The Development of a Predictive Model for the Optimization of High-Speed Cam-Follower Systems with Coulomb Damping Internal Friction and Elastic and Fluidic Elements

1986 ◽  
Vol 108 (4) ◽  
pp. 506-515 ◽  
Author(s):  
Shervin Hanachi ◽  
Ferdinand Freudenstein
Keyword(s):  
Energy Dissipation ◽  
Dynamic Model ◽  
High Speed ◽  
Distributed Parameter ◽  
Predictive Capability ◽  
Valve Spring ◽  
Coulomb Damping ◽  
System Components ◽  
Cam Follower ◽  
Distributed Parameter Modeling

A highly accurate and predictive dynamic model of a high-speed cam-follower system has been developed and verified. In view of the predominance of Coulomb damping in high-speed cam-follower systems, this form of damping has been used as the chief mode of energy dissipation. This has resulted in a significant improvement in the predictive capability of the dynamic model. The accuracy of the model can also be attributed to careful modeling of system components such as the distributed-parameter modeling of the valve spring, the modeling of the hydraulic lifter, and modeling of the damping due to a nested-valve spring. The latter two represent the first such modeling in the area of cam-follower systems.

An Experimental and Analytical Investigation of the Dynamic Response of a High-Speed Cam-Follower System. Part 2: A Combined, Lumped/Distributed Parameter Dynamic Model

1983 ◽  
Vol 105 (4) ◽  
pp. 699-704 ◽  
Author(s):  
A. P. Pisano ◽  
F. Freudenstein
Keyword(s):  
Dynamic Response ◽  
Dynamic Model ◽  
High Speed ◽  
Analytical Investigation ◽  
System Response ◽  
Distributed Parameter ◽  
Normal System ◽  
Cam Follower ◽  
Return Spring ◽  
Pathological Behavior

Part 2 describes the development of a dynamic model of a high-speed cam-follower system in which the return spring is modeled as a distributed-parameter element. The dynamic response requires the solution of a coupled set of differential equations, one ordinary and one partial. The dynamic model has the unique capability of faithfully reproducing the effect of the higher harmonics of the cam lift curve on system performance. The model, which has been refined and verified with the aid of the results described in Part 1, is capable of accurately predicting both normal system response as well as pathological behavior associated with the onset of toss, bounce, and spring surge. In comparison, a lumped-parameter dynamic model (differing only in the modeling of the valve spring) does not adequately predict the onset of pathological behavior.

Dynamic Analysis of a Valve Spring With a Coulomb-Friction Damper

1990 ◽  
Vol 112 (4) ◽  
pp. 509-513 ◽  
Author(s):  
R. S. Paranjpe
Keyword(s):  
Finite Difference ◽  
Difference Scheme ◽  
Finite Difference Scheme ◽  
Coulomb Friction ◽  
Distributed Parameter ◽  
Friction Damper ◽  
Equivalent Viscous Damping ◽  
Valve Spring ◽  
Coulomb Damping ◽  
Explicit Finite Difference

The dynamic behavior of a distributed parameter valve spring with Coulomb damping has been modeled. Such a spring is described by a nonlinear, nonhomogeneous wave equation. This equation is solved using an explicit finite difference scheme. Some sample results are presented. The results of the finite difference scheme are compared with the results of an analytical solution for zero damping. The two compare very well. The spring is also modeled using an equivalent viscous damping coefficient. The results of this analysis are compared with those of the Coulomb damping analysis.

A Rotary Model for Spur Gear Dynamics

1985 ◽  
Vol 107 (4) ◽  
pp. 529-535 ◽  
Author(s):  
D. C. H. Yang ◽  
Z. S. Sun
Keyword(s):  
Energy Dissipation ◽  
Dynamic Model ◽  
High Speed ◽  
Spur Gear ◽  
Tooth Profile ◽  
Gear System ◽  
Gear Dynamics

We develop a dynamic model for a spur gear system with backlash. This model is circular and is geometrically different from the rectilinear gear model of Azar and Crossley. By taking advantage of involute tooth profile, we are able to take material compliance and energy dissipation into account. Furthermore, the complicated phenomenon of contact tooth pairs alternation between one and two during meshing is also included in the model. This model is believed to be closer to reality than the existing model and hopefully is useful in studying gears in high-speed and intermittent motions.

Analytical Dynamic Response of Elastic Cam-Follower Systems with Distributed Parameter Return Spring

1993 ◽  
Vol 115 (3) ◽  
pp. 612-620 ◽  
Author(s):  
Y. Samim U¨nlu¨soy ◽  
S. Turgut Tu¨mer
Keyword(s):  
Dynamic Response ◽  
High Speed ◽  
Systems Approach ◽  
Distributed Parameter ◽  
Lumped Model ◽  
Distributed Parameter Model ◽  
Pole Parameter ◽  
Cam Follower ◽  
Method Of Solution ◽  
Return Spring

An analytical method of solution for the high-speed dynamic response of a lumped/distributed parameter model for cam-follower systems is developed. The model combines the distributed parameter model of the return spring with a viscously damped, single degree-of-freedom, lumped model of the elastic follower train. The cam event is considered as a periodic motion, of period 360 deg, and is represented by its Fourier series approximation. Linear systems approach utilizing four-pole parameter representation of lumped and distributed elements is adopted. The applicability and the accuracy of the method are verified with the aid of the experimental results reported in recent literature on the dynamic response of a high-speed cam-follower system.

Dynamic model for high-speed rotors based on their experimental characterization

2017 ◽  
Vol 2 (4) ◽  
pp. 25
Author(s):  
L. A. Montoya ◽  
E. E. Rodríguez ◽  
H. J. Zúñiga ◽  
I. Mejía
Keyword(s):  
Dynamic Model ◽  
High Speed ◽  
Natural Frequencies ◽  
Mode Shapes ◽  
Experimental Characterization ◽  
Rotating Systems ◽  
Computing Performance ◽  
The Impact ◽  
Stiffness Distribution ◽  
Good Agreement

Rotating systems components such as rotors, have dynamic characteristics that are of great importance to understand because they may cause failure of turbomachinery. Therefore, it is required to study a dynamic model to predict some vibration characteristics, in this case, the natural frequencies and mode shapes (both of free vibration) of a centrifugal compressor shaft. The peculiarity of the dynamic model proposed is that using frequency and displacements values obtained experimentally, it is possible to calculate the mass and stiffness distribution of the shaft, and then use these values to estimate the theoretical modal parameters. The natural frequencies and mode shapes of the shaft were obtained with experimental modal analysis by using the impact test. The results predicted by the model are in good agreement with the experimental test. The model is also flexible with other geometries and has a great time and computing performance, which can be evaluated with respect to other commercial software in the future.

scholarly journals Investigating the Trackability of Silicon Microprobes in High-Speed Surface Measurements

Sensors ◽  
2021 ◽  
Vol 21 (5) ◽  
pp. 1557
Author(s):  
Min Xu ◽  
Zhi Li ◽  
Michael Fahrbach ◽  
Erwin Peiner ◽  
Uwe Brand
Keyword(s):  
Dynamic Model ◽  
High Speed ◽  
High Signal ◽  
Resonant Response ◽  
High Demand ◽  
Surface Measurements ◽  
Tactile Roughness ◽  
Low Mass ◽  
Roughness Measurements

High-speed tactile roughness measurements set high demand on the trackability of the stylus probe. Because of the features of low mass, low probing force, and high signal linearity, the piezoresistive silicon microprobe is a hopeful candidate for high-speed roughness measurements. This paper investigates the trackability of these microprobes through building a theoretical dynamic model, measuring their resonant response, and performing tip-flight experiments on surfaces with sharp variations. Two microprobes are investigated and compared: one with an integrated silicon tip and one with a diamond tip glued to the end of the cantilever. The result indicates that the microprobe with the silicon tip has high trackability for measurements up to traverse speeds of 10 mm/s, while the resonant response of the microprobe with diamond tip needs to be improved for the application in high-speed topography measurements.

Synthesis of Inertially Compensated Variable-Speed Cams

2003 ◽  
Vol 125 (3) ◽  
pp. 593-601 ◽  
Author(s):  
B. Demeulenaere ◽  
J. De Schutter
Keyword(s):  
High Speed ◽  
Design Procedure ◽  
Variable Speed ◽  
Speed Variation ◽  
Design Choice ◽  
Cam Follower ◽  
Speed Fluctuation ◽  
Novel Design

Traditionally, cam-follower systems are designed by assuming a constant camshaft speed. Nevertheless, all cam-follower systems, especially high-speed systems, exhibit some camshaft speed fluctuation (despite the presence of a flywheel) which causes the follower motions to be inaccurate. This paper therefore proposes a novel design procedure that explicitly takes into account the camshaft speed variation. The design procedure assumes that (i) the cam-follower system is conservative and (ii) all forces are inertial. The design procedure is based on a single design choice, i.e., the amount of camshaft speed variation, and yields (i) cams that compensate for the inertial dynamics for any period of motion and (ii) a camshaft flywheel whose (small) inertia is independent of the period of motion. A design example shows that the cams designed in this way offer the following advantages, even for non-conservative, non-purely inertial cam-follower systems: (i) more accurate camshaft motion despite a smaller flywheel, (ii) lower motor torques, (iii) more accurate follower motions, with fewer undesired harmonics, and (iv) a camshaft motion spectrum that is easily and robustly predictable.

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