Two‐Dimensional thermal analysis of resistance welded thermoplastic composites

Abstract

A transient two‐dimensional thermal model for resistance welding of thermoplastic composites is presented. A parametric study is conducted that yields insight into the welding process enabling some critical process and material parameters to be identified. Time to melt is predicted by the model and is successfully compared to experimental observations. Local heating and meltthrough can also be explained by the transient thermal model in agreement with experimental observations. Mode I fracture toughness of unidirectional graphite reinforced poly(etheretherketone) resistance welded double cantilever beam specimens are conducted under various process conditions. Experimental results indicate that under optimum process conditions, the interlaminar fracture toughness of the bulk compression‐molded thermoplastic composite material can be achieved using resistance heating as a joining technique.

Scaling issues in resistance-welded thermoplastic composite joints

“…As shown by Jakobsen et al 25 through a finite difference heat transfer analysis of resistance welding, a minimum power level is required to assure that interface temperatures at the bondline exceed the minimum process temperature. If thermal losses to the environment or tooling are excessive, melting and fusing of the interface will not occur.…”

“…Earlier work by Jakobsen et al 25 has shown the relationship between power level and heater ply geometry for heating elements of different resistivity. A similar approach can be undertaken to determine the power requirements for the heating elements used in this study.…”

“…Uniform heating is essential to obtaining optimum performance and quality in the resistance welded joint. 6,7,25 The sequential resistance welding (SRW) process (U.S. Patent No. 5,225,025) was developed and incorporated into the computer-controlled automated resistance welding machine to reduce large-scale welds to a series of smaller weld steps performed in sequence.…”

Overinjection of thermoplastic composites

“…Xiao et al [11] and Jacobsen et al [12] performed thermal analyses of the process of resistance heating of APC-2 composites with an APC-2 heating element. Two-dimensional finite element models were used with the power input modelled as a uniformly distributed heat flux.…”

“…A number of researchers [11][12][13][14][15] have investigated the resistance welding of thermoplastic composites. Xiao et al [11] and Jacobsen et al [12] performed thermal analyses of the process of resistance heating of APC-2 composites with an APC-2 heating element.…”