Original paper(Vol.49 No.5 pp.541)
On Analysis of Joining Process of Polyethylene Pipes
Masaru Zako, Makoto Fujihara, Koji Ichikawa
Abstract:As the welding of polymer materials has a process to phase transformation, the simulation of welding should be considered the thermomechanical coupling effect on stress and strain. In addition, the welding has the contact phenomenon between two bodies incorporated with thermal deformation. So it is also necessary to consider the contact between two bodies in any shape and the change of thermal boundary conditions. In this paper, a numerical procedure with phase transformation for welding of polymer is proposed and the computer program has been developed.
As an example, the processes of heating and cooling for polyethylene joint with shape recovery have been simulated. In case of the coupler without shape recovery, it is also revealed that the end of coupler does not contact with the pipe, since the bending deformation is taken place by non-uniform distribution of temperature to thick direction. But the whole part of coupler can be joined by shape recovery effect. The change of stress with time on the contact surface is calculated in cooling process and the residual stress can be evaluated. As the result, it is recognized that the effect of shape recovery on fusion joint is evaluated by the developed computer program.
Key Words:Electrofusion joining, Welding of polymer, Thermomechanical coupling, Contact, FEM, Shape recovery