In addition to lightweight and moldable characteristics, polymeric foams possess an excellent energy-absorbing capability that can be used for a wide range of commercial applications, especially for crash protection in automobiles. The purpose of the present study is to develop an experimental methodology to characterize the pressure dependent yield behavior of energy-absorbing polymeric foams. A device was designed to perform a compression test in a triaxial stress state. For the test material, polyurethane foams of two different densities were used. The displacement of the specimen, the load applied to the specimen, and hydrostatic pressure applied to the specimen were measured and controlled. Stress-strain curves and yield stresses for different hydrostatic pressures were obtained. The experiments conducted in this study revealed that the polyurethane foams exhibited significant increase in yield stress with applied hydrostatic pressure or mean normal stress. Based on this observation, a yield criterion which included the effect of the stress invariant was established for the foams. The experimental constants obtained which constituted the pressure-dependent yield criterion were verified.
Bibliographical noteFunding Information:
This work was funded by Woodbridge Foam Corp. and the Korea Science and Engineering Foundation through Center for Information Storage Device (2001 00203) at Yansei University. The authors are grateful for their support.
All Science Journal Classification (ASJC) codes
- Organic Chemistry
- Polymers and Plastics