(A) study on the resistance spot weldung process considering the eletric contact phenomena

Abstract

Using the conformal mapping method, the current density distribution at the contact interface and the constriction resistance of a single and multiple line contact were calculated for various space angles. The distribution of heat generation rate in neighborhood of a single line contact was also determined for various space angles. The results of the calculation revealed that the influence of space angle on the current density distribution, contact resistance and heat generation rate distribution is considerable and can not always negligible. The influence of the axisymmetric contact pressure distribution on the current density in the circular contact surface between two conducting semiinfinite bodies was also theoretically analyzed by using the newly proposed mechanical asperity contact model and the electrical current flow model. The shape of the nominal current density distribution approximates to the distribution shape of the contacting pressure but the current density on a micro contact approximates to the inverted shape of the contacting pressure, and that the effect of the pressure distribution shape of the contacting pressure, and that the effect of the pressure distribution shape on the contacting pressure, and that the effect of the pressure distribution shape on the overall contact resistance is not negligible and must be considered, when the mean pressure level is lower than several percentage of the hardness of the contacting materials. On the other hand, increasing mean pressure level causes both the current densities to increase as approaching the contact surface margin and the effect of the pressure distribution shape on the overall contact resistance to weaken. The effect of contact force, micro asperity and contamination on the potential, joule heat generation rate distribution and the temperature response was analyzed and discussed by using a hybrid finite element model. In this model, the analytical solution of constriction resistance for si...