Shaker Vibration Testing System

Vibration and shock testing is environmental testing in which the unit under test is rigidly mounted on a shaker and subjected to controlled motion that mimics field conditions. A complete system has four parts: the shaker, a power amplifier, the vibration controller and the accelerometer. The controller loads the test specification and emits a low-voltage drive signal; the amplifier scales it to high power; the shaker excites the test object and the accelerometer, which returns measured acceleration to the controller as closed-loop feedback. The controller then adjusts the drive so the measured spectrum keeps tracking the target.

Three test classes dominate. Random testing excites all frequencies across a band (for example 5 Hz to 2000 Hz) to a target PSD defined by a breakpoint table; field-recorded data can be converted into a damage-equivalent profile using fatigue damage theory. Sine testing excites one frequency at a time with a pure sine drive, dwelling or sweeping logarithmically or linearly, with the spectrum accumulated over the sweep. Shock testing is defined in the time domain over a pulse of one second or less and is characterized by a Shock Response Spectrum — the peak response of a single-degree-of-freedom system plotted against its natural frequency; pulses may be mathematical (half-sine) or synthesized to match a target.

Crystal Instruments Spider controllers drive large and small electrodynamic, hydraulic and electrically driven shakers. Platforms include the expandable Spider-81 (8 inputs, 4 outputs), the basic Spider-81B (8 inputs, 1 output), the combined temperature/humidity/vibration Spider-101i (8 inputs, 2 outputs) and the VCS/DSA Spider-80X. Software covers sine, random, classical shock and transient control; Time Waveform Replication and Kurtosis control; Sine-on-Random and Random-on-Random modes; SRS analysis and synthesis; shock/drop and HALT/HASS, with full alarm, limit and notching protection. Markets include automotive, aerospace, avionics, telecom, consumer electronics and military equipment.