Topology optimization of wind tunnel balance axial section. Wind tunnel force balances have been used for over a century to help aerodynamicists predict forces and moments exerted on aircraft and they…

This is a $206,392 cost-plus-fixed-fee delivery order contract awarded by the National Aeronautics and Space Administration (NASA) Langley Research Center to the National Institute of Aerospace Associates (NIA), a non-profit research institute. The contract is for the topology optimization of the axial section of wind tunnel force balances, which are critical devices used to measure forces and moments on aircraft models during wind tunnel testing. The primary objectives are to develop optimization code to meet the design requirements and to optimize the placement of strain gauges used to measure balance deformation. This effort supports NASA's broader research into aerodynamics and wind tunnel testing capabilities. The contract has no set-aside designation. A subcontract was issued to the University of Maryland Baltimore County (UMBC) to assist with the optimization code development and strain gauge placement work.

Topology optimization of wind tunnel balance axial section. Wind tunnel force balances have been used for over a century to help aerodynamicists predict forces and moments exerted on aircraft and they continue to remain the primary force measurement devices used during wind tunnel testing. Force balances provide the connection between the wind tunnel model and the sting that is used to suspend the model in the tunnel flow. Therefore, balances perform two important but competing objectives: 1) safely support the wind tunnel model throughout the tunnel test, 2) accurately resolving the forces and moments exerted on the aircraft, which requires sufficient resolution and a mathematical model. Wind tunnel force balances are effectively a coupling of many spring elements. The springs have been designed for the loads expected in the test. While there are many approaches to measuring force, in this application, the springs become transducers with the application of strain gages that provide electrical feedback proportional to the applied strain experienced by the strain gage. The primary objectives of this effort are to develop topology optimization code attempting to meet the four design optimization objectives as outlined in the statement of work, and to develop a novel approach to optimizing strain gage placement using local variables within the larger traditional topology optimization global variable optimization (for VON mises stress for instance).