TITLE:
A New Characterization Approach of Weld Nugget Growth by Real-Time Input Electrical Impedance
AUTHORS:
Yoke-Rung Wong, Xin Pang
KEYWORDS:
In-Process, Input Electrical Impedance, Dynamic Contact Resistance, Weld Nugget, Hilbert Transform
JOURNAL NAME:
Engineering,
Vol.6 No.9,
August
7,
2014
ABSTRACT: The in-process
changes of weld nugget growth during the Resistance Spot Welding were investigated
based on the resistance of input electrical impedance. To compute the time
varying resistance of input electrical impedance, the welding voltage and
current signals are measured simultaneously and then converted into
complex-valued signals by using Hilbert transform. Comparing with the dynamic
contact resistance as reported in literature, it showed that the time varying
resistance of input electrical impedance can be accurately correlated with
the physical changes of weld nugget growth. Therefore, it can be used to
characterize the in-process changes of weld nugget growth. Several new
findings were reported based on the investigation of spot welds under no weld,
with and without weld expulsion conditions.