<title>Deformation measurements of smart aerodynamic surfaces</title>

Abstract

Video Model Deformation (VMD) and Projection Moiré Interferometry (PMI) were used to acquire wind tunnel model deformation measurements of the Northrop Grumman-built Smart Wing tested in the NASA Langley Transonic Dynamics Tunnel. The F18-E/F planform Smart Wing was outfitted with embedded shape memory alloys to actuate a seamless trailing edge aileron and flap, and an embedded torque tube to generate wing twist. The VMD system was used to obtain highly accurate deformation measurements at three spanwise locations along the main body of the wing, and at spanwise locations on the flap and aileron. The PMI system was used to obtain full-field wing shape and deformation measurements over the entire wing lower surface. Although less accurate than the VMD system, the PMI system revealed deformations occurring between VMD target rows indistinguishable by VMD. This paper presents the VMD and PMI techniques and discusses their application in the Smart Wing test.

Investigation of Membrane Actuation for Roll Control of a Micro Air Vehicle

“…A detailed study concerning the influence of deformability on a MAV's classical aerodynamic parameters was conducted via experimental windtunnel analysis for a variety of flight conditions [5]. Projection moiré interferometry [6] was used to measure the out-of-plane displacements over a wing, whereas cross-correlation using stereo triangulation [7] successfully recovered the complete displacement field over a membrane wing MAV and thereby also garnered information concerning the membrane strain. Numerically, Lian et al [8] effectively modeled the unsteady aerodynamics over a membrane MAV wing, thereby demonstrating the relationship between membrane dynamics and flight performance.…”

Unified Instrumentation: Examining the Simultaneous Application of Advanced Measurement Techniques for Increased Wind Tunnel Testing Capability

“…PMI is a video-based, non-contacting measurement technique capable of obtaining spatially continuous measurements of out-of-plane structural deformations 33 . The technique is well suited to measuring the deformation of aeroelastic vehicle components or aerodynamic control surfaces [34][35][36][37][38] . Measurement of the out-of-plane surface deformation is critical for many shape-change flow control devices, and determining the overall control authority often requires coupled measurements of the surface deformation and on-and off-body flow characteristics.…”

Aerodynamic Coefficients and Deformation Measurements on Flexible Micro Air Vehicle Wings

“…Experimental results were not available to validate the predicted wing's elastic deformation. Previous efforts to measure wing deformation included projection moiré interferometry (PMI) [16][17][18], videogrammetry [11,18,19], and finite element methods [20]. While PMI provided useful out-of-plane displacements, it does not yield in-plane strains.…”