Multi-axis vibration testing of an aerodynamically excited structure

Missile vibration testing has undergone significant advances in the past decade. This has been the result of improvements in signal processing and test specification development, but more recently due to the implementation of Multi-Input Multi-Output (MIMO) testing. To date, much of the focus of MIMO testing has been on either a twin-shaker, single-axis configuration or multi-axis testing on a 3 or 6 Degree of Freedom (DOF) shaker system. There has been little attention to replication of the 3-dimensional operating deflection shapes that a missile system experiences during its carriage or operation. This paper presents a systematic approach to 3-axis vibration testing, using current MIMO rectangular controller technology, and demonstrates through an experimental setup a near-3 fold improvement in matching the vibration response of the item under test over the more traditional single axis SISO and MIMO test methods.