This paper deals with a theoretical analysis of the dynamic response of shear deformable symmetrically laminated rectangular composite flat panels exposed to sonic boom and explosive blast loadings. The pertinent governing equations incorporating transverse shear deformation, transverse normal stress, as well as the higher-order effects are solved by using the integral-transform technique. The obtained results are compared with their counterparts obtained within the framework of the first-order transverse shear deformation and the classical plate theories and some conclusions concerning their range of applicability are outlined. The paper also contains a detailed analysis of the influence played by the various parameters characterizing the considered pressure pulses as well as the material and geometry of the plate.

Response of laminated composite flat panels to sonic boom and explosive blast loadings

Elementary fluid mechanics

The problem of the dynamic response of sandwich flat panels exposed to blast loadings is addressed. The sandwich model includes a number of non-classical effects such as the anisotropy and heterogeneity of face sheets, transverse orthotropy of the core layer, the geometrical non-linearities considered in the von Karman sense, as well as the initial geometric imperfections. As concerns the blast pulses considered in this analysis, these are due to either an underwater/in-air explosion, or are due to a pressure wave traveling across the panel span. Implications of the explosive charge, stand-off distance, directionality property of face sheets material, damping ratio, geometric non-linearity, initial geometric imperfection, and of the characteristics of the blast, on dynamic response and dynamic magnification factor are put into evidence via a parametric study, and pertinent conclusions are outlined.

Linear and non-linear dynamic response of sandwich panels to blast loading

The paper deals with the dynamic response of anisotropic cantilevered thin-walled beams exposed to blast and sonic boom loadings. The structural model used in this study incorporates a number of nonclassical effects such as transverse shear and warping inhibition. Moreover, implementation of a specific ply-angle scheme in each constituent lamina results in elastic cross-couplings beneficial from the response behavior point of view. The influence of these effects is highlighted and the efficiency of the tailoring technique toward enhancing the dynamic response to various overpressure signatures is demonstrated.

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Dynamic Response of Cantilevered Thin-Walled Beams to Blast and Sonic-Boom Loadings

Optical observations of meteors generating infrasound—I: Acoustic signal identification and phenomenology

Analytical study of sonic boom from supersonic projectiles

: Sutherland's theoretical expression for the absolute or dynamic viscosity of a gas has been modified to represent experimental viscosity data for air. The resulting semi-empirical equation accurately describes measured viscosities of air for temperatures ranging from the boiling point at 78 K to molecular dissociating conditions at 2500 K. Discrepancies between measured values and semi-empirical results rarely exceed 2%. Other more limited expressions for the viscosity of air are also compared to measured viscosity data and discussed. (Author)

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A Semi-Empirical Equation for the Viscosity of Air.

dimensional cases difficult and in some cases impossible by other methods. An additional advantage is that the procedure works as well in the multidimensional case, including nonlinear terms, which are then written as sums of the appropriate Adomian polynomials as discussed in Ref. 1. The procedure is also easily extended to Vu =f(x,y,z) + ku or even Vu + Nu =f(x,y,z) + ku where Nu is an analytic term.

David V. Ritzel

Papers

Analytical study of sonic boom from supersonic projectiles

A Semi-Empirical Equation for the Viscosity of Air.

Numerical evaluation of Whitham's F-function for supersonic projectiles