An Experimental and Analytical Investigation of the Dynamic Response of a High-Speed Cam-Follower System. Part 1: Experimental Investigation

1983 ◽  
Vol 105 (4) ◽  
pp. 692-698 ◽  
Author(s):  
A. P. Pisano ◽  
F. Freudenstein
Keyword(s):  
Dynamic Response ◽  
High Speed ◽  
Dynamic Models ◽  
Analytical Investigation ◽  
System Response ◽  
Pathological System ◽  
Cam Design ◽  
Cam Follower ◽  
System Part ◽  
Basic Experiments

This paper is concerned with filling two gaps in the cam design field: (a) the absence of adequate measurements of the dynamic response of cam-follower systems, and (b) the need for the development of a predictive dynamic model for both normal and pathological system behavior. Part 1 presents the results of basic experiments on the dynamic response of a modern, high-speed cam-follower system. These data, which we believe to be the most comprehensive available in the open literature, and which are described more fully in [11], can be used by research investigators both in understanding system response and in developing and evaluating predictive dynamic models.

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.

Improving the B-Spline Method of Dynamically-Compensated Cam Design by Minimizing or Restricting Vibrations in High-Speed Cam-Follower Systems

2009 ◽  
Vol 131 (4) ◽  
Author(s):  
J. K. Jiang ◽  
Y. R. Iwai
Keyword(s):  
High Speed ◽  
Design Method ◽  
Damping Ratio ◽  
Radius Of Curvature ◽  
Spline Method ◽  
Application Process ◽  
B Spline ◽  
Cam Design ◽  
Cam Follower ◽  
Design Values

This paper presents an improved method for dynamically-compensated (tuned) cam design by minimizing or restricting vibrations in high-speed cam-follower systems. Using this approach, cams can be synthesized with a variety of design requirements and reduced residual vibrations. An example of the dynamically-compensated B-spline method illustrates the application process and demonstrates the improvement effect. While preserving the features of the B-spline method, the improved design method allows the cams to satisfy requirements, such as pressure angle, radius of curvature, and contact stress, and also reduces the residual vibrations caused by deviations in actual cam speed or system damping ratio from their design values.

scholarly journals The Dynamic Response of Tuned Impact Absorbers for Rotating Flexible Structures

2005 ◽  
Vol 1 (1) ◽  
pp. 13-24 ◽  
Author(s):  
Steven W. Shaw ◽  
Christophe Pierre
Keyword(s):  
Dynamic Response ◽  
Flexible Structures ◽  
Experimental Studies ◽  
Analytical Investigation ◽  
Design Parameters ◽  
System Response ◽  
Rotor Speed ◽  
Flexible System ◽  
Restoring Forces ◽  
And Performance

This paper describes an analytical investigation of the dynamic response and performance of impact vibration absorbers fitted to flexible structures that are attached to a rotating hub. This work was motivated by experimental studies at NASA, which demonstrated the effectiveness of these types of absorbers for reducing resonant transverse vibrations in periodically excited rotating plates. Here we show how an idealized model can be used to describe the essential dynamics of these systems, and used to predict absorber performance. The absorbers use centrifugally induced restoring forces so that their nonimpacting dynamics are tuned to a given order of rotation, whereas their large amplitude dynamics involve impacts with the primary flexible system. The linearized, nonimpacting dynamics are first explored in detail, and it is shown that the response of the system has some rather unique features as the hub rotor speed is varied. A class of symmetric impacting motions is also analyzed and used to predict the effectiveness of the absorber when operating in its impacting mode. It is observed that two different types of grazing bifurcations take place as the rotor speed is varied through resonance, and their influence on absorber performance is described. The analytical results for the symmetric impacting motions are also used to generate curves that show how important absorber design parameters—including mass, coefficient of restitution, and tuning—affect the system response. These results provide a method for quickly evaluating and comparing proposed absorber designs.

Application of Optimal Control Theory to the Synthesis of High-Speed Cam-Follower Systems. Part 1: Optimality Criterion

1983 ◽  
Vol 105 (3) ◽  
pp. 576-584 ◽  
Author(s):  
M. Chew ◽  
F. Freudenstein ◽  
R. W. Longman
Keyword(s):  
Optimal Control ◽  
Control Theory ◽  
Dynamic Response ◽  
Optimal Control Theory ◽  
High Speed ◽  
Integrated Approach ◽  
Optimization Criterion ◽  
Design Stage ◽  
Trade Offs ◽  
Cam Follower

The synthesis of the parameters governing the dynamic response of high-speed cam-follower systems ideally involves an integrated approach capable of carrying out the tradeoffs necessary to achieve optimum dynamic response in the design stage. These trade-offs involve a balance between the system characteristics at the output and at the cam-follower interface. In this investigation optimal-control theory has been demonstrated to be a useful tool in developing such a tradeoff. Part 1 describes the development of an optimization criterion while Part 2 describes the application of optimal-control theory to the evaluation of system parameters satisfying the optimization criterion.

A Simple Procedure for Modifying High-Speed Cam Profiles for Vibration Reduction

2004 ◽  
Vol 126 (6) ◽  
pp. 1105-1108 ◽  
Author(s):  
Ulf Andresen ◽  
William Singhose
Keyword(s):  
Real Time ◽  
High Speed ◽  
Simple Procedure ◽  
Vibration Reduction ◽  
Operating Costs ◽  
Input Shaping ◽  
Cam Design ◽  
Experimental Apparatus ◽  
Cam Follower ◽  
Computer Controlled

Unwanted vibration in cam-follower systems causes increased forces, noise, wear, and operating costs. This paper investigates the use of input shaping on cam profiles to reduce vibration. Input shaping is a real-time command modification algorithm developed for computer-controlled machines. In order to apply the concept to cam design, some modifications to the algorithm must be made. To test the validity of high-speed input-shaped cam profiles, an experimental apparatus was constructed with variable operating speeds and follower dynamics. The experimental results demonstrate the effectiveness of the proposed solution.

On the Dynamic Behavior of High Speed Mechanical Systems

1999 ◽  
Author(s):  
L. Yuan ◽  
J. Rastegar
Keyword(s):  
Dynamic Response ◽  
High Speed ◽  
Mechanical Systems ◽  
System Response ◽  
Structural Flexibility ◽  
State Behavior ◽  
Actuation Mechanism ◽  
Existence Of Periodic Solutions ◽  
Simulation Results ◽  
Steady State Behavior

Abstract This article reports a study of the steady state behavior of mechanical systems with nonlinear dynamics in the presence of dynamic response limitations of the actuation mechanism and in the presence of structural flexibility. In particular, the effects of such dynamic response limitations on the periodicity of the system response are studied and conditions for the existence of periodic solutions are derived. The structural flexibility is shown to increase the number of significant harmonics of the required actuating torques. A number of examples together with computer simulation results verifying the aforementioned results are presented.

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.

The Effect of Strain Rate on the Material Characteristics of Nickel-Based Superalloy Inconel 718

2007 ◽  
Vol 340-341 ◽  
pp. 283-288 ◽  
Author(s):  
Jung Han Song ◽  
Hoon Huh
Keyword(s):  
Dynamic Response ◽  
High Strain Rate ◽  
Strain Rate ◽  
Turbine Blade ◽  
Inconel 718 ◽  
High Speed ◽  
High Strain ◽  
Split Hopkinson Pressure Bar ◽  
Experimental Results ◽  
Stress Wave Propagation

The dynamic response of the turbine blade materials is indispensable for analysis of erosions of turbine blades as a result of impulsive loading associated with gas flow. This paper is concerned with the dynamic material properties of the Inconel 718 alloy which is widely used in the high speed turbine blade. The dynamic response at the corresponding level of the strain rate should be acquired with an adequate experimental technique and apparatus due to the inertia effect and the stress wave propagation. In this paper, the dynamic response of the Inconel 718 at the intermediate strain rate ranged from 1/s to 400/s is obtained from the high speed tensile test and that at the high strain rate above 1000/s is obtained from the split Hopkinson pressure bar test. The effects of the strain rate on the dynamic flow stress, the strain rate sensitivity and the failure elongation are evaluated with the experimental results. Experimental results from both the quasi-static and the high strain rate up to 3000/s are interpolated in order to construct the constitutive relation that should be applied to simulate the dynamic behavior of the turbine blade made of the Inconel 718.

Rotor-Dynamics of Different Shaft Configurations for a 6 kW Micro Gas Turbine for Concentrated Solar Power

2016 ◽  
Author(s):  
A. Arroyo ◽  
M. McLorn ◽  
M. Fabian ◽  
M. White ◽  
A. I. Sayma
Keyword(s):  
Gas Turbines ◽  
High Speed ◽  
Dynamic Models ◽  
Solar Power ◽  
Critical Issue ◽  
Rotor Dynamics ◽  
Mode Shapes ◽  
Concentrated Solar Power ◽  
Element Analysis ◽  
Rotor Dynamic

Rotor-dynamics of Micro Gas Turbines (MGTs) under 30 kW have been a critical issue for the successful development of reliable engines during the last decades. Especially, no consensus has been reached on a reliable MGT arrangement under 10 kW with rotational speeds above 100,000 rpm, making the understanding of the rotor-dynamics of these high speed systems an important research area. This paper presents a linear rotor-dynamic analysis and comparison of three mechanical arrangements of a 6 kW MGT intended for utilising Concentrated Solar Power (CSP) using a parabolic dish concentrator. This application differs from the usual fuel burning MGT in that it is required to operate at a wider operating speed range. The objective is to find an arrangement that allows reliable mechanical operation through better understanding of the rotor dynamics for a number of alternative shaft-bearings arrangements. Finite Element Analysis (FEA) was used to produce Campbell diagrams and to determine the critical speeds and mode shapes. Experimental hammer tests using a new approach based on optical sensing technology were used to validate the rotor-dynamic models. The FEA simulation results for the natural frequencies of a shaft arrangement were within 5% of the measurements, while the deviation for the shaft-bearings arrangement increased up to 16%.

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