長久以來，汽車研發(fā)的主題總是離不開“重點”（換言之，就是“妥協(xié)”），在概念設計與工程制造之間找到平衡至關重要。
隨著CAD和CAE軟件解決方案的不斷進步，可以說設計與工程之間“水火不容”的緊張關系已經得到一定程度的緩解，如今這種情況將進一步得到改觀。據了解，捷豹路虎（JLR）及其密切合作的伙伴，也就是模擬軟件開發(fā)專家?？怂构荆‥xa Corp.）表示，如今設計軟件已經非常精密。到2020年，由于軟件方面的進步，汽車廠商在進行車輛研發(fā)時可能不再繼續(xù)需要實體原型車。
當然了，在汽車研發(fā)的最后階段，打造一輛可以真正駕駛的原型車仍必不可少。但這兩家公司表示，憑借埃克斯公司的綜合可視化工具，以及捷豹路虎在軟件應用方面超過十年的經驗，這對合作伙伴將打造一款最先進的模擬仿真研發(fā)平臺，并利用該平臺逐步擺脫汽車研發(fā)中對實體原型車的依賴。
?？怂箽W洲公司巴黎分公司總裁Jean-Paul Roux解釋說：“通過類似?？怂筆owerFLOW CAD工具中集成的可視化模塊，汽車廠商得以在汽車設計的各個階段內獲得超真實的渲染效果，為設計師的工作提供便利。”
他斷言，汽車的研發(fā)流程復雜多變，隨著汽車廠商“逐步邁向未來”，那些使用常規(guī)軟件進行溝通交流的日子早已成為過去。
他強調說，舉例而言，如果能夠更加清晰地了解一項新設計將對車輛的空氣動力學性能帶來哪些影響，我們就可以在設計師與工程人員之間搭建一條更加開放的溝通橋梁。“這樣一來，除了完成自己的工作，雙方還能同時考慮對方的難處和目標。事實上，這種作法并不會捆住設計師和工程人員的手腳，反而可以協(xié)助他們推出外觀更加大膽且更加富有表現力的設計，還能同時提升車輛的空氣動力性能。”
Roux表示，通過這些精密的可視化工具，汽車廠商得以“在最大程度”捕捉車輛周圍的潛在氣流或微氣流，這是現有風道做不到的：“可視化工具允許設計與工程團隊及時了解一些概念的變化，這點非常重要，因為這些變化可能會直接導致一些組件形狀及其制造方式的改變。”
據了解，捷豹路虎在旗下XE轎車的研發(fā)中應用了埃克斯公司的軟件系統(tǒng)，并最終在并未過多犧牲外形的前提下，成功將車輛的空氣動力性能提升至0.26 Cd的超高水平。?？怂沟缆方煌☉貌扛笨偛肁les Alajbegovic告訴《汽車工程》雜志，雖然很多競爭對手可能會覺得不可思議，但事實上，捷豹路虎在XE轎車的研發(fā)過程中并未使用任何空氣動力實體原型車，一切有關空氣動力性能的優(yōu)化，均是通過?？怂构镜腜ower FLOW模擬工具完成的。
捷豹路虎特種車輛部（SVO）總監(jiān)、前任汽車設計總監(jiān)Mark Stanton表示，“在所有現行捷豹路虎量產車型的研發(fā)中，我們均利用了埃克斯的軟件工具來提升車輛的空氣動力性能。此外，捷豹路虎F-Pace跨界車的研發(fā)也采用了模擬軟件解決方案。具體來說，通過?？怂沟能浖覀冊谘邪l(fā)中實現了完美的提升平衡，從而為用戶帶來了真正動力十足的駕駛體驗。
“我們還使用埃克斯的仿真軟件來減少車輛的空氣阻力，”Stanton繼續(xù)表示，“我們在車輛的前保桿上設計了一些孔洞，從而優(yōu)化車輛前角的氣流流動，提高車輛的空氣動力學性能。
Stanton表示，“所有這一切都是在虛擬環(huán)境中完成的。在此之前，我們未曾制造任何實體原型車。我們非常信任這些虛擬工具，只有在整個研發(fā)流程的最后階段才采用了一輛實體原型車進行最終的驗證。”
設計與工程聯手
?？怂构驹O計與可視化總監(jiān)Paul Stewart補充說，同一項目中的設計師和工程人員所關注的要點不同，工作時間安排也有差異，如果溝通不足的話，可能會經常處于不同步的狀態(tài)。
“然而，如今一部分汽車廠商已經發(fā)現，?？怂筆owerFLOW等CAE軟件中集成的可視化工具有助于促進設計與工程團隊之間的溝通交流。”
Stewart表示，對于設計師與工程人員而言，模擬軟件可以協(xié)助雙方實時直觀地了解任何設計變化：“這并不意味著設計師不得不在一些更加大膽的設計項目中前瞻后顧，不能放開手腳，恰恰相反，由于這種整體設計流程從最開始的階段就鼓勵跨部門的合作，設計師反而可以拿出更富有表現力且切實可行的設計方案。”
從空氣動力性能優(yōu)化到整車驗證
?？怂沟陌l(fā)言人表示，捷豹路虎對自己定下的2020年目標非常有信心。通過與我們長達十多年的合作，這家汽車廠商已經顯著降低了汽車設計過程中對原型車的依賴，特別是在研發(fā)的早期階段。
Stanton已經確認，捷豹路虎計劃在2020年前實現基于純軟件模擬的整車驗證。屆時，汽車研發(fā)將直接從虛擬世界進入最終量產環(huán)節(jié)，中間無需原型車的參與。“如今，?？怂管浖诮荼坊⑵囇邪l(fā)中的地位非常重要。2014年，我們在?？怂管浖系姆抡鎽脮r間為3600多萬CPU小時，這相當于7000小時的實體車風道測試，所以你可以看到模擬仿真軟件對我們來說非常重要。”
Stanton補充說：“捷豹路虎正在努力擺脫對實體原型車的依賴，而虛擬設計在這種轉型中非常關鍵。借助虛擬設計，捷豹路虎可以遠遠領先其他公司，提前實現所有項目要求，并在早期階段及時驗證車輛的質量。”
同時，?？怂构镜腁lajbegovic斷言，在產品研發(fā)階段，使用模擬工具進行整車驗證，可以節(jié)省大量的財務和時間成本。
“通過借助虛擬仿真進行設計，汽車廠商最大的收獲在于可以提前發(fā)現問題，從而避免在研發(fā)最后階段的返工。”Alajbegovic表示，“事實上，在項目后期發(fā)現的問題，并進行問題的糾正，可能會將新車上市的時間推遲1到2個月，而廠商可能因此損失數億美元。此外，如果發(fā)現的問題需要更換生產設備和工具才能解決，這也同樣會讓廠商花費數百萬美元。但如果使用了虛擬工具，我們則更有把握在規(guī)定的成本和時間范圍內完成車輛設計。”
Alajbegovic補充說，除了這些流程上可能節(jié)省的開支，降低或擺脫對實體原型車的依賴，本身就可以顯著降低成本。“單說原型車本身，打造一輛不能駕駛的陶土原型車大約需要50到100萬美元，而為了進行早期測試，傳統(tǒng)汽車廠商通常需要2到3輛原型車。”他說，“此外，由于對沿用件與原型零部件的不同選擇，一輛可以駕駛的原型車的成本可能有所差異，但仍在50到100萬美元之間，而為了進行實際測試，汽車廠商一般需要100到200輛可以駕駛的原型車。”
2002年，埃克斯公司在巴黎設立了辦公室，從而進一步擴大了公司的客戶群。除了捷豹路虎，如今?？怂沟目蛻暨€包括寶馬（BMW）、德爾福（Delphi）、電裝（Denso）、菲亞特克萊斯勒（FCA）、福特（Ford）、本田（Toyota）、現代（Hyundai）、日產（Nissan）、標致（Peugeot）、雷諾（Renault）、豐田（Toyota）、大眾（VW）等多家汽車廠商與非公路設備制造商。
作者：Stuart Birch和Bill Visnic
來源：SAE《汽車工程》雜志
翻譯：SAE 中國辦公室
Jaguar, Exa say simulation to eliminate prototypes by 2020
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.
Author: Stuart Birch & Bill Visnic
Source: SAE Automotive Engineering Magazine
?？怂箍諝鈩恿δM仿真軟件在一輛捷豹XE上的應用。
這輛捷豹XE轎車并不是真的燒著了，只是采用了?？怂沟目梢暬浖姆抡婀δ?。
埃克斯歐洲分公司總裁Jean-Paul Roux。
捷豹路虎特種車輛部（SVO）總監(jiān)Mark Stanton。
?？怂乖O計與可視化總監(jiān)Paul Stewart表示，借助仿真工具進行設計，可以讓設計師與工程人員之間的溝通更加便利。