Lumped parameter approximation for the prediction of the dynamic response of the Fleisch pneumotachograph

1988 ◽  
Vol 26 (4) ◽  
pp. 443-448 ◽  
Author(s):  
M. J. Turner ◽  
I. M. MacLeod ◽  
A. D. Rothberg
Keyword(s):  
Dynamic Response ◽  
Lumped Parameter ◽  
Parameter Approximation ◽  
Fleisch Pneumotachograph

Tuning the hygro-mechanical response of paper-based systems using glycerol

2020 ◽  
pp. 1045389X2094716
Author(s):  
Isaias Cueva-Perez ◽  
Roque Alfredo Osornio-Rios ◽  
Aurelio Dominguez-Gonzalez ◽  
Ion Stiharu ◽  
Angel Perez-Cruz
Keyword(s):  
Dynamic Response ◽  
Resonance Frequency ◽  
Mechanical Response ◽  
Water Solution ◽  
Low Cost ◽  
Mechanical Systems ◽  
Lumped Parameter Model ◽  
Glycerol Water ◽  
Energy Harvesters ◽  
Lumped Parameter

In recent years, the need for portable, low-cost, and eco-friendly devices for testing and monitoring has arisen. Paper-based devices have emerged as a response to these needs due to the properties induced by capillarity, flexibility, disposability, and biodegradability. In this work, the authors explored the possibility of tuning the hygro-mechanical response of paper-based cantilever beams using glycerol. A lumped-parameter model with non-linear stiffness is used to describe the dynamic response of the beams using three parameters. An experimental method based on resonance frequency tests is used to study the influence of glycerol on the dynamic response of four different beam configurations. The obtained results demonstrate that the resonance frequency of paper-based mechanical systems can be easily tuned by the imbibition of a glycerol–water solution. This study could lead to the development of tunable paper-based mechanical systems for specific applications such as energy harvesters and hygro-mechanical-based sensors.

A Frequency Domain Finite Element Approach for Three-Dimensional Gear Dynamics

2011 ◽  
Vol 133 (4) ◽  
Author(s):  
Christopher G. Cooley ◽  
Robert G. Parker ◽  
Sandeep M. Vijayakar
Keyword(s):  
Finite Element ◽  
Dynamic Response ◽  
Frequency Domain ◽  
Dynamic Models ◽  
Three Dimensional ◽  
Static Solution ◽  
System Level ◽  
Element Formulation ◽  
Lumped Parameter ◽  
Element Approach

A finite element formulation for the dynamic response of gear pairs is proposed. Following an established approach in lumped parameter gear dynamic models, the static solution is used as the excitation in a frequency domain solution of the finite element vibration model. The nonlinear finite element/contact mechanics formulation provides an accurate calculation of the static solution and average mesh stiffness that are used in the dynamic simulation. The frequency domain finite element calculation of dynamic response compares well with numerically integrated (time domain) finite element dynamic results and previously published experimental results. Simulation time with the proposed formulation is two orders of magnitude lower than numerically integrated dynamic results. This formulation admits system level dynamic gearbox response, which may include multiple gear meshes, flexible shafts, rolling element bearings, housing structures, and other deformable components.

Effects of Bearing Radial Internal Clearance on Dynamic Behavior and Bifurcations in Planetary Gears

2011 ◽  
Author(s):  
Yi Guo ◽  
Robert G. Parker
Keyword(s):  
Dynamic Response ◽  
Harmonic Balance Method ◽  
Nonlinear Behavior ◽  
Nonlinear Effects ◽  
Lumped Parameter Model ◽  
Solution Stability ◽  
Planetary Gears ◽  
Gear Mesh ◽  
Bearing Clearance ◽  
Lumped Parameter

This study investigates the dynamics of planetary gears where nonlinearity is induced by bearing clearance. Lumped-parameter and finite element models of planetary gears with bearing clearance, tooth separation, and gear mesh stiffness variation are developed. The harmonic balance method with arc-length continuation is used to obtain the dynamic response of the lumped-parameter model. Solution stability is analyzed using Floquet theory. Rich nonlinear behavior is exhibited in the dynamic response, consisting of nonlinear jumps and a hardening effect induced by the transition from no bearing contact to contact. The bearings of the central members (sun, ring, and carrier) impact against the bearing races near resonance, which leads to coexisting solutions in wide speed ranges, grazing bifurcation, and chaos. Secondary Hopf bifurcation is the route to chaos. Input torque can significantly suppress the nonlinear effects caused by bearing clearance.

Experimental and Analytical Study of Pantograph Dynamics

1991 ◽  
Vol 113 (2) ◽  
pp. 242-247 ◽  
Author(s):  
W. Seering ◽  
K. Armbruster ◽  
C. Vesely ◽  
D. Wormley
Keyword(s):  
Experimental Data ◽  
Dynamic Response ◽  
Coulomb Friction ◽  
Close Agreement ◽  
Analytical Study ◽  
Model Performance ◽  
Nonlinear Effects ◽  
Variable Stiffness ◽  
Response Data ◽  
Lumped Parameter

A nonlinear, lumped parameter pantograph model including geometric and coulomb friction nonlinearities and variable stiffness has been developed. The model performance has been compared with experimental dynamic response data measured on a prototype pantograph. Responses of the model and the experimental data including subharmonic and harmonic resonances are in close agreement for motions excited by comparable forcing functions for input frequencies of 0 to 12 Hz. The model has been used to identify the primary parameters and nonlinear effects which influence dynamic pantograph performance.

The Numerical Analysis of Spiral Heat Exchanger

2013 ◽  
Vol 860-863 ◽  
pp. 1474-1477
Author(s):  
Xin Jun Li
Keyword(s):  
Temperature Field ◽  
Heat Exchanger ◽  
Dynamic Response ◽  
Measurement Accuracy ◽  
Initial Conditions ◽  
Parameter Method ◽  
Spiral Heat Exchanger ◽  
Lumped Parameter ◽  
Steady Temperature Field ◽  
Lumped Parameter Method

The lumped parameter method was used to establish a mathematical model for the spiral heat exchanger with complex structures and specific heat transfer. By implementing the finite difference method, the differential equation was discretized, and then the steady temperature field of the spiral heat exchanger and the dynamic response of temperature can be obtained under boundary conditions and initial conditions. And the essential correctness and measurement accuracy of the model was proved by fluent. The results show that this model can simulate the temperature field and the dynamic response of it well.

Dynamic Response of a Cam-Actuated Mechanism With Pneumatic Coupling

1977 ◽  
Vol 99 (3) ◽  
pp. 598-603 ◽  
Author(s):  
F. Y. Chen
Keyword(s):  
Dynamic Response ◽  
Dynamic Characteristics ◽  
Lumped Parameter Model ◽  
System Equation ◽  
Variation Of Parameters ◽  
Lumped Parameter ◽  
Cam Follower ◽  
The Stability

The dynamic characteristics of a cam-actuated system whose follower mass is coupled with a nonlinear pneumatic mechanism of hysteretic type are investigated using a lumped-parameter model. The dynamic response of the cam follower is obtained from the solution of the formulated system equation by the Krylov-Bogoliubov method of variation of parameters. The stability of the system is also investigated.

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