Failure Analysis for Polycarbonate Transparencies.
Abstract
Today polymers are increasingly used in advanced structural applications such as aircraft canopies. However, there are no well established models which could be used by design engineers for predicting time to failure for these materials. Development of adequate criteria for three basic stages of fracture (crack initiation, stable crack growth and dynamic crack propagation) is necessary for the accurate prediction of service lifetime. Part 1 of this report reflects a recent progress in understanding of various failure initiation mechanisms in transparency-grade Polycarbonate (PC). A new fatigue crack initiation map for PC is proposed. Another important stage of the fracture process which may strongly influence the total lifetime is crack propagation. Propagation of a crack surrounded by the process zone is a well-known phenomenon for the PC. The properties of the material in the process zone may strongly influence such critical fracture parameters as lifetime, fracture toughness, etc. The deformation of PC by shear banding at a notch-tip was found very similar to that obtained by cold-drawing of PC. In the Part 2 of this report the tensile cold-drawing (necking) behavior of PC is further examined using simple tensile extension coupled with temperature measurements via an infrared camera. (AN)
Document Details
- Document Type
- Technical Report
- Publication Date
- May 01, 1994
- Accession Number
- ADA292992
Entities
People
- A. Chudnovsky
- C. P. Bosnyak
- K. Sehanobish
- T. J. Chen
- Zheyu Zhou
Organizations
- University of Illinois at Chicago