Vibration is a potential source of the failure for many systems, and can be a major contributor to problems related to the operating environment of electronic equipment. Most electronics equipment is exposed to some amount of vibration, even if just from shipping and transportation. Portable electronics often need a degree of protection from the shock and impact of being dropped from moderate heights. In other industries, such as mil/aero and harsh industrial settings, vibration isolation and resilience can be a crucial design consideration.
Although modeling and analysis are helpful tools, testing is often necessary to ensure product reliability under harsh conditions. This is not as simple as it may seem, however. A 20-year product life is typical and expected for military qualified electronics. How can this be tested? Accelerated stress testing techniques such as HALT (Highly Accelerated Life Test) and HASS (Highly Accelerated Stress Test) offer solutions that are both practical and effective. Methods like HALT/HASS go further than mere design verification testing because they stress products beyond their specifications to determine both operational and destruct limits.
The MIL-STD-202 Test Method Standard, used by the U.S. military, specifies the testing procedure for vibration, which involves simple harmonic motion at 0.03 inches amplitude over a range of frequencies from 10 to 55Hz. Under electrical load conditions, the motion is applied for at least two hours along each axis (for a total of six hours), and the product is tested both during and after vibration.