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2. Effects of fibre mass on the dynamic response of an inverted pendulum driven by fibres
- Creator:
- Polach, Pavel, Hajžman, Michal, Šika, Zbyněk, Mrštík, Jakub, and Svatoš, Petr
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- inverted pendulum, fibres, and vibration
- Language:
- English
- Description:
- Fibres, cables, wires and fibres can play an important role in design of many machines. One of the most interesting applications is replacement of chosen rigid elements of a manipulator or a mechanism by cables. The main advantage of this design is the achievement of a lower moving inertia, which leads to a higher mechanism speed, and lower production costs. An inverted pendulum attached and driven by two fibres serves as a typical testing system for the investigation of the fibres properties influence of the system dynamic response. Motion of the pendulum of this nonlinear system is investigated using the alaska simulation tool and an in-house program created in the MATLAB system. Since mass of fibres can influence employed types of fibre models, chosen dynamic quantities (e.g. pendulum angle, vibration amplitude etc.), are investigated in dependence on the excitation frequency for various fibres weights. and Obsahuje seznam literatury
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
3. Evaluation of the suitability of the bladed disk design regarding the danger of the resonant vibration excitation
- Creator:
- Polach, Pavel
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- bladed disk, resonant vibration, SAFE diagram, and continuous binding
- Language:
- English
- Description:
- A suitability of the bladed disk design regarding the possibility of the resonant vibration excitation can be assessed on the basis of several approaches. Most information concernng the evaluation of the bladed disk design suitability is provided in theSAFE diagram but the possibility of exciting the action wheel resonant vibration can also be evaluated from the Campbell diagram. Further criterion is the assessment of the design suitability on the basis of a critical speed of the bladed disk. It expecially causes breakdowns of relatively flexible disks. The suitability of the bladed disk with the blades of the ZN340-2 type was evaluated. and Obsahuje seznam literatury
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
4. Experimental and computational investigation of a simple mechanical system with fibre
- Creator:
- Polach, Pavel, Hajžman, Michal, and Václavík, Jaroslav
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- fibre, mechanical system, phenomenological model, dynamic response, experiment, and simulation
- Language:
- English
- Description:
- Experimental measurement is performed on a simple fibre-mass system: a moving mass coupled with the frame by a fibre. Dynamic response of the mass is measured. The same system is numerically investigated by means of a simple multibody model. The influence of the model parameters on the coincidence of results of experimental measurements and of simulations are evaluated. The simulations aim is to create a phenomenological model of a fibre, which will be utilizable in fibre modelling in the case of more complicated mechanical or mechatronic systems. and Obsahuje seznam literatury
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
5. Sensitivity analysis of gearbox torsional vibrations
- Creator:
- Hajžman, Michal and Polach, Pavel
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- flexible shafts, mesh gear, modal analysis, eigenfrequencies, resonance, and tuning
- Language:
- English
- Description:
- The paper deals with the modelling of a real gearbox used in cement mill applications and with the sensitivity analysis of its eigenfrequencies with respect to design parameters. The torsional model (including a motor and couplings) based on th finite element method implemented in an in-house MATLAB application is described. The sensitivity analysis of gearbox eigenfrequencies is performed in order to avoid possible dangerous resonance states of the gearbox. The parameters chosen with respect to the sensitivity analysis are used for tuning the gearbox eigenfrequencies outside resonance areas. Two approaches (analytical and numerical) to the sensitivity calculation are discussed. and Obsahuje seznam literatury
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
6. Verification of the calculation of natural vibration characteristics of linear undamped rotationally periodic structures
- Creator:
- Polach, Pavel
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- rotational periodicity, natural vibration characteristics, subsystem, and circular plate
- Language:
- English
- Description:
- The article presents results of the verification calculation of the method for the calculation of natural frequencies and mode shapes of a linear undamped rotationally periodic systems considering the possibility of the elimination of degrees of freedom. As the test example a thin circular plate was chosen. The method can be applied e.g. for the calculation of the natural vibration characteristics of the steam turbine bladed disks. and Obsahuje seznam literatury
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
7. Verification of the stabilizer bar of an articulated trolleybus
- Creator:
- Polach, Pavel
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- articulated trolleybus, driving stability, stabilizer bar, multibody dynamics, and experiment
- Language:
- English
- Description:
- At the modernization of the ŠKODA 22 Tr low-floor articulated trolleybus a different type of an articulated joint and a different type of driving axles were used in its construction besides other changes. During test drives with the modernized trolleybus, which were focused on the driving stability of the vehicle, a large roll of the rear section appeared. A suitable structural solution for reducing the rear section roll angle of the modernized trolleybus was the using of a rear section stabilizer bar. The stabilizer effect on dynamic properties of the vehicle and a suitable bar diameter were determined on the basis of the results of the computer simulations with the trolleybus multibody models. The text drives focused on the vehicle driving stability were performed again with the loaded real trolleybus, in the structure of which the designed rear section stabilizer bar was applied. On the basis of computer simulations of the test drives with the trolleybus multibody models the correctness of the experimantal-simulation approach used for the stabilizer bar structural design was verified. and Obsahuje seznam literatury
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public