Stiffness and Vibration Characteristics of Inflatable Delta Wing Models at Temperatures up to 650°F
Report Number: AFFDL TR 66-14
Author(s): Pollock, Samuel J.
Corporate Author(s): Air Force Flight Dynamics Laboratory
Laboratory: Air Force Flight Dynamics Laboratory
Date of Publication: 1966-06
Pages: 108
Contract: AF 33(615)-1880
DoD Project: 1370
DoD Task: 137003
Identifier: AD0803266
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.
Provenance: Lockheed Martin Missiles & Fire Control
Author(s): Pollock, Samuel J.
Corporate Author(s): Air Force Flight Dynamics Laboratory
Laboratory: Air Force Flight Dynamics Laboratory
Date of Publication: 1966-06
Pages: 108
Contract: AF 33(615)-1880
DoD Project: 1370
DoD Task: 137003
Identifier: AD0803266
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.
Provenance: Lockheed Martin Missiles & Fire Control