Finding the right ratio of "emphasis" (aka "compromise") between design and engineering priorities has long been part of the enduring magic behind the conception and creation of vehicles.
Today's increasingly advanced CAD and CAE software solutions have arguably eased this tension and reduced the longstanding conflict to more of a mere tussle, but now it's going a step further: Jaguar Land Rover (JLR) and its close partner, simulation-software expert Exa Corp., say design software has become so sophisticated that by 2020 they can eliminate the need to build physical prototypes of a new vehicle under development.
At later stages of development, there always will be the need for driveable prototypes, of course. But the two companies said Exa's integrated visualization tools—and Jaguar's decade-plus of focused experience in applying them—create a technology platform for state-of-the-art, simulation-driven development that they project can eventually eradicate prototypes.
Jean-Paul Roux, Paris-based President of European Operations for Exa, explains: “Carmakers that utilize visualization modules integrated within CAE software, such as Exa PowerFLOW, are beginning to reap the benefits of immersive, photorealistic rendered representations of every stage of the design process.”
Long gone are the days of “stock” presentation software for communicating intricate and continually changing design phases as carmakers “step into the future,” he asserted.
He emphasized, for example, that gaining a clearer understanding of which design feature impacts which area of aerodynamic performance on a vehicle plays an integral part in creating a more open discourse between the design studio and engineers: “This allows both parties to undertake the creative process with one another’s priorities and objectives in mind, actually resulting in bolder and more expressive design concepts with greater aerodynamic capabilities.”
Roux added that large-scale, latent- or minute-flow dynamics now can be detected to what he terms “the utmost degree of accuracy” with these sophisticated visualization tools—and such intricate views are not available in the wind tunnel: “This provides design and engineering teams with a level of insight into their conceptual alterations, in real-time, which revolutionizes what components look like and how they are created.”
JLR used Exa’s system for the XE, which particularly helped to achieve excellent aerodynamics (a best Cd figure of 0.26) without requiring excessive styling compromises. In what may amaze many rivals, JLR did not use a single physical aerodynamic prototype during development of the XE — all aerodynamic optimization was done exclusively through Exa PowerFLOW simulation, Ales Alajbegovic, Exa’s Vice President of Ground Transportation Applications, told Automotive Engineering.
Mark Stanton, JLR’s Director of Special Vehicle Operations (SVO) and formerly its Director of Vehicle Engineering, said, “We use Exa for all of our current-production vehicles to work on development the aerodynamic properties of those vehicles. Another example is the F-Pace (crossover). Here we use Exa to achieve perfect lift balance—you have seventy 'counts' of lift on the front and rear, which really contributes to the sporty driving experience of the vehicle.
“We've also used it [Exa simulation software] to help improve the aerodynamic drag,” Stanton continued. "We have apertures in the front bumper which we use to turn the airflow around the front corner to really improve the aerodynamic efficiency of the vehicle.
"All of this," he said, "was done in the virtual world before we ever had any physical properties. We really only validated with a physical (prototype) right at the end of the process, as we have all of the confidence in these virtual tools."
Aligning design with engineering
Paul Stewart, Exa’s Design and Visualization Director at the company’s Burlington, Massachusetts, headquarters, added that when working on different timescales—perhaps with conflicting objectives—it had not been uncommon for designers and engineers to find themselves out of sync when working on the same project, particularly when day-to-day contact may be limited.
“What some carmakers have now discovered, however, is that simulation-driven design can help repair this disconnect thanks to integrated visualization tools provided in CAE software such as Exa PowerFLOW.”
Stewart said that for both designers and engineers, simulation software provides an “intricate” real-time understanding of design alterations: “This doesn’t mean that designers are now having to concede ground on more daring projects—quite the opposite, as this holistic approach to design encourages multidisciplinary collaboration right from the start of the development process, resulting in expressive yet feasible designs.”
Beyond aerodynamics to full-vehicle validation
Jaguar is confident about its 2020 timeframe for eliminating prototype builds largely because its decade of collaboration with Exa has generated an "evolution" of prototype reduction, starting with the elimination of earliest prototype phases, said the Exa spokesperson.
Stanton confirmed the company is aiming to achieve full-vehicle verification exclusively through digital simulation by 2020, going straight from virtual into the final physical production vehicle: “The use of Exa software now is really key in what we do at Jaguar Land Rover. We used over 36 million hours of CPU time in 2014 on Exa and that’s the equivalent of about 7000 physical wind tunnel tests, so that’s pretty immense!”
He added: “We are trying to ‘left shift’ (from physical) our engineering, and virtual engineering is absolutely a key part of that shift. It enables us, far earlier, to validate that we have met all requirements for the program and ensure that we have the quality baked in right up front.”
Meanwhile, Exa’s Alajbegovic asserted that full-vehicle verification by simulation likely will generate immense cost and time reductions in the product-development process.
“The most significant cost savings when an automaker commits to virtual design comes from avoiding late changes and fixes,” he said. “Late-discovery and fixes that prompt a one- or two-month delay of the market launch can cost an automaker hundreds of millions of dollars. Problems requiring tooling changes also cost several million dollars. (Improved) ability to design vehicles on cost and time will be enabled using virtual design.”
Apart from process savings, reducing or eliminating prototypes also will have a significant bottom-line impact, Alajbegovic added. “Considering just the prototype vehicle costs (not including testing costs), static clay models may cost between $500,000 to $1 million per unit and traditional automakers may build two or three models for early testing,” he said. “Drivable prototypes may cost between $500,000 - $1 million per unit (depending on the carryover versus prototype-parts content), with automakers building between 100-200 driving prototypes for physical tests.”
Roux opened the company’s Paris office in 2002, further expanding the company’s client list. Together with JLR, that lineup now includes BMW, Delphi, Denso, Fiat Chrysler, Ford, Honda, Hyundai, Nissan, Peugeot, Renault, Toyota, VW and major commercial vehicle and off-highway companies.