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Full-Text Articles in Mechanical Engineering

Three Dimensional Stress Intensity Factor For Large Arrays Of Radial Internal Surface Cracks In A Cylindrical Pressure Vessel, Javier Pierola Nov 1993

Three Dimensional Stress Intensity Factor For Large Arrays Of Radial Internal Surface Cracks In A Cylindrical Pressure Vessel, Javier Pierola

FIU Electronic Theses and Dissertations

The objective of this study is to present the mode I stress intensity factor distribution (SIF) along the crack-front for a wide array of semicircular and semi-elliptical surface cracks inside of a pressurized thick-walled cylinder. A three-dimensional finite element package ANSYS is used to evaluate the SIF for multicracked cylinder with number of cracks from n=1 to 128, the ratio of crack-depth to the wall thickness a/t=0.05 to 0.6, the ellipticity of the crack (the crack-depth to the semi-crack length) a/c=0.2 to 1.5, the ratio of the outer to the inner ...


Performance Assessment Of Prosthetic Heart Valves Using Orifice Area Formulae And The Energy Index Method, Flavio Ballerini Souza Campos Nov 1993

Performance Assessment Of Prosthetic Heart Valves Using Orifice Area Formulae And The Energy Index Method, Flavio Ballerini Souza Campos

FIU Electronic Theses and Dissertations

Valve function is commonly assessed by effective orifice area (EOA) estimates using equations derived from conservation of mass and energy. Errors have been found with the method due to difficulties in determining the valve’s coefficient of discharge (Cd). The Cd, a factor that corrects the EOA for losses in the valvular wake region, has been shown previously to vary with the Reynolds number and valve geometry. In this study, a Cardio-Vascular Duplicator (CVD) is used to determine the Cd for three types of mitral valves, operating in modes ranging from normal to severely stenotic. Since orifice area methods do ...


Numerical Analysis Of The Pullout Problem Of A Fiber Embedded In A Matrix : Comparison With An Approximate Analytical Solution, Ivan Enrique Esparragoza Jul 1993

Numerical Analysis Of The Pullout Problem Of A Fiber Embedded In A Matrix : Comparison With An Approximate Analytical Solution, Ivan Enrique Esparragoza

FIU Electronic Theses and Dissertations

The classical problem of pullout of a long elastic rectilinear round bar (fiber) embedded in an elastic half-space (matrix) is considered before and while local debonding occurs. An approximate analytical solution derived from the elasticity theory, the intuitive Saint Venant's principle, the idea of boundary layer in hydrodynamics, and invariant Γ-integrals is presented. The problem is analyzed numerically by means of the finite element method using the ANSYS program. The cases of loading before and after the initiation of the debonding are studied. Both approaches, analytical and numerical, are compared in order to establish the concidence between them. The ...