Scanning apparatus and method for non-destructive materials evaluation and mapping through use of acoustic waves

摘要

Columns, walls and other solid structures of concrete, wood, masonry or other materials are non-destructively tested by acoustic signals transmitted from a carriage. The carriage has a frame which is wheel mounted to move over the surface of the test candidate. An internally- mounted piezoelectric crystal roller as an acoustic signal generator or receiver is suspended from the carriage with two degrees of spring freedom to allow accommodation of irregularities in the test candidate surface. The assembly including the piezoelectric crystal roller and its flexible mounting are configured as a replaceable module relative to the carriage frame. The same carriage is useable as an echo type acoustic scanner or, in combination with other devices or carriages, as either an acoustic transmitter or receiver although inclusion of elements to perform both functions within the same carriage is contemplated. The carriage frame can also mount one or more hammer mechanisms to impact the test candidate surface at regular intervals as the carriage moves along the specimen surface. The device is suitable for detecting or generating compression, shear or surface waves in the test specimen.