Numerička analiza utjecaja zaostalih naprezanja nastalih postupkom zavarivanja na deformiranje konstrukcije pri vlačnom opterećenju

undergraduate thesis

• Title (english): Numerical analysis of the influence of residual stresses caused by welding on the deformation of the structure under tensile load
• Author: Antonio Vrbanus
• Mentor: Zdenko Tonković (mentor)
• Mentor: Boris Jalušić (komentor)
• Granter: University of Zagreb; Faculty of Mechanical Engineering and Naval Architecture; Zagreb
• Defense date and country: 2023-09-27, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Mechanical Engineering; General Mechanical Engineering (Construction)

Abstract

Razvojem tehnologije pokušavaju se unaprijediti i postupci zavarivanja. Široko primjenjiv MAG postupak zavarivanja pokazuje nedostatke kod zavarivanja debelih ploča zbog velikog broja prolaza. Rješenje tog problema nalazi se u njegovoj modifikaciji, zavarivanju tehnologijom zakopanog električnim lukom, koja omogućuje zavarivanje uzoraka veće debljine u jednom prolazu. Međutim, zavarivanje u konstrukciji uzrokuje zaostala naprezanja koja mogu dostići vrijednosti granice tečenja. Štoviše, uz navedena zaostala naprezanja na konstrukciju djeluju i vanjska opterećenja pa iznosi naprezanja mogu dostići vrijednosti iznad granice tečenja,što može uzrokovati neželjene posljedice.
Zbog toga je u radu detaljno ispitan utjecaj zaostalih naprezanja na vlačno opterećeni sučeono zavareni spoj izrađen postupkom zakopanog luka. Tehnikom mapiranja zaostala naprezanja su prebačena s validiranog modela na identični model za koji su napravljene 3 različite gustoće mreža i koji je naknadno opterećen sa 3 različita iznosa pomaka. Nadalje, provedena je numerička analiza metodom konačnih elemenata u programu Abaqus te su rezultati uspoređeni s dosadašnjim istraživanjem.

Abstract (english)

Engineers are trying to improve welding procedures with the development of new
technologies. Widely used MAG welding process shows disadvantages when it
comes to welding thick plates due to the large number of passes needed. The
solution to this problem is found in its modification, buried-arc welding, which enables
welding of thick specimens in one pass. However, welding causes residual stress
within the structure, which can reach the values of yield point. Moreover, in addition
to the mentioned residual stresses, extreme loads also act on the structure so the
amount of stress can be much higher than the yield stress, causing undesired
consequences.
For this reason, the impact of the residual stresses on a butt-welded joint, welded by
buried arc methodology was investigated in this paper. Using the mapping technique,
the residual stresses were transferred from the validated model to an identical model
for which 3 different finite element mesh densities. After that, 3 different values of
displacements were prescribed onto the meshes. Numerical analysis was then
carried out using the finite element method in the Abaqus program, and the results
were compared with previous research.

• Keywords: zakopani električni luk; zaostala naprezanja; mapiranje naprezanja; numerička analiza; metoda konačnih elemenata; Abaqus; vlačno opterećenje
• Keywords (english): buried arc; residual stresses; stress mapping; numerical analyses; finite element method; Abaqus; tensile load
• Language: croatian
• URN:NBN: urn:nbn:hr:235:952367
• Study programme: Title: Mechanical Engineering; Study programme type: university; Study level: undergraduate; Academic / professional title: sveučilišni/a prvostupnik/ prvostupnica (baccalaureus/baccalaurea) inženjer/inženjerka strojarstva (sveučilišni/a prvostupnik/ prvostupnica (baccalaureus/baccalaurea) inženjer/inženjerka strojarstva)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2023-09-24 20:55:30