Related Experiment Video
Updated: Aug 29, 2025

Mechanical Expansion of Steel Tubing as a Solution to Leaky Wellbores
Published on: November 20, 2014
Effect of Pressure Difference between Inner and Outer Gas Layer on Micro-Tube Deformation during Gas-Assisted
Bin Liu1, Xingyuan Huang1, Shaoyi Ren1
1College of Advanced Manufacturing, Nanchang University, Nanchang 330031, China.
Abstract:
In the process of double-layer gas-assiste extrusion of a plastic micro-tube, the tugging effect caused by the pressure difference of the gas cushion layer inside the die has a great influence on the external dimensions of the micro-tube. Therefore, this study establishes a two-phase extrusion model based on compressible gas and incompressible melt. Ansys Polyflow finite element software was used to numerically simulate the extrusion process of the melt to analyze the effect of the gas cushion layer pressure difference on the micro-tube deformation. The research shows that the shrinkage rate of the micro-tube increases with increasing pressure of the outer cushion layer, and the degree of tube wall migration increases, too. In the process of extrusion, the first normal stress difference at the entrance of the gas cushion layer shows a significant effect on the melt velocity field distribution and the extruded micro-tube cross-sectional deformation.
Related Concept Videos
Excess Pressure Inside a Drop and a Bubble
Temperature Dependent Deformation
Residual Stresses
Steady, Laminar Flow in Circular Tubes
Thermal Strain
Relation between Poisson's ratio, Modulus of Elasticity and Modulus of Rigidity

