A Design Criterion for Avoiding Resonance in Lumped Mass Normal Mode Systems

1989 ◽  
Vol 111 (1) ◽  
pp. 48-52
Author(s):  
A. D. S. Ross ◽  
D. J. Inman

A simple design criterion that determines whether a normal mode multiple degree of freedom damped linear lumped parameter system can or cannot resonate is presented. The relations are derived based on criteria for resonance in the single degree of freedom case, and on the definiteness of certain combinations of coefficient matrices. An example follows that both numerically verifies the derivation and illustrates the simplicity of implementing the result as a design criterion.

1986 ◽  
Vol 108 (2) ◽  
pp. 313-318 ◽  
Author(s):  
A. Sinha ◽  
J. H. Griffin ◽  
R. E. Kielb

This paper deals with the stabilizing effects of dry friction on torsional blade flutter. A lumped parameter model with single degree of freedom per blade has been used to represent the rotor stage. The well-known cascade theories for incompressible and supersonic flows have been used to determine the allowable increase in fluid velocity relative to the blade. It has been found that the effectiveness of friction dampers in controlling flutter can be substantial.


2001 ◽  
Author(s):  
John E. Speich ◽  
Liang Shao ◽  
Michael Goldfarb

Abstract This paper describes the development of a linear single degree-of-freedom lumped-parameter hand/arm model for the operator of a telemanipulaton system. The model form and parameters were determined from experimental data taken from a single degree-of-freedom telemanipulation system. Typically, the human is modeled as a second order mass-spring-damper system [1, 2]. The model developed in this paper, however, includes an additional spring and damper to better approximate the dynamics of the human while interacting with the manipulator. This model can be used in the design and simulation of control architectures for telemanipulation systems and haptic interfaces.


Author(s):  
Eric A. Butcher

Abstract The effects of a clearance or interference on the normal mode frequencies of a two-dof system with bilinear stiffness and without damping are investigated through various modifications of the bilinear frequency relation. First, the exact bilinear natural frequencies of a single degree-of-freedom system are analytically obtained in terms of the amount of clearance and the strength of nonlinearity, and an equivalent linear system is derived. These results are in turn used to construct three methods which approximate the bilinear frequencies for the 2-dof system in which the resulting approximate frequencies are compared with those obtained from numerical simulations. The results demonstrate how these bilinear normal mode frequencies vary with the magnitude of the clearance/interference and thus point toward the need of including such effects in methods which utilize the bilinear frequency relation.


Sign in / Sign up

Export Citation Format

Share Document