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Evaluation of noise of ventilation outlet for a passenger car cabine
Libřický, Stanislav ; Vaňková, Marie (referee) ; Jedelský, Jan (advisor)
The thesis deals with issues of noise ventilation outlets in a passenger car. There is a description of the noise reduction in the acoustic background, optimizing experimental measurement methodology and familiarization with measuring equipment. The next step includes measuring of individual outlet options, results post-processing and comparison of tested alternatives. Based on these results the best variants are chosen and measures for decreasing noise in the ventilation outlets are proposed.
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Dynamic Characteristics of Exhaust System and Noise Transmition to the Car Cocpit
Novotný, Václav ; Ramík, Pavel (referee) ; Svída, David (advisor)
This thesis deals with the complex analysis of dynamic characteristics of the exhaust system and the transmission of noise from exhaust system to the vehicle. In the first part is performed modal analysis, which is compared to experimentally measured data. Modal analysis of the complete exhaust system is made with focusing on the influence of temperature of the exhaust system. There is also performed an analysis of noise transmission from exhaust system to the car cockpit.
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Proposal to change the categorisation of work at the selected workplace
Plánková, Barbora ; Rozehnalová, Jana (referee) ; Maradová, Karla (advisor)
The diploma thesis deals with work categorization falling into the issue of occupational health protection. The theoretical part is devoted to current legislative reguirements of the EU, the Czech Republic and relevant standards. It also provides a general overview of the system of public health authorities together with a more detailed description of the work categorization topic and related concepts and requirements. This thesis has been made in cooperation with Varroc Lighting Systems, s.r.o., Nový Jičín. The practical part deals with the suggested change of categorization of the optimized assembly line work positions for car rear lighting (B479 OUTER RL). The main aim of this work is to check the correctness of the classification of individual work positions. The intention of updating the categorization is also to reduce the negative impact of critical risk factors of working conditions, which brings benefits for both employees and employers. The specific course of the classification of individual risk factors with a focus on the noise as a critical risk factor is demonstrated on the riskiest work position of the assembly line. In the end, the achieved results of updated classification of all positions are evaluated. The follow-up changes and the resulting benefits of updating the categorization, including other practical recommendations, are also summarized.
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Passenger Car Internal Acoustics
Prokšová, Lucie ; Řehák, Kamil (referee) ; Novotný, Pavel (advisor)
The thesis is focused on the analysis of the acoustic properties of the interior of the passenger car by using the finite element method. Part of the work is an analysis of the excitation effects of individual vibration sources and the evaluation of the response in the interior of the cabin with a focus on the passengers of the vehicle and also solving the problem of the design of structural modifications in order to reduce the noise inside the cabin.
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Noise control of computers-application of optimal sound isolation layers and fun rotation speed
Kunovský, Martin ; Mišun, Vojtěch (referee) ; Pellant, Karel (advisor)
This thesis deals with the distribution of noise in the computer case and radiation into the neighborhood. Influence of geometrical shape and size of the computer case on radiated noise from the computer was investigated as well as effect of placement of the fan. Reducing noise by using sound absorbing material into computer case and result of the suitable position of the computer in the working environment were also tested. Simulation of the noise diffusion and effectivity of anti-noise equipment was executed in Ansys FEM program.
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Possibilities of Determining NVH Parameters of the Seat Track Release Mechanism in a Passenger Car
Ondriska, Viktor ; Řehák, Kamil (referee) ; Prokop, Aleš (advisor)
The focus of this thesis is the noise produced by a seat track release mechanism used in road vehicles. The goal of this work is exploring the possibilities of determining the radiated sound through experimental and computational means. The introduction is dedicated to different seat track designs. In the next chapter is a summary of computational means used to determine vibrations and noise. Further on, measurement methods of NVH parameters are described. Near the conclusion of the thesis there’s a breakdown of a newly developed seat track mechanism and the results of measurements that were carried out.
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Simulation of Noise Emitted by a Single-stage Gearbox
Motl, Daniel ; Hadaš, Zdeněk (referee) ; Lošák, Petr (advisor)
The level of noise and vibration of gearboxes is one of the most important parameters for today´s customers. This thesis deals with mathematical acoustic behavior modelling and its contribution to the gearbox design using finite element method. The process is presented at three computations models. Two of those were validated with experimental measurement. Acoustic analysis were performed with software FFT ACTRAN.
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NVH Analysis of Transmissions
Gazda, Silvester ; Zubík, Martin (referee) ; Prokop, Aleš (advisor)
This bachelor's thesis deals with the design of measuring noise and vibration of vehicle transmissions. First describes the main parts of the transmission. This is followed by a description of sources of vibration and noise, and their travel. Significant work is devoted to analysis of the frequency spectrum, of its creation and evaluation. It also includes a description of the measurement and the necessary equipment, along with a description of the basic principles of its functioning.
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Acoustic insulation of the hydraulic actuator INOVA
Kaščák, Pavol ; Skuhravý, Pavel (referee) ; Klapka, Milan (advisor)
This thesis deals with the design and testing of the acoustic enclosure for the Inova hydraulic actuator. The purpose of this enclosure is the acoustic insulation of the actuator and its parts, to achieve better acoustic conditions when performing acoustic diagnostics on this device. The first part deals with the theoretical basis of acoustic enclosures, the possibilities of modelling of acoustic problems and market research in materials usable for enclosure construction. The second part deals with the analysis of actuator noise and the localization of noise sources in the laboratory. Subsequently, the choice of material and concepts of the acoustic enclosure was made. Then, the final design solution was selected. The final design solution was subjected to acoustic simulations to predict insertion loss and determine the dimensions of the enclosure. The manufactured enclosure was tested in a semi-anechoic chamber and finally on the Inova actuator. Finally, the measurement results and simulation results are compared with each other.
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