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【答案】应助回帖
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真强必胜: 金币+1, 谢谢 2014-01-13 21:34:55
zoe122208: 金币+100, 翻译EPI+1, ★★★★★最佳答案 2014-01-14 07:15:57
The reason why this kind of wave peaks and a transition area are resulted is due to the high speed impact, during the welding process, between the aluminum alloy and steel which causes shear between the two metals. For this shear problem Stokes First Theorem can be used to describe the physical process, i.e., when a stationary plate horizontally placed on the surface of a liquid starts to move, it will cause the viscous fluid below the plate to move along. As the amplitude of the special wave peaks is the same as the width of the transition area, this width can be calculated as soon as the height of fluid that is carried along is calculated.
Within the technology of welding by magnetic pulse, under the same collision speed and joint angle, the speed of movement at collision point is a constant and the speed of impact between the inner and outer pipe is of an order of magnitude of 10^2 and the wavelength of the joint of 10^-2. Hence it can be seen that in the formula, t is inversely proportional to the speed of movement at the collision point and the width of transition area is related to η and v. Although the inner and outer metal pipes are treated as fluid in this paper, the viscosity coefficients of aluminum and steel are far greater than those of the most common liquids. This study shows that the shear viscosity coefficients of aluminum and steel under an impact pressure of 100GPa are 1000Pa•s and 1200Pa•s respectively. In order to determine the parameter η, calculations are done using widths of the transition area and speeds under different process conditions, with process parameter being given in the table and then η under different test conditions are obtained.
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