Building Stiffness Estimation by Wave Traveling Times

2014 ◽  
Author(s):  
Jesús Morales-Valdez ◽  
Luis Alvarez-Icaza
Keyword(s):  
Wave Propagation ◽  
Modal Analysis ◽  
Single Layer ◽  
Original Formulation ◽  
Arrival Times ◽  
Identification Methods ◽  
Novel Technique ◽  
Wave Propagation Method ◽  
Local Technique ◽  
Interesting Alternative

A novel technique to estimate stiffness in buildings is presented. In contrast with most of the available work in the literature that resorts to diverse forms of modal analysis, this local technique is based on the propagation of a Ricker pulse through the structure and on measuring the wave arrival times at each story of the building, represented as a single layer in a multiple stratum model. These arrival times are later used to recuperate building stiffness at each story. Wave propagation is based on the Thomson-Haskell method, that allows to generalize the wave propagation method to multi-story buildings without significant changes to the original formulation. The number of calculated parameters is small in comparison with methods based on modal analysis. This technique provides and quick and easy methodology to assess building integrity and is an interesting alternative to verify results obtained by other identification methods. Simulation results for building with heterogeneous characteristics across the stories confirm the feasibility of the proposal.

Non-iterative bi-directional wave propagation method for treating reflections

2007 ◽  
Vol 276 (2) ◽  
pp. 246-250 ◽  
Author(s):  
Manmohan Singh Shishodia ◽  
Anurag Sharma
Keyword(s):  
Wave Propagation ◽  
Wave Propagation Method ◽  
Directional Wave

scholarly journals A Discrete Huber-braun Neuron Model: From Nodal Properties to Network Performance

2021 ◽  
Author(s):  
Shaoba He ◽  
Karthikeyan Rajagopal ◽  
Anitha Karthikeyan ◽  
Ashokkumar Sriniva
Keyword(s):  
Wave Propagation ◽  
Network Performance ◽  
Neuron Model ◽  
Coupling Effect ◽  
Single Layer ◽  
Simple Wave ◽  
Spiral Waves ◽  
Neuron Models ◽  
Positive Role ◽  
Multiple Wave

Abstract Many of the well-known neuron models are continuous time systems with complex mathematical definitions. Literatures have shown that a discrete mathematical model can effectively replicate the complete dynamical behaviour of a neuron with much reduced complexity. Hence, we propose a new discrete neuron model derived from the Huber-Braun neuron with two additional slow and subthreshold currents alongside the ion channel currents. We have also introduced temperature dependent ion channels to study its effects on the firing pattern of the neuron. With bifurcation and Lyapunov exponents we showed the chaotic and periodic regions of the discrete model. Further to study the complexity of the neuron model, we have used the sample entropy algorithm. Though the individual neuron analysis gives us an idea about the dynamical properties, it’s the collective behaviour which decides the overall behavioural pattern of the neuron. Hence, we investigate the spatiotemporal behaviour of the discrete neuron model in single- and two-layer network. We have considered noise and obstacles as the two important factor which changes the excitability of the neurons in the network. When there is no noise or obstacle, the network display simple wave propagation with highly excitable neurons. Literatures have shown that spiral waves can play a positive role in breaking through quiescent areas of the brain as a pacemaker by creating a coherence resonance behaviour. Hence, we are interested in studying the induced spiral waves in the network. In this condition when an obstacle is introduced the wave propagation is disturbed and we could see multiple wave re-entry and spiral waves. Now when we consider only noise with no obstacle, for selected noise variances the network supports wave re-entry. By introducing an obstacle in this noisy network, the re-entry soon disappears, and the network soon enters idle state with no resetting. In a two-layer network when the obstacle is considered only in one layer and stimulus applied to the layer having the obstacle, the wave re-entry is seen in both the layer though the other layer is not exposed to obstacle. But when both the layers are inserted with an obstacle and stimuli also applied to the layers, they behave like independent layers with no coupling effect. This in a two-layer network stimulus play an important role in spatiotemporal dynamics of the network. Similar noise effects like the single layer network are also seen in the two-layer network.

scholarly journals On Transducers Localization in Damage Detection by Wave Propagation Method

Sensors ◽  
2019 ◽  
Vol 19 (8) ◽  
pp. 1937 ◽  
Author(s):  
Adam Stawiarski ◽  
Aleksander Muc
Keyword(s):  
Wave Propagation ◽  
Damage Detection ◽  
Composite Structures ◽  
Detection Efficiency ◽  
Detection System ◽  
Damage Index ◽  
Detection Methods ◽  
Levels Of Analysis ◽  
Wave Propagation Method ◽  
Different Levels

In this paper, the elastic wave propagation method was used in damage detection in thin structures. The effectiveness and accuracy of the system based on the wave propagation phenomenon depend on the number and localization of the sensors. The utilization of the piezoelectric (PZT) transducers makes possible to build a low-cost damage detection system that can be used in structural health monitoring (SHM) of the metallic and composite structures. The different number and localization of transducers were considered in the numerical and experimental analysis of the wave propagation phenomenon. The relation of the sensors configuration and the damage detection capability was demonstrated. The main assumptions and requirements of SHM systems of different levels were discussed with reference to the damage detection expectations. The importance of the damage detection system constituents (sensors number, localization, or damage index) in different levels of analysis was verified and discussed to emphasize that in many practical applications introducing complicated procedures and sophisticated data processing techniques does not lead to improving the damage detection efficiency. Finally, the necessity of the appropriate formulation of SHM system requirements and expectations was underlined to improve the effectiveness of the detection methods in particular levels of analysis and thus to improve the safety of the monitored structures.

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