The real vibration environment for a structure is complex with multiple excitation sources in multiple directions. Consequently it is often desirable to perform testing in more than one direction, or degree of freedom, simultaneously. Applications include multi axis seismic testing, 6 degree of freedom (6 DOF) time replication testing, simultaneous three axis testing, and even single axis testing with multiple shakers.
Using SignalStar Matrix, it is now possible to perform more precise and realistic testing than ever before. Matrix addresses the complete range of multi shaker test requirements, from IEEE 344 multi axis seismic testing to 6 Degree of Freedom (DOF) time data replication testing. The SignalStar Matrix uses continuous control to adapt to the dynamics of the system under testing. Compensating the cross coupled dynamic responses of the multiple inputs simultaneously yields high control accuracy. Matrix offers independent reference definition of each control point with defined phase and coherence between control points. Learn more about the world’s most complete multi shaker controller, SignalStar Matrix.
More than ever, electrodynamic shakers are being used in various arrangements for use together. Dual shaker single axis use, simultaneous three axis, and even six degree of freedom arrangements are all becoming more common place in electronics, automotive, and defense industry testing. Data Physics has engineering capability for configuring SignalForce Electrodynamic Shakers in various arrangements to achieve the desired results. Learn more about SignalForce Electrodynamic Shakers.
Multi Degree of Freedom Testing
Equipment typically experiences simultaneous vibration in multiple degrees of freedom. As a result, more accurate simulation of the vibration conditions seen in a product’s real operating environment is best performed by multi degree of freedom vibration testing. Results show that multi degree of freedom testing can often reproduce failures seen in the field that cannot be duplicated with standard single shaker testing.
Multi Shaker Single Axis Testing
Multi shaker single axis tests are usually performed on large products, particularly those that are physically long such as missiles or space vehicles.
High frequency electrodynamic shakers are used most often for multi shaker single axis testing of satellites. These systems are designed to test very large payloads, without the normal sacrifice of high frequency response that you would typically find with a multi axis shaker system.
In some cases, the shakers can be directly coupled to the test fixture, assuming that the vibration control system can achieve accurate phase control between the two shaker systems. If required, hydrostatic spherical couplings can be installed between the shakers and fixture. The hydrostatic spherical couplings will allow for any out of phase rotations during testing and will allow for any foreshortening that will occur as a result of this out of phase condition.