Experimental Investigation of Wave and Fracture Phenomena in Impacted Ceramics
Abstract
Four types of glass which differ in their chemical composition, hardness and material density and tiles of SiC, TiB2, and Al2O3 were impacted edge-on with blunt steel projectiles at striking velocities between 20 m/s and 1000 m/s. The propagation of shock waves, of primary and secondary cracks and crack systems and the growing of crack systems from nucleated centers were visualized by means of a Cranz-Schardin high-speed camera within the first twenty microseconds, before the projectile penetrated the target more than a few millimeters. The concept of damage velocity was introduced to describe the different damage processes quantitatively. All four types of glass reveal a similar behavior. The damage velocity equals terminal crack velocity at low loadings. Other than in glass, in the ceramics different types of cracks are generated and different fracture velocities were observed at one impact velocity of continuously growing cracks, including the secondary cracks with sharp edges, fuzzy crack traces and crack fronts. In each of the ceramics the damage velocity increases with increasing striking velocity and approaches the longitudinal wave velocity at high loadings. A terminal crack velocity was found for one type of fracture in SiC. Ceramographical investigations of TiB2 fragments have shown that cracks within large grains as well as intercrystalline cracks are generated by coalescence of voids.
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 01, 1994
- Accession Number
- ADA286589
Entities
People
- E. Strabburger
- H. Senf