مقاله جوشکاری Electrical contact resistance effect on resistance spot welding

مقاله جوشکاری با عنوان : Electrical contact resistance effect on resistance spot welding

P.S. Wei a,., T.H. Wub

چکیده :

The effects of local electrical contact resistance on transport variables, cooling rate, solute distribution,
and nugget shape after solidification responsible for microstructure of the fusion zone during resistance
spot welding are realistically and systematically investigated. The model accounts for electromagnetic
force, heat generation and contact resistances at the faying surface and electrode–workpiece interfaces
and bulk resistance in workpieces. Contact resistances are composed of film and constriction resistances,
as functions of hardness, temperature, electrode force and surface condition. The computed results show
that the bulk dynamic electrical resistance cannot reliably reflect transport processes and nugget shape,
unless the local constriction resistance and electric current density are known. Regardless of high film
resistance, nugget growth and transport processes are independent of film resistance due to delayed
response time of local electric current in the early stage. A decrease in constriction resistance, however,
delays nugget formation, enhances convection and solute mixing, and changes circulation direction of the
stronger convection cell during cooling period.

مقاله جوشکاری A study on numerical analysis of the resistance spot welding process

مقاله جوشکاری با عنوان : A study on numerical analysis of the resistance spot welding process

H. Zhigang a, I.S. Kim b,*, J.S. Son b, H.H. Kim b, J.H. Seo b, K.C. Jang c,
D.K. Lee c, J.M. Kuk c

چکیده:

Purpose: Over the last few years, there has been a growing interest in quantitative representation of heat transfer
and fluid flow phenomena in weld pools in order to study relationships between the processing variables and
the quality of the weldment produced and to use this information for the optimization and mobilization of the
welding process.
Design/methodology/approach: A 2D axisymmetric Finite Element Method (FEM) model has been developed
to analyze the transient thermal behaviors of Resistance Spot Welding (RSW) process. In this model, the
temperature dependent material properties, phase change and convectional boundary conditions were taken
account for the improvement of the calculated accuracy, but the determination of the contact resistance at the
surface is moderately simplified in order to reduce the calculating time through the analysis.
Findings: The developed model has been employed the thermal history of the whole process (including cooling)
and temperature distributions for any position in the weldment

مقاله جوشکاری Finite element analysis of the thermo-mechanical behavior of the resistance spot welding

مقاله جوشکاری با عنوان : Finite element analysis of the thermo-mechanical behavior of the resistance spot welding

Murat Vural

چکیده:

In this study, the formation of the welding nugget and the effect of welding process parameters on nugget shape and size, have been studied. And a combined thermal-electrical-mechanical simulation system is done using a Finite Element Analysis program, and the effect of the welding parameters such as current, time, electrode force, contact resistance temperature distribution on the contact resistance were investigated. The results provided useful information source on the formation of the nugget, and thus provided opportunities to play first true estimate of the quality of welding process.

مقاله جوشکاری Finite element analysis of resistance spot welding process

مقاله جوشکاری با عنوان : Finite element analysis of resistance spot welding process

Guo Zhong

چکیده :

A coupled finite element model is developed to
analyze the transient thermal and mechanical behaviors of
Resistance Spot Welding (RSW) process using commercial
software ANSYS. A direct-coupled electrical-thermal Finite
Element Analysis (FEA) is firstly performed to simulate the
transient thermal characteristics of RSW process. The thermal
history of the whole process and the temperature distribution of
the weldment are obtained through the analysis. Then based on
the thermal results a sequential coupled thermo-elastic-plastic
analysis is conducted to determine the mechanical features of
RSW process. The mechanical features, including the
distributions of the contact pressure at both the faying surface
and the electrode-workpiece interface, the stress and strain
distributions in the weldment and their changes during the RSW
process and the deformation of the weldment are also calculated.

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