As technology moves forward it has a tendency to consume more and more power that needs to be cooled by bigger and louder fans, this is especially true for the new generation of 5G radio equipment. This Master thesis is a collaboration with Ericsson and attempts to construct a shroud for containing a number of 5G radio units whilst attenuating the fan noise of the units as effectively as possible. In this project are air ducts used and at the ends silencers are created utilizing the Cremer impedance; the optimal wall impedance for damping an acoustic mode of a propagating wave. To predict the result, a simplified model in an acoustic FEM program was also explored and compared to the sound level of the constructed shroud. The finished shroud successfully reduces the noise of the radio units by 13 dB(A) while causing an increase in temperature of between 2.8°C to 5.9°C. This result was deemed to be a success and the Cremer impedance approach of reducing noise is therefore advised for future development. / Allt eftersom tekniken går framåt tenderar den att också förbruka mer och mer energi som i sin tur måste kylas av kraftigare och mer högljudda fläktar, detta fenomen är särskilt påtagligt när det kommer till den senaste generationens radioutrustning för 5G. Detta examensarbete är ett samarbete mellan KTH och Ericsson med avsikt att skapa en kåpa som är designad för att innesluta ett bestämt antal 5G radiomoduler. Denna kåpa ska i så stor utsträckning som möjligt dämpa det fläktinducerade bullret. I det här projektet nyttjas kanaler med ljuddämpare vid ändarna som dämpar ljudet med hjälp av Cremerimpedans, dvs: den väggimpedans som optimalt dämpar en akustisk mod. För att kunna förutspå resultatet skapades en förenklad akustisk modell i ett FEM program. Resultatet från denna modell jämförs sedan med ljudeffektnivån från slutmätningen av den färdiga kåpan. Resultatet från slutmätningen visar att kåpan lyckas sänka radioenheternas totala ljudeffektnivå med 13 dB(A) samtidigt som en temperaturökning på mellan 2.8°C och 5.9°C erhålls. Det här resultatet bedöms vara en framgång, vilket leder till slutsatsen att ljuddämpning med användning av Cremerimpedans rekommenderas för vidare arbete.

The process of design is time consuming and result oriented. There is always a better scope for any design that reduces the time with better precision. Considering this as a major factor during design process, two of the vital parts of the aircraft conceptual design are taken into account where a lot of time can be saved. Major components considered in this work are fairings for the lift generating surfaces and cockpit windshield. In this work the major inference is to reduce the time spent on the initial conceptual design. The two components designed in this work are fairings and windshield. The fairing design in this work provides a flexible template which can be used for various fuselage and wing configurations for transport aircrafts. The windshield is classified into two types in this work, flat and blend windshield. Both the type of windshields can be implemented on appropriate fuselage. Both the components are designed to be implemented in single pilot as well as double pilot aircrafts. They also have parameters which can be modified according to the user requirement. The changes in the parameters provide the change in shape, size and volume of the components. The software used for this is CATIA V5. The process is carried out using two automation methods available in CATIA namely Power-Copy and Knowledge pattern. A comparison between the effectiveness of two automation methods used in this work is performed.