253 research outputs found
Aerodynamic Characteristics of Two All-movable Wings Tested in the Presence of a Fuselage at a Mach Number of 1.9
Effect of Reflex Camber on the Aerodynamic Characteristics of a Highly Tapered Moderately Swept-back Wing at Reynolds Numbers up to 8,000,000
Deformation and crystallization of Zr-based amorphous alloys in homogeneous flow regime
The purpose of this study is to experimentally investigate the interaction of inelastic deformation and microstructural changes of two Zr-based bulk metallic glasses (BMGs): Zr_(41.25)Ti_(13.75)Cu_(12.5)Ni_(10)Be_(22.5) (commercially designated as Vitreloy 1 or Vit1) and Zr_(46.75)Ti_(8.25)Cu_(7.5)Ni_(10)Be_(27.5) (Vitreloy 4, Vit4). High-temperature uniaxial compression tests were performed on the two Zr alloys at various strain rates, followed by structural characterization using differential scanning calorimetry (DSC) and transmission electron microscopy (TEM). Two distinct modes of mechanically induced atomic disordering in the two alloys were observed, with Vit1 featuring clear phase separation and crystallization after deformation as observed with TEM, while Vit4 showing only structural relaxation with no crystallization. The influence of the structural changes on the mechanical behaviors of the two materials was further investigated by jump-in-strain-rate tests, and flow softening was observed in Vit4. A free volume theory was applied to explain the deformation behaviors, and the activation volumes were calculated for both alloys
Investigation of Pressure Distribution over an Extended Leading-Edge Flap on a 42 Degrees Sweptback Wing
Pressure distribution over an extended leading-edge flap on a 42 degree swept-back wing was investigated. Results indicate that the flap normal-force coefficient increased almost linearly with the angle of attack to a maximum value of 3.25. The maximum section normal-force coefficient was located about 30 percent of the flap span outboard of the inboard end and had a value of 3.75. Peak negative pressures built up at the flap leading edge as the angle of attack was increased and caused the chordwise location of the flap center of pressure to be move forward
Effects of a Fuselage and Various High-lift and Stall-control Flaps on Aerodynamic Characteristics in Pitch of an NACA 64-series 40 Degree Swept-back Wing
Low-speed characteristics in pitch of a 34 degree sweptforward wing with circular-arc airfoil sections
Preliminary investigation at a Mach number of 1.9 and a Reynolds number of 2,200,000 of three ailerons applicable to the Bell XS-2 airplane design
Correlation between fracture surface morphology and toughness in Zr-based bulk metallic glasses
Fracture surfaces of Zr-based bulk metallic glasses of various compositions tested in the as-cast and annealed conditions were analyzed using scanning electron microscopy. The tougher samples have shown highly jagged patterns at the beginning stage of crack propagation, and the length and roughness of this jagged pattern correlate well with the measured fracture toughness values. These jagged patterns, the main source of energy dissipation in the sample, are attributed to the formation of shear bands inside the sample. This observation provides strong evidence of significant “plastic zone” screening at the crack tip
Control effectiveness and hinge-moment measurements at a Mach number of 1.9 of a nose flap and trailing-edge flap on a highly tapered low- aspect-ratio wing
Control Effectiveness and Hinge-moment Characteristics of a Tip Control Surface on a Low-aspect-ratio Pointed Wing at a Mach Number of 1.9
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