Investigation of Dynamic Mechanical Stress with Photoelastic Techniques
Abstract
The technique of dynamic photoelasticity has been applied to a study of hypervelocity impact phenomena. The target consisted of a cadmium front plate, followed either by a void or a foam filled space, and a rear plate of steel or aluminum. Two series of tests were carried out. The first, employing a Plexiglas rod, acting as a Hopkinson pressure bar in a transmission polariscope arrangement, sensed the pressure time history resulting from debris stagnation in the second plate. In the second series, the rear plate was provided with a photoelastic coating as part of a reflection polariscope. Dynamic stress patterns, produced by a debris impact, were photographed as they developed in time and provided a whole field view of the nature of the pattern. The experimental results indicate that Plexiglas can be used successfully as a pressure bar for dynamic stress measurements in the range of several kilobars. Analysis of dynamic plate motion indicates the presence of elastic extensional waves and shows that second plate deformation and rupture are accompanied by elastic effects.
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 01, 1970
- Accession Number
- AD0870792
Entities
People
- C. C. Berggren
- V. R. Honnold
- W. M. Peffley
Organizations
- Hughes Aircraft Company