• [2012-08-07]

  Date posted: August 6 , 2012 A study of plastic flow and thermal aging on the response of glassy polycarbonate with an emphasis on characterization and modeling of the development of elastic anisotropy, and of anisotropic toughening

Title：<span verdana','sans-serif';="" mso-bidi-font-family:="" 宋体"="" lang="EN-US"> A study of plastic flow and thermal aging on the response of glassy polycarbonate with an emphasis on characterization and modeling of the development of elastic anisotropy, and of anisotropic toughening

<span verdana','sans-serif';="" mso-bidi-font-family:="" 宋体"="" lang="EN-US">Speaker：Mehrdad Negahban

Host：Zheng Li

Time：9:30 am

Date：August 10, 2012

Venue：Conference Room 210, Building No.1, Engineering College   Abstract：There is a substantial change in the anisotropy of some glassy polymers when they are subjected to large plastic deformations. The most pronounced case is probably seen in polycarbonate (PC), which is a tough thermoplastic used for many structural applications, including its use as protective transparent armor for such applications as bulletproof glass. The scale of the change in anisotropy is in the same order as the induced plastic strain, and reflects itself in practically all aspects of the materials response including its wave speed, fracture energy, fracture mode, and thermal conductivity. Typically, this changed takes an initially isotropic material into a highly anisotropic one. This feature, that is highly pronounced, is totally ignored in modeling these polymers, a fact that can result in substantial error in simulations. In addition, thermal aging can have a substantial influence on these plastic flow induced anisotropic characteristics. The presentation will cover many of these issues in addition to show how current models can be modified to capture the development of anisotropy in the wave speeds.