Bruel and Kjaer instrumentation series (namely, portable and
multi-channel analyser PULSE type 3560D, PULSE Labshop
(a) (b)
software with four ENDEVCO Isotron [uniaxial] accelerometers
model 751-100 and B & K triaxial accelerometer type
4506B) were utilized in the measurement devices. The B & K
calibration-exciter type 4294 was used to calibrate the accelerometers
before and after the measurements. The dynamic
frequency response of the uniaxial transducers was up
to 10 kHz while that of the triaxial one was up to 5.5 kHz for
the x axis and 3.0 kHz for the y and z axes. The sensitivity of
both types of accelerometers was 10 mV/ms