Accession Number : ADA308521

Title :   An Experimental Investigation of Nonlinear Behaviour of Beam an Plates Excited to High Levels of Dynamic Response.

Descriptive Note : Final technical rept. Oct 89-Oct 95,

Corporate Author : WRIGHT LAB WRIGHT-PATTERSON AFB OH FLIGHT DYNAMICS DIRECTORATE

Personal Author(s) : Wolfe, Howard F. ; Shroyer, Cynthia A. ; Brown, Dansen L. ; Simmons, Larry W.

PDF Url : ADA308521

Report Date : 31 OCT 1995

Pagination or Media Count : 470

Abstract : Dynamic tests were conducted utilizing clamped aluminum and composite beams and plates excited by shakers and acoustic progressive wave tubes. The total strains and the components, bending and axial and the displacements were measured with increasing levels of excitation. Bistable behaviour is observed with sinusoidal excitation for both the beams and plates. The beams randomly excited exhibit a slight frequency shift and peak broadening, which can be attributed to an increased stiffening or hard spring geometric nonlinearity. The plates randomly excited exhibit a greater frequency shift and peak broadening than the beams. The implications of nonlinear behaviour of beams and plates relative to fatigue lives are studied. The Miles single mode model is modified to account for multimodal response. Trends in the strain peek probability densities at low level and high levels of excitation are analyzed to determine the effects of axial strain on their shape. An effective multimodal cyclic frequency model is developed. A method to incorporate the effects of multimodal response of simple structures is presented with fatigue life estimates.

Descriptors :   *BEAMS(STRUCTURAL), *DYNAMIC RESPONSE, *PLATES, FATIGUE LIFE, EXCITATION, DISPLACEMENT, STRUCTURES, STIFFENING, COMPOSITE STRUCTURES, PROBABILITY DENSITY FUNCTIONS, CYCLES, ESTIMATES, NONLINEAR SYSTEMS, RESPONSE, LOW LEVEL, GEOMETRY, MULTIMODE, BEHAVIOR, MICROWAVE TUBES, DYNAMIC TESTS, SPRINGS, BISTABLE DEVICES, FREQUENCY SHIFT, SHAKING.

Subject Categories : Structural Engineering and Building Technology
      Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE