Accession Number : AD0803266

Title :   STIFFNESS AND VIBRATION CHARACTERISTICS OF INFLATABLE DELTA WING MODELS AT TEMPERATURES UP TO 650 F.

Descriptive Note : Final rept. Oct 63-Oct 65,

Corporate Author : AIR FORCE FLIGHT DYNAMICS LAB WRIGHT-PATTERSON AFB OH

Personal Author(s) : Pollock, Samuel J.

Report Date : JUN 1966

Pagination or Media Count : 94

Abstract : Stiffness and vibration data were obtained on inflatable Airmat models for various internal pressures from 2 to 10 psi and temperatures up to 650 F. The semi-span 65 deg delta wing models were woven from stainless steel monofilament wire and coated with high temperature silicone elastomer. Deflection and vibration characteristics were predicted using shear theory. Vibration predictions were also made using measured influence coefficients. Shear theory agreed with experimentation for deflections due to uniform load except near the leading edge where experimental deflections were smaller due to the stiffening effect of the rounded edges. Correlation of shear theory prediction for vibration frequencies with experiment improved as internal pressure increased to 10 psi. Vibration calculations using measured small deflection influence coefficients agreed with experimentation. Model vibration frequencies decreased as temperature was increased from 70 F to about 300 F. From 300 F to 650 F, vibration frequencies increased. At 650 F, the vibration frequency for a model without ceramic frits in the silicone elastomer coating was 32% higher than the room temperature frequency; for a model with ceramic frits the frequency was 10% lower. Mode shapes did not change appreciably with temperature. Structural damping coefficients decreased with increasing temperature.

Descriptors :   (*DELTA WINGS, AEROTHERMOELASTICITY), (*REENTRY VEHICLES, DELTA WINGS), VIBRATION, SHEAR STRESSES, AERODYNAMIC LOADING, DEFLECTION, METALLIC TEXTILES, STAINLESS STEEL, HEAT RESISTANT MATERIALS, SILICONE PLASTICS, ELASTOMERS, BOOST GLIDE VEHICLES, INFLATABLE STRUCTURES, AERODYNAMIC CONFIGURATIONS.

Subject Categories : Fluid Mechanics
      Unmanned Spacecraft

Distribution Statement : APPROVED FOR PUBLIC RELEASE