The challenge
In 2014, the call for greener, more sustainable alternatives to city transport had led to the Mayor of London’s plans to gradually phase-out traditional combustion driven taxis. Specifically, starting from January 2018, no new diesel taxis would be granted vehicle licenses, and all new registered taxis must be zero-emissions capable.
For the London Electric Vehicle Company (LEVC), manufacturers of the iconic TX taxi series, this was an opportunity to re-engineer the London Taxi for the 21st century. Firstly, it would need to undergo a radical architectural redesign, from its material to its overall structure to properly house an electric powertrain. Secondly, the vehicle’s safety features would need to be lifted to the highest standards, to ensure the protection of the driver, passengers, and vulnerable road users (VRUs) in the city comprising pedestrians, cyclists, and powered two-wheelers. Finally, despite significant part differences from its predecessors, the vehicle was to retain the distinctive design features that gave the TX series its popularity.
With an ambitious launch date of early 2018, the TX electric taxi’s development programme time frame was short. Designs had to be finalised with limited prototype testing and in conjunction with the construction of a new manufacturing facility. To meet this deadline and stringent requirements, LEVC had to find additional resources and expertise that could help accelerate the design process.
The solution
Given the limited rounds of prototype testing available, the use of Computer-Aided Engineering (CAE) was crucial as it provided accurate and reliable predictions to guide the design process from the earliest concept stages. LEVC enlisted Arup’s team of automotive CAE specialists to provide all structural safety simulations and to support the development of the vehicle’s adhesively bonded body structure. Additionally, Arup was also responsible for conducting analysis on:
- Occupant and pedestrian safety
- Strength and durability
- Noise Vibration and Harshness
- Closures
- Interior and exterior systems
LS-DYNA was the primary analysis package used due to its flexibility to solve a range of linear and non-linear problems, as well as the modularity of its keyword file structure. This single-solver approach created a streamlined process that provided considerable time benefits as all load-cases drew from the same set of LS-DYNA include files. This eliminated the time-consuming need to convert large models into other formats and reduced the risk of information loss during the process.
The Arup team created a workflow, enabled by the Oasys LS-DYNA Environment, to efficiently construct and analyse the many simulation models required to support the design programme.
Oasys PRIMER, a pre-processor fully compatible with all LS-DYNA keywords, provided a safe environment in which to create and manage models. The include file manager was used to easily combine the vehicle systems required for each load case, from analysis of the bare structural frame through to a crash analysis of the entire vehicle complete with crash test dummies. PRIMER’s specialist tools aided connection management, model numbering and pedestrian mark-up with comprehensive keyword support. Model modifications could be made in confidence and verified with the powerful error checking function before submission.
Following LS-DYNA execution, the results extraction and report creation processes were accelerated using the post-processing software suite. Oasys D3PLOT enabled the team to visualise their analysis results and inspect specific parts of the model, while Oasys T/HIS allowed manipulation of data via mathematical functions, industry standard filters, and specialist functions for calculating injury criteria in automotive impact analysis. Lastly, in-built templates in Oasys REPORTER automated repetitive tasks, leaving the engineers more time for decision making.
Arup’s global team provided high value benefits for the development programme. Split between the UK and Shanghai, the engineers were able to directly support LEVC by sitting client-side in their design studio whilst leveraging the time difference to reduce the downtime on analysis and other urgent tasks. This setup also allowed Arup to utilise the depth of their automotive CAE experience and computing infrastructure.
Read ‘The Role of LS-DYNA® in the Design of the New London Electric Taxi‘ to find out more.
The results
By partnering with Arup and the Oasys LS-DYNA Environment for their CAE needs, LEVC were able to refine and develop their iconic vehicle design to meet tight deadlines and stringent safety standards, including Transport for London’s (TfL) Conditions of Fitness. Production for the new EV taxi began in late 2017 and was officially introduced to service the city in January 2018, marking the start of a new era for black cabs and the evolution of sustainable city transport. “The specialist team at Arup and the Oasys LS-DYNA Environment software supported LEVC to meet the ambitious deadline for our vehicle. More than half of London’s entire black cab fleet is now zero emission capable because of our electric TX taxi, which continues to play a vital role in providing green and accessible mobility solutions for all.” - Chris McCoy, Technical Director at LEVC.