Experiments with violin plates and different boundary conditions

Abstract

This paper reports on a continued investigation of violin plate properties. The plates were thinned in steps, and the shifts of the resonance frequencies were measured with different boundary conditions: free, glued to rigid ribs, and glued to the flexible ribs of a simplified violin model. It was found that, in spite of large frequency shifts for the free plates, the corresponding shifts for the glued plates were small. The experimental results imply that the boundary conditions have a major effect on the resonance frequencies and that the fundamental plate mode of the violin model is related to that of the free plate mode 5; i.e., the frequencies of both modes were most sensitive to thinning off-center and less sensitive to thinning in the center. The investigation is empirical; the information is collected under controlled conditions to serve as a base for future refined theoretical and experimental work.