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Cavin, R. K., III

Publications and source records attributed to Cavin, R. K., III.

8 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1978

Estimate of Orbiter static aeroelasticity properties via FLEXSTAB

The theory underlying the use of rigid-model experimental data in FLEXSTAB aeroelasticity calculations is summarized. A description is given of the aerodynamic and structural models used in the calculation of Space Shuttle Orbiter aeroelasticity properties during the re-entry phase. Experience gained with the use of pressure, nonlinear force and moment, and area-ratio correction methods in the Orbiter application is described and typical program output data are included. The inability of the program to correctly estimate differential control surface pressures and to accept external corrections for these terms is shown to be a major limitation in the Orbiter application.

Cavin, R. K., III↗
NASA NTRS1977

Hamilton's principle - Finite-element methods and flexible body dynamics

A variational formulation is given for the equations of motion for an unconstrained elastic body, and Hamilton's principle is used to derive the equations of motion and deformation of the body. Finite-element approximations are developed for these dynamical equations with respect to a body axis system satisfying the mean axis conditions. The free-body influence matrix for the body then is developed in terms of the finite-element model parameters.

Cavin, R. K., III↗
NASA NTRS1976

Eigenvalue properties of structural mean-axis systems

The authors review some of the properties of the pseudoinverse and oblique pseudoinverse of a linear transformation T from one finite-dimensional inner-product space into another, and then use these properties and a theorem of Milne (1968), which states that the oblique pseudoinverse can be expressed in terms of a weak generalized inverse and two projection operators, in order to compute a mean-axis influence coefficient matrix for the dynamic analysis of an elastic body. Some eigenvalue invariance properties of the mean-axis structural dynamics equations are demonstrated, and on the simple example of a uniform beam, it is shown that the finite frequencies and mode shapes of the mean axis structural system are identical to the nonzero frequencies and mode shapes of the free structure.

Cavin, R. K., III↗
NASA NTRS1975

User's guide to program FLEXSTAB

A manual is presented for correctly submitting program runs in aerodynamics on the UNIVAC 1108 computer system. All major program modules are included. Control cards are documented for the user's convenience, and card parameters are included in order to provide some idea as to reasonable time estimates for the program modules.

Cavin, R. K., III↗
NASA NTRS1974

The design, analysis and experimental evaluation of an elastic model wing

An elastic orbiter model was developed to evaluate the effectiveness of aeroelasticity computer programs. The elasticity properties were introduced by constructing beam-like straight wings for the wind tunnel model. A standard influence coefficient mathematical model was used to estimate aeroelastic effects analytically. In general good agreement was obtained between the empirical and analytical estimates of the deformed shape. However, in the static aeroelasticity case, it was found that the physical wing exhibited less bending and more twist than was predicted by theory.

Cavin, R. K., III↗