Reduction of Dynamic Response of a Wind Tunnel Sting Mount Using Passive Damping

The Phase I research has established the feasibility of achieving substantial reductions in the dynamic response of wind tunnel sting mounts using passive damping techniques. Of the three principal passive damping concepts evaluated, the Hub Damper Unit (HDU) concept was determined to be the most suitable, and further development of this is planned in the Phase II research program. The primary selection factors were the need for general application to a variety of existing stings at AEDC and the avoidance of flow disturbance near the model. Extended theoretical modeling will be carried out to ensure that optimum levels of damping are achieved, targeting a 40 dB reduction in amplitude of the fundamental vibration mode. A test unit will be designed, constructed and tested for static and dynamic characteristics, ultimately in an AEDC wind tunnel environment. The second preferred concept is cocured visco-elastic material (VEM) in a new-build composite sting design, for which extended theoretical evaluation will be conducted to determine optimum performance, but no practical tests are planned within Phase II. The Phase II program will continue development of the product specification and will provide detailed documentation of the design process for general application to future HDU and VEM stings.