Mechanical shock (Test Ea) - half-sine, final-peak saw-tooth and trapezoidal pulses.
A method for testing specimen resistance to single and repeated shocks of specified severity. The test reveals mechanical weaknesses, degradation of functional performance and cumulative damage caused by shock. It applies primarily to unpackaged products and products in a transport case when the case forms part of the specimen; it covers components, equipment and other electrotechnical products.
The test demonstrates that the specimen withstands shocks with a specified pulse shape, peak acceleration, duration and number without loss of function or mechanical damage. A reference to the method alone says nothing about severity: pulse shape and severity are prescribed by the product standard or detail specification, while 60068-2-27 describes only how to perform the test.
Without stated severity, the reference confirms only the laboratory procedure.
The specimen is mounted on the shock-machine table or fixture according to IEC 60068-2-47 and remains mounted throughout the test. The standard defines three nominal pulse shapes: half-sine, final-peak saw-tooth and trapezoidal; the measured waveform must remain within the tolerance bands in Figures 1–3, with peak acceleration within ±0.2 A of nominal and velocity change within ±15% of the calculated value.
Shocks are applied along three axes, in both directions of each axis, as specified; transverse acceleration must not exceed 30% of peak acceleration in the test direction. Initial measurements and a functional test are performed before testing, followed by recovery and final measurements.
The number of shocks in each direction is selected from 3 ± 0, 100 ± 5, 500 ± 5, 1000 ± 10 or 5000 ± 10. Pulse shape and severity are prescribed by the detail specification; Annex A gives guidance on pulse-shape selection and examples of typical severities.
A datasheet entry is meaningful only with the full set: pulse shape, peak acceleration (m/s² or g), duration (ms), number of shocks per direction and number of axes; the standard number alone describes only the procedure. Compare the stated values with severities referenced by the product standard for the installation location.
