Showing papers by "Langley Research Center published in 1969"
TL;DR: In this article, the effects of stress ratio on fatigue-crack growth were analyzed using Paris' stress-intensity analysis, and the results from the R = 0 tests on a plot of rate against stressintensity range.
110Â citations
90Â citations
TL;DR: Spherical caps axisymmetric static and dynamic buckling under load, using axismmetric nonlinear elastic shell theory approximation and finite difference equations, were used in this paper.
Abstract: Spherical caps axisymmetric static and dynamic buckling under load, using axisymmetric nonlinear elastic shell theory approximation and finite difference equations
81Â citations
01 Aug 1969
76Â citations
TL;DR: In this article, the authors proposed a compressed hypersonic turbulent boundary layers solution by finite difference method, relating mixing length to velocity profile shape factor and the mixing length with the shape factor.
Abstract: Compressible hypersonic turbulent boundary layers solution by finite difference method, relating mixing length to velocity profile shape factor
72Â citations
TL;DR: In this paper, a computer model for evolution investigation of disks of stars, discussing methods to obtain gravitational potential, is presented, where the authors also discuss methods for obtaining gravitational potential.
61Â citations
01 Oct 1969
TL;DR: Matrix theorem and application to establishing independent coordinates for complex dynamical systems with constraints as discussed by the authors, where the matrix theorem is used to establish independent coordinates of dynamical system with constraints and constraints.
Abstract: Matrix theorem and application to establishing independent coordinates for complex dynamical systems with constraints
60Â citations
01 Oct 1969
TL;DR: In this paper, the leading edge suction analogy for predicting low speed lift and drag due-to-lift characteristics of sharp edge delta and related wing planforms was used to predict a low speed aircraft.
Abstract: Leading edge suction analogy for predicting low speed lift and drag-due-to-lift characteristics of sharp edge delta and related wing planforms
57Â citations
01 Jan 1969
TL;DR: Transonic wind tunnel studies on airfoil to determine effects of Reynolds number and boundary layer transition location on shock induced separated flow were conducted by as discussed by the authors, where the authors found that Reynolds number was positively associated with separation flow.
Abstract: Transonic wind tunnel studies on airfoil to determine effects of Reynolds number and boundary layer transition location on shock induced separated flow
49Â citations
01 Feb 1969
TL;DR: Computer program for calculating wall interference factors of V/STOL aircraft and conventional airplanes.
Abstract: Computer program for calculating wall interference factors of V/STOL aircraft and conventional airplanes
47Â citations
01 Jan 1969
TL;DR: Finite element method for computing natural frequencies and mode shapes of thin shells of revolution is presented in this paper, where a finite element method is used to compute the frequency and mode of a shell of revolution.
Abstract: Finite element method for computing natural frequencies and mode shapes of thin shells of revolution
01 Oct 1969
TL;DR: Flow field and drag characteristics of several laminar boundary layer tripping elements in hypersonic flow were analyzed in this article, showing that the tripping element has better performance than other trippers.
Abstract: Flow field and drag characteristics of several laminar boundary layer tripping element in hypersonic flow
TL;DR: In this article, structural and aerodynamic developments in attached inflatable decelerators for deployment of payload at supersonic speeds were presented for the deployment of a payload at subsonic speeds.
Abstract: Structural and aerodynamic developments in attached inflatable decelerators for deployment of payload at supersonic speeds
01 Jul 1969
TL;DR: Load distribution calculations for subsonic compressible flow of arbitrary wings and lifting surfaces were performed in this paper for the case of a single wing and a single lifting surface with arbitrary lifting surface.
Abstract: Load distribution calculations for subsonic compressible flow of arbitrary wings and lifting surfaces
05 Oct 1969
01 Jan 1969
TL;DR: In this article, the effect of unit Reynolds number, nose bluntness, angle of attack, and roughness on transition on 5 degree half-angle cone at Mach 8 was investigated.
Abstract: Effect of unit Reynolds number, nose bluntness, angle of attack, and roughness on transition on 5 degree half-angle cone at Mach 8
01 Aug 1969
01 Mar 1969
01 Oct 1969
TL;DR: In this paper, stress distributions around single and double cuts (groups of adjacent broken filaments) in an idealized composite sheet consisting of parallel tension-carrying filaments embedded in a shear carrying matrix are analyzed by an influence function technique.
Abstract: : Stress distributions around single and double cuts (groups of adjacent broken filaments) in an idealized composite sheet consisting of parallel tension-carrying filaments embedded in a shear-carrying matrix are analyzed by an influence-function technique Static-load concentration factors for two equal collinear cuts are obtained and are compared with some related results for a single cut Dynamic-load concentration factors, corresponding to sudden breaking ot filaments, also are obtained tor two ot the simplest double-cut cases In addition, matrix shear forces are investigated for some single-cut and double-cut cases Finally, loads in broken filaments are calculated for some single-cut cases, and their implications in some current failure analyses of composite materials are briefly discussed The interaction between two collinear cuts is essentially local and is roughly confined to separation distances on the order of the cut length For closely spaced cuts, however, the interaction between cuts is seen to be pronounced For a single cut, an expression analogous to the filament load concentration factor is obtained for the maximum shear force in the matrix as a function ot the cut length The results suggest that for some combinations of constituent mechanical properties, the composite might be more susceptible to filament tensile failure at some cut lengths, but more susceptible to matrix shear failure at others (MM)
01 Apr 1969
TL;DR: Ablation behavior of heat shield of Apollo command module over wide range of thermal environments was studied in this article, showing that the heat shield exhibited different behavior in different thermal environments.
Abstract: Ablation behavior of heat shield of Apollo command module over wide range of thermal environments
01 Apr 1969
01 Dec 1969
01 Jan 1969
TL;DR: In this article, the effect of trip geometry, size, and location on the position of transition at local Mach numbers up to 8.5 were investigated, where trip-produced multiple vortex filaments were assumed to be responsible for introducing the disturbances that lead to transition.
Abstract: Experiments on the effect of trip geometry, size, and location on the position of transition at local Mach numbers up to 8.5 are presented. The pressure drag of the trip is investigated at local Mach numbers of 4.7 and 5.5. Based on test results, a flow model was constructed which includes trip-produced multiple vortex filaments similar to those found at supersonic speeds that are assumed to be responsible for introducing the disturbances that lead to transition. The Reynolds number based on the distance from the leading edge to the roughness position as well as Mach number and wall-to-total temperature ratio should be considered in choosing the smallest effective trip size. The effect of trip shape on the position of transition at hypersonic speeds is small; however, certain shapes exhibit the advantageous characteristic of having drag coefficients which were relatively independent of roughness height over a restricted range of the variables tested.
01 Jul 1969
TL;DR: In this paper, the TE 03 mode can be strongly excited in the plug, resulting in a resonant perturbation of the admittance of a rectangular aperture antenna, loaded with a dielectric plug.
Abstract: The admittance of a rectangular aperture antenna, loaded with a dielectric plug, was previously formulated as a boundary-value problem [1], and the results are summarized. Calculations and supporting measurements show that a TE 03 mode can be strongly excited in the plug, resulting in a resonant perturbation of the admittance.
01 Jun 1969
TL;DR: In this article, the authors studied the stress-strain behavior at notch roots in sheet specimens under constant amplitude loading and showed that the stress strain at the notch roots at sheet specimens is linear in the length of the root.
Abstract: Elastoplastic stress-strain behavior at notch roots in sheet specimens under constant amplitude loading
01 Feb 1969
01 Sep 1969