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W systemach ciągłego monitoringu połączeń spawanych konstrukcji cienkościennych, najbardziej obiecującą jest metoda wibrodiagostyczna. Najważniejszą jej zaletą jest to, że jest efektywna i stwarza największe możliwości badań w czasie rzeczywistym. W pracy zastosowano metodę pomiarów charakterystyk dynamicznych konstrukcji przy pomocy czujników piezoelektrycznych. W artykule przedstawiono założenia...
The paper presents the analysis of dynamic interaction between a hand-arm and a hand-held grinder. A model of the system has been introduced that consists of a discrete model of a grinder and a simply biodynamic model of the human hand-arm. Basic equations describing the motion of the system were introduced. The random vibration (PSD) analysis was done. Some general conclusions were presented and...
Examination of structures integrity and failures detection are nowadays of great interest for both civil infrastructure and industry systems. This paper presents Structural Health Monitoring (SHM) technique that was tested on several laboratory models and utilizes elastic wave propagation phenomenon. Furthermore, it describes signals feature extraction procedure by using Principal Component Analysis...
Feed-forward layered Artificial Neural Networks (ANN) learnt by means the evidence procedure for Bayesian technique are used for simulation and prediction of hysteresis loops. Concrete hysteresis loops obtained by cyclic loading are considered. ANN were learned and tested on the experimental data. The prediction of the stress - strain relation was made for the last part of the experiment, basing on...
In the work presented of physical model of the system with joint elastic strip in the rigid clamp. Nonlinear friction model contact between elastic strip and rigid clamp, taking structural friction into account is presented. During load, relieve and again load free part of the strip, displacement in a function of the longitudinal force external was determined. The obtained dependences of the displacement...
The paper is concerned with qualitative analysis of a non-linear model describing the vibrations in cutting processes. The model of the regenerative turning process is described by two delay differential equations. The influence of selected parameters such as the rotational velocity and the frequency of the kinematic excitations as well as the cutting speed and the cutting resistance on the character...
The paper deals with the analysis of the soil-structure interaction in case of the transmission of ground vibrations from mining tremors to medium-height building foundation. The one of parameters used in scales of mine-induced dynamic influences (GSI-2004) to evaluate the harmfulness of ground vibrations to surface structures - maximal values (amplitudes) of resultant acceleration of horizontal vibrations...
The report refers to the identification of dynamic properties of tall buildings subjected to mining tremors. Taking into consideration the theoretical analysis from [2], the identification of natural frequencies of 2 high buildings (12 story) subjected to strong and very strong mining tremors was carried out for the buildings on flexible ground and with the assumption of non flexible ground. The amplitude...
This paper presents the application of Bayesian Neural Networks (BNN) in the identification of parameters of a load causing partial yielding of a cross-section of a portal frame. As the source of the data in the identification procedure the eigenfrequencies and eigenvectors are used. The applied BNN are either of SSN/MAP (Maximum A Posteriori) or of T-BNN (True Bayesian Neural Networks) type, the...
The article describes basic tests of the following: power consumption (supply voltage 1-6 kV, current intensity 5-25 A/cm2, power supply 10-100 W), temperature increases as well as technical solutions and construction of the tested electrorheological clutch. Two types of fluid were described: one-phase liquid in the form of "liquid crystals", which does not undergo sedimentation or coagulation,...
This paper is devoted to research on using artificial neural networks as the neural Kalman filters. The Kalman filters are widely used in the active control of building structures. There are described two types of neural networks worked as Kalman filters: linear neural filters and two-layer feedforward neural networks. The neural Kalman filters were tested in simulations of the active control of the...
The paper presents analysis of dynamic response of multiple support structures to seismic and mining related paraseismic excitation. Dimensions of the basis of structures are comparable with the length of the wave propagating in the ground and due to it they are exposed to non-uniform kinematic excitation. Calculations of the dynamic response were performed for earth dam at Niedzica and for concrete...
The paper presents the collocation method of determination damping coefficients of structural vibration. Moreover, usage of this method for several different building structures have been presented.
Mechanical vibration dampers (MVD) can be used for reduction of tower type structures vibrations. A method of determination of optimum parameters of MVD mating with this type of structures was described in [1]. The worked out computational method became the basis for design solutions. Talcing in the consideration the type of the structure (tower), the analysis concerned the amplitude-frequency characteristic...
The results of theoretical and numerical research into the stability and transversal vibrations of columns rested on Winkler type elastic base, are discussed in the paper. Systems realizing load by a force directed towards the positive pole and load by following force directed towards the positive pole are taking into account. The equations of motion and the boundary conditions of the considered columns...
General description of fluids applied to viscotic torsional dampers are presented in this paper. Results of experimental investigations of fluid viscosity influence on dissipated energy and angle of torsion of crankshaft as well as results of numerical computations are also included.
This paper discusses a theoretical-numerical model formulation for the prediction of vibrations from underground railway traffic. The model takes into consideration transfer junctions between the track lying in the underground tunnel and a free field. The rolling stock can be modeled as a multi-body vehicle chain. The dynamic axle loads due to the rails and wheels irregularities may be estimated....
The model of a carrying rope of a bicable ropeway system under in-service loads is introduced to analyze dynamic response of the cable during: start and steady ride of passenger carriers, an emergency stop of operating system. The pendulum model of amoving carrier is formulated to define loads acting on the cable. Equations of motion of system composed of continuous cable and a set of traveling pendulums...
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