Eigen vector buckling based boundary analysis method for free vibration of rectangular thin plates
The main research topic of this paper is the application of the finite element method boundary analysis theory to study the stability of plate in irregular shape. First of all, the basic theory of free vibration of elastic plate and the basic equations of elastodynamics are introduced, and the governing equation of small deflection of free vibration of plate is given. Secondly, the finite element method boundary analysis method is introduced in details, including the basic idea and analysis steps of finite element method boundary analysis, and some element types, so as to lay a theoretical foundation for better understanding of finite element method boundary analysis method and application of it to analyze the stability of plate. At last, finite element method boundary analysis is applied to analyze the stability of plate, among which, the structural analysis types in ANSYS software and its analysis steps are introduced, and buckling (eigenvalues) analysis in ANSYS software is mainly introduced, and the effective performance of algorithm is verified by applying ANSYS software.
Weak form quadrature element method for accurate free vibration analysis of thin skew plates
In this paper, a novel weak form quadrature element method (QEM) is proposed for accurate free transverse vibration analysis of thin isotropic skew plates with general boundary conditions. In the formulation of the stiffness matrix, the first and second order derivatives of the shape functions at integration points are computed explicitly by using the differential quadrature rule. This leads to a great simplicity in formulating an N × N -node quadrature plate element and a large reduction of programming effort. Different from the existing weak form quadrature element method or differential quadrature finite element method, the element nodes can be either the same or different from the integration points. Convergence studies are performed. Free vibration of skew thin plates with various skew angles and different combinations of boundary conditions is analyzed. It is shown that although the assumed displacement field does not explicitly consider the bending moment singularities at the obtuse angles, the proposed QEM can yield accurate frequencies even for the thin isotropic skew plate with large skew angles.
Solitary Orbital Paget Disease: A Case Report
Purpose: To describe the clinical findings in a patient who had developed painless supraorbital prominence. Methods: Clinical and histopathological findings of the case are reviewed and presented. Results: The patient had an isolated histologically confirmed Paget disease of the orbit. Local excision of the lesion was performed. Conclusion: Paget disease can present not only as a diffuse process but also as a painless, solitary lesion of the orbit.