Finite Element (FE) post-processing for the rapid identification and visualisation of non-redundant structural failure modes and locations in global vehicle design

Abstract

A challenge in structural design is the inability to quickly assess how a change in use can affect the structural performance of the system. This is particularly important in the bus industry where there is often multiple variations of one base product type for many customers. Thus for a single design there can be frequent changes to mission profiles or customer constraints, which must be considered within short time periods before production commences for a particular customer. This can often limit full understanding of the structural performance, key structural features or critical failure modes, ultimately limiting the potential for producing buses with minimum structural mass. The aim of this research is to use performance envelopes to develop a design tool capable of rapidly informing structural design engineers with respect to the structural limitations of various vehicle components using performance envelopes.

Vehicle performance envelopes define the combinations of global vehicle accelerations (lateral, vertical and longitudinal) that cause structural failure of any feature or component included in the envelope. Additionally, envelopes will enable definition of the critical (non-redundant) and redundant structural failure modes for each feature considered, e.g. material yielding, buckling or fatigue. The methods presented in this research have shown that structural performance envelopes can be developed in the global vehicle-level load space, that is, in terms of the longitudinal, lateral and vertical acceleration directions of the vehicle in question. The method uses equations of failure to calculate the accelerations required to cause failure at iterative loading conditions in the global vehicle acceleration space. Alongside these structural performance envelopes, an applied loads envelope can be plotted in the same load space to allow a visual representation of the performance of the vehicle with respect to the loads it will experience in-service. This tool can be used to quantify the gap between the loads and performance envelope, in turn, identifying any areas of the vehicle’s structure that may be lightweighted, or that may fail during service. This design tool provides a more rapid approach to structural design analysis, compared with current practices in the industry, which are very manual and laborious, mostly depending on engineering skill and judgement.

Thesis is embargoed until 31 December 2027.

Date of Award	Dec 2022
Original language	English
Awarding Institution	Queen's University Belfast
Sponsors	Northern Ireland Department for the Economy & Bamford Bus Company Limited trading as Wrightbus
Supervisor	Adrian Murphy (Supervisor), Damian Quinn (Supervisor) & Trevor T Robinson (Supervisor)