J. L. Nowinski

Bio: J. L. Nowinski is an academic researcher from University of Delaware. The author has contributed to research in topics: Galerkin method & Deflection (engineering). The author has an hindex of 3, co-authored 4 publications receiving 164 citations.

Nonlinear transverse vibrations of orthotropic cylindrical shells

Abstract: h,a,l qQ p i,j Nonlinear transverse vibrations of elastic orthotropic shells are investigated using von Karman-Tsien equations generalized to dynamic and orthotropic case. The deflection function is chosen in a simple separable form and the stress function is determined from the compatibility equation. The governing equation for the time function is derived by Galerkin's procedure, and its solution discussed for two types of orthotropy and for the isotropic case. A sharp decrease of the period of nonlinear vibrations with an increasing amplitude is corroborated, the mode pattern influencing the period more than the degree of anisotropy . Parenthetically, the influence of anisotropy on free linear vibrations and on the buckling under normal pressure is discussed.

Bone Articulations as Systems of Poroelastic Bodies in Contact

Abstract: Two-phase poroelastic material is taken as a model of a living bone, in the sense that the osseous tissue is considered as a perfectly elastic solid and the fluid substances filling the cavities as a viscous fluid. Using Heinrich-Desoyer equations, derived from the consolidation theory, equations for the normal displacements on the boundary of a half-infinite poroelastic solid subjected to a normal concentrated force are found. Theory identical with Hertz's theory for elastic bodies in contact is applied to the contact problem of poroelastic bodies. Two particular cases are analyzed in more detail: a) when the shape of the poroelastic bodies at the point of contact is spherical, whereas one of the bodies represent a spherical seat; and b) when the spherical seat becomes flat and its material perfectly rigid (a metallic prosthesis). Viscoelastic properties of the adopted bone model appear to be in full agreement with the experimental findings of Sedlin.

Large-amplitude oscillations of oblique panels with an initial curvature

Abstract: Von Karman field equations for flexible oblique plates with an initial curvature are extended to a dynamical case Using series iepresentation of initial and additional deflections and Galerkin's procedure, the governing equation for an admissible mode time function is established Using this single assumed modal deflection, and assuming built-in edge fiee to move in the inplane directions, the following particular cases are discussed: buckling of an oblique plate under uniaxial compressive load, free linear vibrations of a square plate, large deflections of a uniformly loaded square plate, snap-through phenomena of a curved oblique plate under uniform transverse load, and free nonlinear vibrations A numeiical example concerning a rhombic plate is discussed in more detail The well-known fact of a decrease of the period of nonlinear vibrations with an increasing amplitude is corroborated, this relation being less pronounced for larger sweep angles

Liquid Sloshing Dynamics

Abstract: Preface Introduction 1. Fluid field equations and modal analysis in rigid containers 2. Linear forced sloshing 3. Viscous damping and sloshing suppression devices 4. Weakly nonlinear lateral sloshing 5. Equivalent mechanical models 6. Parametric sloshing (Faraday's waves) 7. Dynamics of liquid sloshing impact 8. Linear interaction of liquid sloshing with elastic containers 9. Nonlinear interaction under external and parametric excitations 10. Interactions with support structures and tuned sloshing absorbers 11. Dynamics of rotating fluids 12. Microgravity sloshing dynamics Bibliography Index.

Nonlinear Vibrations and Stability of Shells and Plates

Abstract: Introduction. 1. Nonlinear theories of elasticity of plates and shells 2. Nonlinear theories of doubly curved shells for conventional and advanced materials 3. Introduction to nonlinear dynamics 4. Vibrations of rectangular plates 5. Vibrations of empty and fluid-filled circular cylindrical 6. Reduced order models: proper orthogonal decomposition and nonlinear normal modes 7. Comparison of different shell theories for nonlinear vibrations and stability of circular cylindrical shells 8. Effect of boundary conditions on a large-amplitude vibrations of circular cylindrical shells 9. Vibrations of circular cylindrical panels with different boundary conditions 10. Nonlinear vibrations and stability of doubly-curved shallow-shells: isotropic and laminated materials 11. Meshless discretization of plates and shells of complex shapes by using the R-functions 12. Vibrations of circular plates and rotating disks 13. Nonlinear stability of circular cylindrical shells under static and dynamic axial loads 14. Nonlinear stability and vibrations of circular shells conveying flow 15. Nonlinear supersonic flutter of circular cylindrical shells with imperfections.