Showing papers by "Leif Kari published in 2013"
TL;DR: In this article, a novel dynamic model for a pretwisted rotating compressor blade mounted at an arbitrary stagger angle using general shell theory and including the rotational velocity is developed to study the eigenfrequencies and damping properties of the pre-strained rotating blade.
67 citations
TL;DR: In this paper, a dynamic model based on classical plate theory is presented to investigate the vibration behavior of a rotating blade at an arbitrary stagger angle and rotation speed, and the Hamilton's principle is applied to the model.
58 citations
TL;DR: In this article, a model for a multilayer rotating blade mounted at an arbitrary stagger angle using a quadratic layerwise theory is developed to study structural dynamics of the blade, particularly damping properties, using various coating layer configurations.
20 citations
TL;DR: In this article, a highly nonlinear model of the energy flow in a magneto-sensitive (MS) vibration isolation system is developed where it is possible to investigate the influences of MS rubber material parameters; magnetic field strength; MS isolator dimension and position; excitation force magnitude, position and frequency; engine mass, inertia and dimension and, finally, foundation inertance.
17 citations
TL;DR: In this article, a measurement study was conducted to investigate how changes in temperature, dynamic strain amplitude, and magnetic field strength influence the behavior of a magnetosensitive material, and the results indicated that the temperature is the most influential of the parameters as the material stiffens significantly when the temperature reaches the transition phase.
Abstract: A measurement study is conducted to investigate how changes in temperature, dynamic strain amplitude, and magnetic field strength influence the behavior of a magnetosensitive material. During the measurements seven temperatures, four magnetic fields, and three dynamic strain amplitudes are used over a 200 to 800 Hz frequency range. The results indicate a decrease in shear modulus magnitude as the dynamic strain amplitude is increased. As the frequency and magnetic field strength increases the magnitude increases. However, the measurements indicate that the temperature is the most influential of the parameters as the material stiffens significantly when the temperature reaches the transition phase. Understanding the temperature dependence increases the knowledge of magnetosensitive materials.
12 citations
TL;DR: In this paper, the dynamic stiffness of hollowed cylindrical vibration isolators using a wave-guide modelling approach is given, where the isolators consist of rubber and metal elements in series and the boundary conditions at the lateral and radial surfaces of each rubber component are locally non-mixed and simultaneously satisfied by using the modes corresponding to the dispersion relation for axial waves in infinite hollow cylinders.
11 citations
TL;DR: In this paper, the indirect energy flow measurement method is extended to cover highly nonlinear, frequency, amplitude and magnetic field dependent magneto-sensitive natural rubber isolators applied in a real vib...
6 citations
03 Jun 2013
TL;DR: In this paper, a non-linear constitutive model, depending upon the frequency, magnetic field strength, dynamic strain amplitude and static prestrain, is presented and experimentally verified.
Abstract: Magneto-sensitive elastomers consist of irregularly shaped, magnetically polarizable iron particles embedded in a rubber matrix, that instantly and reversibly alter their mechanical properties under the influence of an external magnetic field. A non-linear constitutive model, the stress depending upon the frequency, magnetic field strength, dynamic strain amplitude and static prestrain, is presented and experimentally verified. Finally, magneto-sensitive elastomers applied in a vibration isolation system are experimentally investigated with a focus on the energy flow transmitted into the receiving structure. The paper covers magneto-sensitive elastomer modeling, experiments and applications.