Accession Number : AD0709239

Title :   ON VIBRATIONS OF HETEROGENEOUS ORTHOTROPIC CYLINDRICAL SHELLS,

Corporate Author : TECHNION - ISRAEL INST OF TECH HAIFA DEPT OF MECHANICS

Personal Author(s) : Stavsky,Yehuda ; Loewy,Raphael

Report Date : AUG 1969

Pagination or Media Count : 46

Abstract : A refined Love-type theory of motion is established for orthotropic composite cylindrical shells. An extensional-rotational dynamic coupling effect is shown to exist, expressed by R sub 1 inertia terms. An extended version of the theory is formulated to account for dynamic stability problems involving time-dependent and non-conservative forces. The frequency spectra of free natural vibrations are investigated for numerous layered shells, using Love and Donnell-type theories, including the effects of R sub 1 terms. Heterogeneity is found to considerably affect the results for the natural frequencies; for certain shells produced of a fixed amount of materials, differing only in their arrangement, a suitable composition raises the lowest frequency by a factor of 1.50. A study of the error involved in a Donnell-type theory is carried out. For length-to-radius ratios of about 5 the resulting first lowest frequency may be higher by a factor of 1.10 than the one given by the present Love-type theory. However, when higher frequencies are considered this factor may go down to 0.66. These deviations are, in several instances, associated with different predictions of the corresponding lowest characteristic mode shapes. Higher errors, strongly depending on shell heterogeneity, are noted as the length-to-radius ratios increase beyond 5.

Descriptors :   (*SHELLS(STRUCTURAL FORMS), VIBRATION), CYLINDRICAL BODIES, ELASTIC SHELLS, RESONANT FREQUENCY, STRESSES, ELASTIC PROPERTIES, STRAIN(MECHANICS), EQUATIONS OF MOTION, ISRAEL

Subject Categories : Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE