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Showing 1 to 20 of 44 for “"harmonic excitation"”.
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Prediction of snap-through instability under harmonic excitation
A method is developed to predict the critical harmonic excitation of systems undergoing nonlinear oscillations. The method is based on the total energy approach which limits the system responses within a region bounded by a critical total energy in the phase space. Three one-degree-of-freedom …
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Nonlinear vibrations of straight and buckled beams under harmonic excitation.
Massachusetts Institute of Technology. Dept. of Aeronautics and Astronautics. Thesis. 1970. Ph.D.
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Prediction of high-speed shaft natural frequencies employing harmonic excitation
… of determining the practicality of low-speed harmonic excitation of high-speed natural frequencies. The analytical development and analysis utilized SPAR, a finite element program, and a bearing stiffness program to determine frequencies for the first through fourth harmonics of natural …
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The harmonic excitation of a cylindrical bubble pinned to a plane surface: flow field and oscillation dynamics
This work aims to describe the response of a hemicylindrical gas bubble pinned to rigid substrate to an imposed oscillatory far field pressure, and subsequently describe the resulting steady flow that results in the fluid in the exterior of such a bubble. We first derive an analytical expression …
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An experimental investigation of the harmonic excitation of simply supported plates with multiple surface-bonded piezoceramic actuators
The harmonic excitation of simply supported Euler plates is performed experimentally using arrays of piezoceramic patch pair actuators bonded to the plate surface. The experimental techniques used are presented, and the effects of patch location, relative actuator phasing, and excitation frequency …
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Vibration localization and statistical energy analysis in coupled systems
… of the system. The response of the system for harmonic excitation and random input is developed. Two single Euler-Bemouilli beams coupled by a torsional spring constitute the multi degree of freedom extension of the study. Special care is given to show the variation of the natural frequencies …
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Otimização estrutural em problemas dinâmicos
… computer program for the truss element under harmonic excitation to make the following analysis: a) static analysis b) natural frequencies e) dynami e response (P = Pₑ ⁱᵚᵗ) d) dynami e response optimization (P = Pₑⁱᵚᵗ) e) frequency optimization.
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Seismic isolation of buildings for vertical earthquake excitations
… subjected to static loading as well as time harmonic excitation is investigated. The harmonic balance method and the direct numerical integration method are employed to solve the equations of motion for the system. In addition, the effect of each design parameter is studied when the structure …
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Análise de fundações de máquinas sujeitas a excitações verticais
… were carried out on blocks submitted to vertical harmonic excitation with amplitude as function of frequence. In the analyses the soil was considered either as an elastic half space or as a set of linear springs. In order to achieve the research purpose, test results carried out on silty clay soil …
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Stochastic Stability and Nonlinear Control in Mechanical Systems
… systems under small intensity stochastic excitations is investigated. The method of stochastic averaging is used to derive a set of approximate Ito equations which are then examined to obtain the almost-sure stability conditions. The sample properties of the process are based on the …
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An experiment in state-space vibration control of steady disturbances on a simply-supported plate
… supported plate. The plate is excited by a 60 Hz harmonic excitation, a narrowband excitation centered at 60 Hz, and an impulse excitation caused by an impact hammer. The extraction of the eigen-properties of the first four modes of the plate is presented. The eigen-properties form the basis of …
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Development of Multidisciplinary Design Optimization Process for a Large Scale Hybrid Composite Wind Turbine Blade
… are demonstrated to withstand the loads due to harmonic excitation from rotor rotation. An MDO process for obtaining an optimum hybrid composite laminate layup and an optimum length of a wind turbine blade is developed and illustrated in this research. The finite element (FE) model and cost …
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Vibration of a nonlinear shear deformable beam by numerical simulation
… shear deformable beam subjected to a transverse harmonic excitation is investigated by the method of numerical simulation. Rotatory and axial inertia are included in the model. The beam is simply supported with supports a fixed distance apart. The nonlinear partial differential equations of …
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Nonlinear Finite Element Analysis of Laminated Composite Beams Subjected to Harmonic Excitations Using a 20 DOF Beam Element
… beams including shear deformation subjected to harmonic excitation, using a 20-degree of freedom finite element beam. The beam has 10 degrees of freedom at each node: The axial displacements, the transverse deflection due to bending and transverse shear, the twisting angle, the in-plane shear …
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Effects of a tuned mass damper on wind-induced motions in tall buildings
… However, the theory is often based on a harmonic excitation of a building, which is not necessarily the exact representation of wind loads. This paper analyzes the effects of a Tuned Mass Damper on the response of a building to a saw tooth excitation with white noise, which seems to be a …
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Neuromuscular control adaptation during recovery from injury
… two-degree-of-freedom nonlinear oscillator under harmonic excitation are investigated. The adaptive strategy involves a frequency-dependent adjustment to the excitation amplitudes and phases on each degree of freedom in an attempt to maintain symmetric oscillations. The analysis shows the …
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Electromagnetic scattering and induction models for spheroidal geometries
… a conducting and permeable spheroid under time harmonic excitation is demonstrated. Analytical electromagnetic solutions for spheroidal geometries are desirable because of their versatility in modeling manmade and natural shapes includ- ing solid and hollow needles, spheres, and disks, while at …
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Nonlinear Dynamics of Tapping Mode Atomic Force Microscopy
… force microscopes (AFM) subjected to a base harmonic excitation. The nonlinear dynamics of the AFM microcantilever are studied in both of the monostable and bistable phases with the microcantilever tip being, respectively, located in the monostable and bistable regions of the static …
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Stress Response of Tall and Heavy Electronic Components Subjected to Multi-axial Vibration
… are susceptible to under simultaneous multiaxial excitation, termed multi degree of freedom (MDoF) excitation. However, it is still common practice to conduct vibration durability testing on electronic assemblies one axis at a time – in what is termed sequential single degree of freedom (SSDoF) …
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Two Dimensional Analysis of Vibration Isolation of Rigid Bar Supported by Buckled or Pre-bent Struts
… also exhibit a low axial stiffness when dynamic excitation is introduced. Three models consisting of buckled or pre-bent struts serving as vibration isolators which support a rigid bar are examined in this research. The three cases studied are 1) two buckled struts supporting a symmetric rigid …
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