Reliable lightweight design of cast components in trains and trucks

Purpose and goal

The pre-project goals were to develop a method to allow the incorporation of probabilistic fatigue constraints related to casting defects directly in topology optimisation and to study the benefits of using advanced materials (ADI). A global stress measure was developed that allows the required reliability to be defined at the start of the optimisation process. An industrial case study using a railway motor component gave a weight reduction of 21% with a specified maximum failure rate of 2%. Weight reductions of around 10% were identified in other components using advanced materials.

Expected results and effects

The project has exceeded expectations in identifying a simple and easy to implement methodology for the inclusion of probabilistic fatigue failure. A more advanced model has also been developed for estimating the effect of casting defects on the fatigue life with the intent of incorporating this into topology optimisation in a later full project. The proposed design methodology results in lighter components with a more well defined probabilistic fatigue life than previous approaches. This has been demonstrated for industrial components for applications in road and rail transport.

Planned approach and implementation

The project was split into 4 work packages to be completed by both industrial and academic partners. The work packages included formulation of a new methodology, demonstration of the methodology using industrial case studies and validation through fatigue testing of cast prototypes. A new approach to topology optimisation was developed successfully and 3 industrial components have been used as case studies. A number of cast prototypes have been ordered for one of these components and fatigue testing will be performed at KTH as soon as the prototypes are available.