Structural Optimization of Mechanical Systems - Topology optimization with parametrization of hardpoint positions
Typ
Examensarbete för masterexamen
Program
Applied mechanics (MPAME), MSc
Publicerad
2019
Författare
Berndtsson, Aliki
Mattiasson, Andreas
Modellbyggare
Tidskriftstitel
ISSN
Volymtitel
Utgivare
Sammanfattning
This is the report for a master’s thesis project on structural optimization of mechanical
systems, at Volvo Cars. The shift towards electric propulsion and high cost
of battery capacity puts further need for lightweighting since it can bring significant
cost advantages in terms of price per range. Topology Optimization (TO) is
a method that finds its true potential in context with additive manufacturing due
to high level of design freedom, but it can also be beneficial in context with other
manufacturing techniques such as casting. Previous thesis projects at Volvo Cars
have emphasized TO in the context of casted components and it is widely used today.
However, TO is often used to refine the geometry relatively late and applied to
single components with predetermined boundary conditions such as joint loads and
joint positions, i.e. constraints that narrows the solution space. The main idea for
this project is therefore to broaden the solution space by introducing TO on system
level together with an outer parametric loop for joint positions. This method can
be applied to mechanical systems in general, but the main focus is to provide a
prestudy for applications within automotive wheel suspension systems.
A Finite Element (FE) model of a rear wheel suspension system is developed and
validated with respect to force signals from an existing, dynamic, full vehicle model.
The linkages are then optimized with respect to stiffness and weight based on current
joint positions. The proposed scheme for parametrization of joint positions is
limited to a two-component system.
Over all, the FE-model correlates well with respect to force signals, but there are still
room for improvements, especially with respect to modeling of dampers. In order
to introduce proper stiffness constraints during optimization, there is also a need
for correlation of the FE-model with respect to displacements. The future potential
for TO on system level seems promising. In addition to a broader solution space
through parametrization of joint positions the relative mass distribution between
different components are treated within one single system optimization.
Beskrivning
Ämne/nyckelord
Structural optimization of a multibody systems , Topology optimization , Parametrization of joint positions