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Computational modelling of noise inside cabin of aircraft VUT 100 Cobra
Prnka, Jiří ; Houfek, Lubomír (referee) ; Švancara, Pavel (advisor)
This master’s thesis deals with the computational simulation of low-frequency noise inside the cabin of small commercial airplane VUT 100 Cobra. For this low-frequncy range deterministic methods: Final Element Method (FEM) and Boundary Element Method (BEM) are used for simulation of the dynamic behaviour of the object. FEM has been used to compute eigenmodes and eigenfrequences of the structure of the aeroplane cabin and of the acoustic space inside cabin. Then response to harmonic excitation of engine represented by unit forces in place of contact has been computed. Obtained velocities on the surface of the cabin are then used as the basis for the noise calculation inside the cabin using BEM. After that effect of some construction modifications on sound level inside cabin are evaluated by computational modelling.
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Analysis of Possible Crash Avoidance of Personal and Rail vehicles at Railroad Crossings
Glogar, Matěj ; Bradáč, Albert (referee) ; Prnka, Jiří (advisor)
Presented diploma thesis deals with problems connected with accidents at railroad crossings from the road and railway drivers´ perspectives. The theoretical part is particularly focused on the explanation of chosen regulations associated with railroad crossings, with their construction and technical design and also with ways and options of marking in connection with railroad crossing safety system. The paper mentions the most frequent causes why dangerous situations occur. These causes arise from the railway and road drivers´ personal experience, supplemented by statistics of accidents at railroad crossings for the previous periods. The practical part analyses the options for averting a collision on two particular railroad crossings. For this purpose, the railroad crossing secured by lights and the railroad crossing secured only by a warning cross were chosen. Here, with Virtual Crash programme support, the origin of the chosen crisis situations is simulated and later options of their averting are evaluated. Finally, proposals for increasing railroad crossings safety are formulated for both cases. The appendix consists of a list of legislative regulations dealing with railroad crossings, a driving record of the rail vehicle and its technical parameters and simulation programme´s outputs.
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Damage correspondence of car hit by the fragments of roofing
Prnka, Jiří ; Sedlák, Robert
The article deals with the traffic accident with supposed contact of a car with fragments of roofing, which were lost from an oncoming truck, and caused subsequent running off a car into a ditch. Based on correspondence damage, mechanism of damage and movement of fragments of roofing it was researched if the question could arise as mentioned accident plot, as it was described by the participant.
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The issue of longitudinal safe distance between vehicles
Zemánek, Lukáš ; Prnka, Jiří
This technical article deals with the issue of observance of the longitudinal safe distance between vehicles. It contains an analysis of car accidents on roads in the Czech Republic, in respect of car accidents caused by nonobservance of the safe distance. It also deals with the legislative requirements for observance of the safe distance and at the conclusion is accomplished an analysis of observance of the longitudinal safe distance between vehicles (cars, vans and trucks) on D1 highway under various conditions.
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Analysis of Possible Crash Avoidance of Personal and Rail vehicles at Railroad Crossings
Glogar, Matěj ; Bradáč, Albert (referee) ; Prnka, Jiří (advisor)
Presented diploma thesis deals with problems connected with accidents at railroad crossings from the road and railway drivers´ perspectives. The theoretical part is particularly focused on the explanation of chosen regulations associated with railroad crossings, with their construction and technical design and also with ways and options of marking in connection with railroad crossing safety system. The paper mentions the most frequent causes why dangerous situations occur. These causes arise from the railway and road drivers´ personal experience, supplemented by statistics of accidents at railroad crossings for the previous periods. The practical part analyses the options for averting a collision on two particular railroad crossings. For this purpose, the railroad crossing secured by lights and the railroad crossing secured only by a warning cross were chosen. Here, with Virtual Crash programme support, the origin of the chosen crisis situations is simulated and later options of their averting are evaluated. Finally, proposals for increasing railroad crossings safety are formulated for both cases. The appendix consists of a list of legislative regulations dealing with railroad crossings, a driving record of the rail vehicle and its technical parameters and simulation programme´s outputs.
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Computational modelling of noise inside cabin of aircraft VUT 100 Cobra
Prnka, Jiří ; Houfek, Lubomír (referee) ; Švancara, Pavel (advisor)
This master’s thesis deals with the computational simulation of low-frequency noise inside the cabin of small commercial airplane VUT 100 Cobra. For this low-frequncy range deterministic methods: Final Element Method (FEM) and Boundary Element Method (BEM) are used for simulation of the dynamic behaviour of the object. FEM has been used to compute eigenmodes and eigenfrequences of the structure of the aeroplane cabin and of the acoustic space inside cabin. Then response to harmonic excitation of engine represented by unit forces in place of contact has been computed. Obtained velocities on the surface of the cabin are then used as the basis for the noise calculation inside the cabin using BEM. After that effect of some construction modifications on sound level inside cabin are evaluated by computational modelling.
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