DYNAMICS OF SHELL-LIKE LIFTING BODIES. PART II. THE EXPERIMENTAL INVESTIGATION.

Abstract : The vibration characteristics of nine typical shell configurations were experimentally determined. The models were of similar size and construction and consisted of three unstiffened models and six models stiffened with both longitudinal stringers and transverse flexible frames. Models were mounted with free-fixed boundary conditions. At least the twelve lowest natural frequencies and their corresponding mode shapes were determined and recorded for each model. A cursory investigation of panel response was performed upon selected configurations. A static investigation was conducted upon one configuration to obtain structural flexibility influence coefficients. The information obtained was examined briefly and some conclusions were drawn regarding the effects of several parameters including model crosssection (circular or elliptic), degree of longitudinal taper, skin panel thickness, number and spacing of axial and transverse stiffeners and number, orientation, and location of the exciting electromagnetic shakers. (Author)