scholarly journals A Study on Vibration Characteristics and Stability of the Ambulance Nonlinear Damping System

2013 ◽  
Vol 2013 ◽  
pp. 1-12 ◽  
Author(s):  
Meng Yang ◽  
Xinxi Xu ◽  
Chen Su
Keyword(s):  
Approximate Solution ◽  
Primary Resonance ◽  
Nonlinear Behavior ◽  
Singularity Theory ◽  
Nonlinear Damping ◽  
Nonlinear Stiffness ◽  
First Order ◽  
Damping Effect ◽  
Vibration Model ◽  
The Impact

Considering the impact of the nonlinear stiffness, a 2-DOF vibration model with cubic terms was established according to the structural feature and nonlinear behavior. Ignoring the impact of nonlinear terms, the system was linearly analyzed. In the case of primary resonance and 1 : 1 internal resonance, a multiscale method was used to obtain a first-order approximate solution. Taking the parameters of one tracked ambulance for instance, the approximate solution was corroborated and the influence of the parameters on damping effect was investigated. Finally, motion stability of the damping system was analyzed with singularity theory. The theoretical bases for improving efficiency of the damping system were provided.

Primary Resonance of a Vehicle Suspension System With Nonlinear Stiffness and Nonlinear Damping

2006 ◽  
Author(s):  
Shaohua Li ◽  
Shaopu Yang
Keyword(s):  
Primary Resonance ◽  
Singularity Theory ◽  
Nonlinear Damping ◽  
Suspension System ◽  
Vehicle Suspension ◽  
Model Parameters ◽  
Nonlinear Stiffness ◽  
Single Degree Of Freedom ◽  
Single Degree ◽  
Vehicle Suspension System

In this work, primary resonance of a single-degree-of-freedom (SDOF) vehicle suspension system with nonlinear stiffness and nonlinear damping under multi-frequency excitations is investigated. The primary resonance equation is obtained by average method, and then the system’s bifurcation behaviors are studied by singularity theory. In addition, the effect of changing physical model parameters on the system’s primary resonance is studied.

scholarly journals Bifurcation Analysis of a Micro-Machined Gyroscope with Nonlinear Stiffness and Electrostatic Forces

Micromachines ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 107
Author(s):  
Huabiao Zhang ◽  
Xinye Li ◽  
Lijuan Zhang
Keyword(s):  
Primary Resonance ◽  
Singularity Theory ◽  
Driving Voltage ◽  
Nonlinear Stiffness ◽  
Resonance Transition ◽  
Residue Theorem ◽  
Electrostatic Forces ◽  
Mechanical Sensitivity ◽  
Periodic Response ◽  
Stable Periodic

The bifurcation of the periodic response of a micro-machined gyroscope with cubic supporting stiffness and fractional electrostatic forces is investigated. The pull-in phenomenon is analyzed to show that the system can have a stable periodic response when the detecting voltage is kept within a certain range. The method of averaging and the residue theorem are employed to give the averaging equations for the case of primary resonance and 1:1 internal resonance. Transition sets on the driving/detecting voltage plane that divide the parameter plane into 12 persistent regions and the corresponding bifurcation diagrams are obtained via the singularity theory. The results show that multiple solutions of the resonance curves appear with a large driving voltage and a small detecting voltage, which may lead to an uncertain output of the gyroscope. The effects of driving and detecting voltages on mechanical sensitivity and nonlinearity are analyzed for three persistent regions considering the operation requirements of the micro-machined gyroscope. The results indicate that in the region with a small driving voltage, the mechanical sensitivity is much smaller. In the other two regions, the variations in the mechanical sensitivity and nonlinearity are analogous. It is possible that the system has a maximum mechanical sensitivity and minimum nonlinearity for an appropriate range of detecting voltages.

Perturbation Analysis of a Nonlinear Resonator

2012 ◽  
Vol 8 (1) ◽  
Author(s):  
Shahin S. Nudehi ◽  
Umar Farooq
Keyword(s):  
Perturbation Analysis ◽  
Nonlinear Differential Equations ◽  
Primary Resonance ◽  
Nonlinear Behavior ◽  
Original System ◽  
Approximate Solutions ◽  
Singular Perturbation Theory ◽  
First Order ◽  
Nonlinear Resonator ◽  
Resonator System

A perturbation analysis of a Helmholtz-type resonator with one of the resonator ends replaced by a membrane is studied in this work. A membrane is known to exhibit nonlinear behavior under certain conditions; thus, when attached to a resonator system, it modifies the dynamic characteristics of the original system. This modified resonator system is modeled by coupled nonlinear differential equations and investigated by using the singular perturbation theory. The resonant frequency of the nonlinear resonator in the primary resonance case is analytically obtained using first-order approximate solutions. A good agreement is seen when the frequency response of the first-order approximate system is compared with the numerically simulated results.

scholarly journals Perturbation Solution for One-Dimensional Flow to a Constant-Pressure Boundary in a Stress-Sensitive Reservoir

2021 ◽  
Author(s):  
Amarjot Singh Bhullar ◽  
Gospel Ezekiel Stewart ◽  
Robert W. Zimmerman
Keyword(s):  
Approximate Solution ◽  
Pore Pressure ◽  
Constant Pressure ◽  
Initial Permeability ◽  
Order Perturbation ◽  
Zeroth Order ◽  
One Dimensional ◽  
First Order ◽  
Outflow Boundary ◽  
Perturbation Solutions

Abstract Most analyses of fluid flow in porous media are conducted under the assumption that the permeability is constant. In some “stress-sensitive” rock formations, however, the variation of permeability with pore fluid pressure is sufficiently large that it needs to be accounted for in the analysis. Accounting for the variation of permeability with pore pressure renders the pressure diffusion equation nonlinear and not amenable to exact analytical solutions. In this paper, the regular perturbation approach is used to develop an approximate solution to the problem of flow to a linear constant-pressure boundary, in a formation whose permeability varies exponentially with pore pressure. The perturbation parameter αD is defined to be the natural logarithm of the ratio of the initial permeability to the permeability at the outflow boundary. The zeroth-order and first-order perturbation solutions are computed, from which the flux at the outflow boundary is found. An effective permeability is then determined such that, when inserted into the analytical solution for the mathematically linear problem, it yields a flux that is exact to at least first order in αD. When compared to numerical solutions of the problem, the result has 5% accuracy out to values of αD of about 2—a much larger range of accuracy than is usually achieved in similar problems. Finally, an explanation is given of why the change of variables proposed by Kikani and Pedrosa, which leads to highly accurate zeroth-order perturbation solutions in radial flow problems, does not yield an accurate result for one-dimensional flow. Article Highlights Approximate solution for flow to a constant-pressure boundary in a porous medium whose permeability varies exponentially with pressure. The predicted flowrate is accurate to within 5% for a wide range of permeability variations. If permeability at boundary is 30% less than initial permeability, flowrate will be 10% less than predicted by constant-permeability model.

First Order Analysis for Automotive Body Structure Design-Part 2: Joint Analysis Considering Nonlinear Behavior

2004 ◽  
Author(s):  
Yasuaki Tsurumi ◽  
Hidekazu Nishigaki ◽  
Toshiaki Nakagawa ◽  
Tatsuyuki Amago ◽  
Katsuya Furusu ◽  
...  
Keyword(s):  
Nonlinear Behavior ◽  
Structure Design ◽  
Joint Analysis ◽  
Body Structure ◽  
Order Analysis ◽  
First Order ◽  
Automotive Body

Optimal Capacitors Placement of Distribution Systems Using 2nd Order Power Loss Sensitivity Analysis and Hierarchical Clustering

2014 ◽  
Vol 986-987 ◽  
pp. 377-382 ◽  
Author(s):  
Hui Min Gao ◽  
Jian Min Zhang ◽  
Chen Xi Wu
Keyword(s):  
Sensitivity Analysis ◽  
Hierarchical Clustering ◽  
Distribution System ◽  
Power Flow ◽  
Distribution Systems ◽  
Reactive Power ◽  
Digital Simulation ◽  
Second Order ◽  
First Order ◽  
The Impact

Heuristic methods by first order sensitivity analysis are often used to determine location of capacitors of distribution power system. The selected nodes by first order sensitivity analysis often have virtual high by first order sensitivities, which could not obtain the optimal results. This paper presents an effective method to optimally determine the location and capacities of capacitors of distribution systems, based on an innovative approach by the second order sensitivity analysis and hierarchical clustering. The approach determines the location by the second order sensitivity analysis. Comparing with the traditional method, the new method considers the nonlinear factor of power flow equation and the impact of the latter selected compensation nodes on the previously selected compensation location. This method is tested on a 28-bus distribution system. Digital simulation results show that the reactive power optimization plan with the proposed method is more economic while maintaining the same level of effectiveness.

scholarly journals Reuse of Newspaper As An Adsorbent For Cu (II) Removal By Citric Acid Modification

2018 ◽  
Vol 156 ◽  
pp. 02012 ◽  
Author(s):  
Mardiah ◽  
Rif’an Fathoni ◽  
Pratiwi Pudyaningtyas ◽  
Hamdania Gamu ◽  
Rinaldy
Keyword(s):  
Citric Acid ◽  
Adsorption Process ◽  
Kinetic Studies ◽  
Order Reaction ◽  
Acid Modification ◽  
Pseudo First Order Reaction ◽  
First Order ◽  
Pseudo Second Order ◽  
Heavy Metal Adsorbent ◽  
The Impact

High Consumption of paper, bring the impact of the waste paper itself. And the utilization of the paper is limited to recycled products and crafts, whereas paper such as newspaper still contains cellulose that can be potential to be used as a heavy metal adsorbent. In this study, newspaper was dissolved in sodium bicarbonate to reduce various impurities and then was reacted with citric acid (CA). The modified adsorbent was characterized by FTIR and was tested for adsorb Cu(II) in artificial solution. After adsorption process, the solution was filtered and analysed using Atomic Absorption Spectrophotometer (AAS). The adsorption experimental data was fitted to Langmuir, Freundlich, Tempkin, and Dubinin-Radushkevich for equilibrium model and was fitted to pseudo first order reaction and pseudo second order reaction for kinetic studies. The result showed that CA-modification newspaper able to remove heavy metals Cu(II) in solution.

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