Characterisation and synthesis of random acceleration vibration specifications

Abstract

A number of damage spectra to characterise measured or computed random acceleration vibration spectra are discussed in this chapter. The characterisation is based on equivalent damage caused by extreme peaks (SRS, ERS, VRS) and Rayleigh distribution of peaks or cumulative damage (FDS), using relative displacements and pseudo-velocities. The response spectra are all based on the response of single degree of freedom (SDOF) systems exited to random accelerations, both in the time and frequency domain. The principles to compute the response spectra are illustrated and discussed. One general practical example is discussed in very detail. Miles’ equation fulfills a key role in the synthesis process to generate equivalent random acceleration vibration specifications. An envelope of the damage response spectrum is achieved by dividing the spectrum into a number of fields or regions. The lower the number of field more severe and smoother equivalent random acceleration vibration specification is obtained.