Seismic Testing, or Earthquake Testing, is performed to simulate earthquake conditions and test equipment survivability in those conditions.
There are many standards governing seismic testing in different industries. For telecommunications testing, the NEBS (Network Equipment-Building System) guidelines are most often used. IEEE 344 defines test requirements for safety related equipment in nuclear power plants. Another recent earthquake test is the ICC-ES AC156 test that defines the “Acceptance Criteria for Seismic Certification by Shake-Table Testing of Nonstructural Components.”
Earthquake tests are done with hydraulic excitation due to the low frequency, high displacement requirements. They are most often done with three axes simultaneously, but it is also common to see one or two axes of test. Six degree of freedom systems are also becoming more common to induce rotational motion as well.
Some specific standards are focused around replicating particular time histories, such as the NEBS standard, but most use SRS (Shock Response Spectrum) references and require SRS control. Most seismic tests are under 30 seconds in duration.
Because of the multishaker nature of earthquake testing, the SignalStar Matrix is ideally suited to control earthquake tests. The Matrix system has several advantages, and has often proven to be the only commercially available solution that can handle complex problems involved in seismic testing. In particular, the Matrix can control systems that are six degrees of freedom to be contained to three degrees of translation.