This content is not included in
your SAE MOBILUS subscription, or you are not logged in.
High Strain-Rate Characterization of Thermoplastics Used for Energy Management Applications
Annotation ability available
Sector:
Language:
English
Abstract
An interesting characteristic of virtually all materials is their strain-rate sensitivity. In the case of engineering thermoplastics, these materials exhibit ductility and very good impact resistance at low to average strain rates (<10 %/sec) but can become extremely brittle and unforgiving at high strain rates (100 - 5.000++%/sec). This becomes a concern in energy management applications, such as automotive instrument panels and knee bolsters, because, for example, the average head impact on an instrument panel induces a 1,000%/sec strain rate.
Engineering analysis of the impact event typically under-predicts loads and over-predicts deflections. Making material substitutions within a design may be of little use since the newcandidate may be more strain-rate sensitive than the original polymer. Many of the most widely specified engineering thermoplastics behave very differently in standardized ASTM “static” tests than in high strain-rate situations. Therefore, it is difficult, if not impossible, to accurately estimate performance based on extrapolated low-strain data.
Responding to a need for accurate data measured at high strain rates, and recognizing that very few organizations are equipped to perform such testing, GE Plastics and Davidson Instrument Panel have initiated a research program with the University of Dayton Research Institute (UDRI) to characterize the strain-rate sensitivity of common grades of polycarbonate (PC), acrylonitrile butadiene styrene (ABS), polycarbonate/acrylonitrile butadiene styrene (PC/ABS), polybutylene terephthalate (PBT), polycarbonate/polybutylene terephthalate (PC/PBT), and modified-polyphenylene ether (M-PPE) resins.
This paper will disclose the results of the high strain-rate material testing (up to 5.000 %/sec) and resultant performance of these materials. Discussion will center around how engineers can use these data to better predict material behavior in complex assemblies.
Recommended Content
Topic
Citation
Clark, C., Johnson, P., and Frost, C., "High Strain-Rate Characterization of Thermoplastics Used for Energy Management Applications," SAE Technical Paper 940882, 1994, https://doi.org/10.4271/940882.Also In
References
- “Solid Phase Sheet Forming of Thermoplastics-- Part I: Mechanical Behavior of Thermoplastics to Yield,” Journal of Engineering Materials & Technology, Transactions of ASME 108 April 1986 107
- “High Strain Rate Material Behavior Full Report” Clark Christopher L. GE Plastics April 1993
- “Advanced Transparency Development for USAF Aircraft” Bouchard Michael P. Davisson Lt. Joseph C. AIAA 34th Structures, Structural Dynamics and Materials Conference, Paper No. 93-1391 La Jolla, Calif. April 1993
- “Frameless Transparency System Material Property Evaluation” Frank Geoffrey J. Stenger Gregory J. University of Dayton Research Institute Dayton, Ohio July 1992