INVESTIGATION OF SUSPENSION UNITS POSSESSING BILINEAR DAMPING FORCE AND CUBIC-LINEAR SPRING FORCE CHARACTERISTICS Sachs, H. K. Wayne State Univ., 91 pp (Mar. 1971) Refer to Abstract No. 72-17

1972 ◽  
Vol 4 (11) ◽  
pp. 69-70
Author(s):  
A.W. Wildig
Keyword(s):  
Damping Force ◽  
Spring Force ◽  
Linear Spring ◽  
Force Characteristics

A Landing Gear Drop Dynamic Simulation Based on the LMS. Virtual. Lab

2011 ◽  
Vol 55-57 ◽  
pp. 684-687
Author(s):  
Li Zhang ◽  
Cai Jun Xue
Keyword(s):  
Influence Factors ◽  
Landing Gear ◽  
Buffer System ◽  
Air Spring ◽  
Damping Force ◽  
Tire Force ◽  
Virtual Lab ◽  
Spring Force ◽  
Simulation Based ◽  
Fluid Damping

In order to evaluate the dynamic behavior of the buffer of the Seagull 300 aircraft’s main landing gear, a drop model is built to simulate the drop dynamics using the software of LMS Virtual Lab Motion. The fluid damping force of the buffer, the air spring force of the buffer, the tire force of the landing gear and the weight of the fuselage are considered in the model. The simulation results are compared with the results of the Seagull 300 landing gears drop test, which proves the accuracy of the simulation model. Then the buffer performance and its influence factors are computationally discussed. This method gives a new way to study and improve the performance of the buffer system of an aircraft.

Non-Stationary Response of Non-Linear SDOF Systems by Perturbation of Wavelet Coefficients

2001 ◽  
Author(s):  
Pranesh Chatterjee ◽  
Biswajit Basu
Keyword(s):  
Wavelet Domain ◽  
Wavelet Coefficients ◽  
Algebraic Equations ◽  
Single Degree Of Freedom ◽  
Displacement Response ◽  
Spring Force ◽  
Non Linear ◽  
Linear Spring ◽  
Random Vibration Theory ◽  
Statistical Functionals

Abstract A wavelet based random vibration theory has been developed for the non-stationary seismic response of single degree of freedom (SDOF) systems with cubic type non-linearity in the spring force. The ground motion process has been characterized by statistical functionals of wavelet coefficients. The wavelet transformed coefficient of the displacement response of the oscillator has been perturbed to obtain a series of wavelet domain algebraic equations. The stochastic response of the system has been obtained by using these sets of wavelet domain equations. The root mean square (r.m.s.) displacement response has been obtained in terms of the functionals of the input wavelet coefficients. Parametric variations are carried out to observe the effects of variation of the magnitudes of non-linear spring stiffness on the temporal variation of instantaneous r.m.s. values of oscillator displacements.

EASY5 Model of Two Position Solenoid Operated Cartridge Valve

2002 ◽  
Author(s):  
Song Liu ◽  
Gary Krutz ◽  
Bin Yao
Keyword(s):  
Control Valve ◽  
Mathematic Model ◽  
Nonlinear Flow ◽  
Damping Force ◽  
Precise Control ◽  
Directional Control ◽  
Spring Force ◽  
Programmable Valve ◽  
Valve Dynamics ◽  
Nonlinear Performance

The two position solenoid operated cartridge valve is widely used in the applications, such as process control systems, pavers, agricultural machinery, where response and installed costs are more important than precise control through electronic position feedback. In recent years, the combination of multiple cartridge valves, so called ‘smart valve’ or ‘programmable valve’, which is able to break the mechanical linkage between the meter-in and meter-out orifices and enables high precision control as well as optimal usage of energy, is gaining engineering interests. But the control of such combination is far from trivial. It demands good knowledge of the valve dynamics and nonlinear flow properties. Unlike servo valve or proportional directional control valve, a mathematic model of solenoid operated cartridge valve, or even a thorough understanding of the dynamics and nonlinear performance, are not available. This paper presents an EASY 5 model for the two position solenoid operated cartridge valve. The model, which includes the solenoid force, spring force, damping force, flow force and nonlinear mass flow rate, can be used to analyze cartridge valve as well as simulate system or controller performance. It is also able to connect with Matlab for more complicated simulation.

scholarly journals Design and Simulation of Electromagnetic Linear Actuators for Jet Dispensers

2020 ◽  
Vol 10 (5) ◽  
pp. 1653
Author(s):  
Minh-Sang Tran ◽  
Sheng-Jye Hwang
Keyword(s):  
Thrust Force ◽  
Inertia Force ◽  
Resistance Force ◽  
Driving Frequency ◽  
Excitation Current ◽  
Damping Force ◽  
Element Analysis ◽  
Spring Force ◽  
Return Spring ◽  
Linear Actuators

Three electromagnetic-based linear actuators, namely a solenoid actuator (SA), a moving coil actuator (MCA), and a moving magnet actuator (MMA), are proposed for driving the needle in a jet dispenser. The total resistance force acting on the needle during operation, including the damping force, the friction force, the inertia force, the compression spring force, and the backpressure, are measured by an experimental model. The thrust force required to overcome this resistance force is then predicted for each actuator using finite element analysis (FEA) simulations. Simple two-dimensional models of the SA, MCA, and MMA are constructed using the same coil dimensions in every case in order to facilitate an objective comparison between them. Simulations in ANSYS Maxwell software are then performed to adjust the specific dimensions of each actuator structure in such a way as to generate the thrust force required to drive the needle in the jet dispenser with the minimum excitation current possible. The simulation results show that for a maximum needle driving frequency of 250 Hz and a stroke length of 0.5 mm, the excitation current required to generate the necessary thrust force is equal to 1.8 A and 1.9 A for the MCA and MMA models, respectively, when a return spring is not used, and 2.2 A, 3.8 A, and 4.1 A for the SA, MCA, and MMA models, respectively, when a return spring is employed. It is additionally shown that the thrust force drop of the MCA and MMA models is far less than that of the SA model, about 0.7%, 1.8%, and 61% for three models, respectively. Three preliminary designs for jet dispensers incorporating the proposed actuators are also generated for reference purposes.

scholarly journals Numerical Simulation of Cavitation and Damping Force Characteristics for a High-Speed Supercavitation Vehicle

2021 ◽  
Vol 9 (11) ◽  
pp. 1171
Author(s):  
Rui Lu ◽  
Guang Pan ◽  
Kun Tan ◽  
Shaoping Yin
Keyword(s):  
High Speed ◽  
Flow Model ◽  
Hydrodynamic Force ◽  
Angle Of Attack ◽  
Navier Stokes ◽  
Hydrodynamic Characteristics ◽  
Damping Force ◽  
Force Amplitude ◽  
Wet Surface ◽  
Force Characteristics

In this study, an attempt has been made to investigate the supercavitation and hydrodynamic characteristics of high-speed vehicles. A homogeneous equilibrium flow model and a Schnerr–Sauer model based on the Reynolds-averaged Navier–Stokes method are used. Grid-independent inspection and comparison with experimental data in the literature have been carried out to verify the accuracy of numerical methods. The effect of the navigation speed and angle of attack on the cavitation morphology and dynamic characteristics has been investigated. It has been demonstrated that the angle of attack has a remarkable influence on the wet surface and hydrodynamic force, whereas navigation speed has little effect on the position force of the vehicle under the circumstance of no wet surface. The hydrodynamic force changes periodically with the swing of the vehicle, but its maximum is greater than that for the direct navigation state at the same attack angle. Moreover, the damping effect obviously affects the hydrodynamic force amplitude and movement trend.

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