Mechanical Shock Testing

 

Mechanical Shock is the result of suddenly applied forces or abrupt changes in motion. Shocks of this type may disturb operating characteristics or cause damage similar to that resulting from excessive vibration, particularly if the shock pulses are repetitive; mechanical shock testing is designed to simulate these environments.

The Shock Test is intended to determine the suitability of the devices for use in electronic equipment that are subjected to moderately severe shocks as the result of rough handling, transportation, or field operation.

The Shock Apparatus is a commercial piece of equipment designed to provide the Half-Sine Shock Pulse that is the normal test specified for electronic components and assemblies. Typically, the device is subjected to 5 shock pulses of the peak (g) level specified in the selected test condition and for the pulse duration specified in each of the orientations X1, X2, Y1, Y2, Z1 and Z2. For devices with internal elements mounted with the major plane perpendicular to the Y-axis, the Y1 orientation shall be defined as that one in which the element tends to be removed from its mount. Typical conditions are 500 g’s for 1.0 ms, and/or 1500 g’s for 0.5 ms.

Tooling is generally required to attach the component to the Shock Apparatus. The simplest and least expensive is to add holes to Silicon Cert’s existing adapter plates if the component has screw attachment holes. If the component has no such attachment means, special fixtures must be designed and fabricated. These unique fixtures are then attached to the adapter plates and are attached to the “I Beam” mounting block. This unique design allows for the shock testing of all six axes.

The tooling should allow the accelerometer to be mounted as close as possible to the centerline of the component being shocked. As standard practice, the new tooling will be run dry (without test components) to calibrate the machine. In addition, calibration is performed in all orientations before product is run.