6926475987

Dept. of Theoretical and Applied Mechanics, Cornell Univ.. Ithaca. NY, Rept. No. SBI-AD-E001 629.137 pp (July 31.1983)

AD-A136 827

Key Words: Underwater sound, Sound waves. Wave radia* tion, Wave diffraction, Circuter shells, Cylindrical shells. Shelli

Research resultsare shown in three technical report! included in this report. The titles are: Acouttic Radiations of a Sub-merged Cylindrical Shell, Acoustic Radiation from a Sub-merged Finite Circular Cylindrical Shell Driven by a Harmonie Force and Attenuation Constanttand Phase Velocities of Eighteen Polymeric Materials.

SHOCK EXCITATION

(Also seo Nos. 1762.1817.1835. 1849. 1855)

84-1778

Reinforced Concrete Response to Near Field Explo* akma

T.M. Baseheart

Dept. of Civil and Environmental Engrg., Univ. of Cincinnati. OH. Rept. No. AFOSR-TR-83-1064. 49 pp (June 20, 1983)

AD-A135 876

Key Words: Reinforced concrete, Błast re«x>nse

From a review of experimental test results for concrete słabi subjected to convent»nal blast loading. various failure machaniims and their relationship to scaled breech distance ara documented. Analytical studies demonstrate the failure of membrana action when included with the rigid flexural analyiii of itructural re«x>nse. For morę intense blast pres-aurę intensities, procedures available in the literatura are deecribed.

VIBRATION EXCITATION

(AIsoseeNo. 1790)

84-1779

Complex Eigenvalues for the Stability of Couette Flow

R.C. Diprima and P. Hall

NASA langley Res. Ctr., Hampton. VA, Rept. No. NASA-CR-172251.49 pp (Oct 1983)

N84-13492

Key Words: Concentric structures, Cylinders, Fluid-induced excitation, Eigenvalue problems

The eigenvalue problem for the linaar stability of Couette flow between rotating concentric cylinders to exisymmetric disturbances is considered. It is shown by numerical calcula-tions and by formal perturbation methods that when the outer cylinder is at rest there exist complex eigenyalues corresponding to oscillatory damped disturbances. The structure of the first few eigenvalues in the spectrum is dis-cussed.

84-1780

Nonlinear Sloahing AnaJysis of Lkpiid in ConUiner* with Arbitrary Geometries

K. Ko mat su

Natl. Aerospace Lab., Tokyo. Japan, Rept. No. NAL/TR-757, 23 pp (1983)

PB84-137363 (In Japanese)

Key Words: Fluid-filled containers. Sloshing

A method is presented for calculating the nonlinear dynamie behavior of liquid in oontainers with arbitrary geometries. The present formulation is besed on the numerical perturbe-tion technique, which uses the orthogonality of the moda shapes and yields nonlinear coupled ordinary differential equations describing the temporal behavior. The linear modę shapes are obtained by numerical or analytical methods, and the equations describing the temporal behavior ara solved by the classical perturbation method.

84*1781

Laser Holographk Interferometry for an Unsteady Airfoil llndergoing Dynamie Stall

G. Lee. D.A. Buell, J.P. Licursi, and J.E. Craig NASA Ames Res. Ctr.. Moffett Field. CA. Al AA J.. 22 (4). pp 504-511 (Apr 1984) 10 figs. 10 refs

Key Words: Airfoil*. Stalling, Fluid-induced excitation

Laser holographlc interferometry was used to study a two-dimensional airfoil undergoing dynamie stall. The airfoil, fabricated from graphite fiber and epoxy, was testad at Mach numbers of 0.3 • 0.6. Reynolds numbers of 0.6 x 10⁶ to 2.0 x 10⁶, reduced frequancies of 0.016 - 0.16, and maan angles of attack of 0 • 10 deg with amplitudes of 10 deg. Oensity and pressura fields wara obtained from dual-plate interferograms. Doubla-pulte interferograms were also taken.