PHOTOELASTIC STUDY OF WAVE PROPAGATION.
Abstract
This research program was conducted to study some fundamental aspects of wave propagation in layered media and to obtain information on the dynamic state of stress in the vicinity of a point source explosion. The experimental method selected for the program was dynamic photoelasticity. A Cranz-Schardin multiple spark camera was used to record the dynamic isochromatic fringe patterns associated with the stress waves. Columbia Resin CR-39 was used for most of the models. Small lead azide charges were used to load all models. In the study of the effects of interfaces on stress wave propagation model with an acoustical impedance mismatch of 6 to 1 was used for most of the work. In this model six different wave types were clearly identified. Three of these waves were headwaves. In the region near the source the predominant waves were the incident P wave and the reflected P S waves. In regions away from the source the headwaves dominate since their rate of attenuation is much lower than the rate associated with the incident and reflected shear waves. The results from the models with an explosively loaded cavity indicate that a high intensity shear wave is produced as the cavity fractures. The stress distribution in this wave depends upon the manner in which the fracture forms. For the spherically symmetric model, the fracture is a random process; therefore, a unique solution for the stress distribution cannot be obtained. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 01, 1966
- Accession Number
- AD0803631
Entities
People
- J. W. Dally
- W. F. Riley
Organizations
- IIT Research Institute