Jørgen Apeland Application of FE-analysis in Design and Verification of Bolted Joints According to VDI 2230 at CERN MSc Thesis Genève, February 2018 Supervisor: Torgeir Welo, NTNU Antonio Lafuente Mazuecos, CERN 6 0 Luca Dassa, CERN 0 - 18 0 2 - S I S E H8 1 T0 N-/2 R02 E/ C17 Norwegian University of Science and Technology Faculty of Engineering Department of Mechanical and Industrial Engineering Application of FEA in Design and Verification of Bolted Joints According to VDI 2230 Preface This master thesis was written the Fall of 2017 and early 2018, and concludes my degree in Mechanical Engineering at the Norwegian University of Science and Technology. The master project has been carried out while being a technical student in the engineering department at CERN, the European Organisation for Nuclear Research. The thesis is about how computer simulation tools can be combined with VDI 2230, a calculation guideline for bolted joints, to achieve quality and productivity rewards in design and verification of bolted joints. The scope was also to lower the threshold and making it easier to perform such assessments. It takes basis in a specific engineering case, which demonstrates the need for improved knowledge and an analysis strategy. A complete framework with a simplified workflow and support material is presented and demonstrated. In the end, specific recommendations for the initial engineering case are given. The reader is expected to have basic knowledge in mechanics, springs, bolted joints and finite element analysis. ANSYS Workbench V17.2 has been used for FE-analysis, and Mathcad Prime V4.0 for engineering calculations. Genève, 2018 Jørgen Apeland I MSc Thesis 2018 II Application of FEA in Design and Verification of Bolted Joints According to VDI 2230 Acknowledgements I would like to thank my CERN supervisors Luca Dassa and Antonio Lafuente for their guidance, discussions, and thorough feedback during my research. They have been essential for the initiation and development of the project. I would also like to thank my supervisor at NTNU, Torgeir Welo, for his contributions and reviews, and for making this project possible. The design and analysis office in EN-MME has provided a friendly and international working environment, and they have provided useful input on user experiences and needs related to analysis of bolted joints. Finally, I would like to thank CERN and the Technical Student Programme for establishing a framework where students can come and take part in cutting edge technology development, and get practical and valuable experiences in a high competence environment. III MSc Thesis 2018 IV Application of FEA in Design and Verification of Bolted Joints According to VDI 2230 Abstract This thesis investigates how finite element analysis (FEA) can be used to simplify and improve analysis of bolted joints according to the guideline VDI 2230. Some aspects of how FEA can be applied to aid design and verification of bolted joints are given in the guideline, but not in a streamlined way that makes it simple and efficient to apply. The scope of this thesis is to clarify how FEA and VDI 2230 can be combined in analysis of bolted joints, and to present a streamlined workflow. The goal is to lower the threshold for carrying out such combined analysis. The resulting benefits are improved analysis validity and quality, and improved analysis efficiency. A case from the engineering department at CERN, where FEA has been used in analysis of bolted joints is used as basis to identify challenges in combining FEA and VDI 2230. This illustrates the need for a streamlined analysis strategy and well described workflow. The case in question is the Helium vessel (pressure vessel) for the DQW Crab Cavities, which is an important part of the High Luminosity upgrade of LHC (HL-LHC). Investigations are performed into prying, a relevant source of non-linear bolt loads and unpredictable load development, to understand the phenomenon and influence of preload. A complete analysis framework is then presented, which consist of a streamlined basic workflow, associated calculation template, details of more advanced verifications, a detailed guide with best practices and references, examples where the analysis framework has been applied, and a seminar to educate relevant personnel. In the end, suggestions and recommendations are provided for a potential revision of the Helium vessel analysis. The hope is that this thesis can be used as a resource in analysis of bolted joints using VDI 2230 and FEA, and that it will benefit the engineering department at CERN and other relevant users. V MSc Thesis 2018 VI Application of FEA in Design and Verification of Bolted Joints According to VDI 2230 Sammendrag Denne oppgaven tar for seg hvordan datasimuleringer (FEA) kan benyttes til å forenkle og forbedre analyse av boltede forbindelser i henhold til retningslinjene i VDI 2230. Enkelte aspekter av hvordan FEA kan benyttes for å assistere design og verifikasjon av boltede forbindelser er omtalt i retningslinjene, men ikke på en strømlinjeformet måte som gjør det enkelt og effektivt å benytte. Målet med oppgaven er å redegjøre for hvordan FEA og VDI 2230 kan kombineres, og å presentere en strømlinjeformet arbeidsflyt. Håpet er dermed å senke terskelen for å utføre slike kombinerte analyser. Fordelene er forbedret validitet og kvalitet i analysen, samt forbedret effektivitet i prosessen. Det er tatt utgangspunkt i en analyse fra ingeniøravdelingen ved CERN, hvor FEA har blitt benyttet i verifikasjon av boltede forbindelser. Denne er brukt som basis for å identifisere utfordringer med å kombinere FEA og VDI 2230, og illustrerer behovet for en strømlinjeformet analyse strategi og detaljert beskrivelse av arbeidsflyten. Analysen det er tatt utgangspunkt i er en Helium beholder (trykkbeholder) for DQW Crab Cavities, som er en viktig del av en kommende oppgradering av LHC kalt High Luminosity LHC (HL-LHC). En aktuell kilde for ikke-lineære bolt laster og uforutsigbar last utvikling kalt prying er undersøkt for å forstå fenomenet bedre, samt innvirkningen av forspenning. Et komplett analyse rammeverk er presentert, som består av en strømlinjeformet arbeidsflyt, tilhørende beregnings mal, detaljer om mer avanserte beregninger og verifikasjoner, en detaljert guide med «beste praksis» og relevante referanser, eksempler hvor den foreslåtte arbeidsflyten er benyttet, samt et seminar for å undervise relevant personell. Til slutt er spesifikke forslag og anbefalinger for en potensiell revisjon av Helium beholder analysen gitt. Håpet er at denne oppgaven kan bli benyttet som en ressurs innen design og verifikasjon av boltede forbindelser ved bruk av VDI 2230 og FEA, og at den vil være til nytte for ingeniøravdelingen ved CERN og andre relevante brukere. VII MSc Thesis 2018 VIII