From Data to Simulation: A dynamic shift fork analysis
Typ
Examensarbete för masterexamen
Master's Thesis
Master's Thesis
Program
Applied mechanics (MPAME), MSc
Publicerad
2024
Författare
Fahlgren, Elin
Åkesson, Edvin
Modellbyggare
Tidskriftstitel
ISSN
Volymtitel
Utgivare
Sammanfattning
In a truck’s AMT, gear shifting is performed by moving a sleeve with dog-clutch
teeth, to change the load path through the transmission. A pneumatic cylinder
pushes the system, which includes a rod, ring gear, and shift fork. Due to the fast
transient dynamics, rapid shift and high dynamic loads of the system, an explicit
dynamic FE model is used to simulate its behaviour. The aim is to build an FE
model of the fork and validate it against empirical test data, as well as find the
key parameters to describe the loads from a shift. Additionally, a regression was
developed to predict the strain in the fork during tooth collisions.
Boundary conditions, initial conditions, and forces included in the FE model were
estimated from empirical data from 30 shifts. FEA was used to identify key parameters
affecting the shift. The key parameters found were velocity and net force at
impact. The finished model has a 20% average error for the first displacement peak,
and a 32% average error for the second, compared to the empirical data. For the
regression, the key parameters were the acceleration of the ring gear, the velocity of
the rod, and the ring gear position at collision. The regression explains 55% of the
strain variation.
In conclusion, the project contains uncertainties due to the uniqueness of every shift.
However, the FE results correspond well with the test data but future research into
what damping should be used could enhance model accuracy.
Beskrivning
Ämne/nyckelord
FEA , FEM , Explicit , ANSA , ABAQUS , Transmission , Regression , Empirical data