Imagine stretching a long strip of PET, often the plastic deformation is violent, and the sample just breaks.

However, sometimes the film can be stretched for more than 2 times in length, and the stress actually oscillates. The obvious manifestation is a pattern consists of opaque and translucent stripes, shown as the gif on the right. This region is what we called “neck”, which has smaller width and thickness than the undeformed part. Our main purpose is to predict the stress-strain curve when stretching a polymer film, as well as for which parameters there will be such an oscillation.

The following report will include the model and the numerical scheme to this problem.
The slides (extracting from the report) are used to present findings and propose future experiments to Dr. Chaoying Wan, Warwick Manufacturing Group.

Project Report     Slides

This is a summer project supervised by Prof. Ed Brambley from the University of Warwick. I’m very grateful to him for his enthusiastic and responsible supervision on the project.

Photo with Prof. Ed Brambley

Photo with Prof. Ed Brambley