Numerical modelling of the preloaded bolted connections

master's thesis

• Title (croatian): Numeričko modeliranje prednapregnutih vijčanih spojeva
• Author: Matija Kalauz
• Mentor: Zdenko Tonković (mentor)
• Granter: University of Zagreb; Faculty of Mechanical Engineering and Naval Architecture; Zagreb
• Defense date and country: 2020-05-15, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Mechanical Engineering

Abstract

Bolts and bolted connections are the most common compounds that are used in almost all industries, especially in the car industry. Because they are so commonly used, they represent a certain challenge to find a way to stop their loosening and to detect what is their pretension loss due to various influences. In recent times, the car industry is turning to manufacture hybrid and electrical vehicles more and more. Since they are turning to that segment of production, various batteries, which first have to be tested before “the real time use” are developing. Bolts connect many parts in all batteries, and because of that, it is necessary to investigate how much those bolts are able to keep 100% of their initial pretension force, under various conditions. Also, in the world of the bolts and the bolted connections it is very familiar when certain pretension force is applied, it starts to drop immediately. Because of the viscoelastic behavior of the underlaying material, that effect of pretension loss exists. Considering all of that, in this thesis using the theoretical background and finite element method it is going to be investigated what is the pretension loss due to the viscoelastic behavior of the material with which the bolt and the nut are connected. Because of that, it is necessary to develop a method, which will be able to examine how relaxing of the bolted connection is influencing the pretension and which will be usable when real tests are done.

Abstract (croatian)

Vijci i vijčani spojevi su najzastupljeniji spojevi koji se koriste u gotovo svim industrijama, a pogotvo u automobilskoj. Zbog velike zastupljenosti predstavljaju izazov kako bi se zaustavilo njihovo popuštanje, te kako bi se detektiralo koliko je njihovo popuštanje uslijed različitih utjecaja. U novije vrijeme sve više se auto industrija okreće proizvodnji hibridnih i električnih automobila. Kako se okreće tom segmentu proizvodnje razvijaju se različite baterije koje trebaju zadovoljiti testiranja prije upotrebe u stvarnom svijetu. Mnogo dijelova u samim baterijama upravo je spojeno vijcima, te zbog toga je potrebno ispitati koliko će uistinu ti vijci moći zadržati 100% svog prednapregnutog stanja, pod različitim utjecajem. Isto tako, uvelike je poznato u svijetu vijaka i vijčanih spojeva da čim se pojedini vijčani spoj pritegne, njegova sila prednaprezanja počinje gubiti svoju vrijednost. Zbog viskoelastičnog ponašanja podložnog materijala taj efekt gubitka sila prednaprezanja postoji. S toga u ovom radu će pomoću teorijske pozadine i pomoću metode konačnih elemenata biti ispitano koliki je gubitak sile prednaprezanja uslijed viskoelastičnog ponašanja materijala s kojima su vijak i matica spojeni. Iz tog razloga, potrebno je razviti metodu pomoću koje će se moći ispitiati kako relaksiranje vijčanog spoja utječe na gubitak prednaprezanja i koja će biti upotrebljiva onog trenutka kada stvarna testiranja budu gotova.

• Keywords: bolt; relaxation; finite element method; pretension
• Keywords (croatian): vijak; relaksacija; metoda konačnih elemenata; prednaprezanje
• Language: english
• URN:NBN: urn:nbn:hr:235:868819
• Study programme: Title: Mechanical Engineering; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra inženjer/inženjerka strojarstva (magistar/magistra inženjer/inženjerka strojarstva)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2020-05-07 10:32:58