Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
Results
Showing 1 to 20 of 37 for “"Damping coefficients"”.
-
A simulation scheme for strategic distribution of damping coefficients
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2000.
-
Experimental determination of damping coefficients in the stability of aeroplanes
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Aeronautical Engineering, 1915.
-
Analysis of tilting-pad oil seals for high pressure centrifugal compressors
… grooved seal element. The eight stiffness and damping coefficients which represent the hydrodynamic forces between the journal and the seal assembly are computed by an automated computer code for evaluation of both the standard ring seal and the tilting pad elements. Both synchronous and …
-
Nonlinear beam-based vibration energy harvesters and load cells
… and resistant to power decay when parasitic damping is present than the IDOF and 2DOF linear systems. These significant advantages are caused by the 2DOF nonlinear system harvesting its optimal power at large electromagnetic damping coefficients, whereas the optimal power generation for the …
-
Wind Turbine Parameter Calibration Using Deep Learning Approaches
<p>The inertia and damping coefficients are critical to understanding the workings of a wind turbine, especially when it is in a transient state. However, many manufacturers do not provide this information about their turbines, requiring people to estimate these values themselves. This research …
-
Advanced experimental modelling of hydrodynamic and aerodynamic wakes in floating offshore wind turbines using particle image velocimetry
… (CFD) methods are employed to calibrate viscous damping coefficients in POT models to improve accuracy, their high computational cost limits practical use. The reliability of simplified CFD models for refining POT viscous damping remains unexplored, representing a clear knowledge gap. …
-
A simplified representation of damping force in lumped-parameter systems with linear and nonlinear damping
… analysis techniques which determine the damping coefficients for each sub-system in the mathematical model of linear multi-degree-of-freedom systems, and to determine modal dissipation functions for nonlinear systems. For the purpose of this study, typical aerospace vehicle structure is …
-
A frequency domain strip theory applied to the seakeeping of the Zumwalt-Class destroyer
… range. SMA calculates sectional added mass and damping coefficients first. Then, it calculates excitation forces and moments acting on a ship advancing at constant forward speed with arbitrary heading for sway, heave, roll, pitch and yaw modes of motion. Finally, SMA evaluates Response Amplitude …
-
Time domain simulation of hydroelastic response of ships in large amplitude waves
… forces are due to changes in added mass and damping coefficients, as well as restoring and incident wave forces, all evaluated over the instantaneous wetted surface. Non-linear forces due to slamming (bottom impact and flare) and green water (treated in a quasi-static manner) are also added. …
-
NUMERICAL INVESTIGATION OF THE PERFORMANCE OF FLUID FILM JOURNAL BEARINGS
… The attitude angle, load capacity, stiffness coefficients and damping coefficients are computed. The effects of groove number, groove angle, groove depth, ridge/groove width ratio as well as bearing length on the performances of the bearing are presented in details. Some results are compared …
-
A Numerical Method for Computing Radially Symmetric Solutions of a Dissipative Nonlinear Modified Klein-Gordon Equation
… the origin, with constant internal and external damping coefficients and nonlinear term of the form G' (w) = w ^p, with p an odd number greater than 1. We prove that our scheme is consistent of quadratic order, and provide a necessary condition for it to be stable order n. Part of our study will …
-
Measured and Predicted Rotor-Pad Transfer Functions for a Rocker-Pivot Tilting-Pad Journal Bearing
… have compared predicted stiffness and damping coefficients for tilting-pad journal bearings (TPJBs) to measurements. Most have found that direct damping is consistently overpredicted. The thrust of this research is to explain the difference between measured and predicted stiffness and …
-
Non-linear finite element thermo-hydrodynamic analysis of oil ring seals used in high pressure centrifugal compressors
… in the cross-coupled stiffness and direct damping coefficients obtained from this analysis and the finite difference analysis are 5.1 % and 1.5 % respectively. For eccentric seals, use of the true temperature distribution gives significantly different results. At an operating eccentricity …
-
Modeling and Parameter Estimation of Spacecraft Lateral Fuel Slosh
… the pendulum model stiffness constants and damping coefficients.</p>
-
Numerical Analysis and Applications of the Process of Nonlinear Supratransmission in Mechanical Systems of Coupled Oscillators with Damping
… the origin, where the internal and external damping coefficients ƒÀ and ƒÁ, respectively, are constant. The functions ƒÓ and ƒÕ are radially symmetric in D, they are small at infinity, and rƒÓ(r) and rƒÕ(r) are also assumed to be small at infinity. We prove that our scheme is consistent order …
-
Modelling of liquid droplet dynamics in a high DC magnetic field
… used to measure the surface tension and viscous damping coefficients of a liquid droplet. This technique has been the subject of much analysis; theoretical, numerical, and experimental with a number of different external forces used to confine the droplet. These external forces are found to …
-
A variation of the Levenberg Marquardt method : an attempt to improve efficiency
… gradient descent methods, where the amount of damping used in each iteration is central in establishing the behavior of the system. Further, the damping is determined by four parameters, whose optimum values vary from model to model. An inappropriate selection of the damping parameters could …
-
Virtual Planar Motion Mechanism Testing of 8:1 Spheroids
… is a method used to identify the added mass and damping coefficients used in the equations of motion of a vehicle by attempting to decouple the forces on a body due to velocity and acceleration as a result of creating "hydrodynamically pure" velocities and accelerations. This makes it possible to …
-
A numerical investigation of the global stability of ship roll: invariant manifolds, Melnikov's method, and transient basins
… fixed values of the restoring-moment and damping parameters (the "base case"), the manifolds of the saddles of the Poincaré map are repeatedly computed for increasingly higher excitation amplitudes until homo clinic , heteroclinic, and mixed manifold intersections are observed. The …
-
Nonlinear forced response of circular cylindrical shells
… is reached. This threshold is a function of the damping coefficients and ω<sub>b</sub> -2w<sub>f</sub>. Beyond this threshold, a<sub>b</sub> remains constant (i.e., the breathing mode saturates) and the extra energy spills over into the flexural mode. In other words, although the breathing mode …
Page 1 of 2