Method and apparatus for in-flight shake testing of an aircraft fuselage
First Claim
1. A method for in-flight shake testing of an aircraft structure having an active vibration control system comprising a plurality of force-generating actuators connected on the structure for inputting controlling forcing loads into the structure to reduce vibration thereof, comprising the steps of isolating one of said actuators from the vibration control system, operating said one of said actuators independently of the vibration control system so as to input a predetermined load at a predetermined frequency into said aircraft structure to excite said aircraft structure to vibrate, sensing the vibration of said aircraft structure to said input and recording said vibration.
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Abstract
A force-generating actuator connected at or across points of a structure capable of relative motion at an exciting frequency is operated to input a predetermined load into the structure and the response of the structure is measured for analysis. In one form of the invention the actuator is one of a plurality of actuators of an active vibration control system which is isolated and operated independently in a shake test mode. Advantageously, especially in a helicopter application, the remaining actuators can continue to be operated to reduce background vibration.
23 Citations
9 Claims
- 1. A method for in-flight shake testing of an aircraft structure having an active vibration control system comprising a plurality of force-generating actuators connected on the structure for inputting controlling forcing loads into the structure to reduce vibration thereof, comprising the steps of isolating one of said actuators from the vibration control system, operating said one of said actuators independently of the vibration control system so as to input a predetermined load at a predetermined frequency into said aircraft structure to excite said aircraft structure to vibrate, sensing the vibration of said aircraft structure to said input and recording said vibration.
- 3. Apparatus for in-flight shake testing of an aircraft structure having an active vibration control system including a plurality of force-generating actuators connected on said structure for inputting controlling forcing loads into said aircraft structure to reduce vibration thereof, control means for isolating one of said actuators from the vibration control system and operating said one of said actuators to input predetermined shake test excitation forces into said aircraft structure to excite said aircraft structure to vibrate for shake testing said aircraft structure, sensing means for sensing the vibration of said aircraft structure to said shake test excitation forces and recording means for recording said vibration.
Specification