Structural Dynamics at Higher Frequencies using the Finite Element Method

Company Description


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Job Description


The bus industry is currently under development towards new generation electrical vehicles that creates high demands on noise, vibrations, and harshness (NVH) characteristics to sustain adequate comfort and strength. Further, a more simulation-driven design process requires new methodologies and acceptance criteria in terms of what dynamic stiffness the electric driveline require from the chassis in order to be able to realize a proper vibration isolation. Today a rule of thumb is used when dimensioning the chassis attachments that is based solely on the static stiffness of the isolators. However, experience shows that the dynamic stiffness increase with higher frequencies and from an NVH point this means the chassis attachment may be unnecessary stiff at higher frequencies and could be optimised with respect to mass and stiffness. The simulation models used today are too complex to adequately represent the higher frequencies excited by the electric driveline and a new modelling technique is desired to incorporate.
This thesis is a collaboration between AFRY and Scania where the problem formulation is delivered by Scania and the supervision is delivered by AFRY. The thesis student will develop new simulation methodologies and increase the overall knowledge that can pave the way for new modelling guidelines and rules of thumb, calibrated against measured values, with the option of doing new measurements on the test vehicles if needed for further studies. The results of this work is of great interest for Scania’s future development of electrical vehicles and it can contribute to new design criteria used as guidelines.
Proposed execution:
· Literature study regarding FE-modelling and understanding of dynamics stiffness in vehicles, choosing suitable software (preferable Hypermesh and Abaqus)
· Assessing adequate FE-modelling techniques, design criteria, and useful limitations
· Perform measurements of local dynamic stiffness on a Scania bus
· Calibrating the FE-model based on the measurements
· Incorporating new methodologies into the simulation-driven design process
· Proposing strength optimisation based on new derived knowledge




Qualifications


You should be on your final year of an education within Mechanical Engineering/Physics/Mathematics with an emphasis of strength and durability calculations. At least one course within FEM is required and preferably also some course covering structural dynamics.




Additional Information


The location of this thesis will be carried out at AFRY’s office in Solna and at Scania in Södertälje. The proposed thesis work period is during the spring semester of 2022 and you can apply by submitting your resume, cover letter and grades/transcripts. We will review all applications continuously.
For further information, please contact:
Jerk Svedman, jerk.svedman@afry.com
Patrick Jansson, patrick.jansson@afry.com
AFRY is committed to creating an inclusive & diverse environment and we are actively looking for qualified candidates irrespective of gender, gender identity, sexual orientation, ethnicity, religion, disability, or age. You will be part of a global and diverse company where our differences are our strengths. Join us to accelerate the transition towards a sustainable society.