The s’MASH impulse-response is a portable test system used to quickly screen a structure for flaws and identify suspect areas for subsequent detailed investigation. It follows the ASTM C1740, “Standard Practice for Evaluating the Condition of Concrete Plates Using the Impulse-Response test Method”.
The s’MASH uses a low-strain impact, produced by an instrumented rubber tipped hammer, to send stress waves through the tested element. The impact causes the element to vibrate in a bending mode and a velocity geophone transducer, placed adjacent to the impact point, measures the amplitude of the response. The resultant velocity spectrum is divided by the impact force spectrum, to obtain the mobility as a function of frequency. The software analyses this information and derives into 4 parameters (average mobility, mobility slope, dynamic stiffness and voids ratio) that are used for integrity evaluation of the testing area by means of visual representations with contour plots.
s’MASH Impulse-Response test.