National Repository of Grey Literature 18 records found  1 - 10next  jump to record: Search took 0.00 seconds. 
Petri Nets Virtual Machine Persistency
Bayer, Jan ; Janoušek, Vladimír (referee) ; Kočí, Radek (advisor)
This Bachelor's thesis deals with persistence for Java language. It presents and compares already existing standards and systems, and introduces a design and implementation of persistence for Java SE platform with object data stored in XML files. 
Analysis suggestion for vehicle scanning method
Bayer, Jan
An analytical approach is suggested that can be conveniently applied in the framework of the Vehicle scanning method (VSM). It assumes that the modal parameters of a bridge will be imported from a finite element (FE) program into MATLAB, where the structural response caused by a moving mass and a moving spring mass is solved using coupling equations and numerical integration. A mathematical formulation of the solution is presented together with a short numerical case study that compares the results to a traditional closed form solution. It is shown that when comparing both forms of analysis the suggested approach is more accurate in the case of slow velocities of the passing sprung mass. Other advantages are that the method allows for the mass of the vehicle or (tractor) towing vehicle and a damping \nto be included in the calculation. The user-friendly preprocessing in commercial FE programs can also be considered an advantage.
Adaptation of methods for cyclo-stationary processes for noisy structural health data
Fischer, Cyril ; Bayer, Jan ; Náprstek, Jiří ; Urushadze, Shota
In structural health analysis, various techniques, including indirect measurement via monitoring vehicles, often yield data with significant randomness and insufficient frequency separation. Conversely, the desired attributes under scrutiny are periodic in nature. Thus, methodologies designed to identify cyclo-stationary properties within noisy data can be adapted for such scenarios, assuming an adequate length of the recorded data.
Damage detection study for a pedestrian cable-stayed bridge using ANSYS
Bayer, Jan ; Kawulok, Marek ; Urushadze, Shota
In connection to development of new testing techniques for bridges at ITAM, a theoretical damage detection case study was performed for a cable stayed bridge over the Vltava River at Lužec. The results recognise the most susceptible loading modes which should be identified exactly during the in-situ measurements.
Modeling the moving cogwheel load - analysis using ANSYS & Matlab
Bayer, Jan
A moving impulse load generated by a heavy cogwheel (CW) can be used as a testing excitation for bridges. This previously proposed type of dynamic testing offers theoretically short testing times. Laboratory experiments confirmed already its capability of damage indication by repeated testing. This contribution suggests an approach how to solve the cogwheel movement using a Finite Element (FE) solver and Matlab. As the solution is theoretically nonlinear, the necessary limiting conditions for its application are formulated. Then the analysis is applied to simulate the passage of the CW over a simple laboratory model in order to compare it to laboratory experiments.
Protection of historic buildings against vibrations
Urushadze, Shota ; Pirner, Miroš ; Bayer, Jan
The presented heritage procedure was developed in 2018-2021 as part of the NAKI project no. DG18P02OVV040, entitled 'Monuments in Motion', funded by the Ministry of Culture of the Czech Republic. The basis for the design of this heritage procedure is the 30-year activity of Prof. Pirner, Ing. Urushadze and Ing. Bayer in the field of technical seismicity and building dynamics in general. The proposed heritage procedure is actually a methodological guide on how to proceed if there are any failures or negative effects that could be related to vibrations, as well as how to deal with them. For each of the various points of the procedure examples are given from our many years of practice. In general, these investigations involve theoretical and experimental analysis including in situ investigations, non-destructive and laboratory tests on models, using finite element modelling.\n
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Solving the moving mass problem on large finite element models with modal analysis – estimation of the discrete movement error
Bayer, Jan
Solving transient dynamic problems on large finite element (FE) models using a direct integration requires a high sampling rate and therefore also considerable computing times because of the large system matrices. Movement of a mass on a FE model has to follow the discrete pattern of the FEs, and is therefore of a discrete character. This introduces an unknown\nerror into the analytical results. Applying modal analysis (MA) reduces the number of equations used in the subsequent numerical integration by orders of magnitude. Resampling of the mode shapes to the required sampling rate makes it possible to solve the moving mass problem much more quickly and quasi-continuously. The performed comparative analytical study using ANSYS and MATLAB showed that using a discrete movement on the FE mesh when solving a moving mass problem can cause a considerable error.
Stress analysis of vaults in the building of the Masaryk´s University Centre in Telč
Bayer, Jan ; Drdácký, Miloš
The report summarizes the results of local surveys, expert opinions and analysis concerning the vaults in the building of the former Jesuit dormitory in Telč on Zachariáš Square in Hradec no. 2. The investigation was induced by the lack of inputs data for the assessment of the vaults for a new purpose: the establishment of a public library combined with a gallery. The performed FEM calculations estimated the stresses in the vaults of the room 0.22A and do not replace the static calculation, but can serve as an input information for a possible design project.
Damage detection using a cogwheel load - numerical case study
Bayer, Jan
A moving impulse load generated by a heavy cogwheel (CW) can be used as a testing excitation for bridges. This proposed type of dynamic load acts along the entire driving path, its intensity is adjustable, and it can be very efficient in the case of resonance. However, higher harmonic components are an inevitable effect of this type of loading, complicating the vibration analysis. The present study investigates suitable procedures to detect and locate damage in structures using a cogwheel load and only one or a few transducers mounted on the bridge. This arrangement seems to be sensitive to early damage indication. Damage localization is also possible, but further research will be required to increase its credibility.
Moving dynamic test loads for road bridges - a case study
Bayer, Jan ; Urushadze, Shota
Two types of dynamic testing load for bridges - driving sprung mass and driving impulse load - areexamined from the drive-by identification point of view. Numerical studies in ANSYS using contact elements and in MATLAB using a modal solution together with coupling force were performed. Equations for the estimation of the impulse load caused by a rolling cogwheel were suggested. The experiments confirmed that a driving impulse load is more efficient in exciting bridge vibrations. This, together with the fact that impulse loading is not sensitive to surface roughness, leads to the conclusion that, as a method for bridge health monitoring, impulse loading is more promising than using a driving sprung mass

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See also: similar author names
4 Bayer, Jakub
2 Bayer, Jiří
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