Thesis Work

Req ID:531246 

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Impact of Interface Flexibility and Bolt Modelling Techniques on Load Distribution in Mechanical Assemblies       

 **Background
**Alstom’s traction enclosures are consists of many bolted and rivetted assemblies; current simulation uses simple bolt modelling methods to evaluate the bolt load distributions, often ignoring real stiffness of the interface. This often led to more demanding bolted joints in production, i.e. increased friction factors to resist sliding of the joints. This increases the overall production cost of the enclosure. Therefore, deep understanding of bolted joint structural performance under different modelling techniques is required to avoid conservative assumptions in the simulations.               

Problem description and goals

The thesis project will focus on validating different modelling techniques of bolted joints in finite element software. Model a comprehensive detailed bolt model considering all the stiffness and geometry parameters and different mesh gradients. Compare the results of the detailed model with the current simple modelling methods.

Activities

1. Introduction to traction enclosure mechanical design.
2. Understand Structural requirements of railway vehicle bodies, e.g. EN 12663-1
3. Read and understand the bolt modelling methods recommended by literature and across different industries.
4. Introduction to Alstom FEA tools (alternatively model development in relevant tools used at student’s academic institution)
5. Implement different modelling methods for bolted joints in the FE tool.
6. Perform and compare the results between detailed bolt modelling, simple modelling methods and rigid body bolt calculation.
7. Evaluate the bolted joints using VDI2230 and Alstom engineering instructions.
8. Evaluate the results against physical testing.
9. Assessment for static proof loads and dynamic fatigue loads.
10. Recommend an efficient finite element bolt modelling method and mesh gradient in the vicinity of the bolts.
11. Conclusions and reporting.
12. Differentiation of modelling techniques for rivetted & bolted joints can be adapted to the scope.

Prerequisites: Background in Mechanical engineering, understanding of structural design, bolt joint analysis, familiarity with FEA tools. Good analytical skills and systems thinking mindset.

Type of degree project (can be both)                      Language for the thesis       Master (20 weeks):☒                                                Swedish:☒ and/or English:☒
Suggested number of students: 1       
Bachelor/Högskoleingenjör (10 weeks): ☐                 

Is Swedish a language requirement? Yes:☐             
No: ☒
No, but Swedish is a requirement for future employment:☐
**

Possibility to work from our office**
Yes:☒
No:☐

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