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Structural damage detection
Published in You-Lin Xu, Jia He, Smart Civil Structures, 2017
Consider a numerical example, in which the mass, damping ratio and horizontal stiffness of a single-story shear building model are taken as 230.2 kg, 1% and 5.46 × 105 N/m, respectively. The ground excitation is taken as a zero-mean white noise stationary process. Five damage cases, stiffness reduction of 2%, 5%, 10%, 20% and 30% (Scenario 1 through Scenario 5), are considered. The structural displacement, velocity and acceleration responses are obtained, but the displacement responses are utilised hereinafter to effectively conduct damage detection.
Discrete-Time Stochastic Systems
Published in Raymond G. Jacquot, Modern Digital Control Systems, 2019
10.4. For the double-integrator inertial plant predict the response sequence statistics (mean and variance) for a stationary process noise sequence with mean value and variance w¯=E[wk]=0.5,E[(wk−w¯)2]=1. The governing system equation for a sampling interval of T = 0.2 s is [x1x2]k+1=[10.201][x1x2]k+[0.020.2]wk
Analysis of seismic damage using time series models and Artificial Neural Networks
Published in Peter J. Moss, Rajesh P. Dhakal, Progress in Mechanics of Structures and Materials, 2020
O.R. de Lautour, P. Omenzetter
AR models are used in the analysis of stationary time series processes. A stationary process is a stochastic process, i.e. one that obeys probabilistic laws, in which the mean, variance and higher order moments are time invariant. The structure’s response was assumed to be stationary. This is a reasonable assumption given the input into the structure can be considered as a random series of impulses.
Monitoring fractional nonconformance for short-run production
Published in Quality Engineering, 2018
Xin Zhou, Kondaswamy Govindaraju, Geoff Jones
A stationary process is one whose properties do not depend on the time at which it is observed, in particular its mean and standard deviation do not change. In contrast, a non-stationary process does not have a fixed mean or standard deviation. Performance of fractional nonconformance on both stationary and non-stationary process are discussed in this section.