scholarly journals Influence of different parameters on dynamic response of nonlinear oscillations

1995 ◽  
Vol 17 (4) ◽  
pp. 13-16
Author(s):  
Nguyen Nhat Le
Keyword(s):  
Dynamic Response ◽  
Personal Computer ◽  
Nonlinear Oscillations ◽  
Original Position ◽  
Static Deflection ◽  
Elastic Elements

By simulating on personal computer, the nonlinear oscillations with large static deflection of elastic elements have been studied. It is consider the influences of different parameters, in particular, with the numerical value of degrees of smallness. The results at the neighborhood of the original position are accordant with ones of [3].

scholarly journals Nonlinear oscillations in systems with large static deflection of elastic elements

1993 ◽  
Vol 15 (4) ◽  
pp. 7-16
Author(s):  
Nguyen Van Dao
Keyword(s):  
Nonlinear System ◽  
Elastic Element ◽  
Nonlinear Oscillations ◽  
Equations Of Motion ◽  
Neutral Type ◽  
Equation Of Motion ◽  
Nonlinear Characteristic ◽  
Static Deflection ◽  
Soft Or ◽  
Elastic Elements

In mechanical systems the static deflection of the elastic elements is usual not appeared in the equations of motion. The reason is that either a linear model of the elastic elements or their too small static deflection assumption was accepted. In the present paper both nonlinear model of elastic elements and their large static deflection are considered, so that the nonlinear terms in the equation of motion appear with different degrees of smallness. In this case the nonlinearity of the system depends not only on the nonlinear characteristic of the elastic element but on its static deflection. The distinguishing feature of the system under consideration is that if the elastic element has soft characteristic, the nonlinear system also belongs to the soft one. If the elastic element has hard characteristic, the system may be either soft or hard or neutral type, depending on the relation between the parameters of the elastic element and its static deflection.

A Dynamic Response of a Module/Array Simulator Using I-V Magnifier Circuit of a PN Photo-Sensor

Solar Energy ◽  
2003 ◽  
Author(s):  
Hiroshi Nagayoshi
Keyword(s):  
Dynamic Response ◽  
Personal Computer ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Maximum Power ◽  
Current Gain ◽  
Led Driver ◽  
Photo Sensor ◽  
Driver Circuit ◽  
Basic Characteristics

Basic characteristics and dynamic response of a 30W module/array simulator using PV I-V magnifier circuit was studied. It was confirmed that each gain of voltage and current was independently adjustable using feedback control of current signal. Simulator circuit output power is controlled by LED irradiation light which works as an irradiation of sun light to real PV modules. Maximum power of the circuit depends on maximum power of the power amplifier used in the circuit. A photo-current of pn photo-sensor was some micro ampere hence the current gain of the simulator needed more than 50dB. The voltage gain was not more than 3dB because a multi junction pn photo-sensor was used. To control the simulator circuit by personal computer, an LED driver circuit was added. A fill factor was also easily changeable by change of shunt resistor connected with pn photo-sensor in parallel. A dynamic response of short circuit current was measured and confirmed that the circuit has enough response ability to apply the MPPT evaluation. A grand line of each module is isolated, hence any topology of connections is available. This circuit simplifies the control system and makes it easy to handle multi simulator units by one personal computer. This system is suitable for the evaluation of multi inverter system.

Effect of Differential Ballast Settlement on Dynamic Response of Vehicle–Track Coupled Systems

2018 ◽  
Vol 18 (07) ◽  
pp. 1850091 ◽  
Author(s):  
Yu Sun ◽  
Yu Guo ◽  
Zaigang Chen ◽  
Wanming Zhai
Keyword(s):  
Dynamic Response ◽  
Ride Comfort ◽  
Coupled System ◽  
Coupled Systems ◽  
Track Structure ◽  
Static Deflection ◽  
The Finite Element Method ◽  
Dynamics Model ◽  
Running Safety ◽  
Bed Changes

An improved vehicle-track coupled dynamics model that takes into account the differential ballast settlement is presented in this paper. Central to this formulation is an iterative method for acquiring the mapping relationship between the ballast settlement and the deflection of rail and sleepers. The proposed method is validated by comparing the results obtained with those of the finite element method (FEM) and the equilibrium state calculated for the track with the ballast settlement. Using the proposed method and dynamic model, numerical analyses have been performed for the static deflection of the rail and sleepers and for the dynamic response of the vehicle-track coupled system. The results indicate that the upper track structure will settle along with the ballast bed, and sleepers are likely to become unsupported when the settlement amplitude is large or when the settlement wavelength is small. The contact between the sleeper and the ballast bed changes dynamically when the vehicle passes through the settlement area. The ballast settlement has a significant effect on the deformation of the track and sleepers, thereby deteriorating the running safety and ride comfort of the vehicle.

Locomotive Underactuated Implement Guided via Elastic Elements (L.U.I.G.E.E): A Preliminary Design

2015 ◽  
Author(s):  
Thomas Reilly ◽  
Jerome K. O’Rourke ◽  
Daniel Steudler ◽  
Davide Piovesan ◽  
Roberto Bortoletto
Keyword(s):  
Human Body ◽  
Equilibrium Position ◽  
Simulation Software ◽  
Dynamics Simulation ◽  
Original Position ◽  
Preliminary Design ◽  
Top Down ◽  
Body Dynamics ◽  
Multi Body ◽  
Elastic Elements

This paper presents the simulation and fabrication of a bipedal humanoid system actuated with linear springs to produce a standing equilibrium position. The humanoid system is comprised of two leg assemblies connected by a hip bracket. Eleven pairs of springs were attached to the system in locations designed to simulate the muscles and tendons in a human body. The assembly was modeled in the multi-body dynamics simulation software SimWise 4D. Simulations were performed to determine the springs’ stiffness and natural lengths using a top-down heuristic approach. After a set of springs were found to produce a good simulated stable position, they were cross referenced to standard commercially-available parts. A final simulation was then performed to verify that the real-world spring values produced a stable system. Working in tandem with SimWise 4D, the humanoid assembly was fabricated using PLA plastic via an extrusion-type rapid prototyping machine. From the results of the simulation, the set of working springs were implemented onto the plastic model. After final modifications, the assembly then produced a standing equilibrium position. Finally, the assembly was perturbed in several directions to ensure that after the system experienced a displacement it would then return to its original position.

scholarly journals Simulation on personal computer of dynamic system having nonlinear damping force

1993 ◽  
Vol 15 (4) ◽  
pp. 32-35
Author(s):  
Nguyen Nhat Le
Keyword(s):  
Dynamic Response ◽  
Dynamic System ◽  
Personal Computer ◽  
Nonlinear Damping ◽  
Damping Force

A dynamic system having nonlinear damping force and connected with a spring-damper element is simulated on personal computer. It is considered the influences of different parameters on the dynamic response of this system.

scholarly journals DYNAMIC CALCULATION OF A ROOF TRUSS DURING THE PROCESS OF FREE STRUCTURALLY NONLINEAR OSCILLATIONS

2016 ◽  
Vol 16 (3) ◽  
pp. 18-26
Author(s):  
E Ufimtsev ◽  
◽  
M Voronina
Keyword(s):  
Mathematical Model ◽  
Dynamic Response ◽  
Nonlinear Oscillations ◽  
Mechanical Energy ◽  
Dissipative System ◽  
Free Oscillations ◽  
Roof Truss ◽  
Quadratic Matrix Equation ◽  
Total Mechanical Energy ◽  
Flat Steel

A mathematical model of construction of the total mechanical energy of a discrete statically loaded dissipative system in the process of free oscillations in the form the time analysis method, which is based on the study of the characteristic quadratic matrix equation, was given. The features of the behavior of the parameters of the dynamic response when the elastic structurally nonlinear system to a new state was shown. It is also given the expressions to determine the kinematic (displacements, velocities, accelerations) and force (restoring, dissipative and inertial forces) parameters of the dynamic response. The criteria for assessing the load bearing capacity of the structure at the non-linear operation was suggested. Using a mathematical model is illustrated by the example of the calculation of flat steel statically indeterminate roof truss during the process of free oscillations, which was caused by a sudden failure of one of the bearing elements. Turning off the rod caused by the loss of strength as a result of chemical cracking due to corrosion effect.

PSEUDO-DYNAMIC RESPONSE TESTS ON SELF-RETURNING JOINT MECHANISM USING Ni-Ti-Co ALLOY

2006 ◽  
Vol 20 (25n27) ◽  
pp. 4439-4444
Author(s):  
JAE-HYOUK CHOI ◽  
KENICHI OHI
Keyword(s):  
Dynamic Response ◽  
Original Position ◽  
Response Analysis ◽  
Elastic Model ◽  
Test Results ◽  
Frame System ◽  
Joint Mechanism ◽  
Endplate Connection ◽  
Nonlinear Elastic ◽  
Steel Bolts

This paper deals with a beam-to-column connection using mechanical fasteners made of shape memory alloy, abbreviated as 'SMA bolt' hereafter. A flush-type endplate connection at beam-ends is arranged by use of SMA bolts, and the connection works as a super-elastic joint mechanism. This paper describes sub-structure pseudo-dynamic response tests on a super-elastic frame system with fictitious tension-bar diagonal braces. For the comparison, a similar structural system bolted by ordinary mild-steel bolts is also tested pseudo-dynamically. It was observed that the SMA bolt system returned to its original position, while the ordinary bolt system showed some permanent set after earthquakes. Additionally, response analysis based on a nonlinear-elastic model and a slip model is performed and compared with the test results.

scholarly journals Nonlinear Vibrations in Homogeneous Non-Prismatic Timoshenko Cantilevers

2021 ◽  
Author(s):  
Navid Navadeh ◽  
Pooya Sareh ◽  
Vladimir G. Basovsky ◽  
Irina M. Gorban ◽  
Arash S. Fallah
Keyword(s):  
Dynamic Response ◽  
Analytical Model ◽  
Timoshenko Beam ◽  
Nonlinear Oscillations ◽  
Vibration Modes ◽  
Cantilever Beams ◽  
Nonlinear Dynamic Response ◽  
Beam Motion ◽  
The Mathematical Model ◽  
Special Case

Abstract Deep cantilever beams, modelled using Timoshenko beam kinematics, have numerous applications in engineering. This study deals with the nonlinear dynamic response in a non-prismatic Timoshenko beam characterized by considering the deformed configuration of the axis. The mathematical model is derived using the extended Hamilton's principle under the condition of finite deflections and angles of rotation. The discrete model of the beam motion is constructed based on the finite difference method (FDM), whose validity is examined by comparing the results for a special case with the corresponding data obtained by commercial finite element (FE) software ABAQUS 2019. The natural frequencies and vibration modes of the beam are computed. These results demonstrate decreasing eigenfrequency in the beam with increasing amplitudes of nonlinear oscillations. The numerical analyses of forced vibrations of the beam show that its points oscillate in different manners depending on their relative position along the beam. Points close to the free end of the beam are subject to almost harmonic oscillations, and the free end vibrates with a frequency equal to that of the external force. When a point approaches the clamped end of the beam, it oscillates in two-frequency mode and lags in phase from the oscillations of the free end. The analytical model allows for the study of the influence of each parameter on the eigenfrequency and the dynamic response. In all cases, a strong correlation exists between the results obtained by the analytical model and ABAQUS, nonetheless, the analytical model is computationally less expensive.

scholarly journals Railway Vehicle Pneumatic Rubber Suspension Modelling and Analysis

2018 ◽  
Vol 55 (1) ◽  
pp. 24-27 ◽  
Author(s):  
Marius Adrian Spiroiu
Keyword(s):  
Dynamic Response ◽  
Railway Vehicle ◽  
Railway Vehicles ◽  
Pneumatic Suspension ◽  
Suspension Stiffness ◽  
Secondary Suspension ◽  
Elastic Elements

The pneumatic elastic elements are widely used in the secondary suspension of modern railway vehicles due to their important advantages compared to the conventional ones. In the present paper, the modelling and analysis of the pneumatic suspension is approached, taking into account the main elements, pneumatic enclosures and rubber elements. The analysis performed investigates the influence of relevant parameters on suspension stiffness and on its dynamic response.

Quantitative parallel EELS spectrum imaging developed as a new tool in AEM

1992 ◽  
Vol 50 (2) ◽  
pp. 1202-1203
Author(s):  
Gianluigi Botton ◽  
Gilles L'espérance
Keyword(s):  
Statistical Analysis ◽  
Spatial Resolution ◽  
Personal Computer ◽  
Systematic Study ◽  
Present Author ◽  
Chemical Elements ◽  
Detection Limits ◽  
Research Groups ◽  
Quantitative Performance ◽  
Spectrum Imaging

As interest for parallel EELS spectrum imaging grows in laboratories equipped with commercial spectrometers, different approaches were used in recent years by a few research groups in the development of the technique of spectrum imaging as reported in the literature. Either by controlling, with a personal computer both the microsope and the spectrometer or using more powerful workstations interfaced to conventional multichannel analysers with commercially available programs to control the microscope and the spectrometer, spectrum images can now be obtained. Work on the limits of the technique, in terms of the quantitative performance was reported, however, by the present author where a systematic study of artifacts detection limits, statistical errors as a function of desired spatial resolution and range of chemical elements to be studied in a map was carried out The aim of the present paper is to show an application of quantitative parallel EELS spectrum imaging where statistical analysis is performed at each pixel and interpretation is carried out using criteria established from the statistical analysis and variations in composition are analyzed with the help of information retreived from t/γ maps so that artifacts are avoided.

Sign in / Sign up

Export Citation Format

Share Document