scholarly journals Deterministic and Probabilistic Foundation Forces Resulting From an Unbalanced Turbine

1976 ◽  
Author(s):  
L. Boyce ◽  
T. J. Kozik

This paper considers the problem of the unbalanced rotating turbine as a single degree of freedom system, wherein the principal mode of vibration is a translation in the direction of the machine supports. The distance from the center of mass of the rotating mass to the geometric axis, also known as the effective eccentricity, is modeled as a random variable. The expression for the root mean square response of the rotating machine is derived and related to the statistical analog for the deterministic expression for the foundation force. These results are numerically compared to their equivalent deterministic values.

Author(s):  
D. Yurchenko ◽  
A. Burlon ◽  
M. Di Paola ◽  
G. Failla ◽  
A. Pirrotta

The paper deals with the stochastic dynamics of a vibroimpact single-degree-of-freedom system under a Gaussian white noise. The system is assumed to have a hard type impact against a one-sided motionless barrier, located at the system's equilibrium. The system is endowed with a fractional derivative element. An analytical expression for the system's mean squared response amplitude is presented and compared with the results of numerical simulations.


2021 ◽  
Vol 159 ◽  
pp. 104258
Author(s):  
Jeonghwan Lee ◽  
Lailu Li ◽  
Sung Yul Shin ◽  
Ashish D. Deshpande ◽  
James Sulzer

2014 ◽  
Vol 567 ◽  
pp. 499-504 ◽  
Author(s):  
Zubair Imam Syed ◽  
Mohd Shahir Liew ◽  
Muhammad Hasibul Hasan ◽  
Srikanth Venkatesan

Pressure-impulse (P-I) diagrams, which relates damage with both impulse and pressure, are widely used in the design and damage assessment of structural elements under blast loading. Among many methods of deriving P-I diagrams, single degree of freedom (SDOF) models are widely used to develop P-I diagrams for damage assessment of structural members exposed to blast loading. The popularity of the SDOF method in structural response calculation in its simplicity and cost-effective approach that requires limited input data and less computational effort. The SDOF model gives reasonably good results if the response mode shape is representative of the real behaviour. Pressure-impulse diagrams based on SDOF models are derived based on idealised structural resistance functions and the effect of few of the parameters related to structural response and blast loading are ignored. Effects of idealisation of resistance function, inclusion of damping and load rise time on P-I diagrams constructed from SDOF models have been investigated in this study. In idealisation of load, the negative phase of the blast pressure pulse is ignored in SDOF analysis. The effect of this simplification has also been explored. Matrix Laboratory (MATLAB) codes were developed for response calculation of the SDOF system and for repeated analyses of the SDOF models to construct the P-I diagrams. Resistance functions were found to have significant effect on the P-I diagrams were observed. Inclusion of negative phase was found to have notable impact of the shape of P-I diagrams in the dynamic zone.


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