Computational modelling of noise inside cabin of aircraft VUT 100 Cobra

Tato diplomová práce se zabývá výpočtovým modelováním nízkofrekvenčního hluku uvnitř kabiny malého dopravního letadla VUT 100 Cobra. Pro tuto nízkofrekvenční oblast jsou pro modelování dynamického chování objektů použity deteministické metody: Metoda konečných prvků (MKP) a Metoda hraničních prvků (MHP). Pomocí MKP byly počítány vlastní tvary a frekvence struktury kabiny a akustického prostoru uvnitř kabiny. Dále byla také řešena odezva na harmonické buzení od motoru, reprezentované jednotkovými silami v místě působení. Napočítané rychlosti na povrchu kabiny byly následně podkladem pro výpočet hluku uvnitř kabiny prostřednictvím MHP. Poté byl pomocí výpočtu posouzen vliv některých konstrukčních úprav na snížení hlučnosti.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.

The issue of longitudinal safe distance between vehicles

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

Damage correspondence of car hit by the fragments of roofing

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