The shock exciter is used for the generation of high accelerations. Its mode of operation is based on the propagation of elastic wave pulses in a long thin bar. A steel ball driven by compressed air hits another steel ball of equal diameter. By a vacuum, this second steel ball is kept in close contact with the end surface of a bar 4 m in length. After the steel balls have bounced against each other, an elastic wave propagates along the bar. The accelerometer to be calibrated is attached to the other end of the bar and experiences accelerations which can be chosen between 103m/s2 and 105m/s2. Three bars of different diameter (material: steel or titanium) are arranged in parallel, which are hit by steel balls of different diameter. The automated pneumatic supply system allows the adjustment of defined pressure values within a wide range. This makes a great number of combinations possible which are used to set different acceleration peak values, with the shock duration remaining approximately the same (for example, for linearity tests of accelerometers), or to set different shock durations with the peak value remaining unchanged.
Shock acceleration exciter
Part of the shock exciter is an interferometer table with automated displacement arrangement with the aid of which the laser interferometer can easily be adapted to the shock wave bar chosen. The novel shock transmission by means of steel balls of equal diameter allows impulse shaping and suppression of high-frequency oscillations: the velocity has the shape of the Gaussian density distribution whose frequency spectrum does not contain significant high-frequency spectral components (this is also valid for the "acceleration dipole"). The excitation of resonances (e. g. the resonance of the accelerometer to be calibrated) can thus be avoided.