BLAST VIBRATION IMPLICATIONS OF CYCLIC SHEAR BEHAVIOR OF MODEL PLASTER PANELS.

Commercially produced gypsum wallboard was stripped of its paper backing and subjected to cyclic, in-plane shear fatigue tests in the laboratory. The cyclic frequency and loading conditions where chosen to simulate as closely as possible strains in brittle wall coverings induced by blasting vibrations. These results are compared to those of similar laboratory studies that simulated wall response to sonic-boom strains. The unpapered gypsum exhibited definite fatigue behavior and preexistent strains further reduced its effective lifetime. Implications of these findings for cracking induced by blast vibration are also explored.