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Applied Mechanics Commons

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Articles 31 - 39 of 39

Full-Text Articles in Applied Mechanics

Studies Of Dynamic Crack Propagation And Crack Branching With Peridynamics, Youn Doh Ha Ph.D., Florin Bobaru Ph.D. Jul 2013

Studies Of Dynamic Crack Propagation And Crack Branching With Peridynamics, Youn Doh Ha Ph.D., Florin Bobaru Ph.D.

Florin Bobaru Ph.D.

In this paper we discuss the peridynamic analysis of dynamic crack branching in brittle materials and show results of convergence studies under uniform grid refinement (m-convergence) and under decreasing the peridynamic horizon (δ-convergence). Comparisons with experimentally obtained values are made for the crack-tip propagation speed with three different peridynamic horizons.We also analyze the influence of the particular shape of themicro-modulus function and of different materials (Duran 50 glass and soda-lime glass) on the crack propagation behavior. We show that the peridynamic solution for this problem captures all the main features, observed experimentally, of dynamic crack propagation and branching, as well …


Us Patent 8,338,976: Magnetically­-Levitated Wind Turbine, Sanza Kazadi Dec 2012

Us Patent 8,338,976: Magnetically­-Levitated Wind Turbine, Sanza Kazadi

Sanza Kazadi

A novel wind turbine configuration utilizes a permanent magnetic male and female levitation support for magnetic levitation. The novel wind turbine has a female part attached to a payload which is magnetically levitated above a male part of the levitation support. The female part and the payload are further operatively attached to a vertical axle structure which is held stationary by a point of contact. The point of contact and the vertical axle structure provide a stable axis of rotation for the payload and the female part, which can be rotated with near ­zero friction due to the magnetic repulsion …


Stochastic Optimal Control In Nonlinear Systems, Celestin Nkundineza Nov 2012

Stochastic Optimal Control In Nonlinear Systems, Celestin Nkundineza

Celestin Nkundineza

Stochastic control is an important area of research in engineering systems that undergo disturbances. Controlling individual states in such systems is critical. The present investigation is concerned with the application of the stochastic optimal control strategy developed by To (2010) and its implementation as well as providing computed results of linear and nonlinear systems under stationary and nonstationary random excitations. In the strategy the feedback matrix is designed based on the achievement of the objectives for individual states in the system through the application of the Lyapunov equation for the system. Each diagonal element in the gain or associated gain …


Crack Identification By Multifractal Analysis Of A Dynamic Rotor Response, Grzegorz Litak, Jerzy Sawicki Nov 2012

Crack Identification By Multifractal Analysis Of A Dynamic Rotor Response, Grzegorz Litak, Jerzy Sawicki

Jerzy T. Sawicki

Multifractal analysis has been used to diagnose cracked and healthy rotors. Is has been shown that the complexity and regularity criteria of the dynamical systems defined by the multiple scaling of the time series can indicate the damages of the rotating shaft. Relation to the standard power spectrum technique has been also discussed.


Investigation Of Thermomechanical Effects Of Lighting Conditions On Canvas Paintings By Laser Shearography, Morteza Khaleghi, Ivo Dobrev, Philip Klausmeyer, Ellery Harrington, Cosme Furlong Jul 2012

Investigation Of Thermomechanical Effects Of Lighting Conditions On Canvas Paintings By Laser Shearography, Morteza Khaleghi, Ivo Dobrev, Philip Klausmeyer, Ellery Harrington, Cosme Furlong

Morteza Khaleghi

Quantitative techniques to characterize thermomechanical effects of light on canvas paintings are necessary in order to better understand the deleterious effects that light has on precious art collections in museum exhibitions. In this paper, we present advances in the development of a customized laser shearography system for temporal characterization of in-plane displacements of canvas paintings when subjected to specific lighting conditions. The shearography system is synchronized with a thermal IR camera and concomitant measurements of derivatives of displacements along two orthogonal shearing directions as well as thermal fields are performed. Due to the nature of the measurements, we have developed …


Us Patent 8,149,079: Magnetically Levitated Mount, Sanza Kazadi Apr 2012

Us Patent 8,149,079: Magnetically Levitated Mount, Sanza Kazadi

Sanza Kazadi

A levitating mount apparatus is provided which utilizes a permanent magnetic male and female levitation support as described in U.S. Pat. No. 7,501,922. The mount has two general forms. In one general class, the mount is attached to an axle aligned with the axis of symmetry of the female part of the permanent magnetic male and female levitation support. In the second class, the female part of the permanent magnetic male and female levitations support is attached to the bottom of the mount, and no axle is utilized. The mount is stabilized using a stationary support structure which has limited …


Reverse Logic - Safety Of Spent Nuclear Fuel Disposal, Antti Lempinen, Marianne Silvan-Lempinen Dec 2010

Reverse Logic - Safety Of Spent Nuclear Fuel Disposal, Antti Lempinen, Marianne Silvan-Lempinen

Antti Lempinen

No abstract provided.


The Homotopy Perturbation Method For Free Vibration Analysis Of Beam On Elastic Foundation, Baki Ozturk, Safa Bozkurt Coskun Dec 2010

The Homotopy Perturbation Method For Free Vibration Analysis Of Beam On Elastic Foundation, Baki Ozturk, Safa Bozkurt Coskun

Safa Bozkurt Coskun

In this study, the homotopy perturbation method (HPM) is applied to free vibration analysis of beam on elastic foundation. This numerical method is applied on three different axially loaded cases, namely: 1) one end fixed, the other end simply supported; 2) both ends fixed and 3) both ends simply supported cases. Analytical solutions and frequency factors are evaluated for different ratios of axial load N acting on the beam to Euler buckling load, Nr. The application of HPM for the particular problem in this study gives results which are in excellent agreement with both analytical solutions and the variational iteration …


Us Patent 7,501,922: Permanent Magnetic Male And Female Levitation Supports, Sanza Kazadi Mar 2009

Us Patent 7,501,922: Permanent Magnetic Male And Female Levitation Supports, Sanza Kazadi

Sanza Kazadi

A  permanent   magnetic   male   and   female   levitation  support  has   a  first   part  with   a  cavity   and   a  plurality   of  retainment   mechanisms incorporated therein, and a plurality of first permanent magnets evenly distributed around the perimeter of the cavity and held in place by the retainment mechanisms, wherein the first permanent magnets produce a first rotationally invariant magnetic field around a first axis.  A second part is rigidly connected to a base and produces a second rotationally invariant magnetic field around a second axis. When the  
first axis is aligned with the second axis, the first magnetic field and the …