STRUCTURAL RESPONSE TO INTENSE ELECTROMAGNETIC RADIATION.
Abstract
An exploding wire apparatus was used to study conversion of electrical energy into strain energy in glass, plastic, and metal samples that had been either irradiated by the electromagnetic waves emitted by the wire or enveloped by plasma formed by the wire. The strain energy left permanent marks on the sample in the form of discoloration, weight loss, erosion, and surface cracks. These were used to confirm the theoretical analysis as to method and to dimensions. Thus, a new method for measuring absorption coefficients was demonstrated. For glass samples, the surface crazed to a depth of 0.001 cm. Photomicrographs and profilometer measurements of the surface are presented to support the following conjectures as to the cause of cracking: the energy radiation by the hot wire is absorbed by a thin surface layer of the glass, the associated temperature rise generates thermal stresses, flaws below the glass surface form stress raisers according to the Griffith crack theory, and the cracks subsequently propagate to the surface. The theoretical derivation of the adapted thermoelastic stress theory predicts the dimensions of the cracks and the power levels required if the absorption coefficient is at least 10(3) reciprocal centimeters. Thus, a cracking phenomenon has been postulated and verified experimentally. The resistance of the exploding wire was measured empirically, and a theoretical justification made of its variation. This study added to a characterization of the exploding wire along with spectral, calorimetric, and photographic studies. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 01, 1965
- Accession Number
- AD0616336
Entities
People
- R. C. Good Jr.
Organizations
- General Electric