of pass reduction on metal flow, stress-strain field, contact stress and rolling force were researched. The study revealed that pass reduction should be at least 20% by increase depress in pass in addition to rolling efficiency. As that, rolling efficiency be increased, roll contact stress be brought down, and its service life be prolonged. And metal plastic strain enhanced, metal flow increased, but its strain field non-uniformly distributed, metal flow and plastic deformation would be strengthen by increase pass reduction, and the lateral broadening in the head is bigger than that in the tail.