Impact device used for impact elastic wave method

摘要

PROBLEM TO BE SOLVED: To provide a striking device used for an impact elastic wave method capable of stably applying an elastic wave of a constant frequency to an inspection object without being affected by the state of the inspection object (mainly, concrete).SOLUTION: The striking device includes: a plunger 10 that is a steel bar of a prescribed length manufactured at a constant cross section over the entire length, has a spherical-crown-shaped tip surface 10a to be collided against an inspection object, and has a flat upper end surface 10b; and a steel ball 11 of a prescribed diameter to be collided against the upper end surface of the plunger 10. A frequency f (Hz) of an elastic wave applied to the inspection object by the plunger 10 and a length L (m) of the plunger are determined on the basis of the relational expression of f=Cp(longitudinal elastic wave speed of steel bar)/2L.SELECTED DRAWING: Figure 1