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How to boost the performance of an F3 race car with Artec Leo
Product: Artec Leo
Industry: Automotive and Transportation
A race car, such as the Dallara F399/01, is the product of decades of engineering advancements. Motors, frames, and materials have all progressed tremendously in order to comply with the technical regulations of motorsports while ramping up performance. In fact, the remarkable breakthroughs already made over the years in race car engineering make it appear as if there’s not much room left for further improvement. At least not without investing a fair amount of financial resources and time. Considering this, what options are possible if someone wants to gain a technical edge over the competition? John Hughes, a postgraduate engineering student at the University of Wales Trinity Saint David (UWTSD), offered up a simple answer: Aerodynamics.
“Every little detail, every little gain you get, is better than nothing. At the moment, we have managed to gain roughly 10 miles an hour in straight line speed, compared to where we started off with the car. Just through aerodynamic development.”
John has been working on the Dallara’s front wing as part of his master’s degree project with another aerodynamics student together with the two owners of the car. Their objective is to get better performance out of the vehicle, currently running in the British Sprint Championship, a prestigious 16 events per season championship held at venues across the United Kingdom. Between events, John and his team have small windows of time for working on the car at the University motor shop, located right next to Swansea’s harbor.
For a while, the team used manual measuring tools to obtain the dimensions of the F3, but the results lacked precision in addition to being time-consuming. They naturally came to the conclusion that they needed a reliable way to get better measurements faster. This is where the idea of 3D scanning technologies entered into their field of view. At first, they tried basic methods of 3D scanning to get a CAD model they could work on, but it still wasn’t precise enough. As soon as they learned about professional 3D scanning solutions, they contacted UK-based Artec 3D Ambassadors Central Scanning, hoping they could provide the results needed. Seeing preliminary scans done with the brand new 3D scanner Artec Leo, John knew he had made the right call. “From looking at what has been captured, the amount of detail, compared to what I’ve seen previously, is second to none. It’s incredible, for what I’ve actually seen produced before,” he said.
Nick Godfrey and Tom White from Central Scanning had preliminarily analyzed the task at hand, and concluded that the Artec Leo would be the best tool for the job. “Leo is capable of capturing medium to large objects very quickly. It doesn’t require any preparation beforehand, and the scanning can be done directly on-site” said Nick. “The scanner is entirely autonomous, which means there are no cables or computers attached to it that limit your movements. We can capture virtually everything more easily than with any other 3D scanning solution.”
Leo comes equipped with its own battery, a touch screen that shows the scanning in real time, and saves the data on a memory card that can be subsequently transferred to a computer. Tom scanned the Dallara in the UWTSD motor shop, without the need for any superfluous gear. All in all, the scan of the whole car took less than 2 hours. The scan data was treated on Artec Studio in a day, and a complete CAD model was sent to John a few days later.
It is important to note that in the field of aerodynamics, millimetric changes in the design can go a long way. The Artec Leo boasts an impressive data capture rate of 3 million points per second, with real-time 3D processing displayed directly on its screen. By having the geometry of the entire car digitally scanned with utmost precision, John can run a better computational fluid dynamics (CFD) simulation on Ansys, analyzing all the options for fine-tuning the aerodynamic profile of the car from the most realistic 3D model.
“I usually start off by trying to optimize the current component as best as I can without altering the geometry of individual components. For example, the current front wing has multiple elements, such as flaps and winglets. I would study if moving the position of the flaps would enhance the overall performance of the wing,” explained John. “This process can take months to get right. However, it can be sped up with the use of Design of Experiment (DoE) software. Once the original geometry has been optimized, I can then go on and start to develop the original geometry by studying CFD results. Using this method saves on manufacturing time and cost, as I’m trying to maintain as much of the original front wing as possible.”
After the analysis and the design work, the modified parts were sent to Fibre-Lyte, a carbon fiber manufacturer specialized in high-performance sports. With the help of a 3D milling machine, they are able to create cost effective one-off parts that can be repeated, or scaled up, if higher volumes are required.
The manufactured parts have been installed on the race car, and John already began noticing the difference: “We have seen gains in straight line and cornering speeds since modifications began. I created a number of bargeboard design iterations, with each one showing performance improvements. The simulation results show good promise in enhanced performance.”
Startup Exept uses Simcenter Femap with Nastran to develop monocoque frame for road bikes in a virtual environment
Product: Femap
Industry: Consumer Products and Retail
Siemens solution enables EXEPT to go from concept design to product launch in less than a year
Developing the custom monocoque
Until recently any cyclist who wanted to buy a new bicycle had two options: Either purchase one of the big brands with a monocoque frame that is available in a fixed range of sizes with performance based on stiffness by weight, or a tailor-made frame manufactured with the tube-to-tube technique. This kind of bike has tubes that are cut, welded and wrapped with carbon fiber around the joints (knots), with the inevitable drawbacks in stiffness.
Now the Italian startup EXEPT, which is based in Savona, is providing a third way. It has developed a process that combines the benefits of both traditional approaches to create tailor-made monocoque frames. The custom monocoque technique invented by EXEPT uses movable molds to cast monocoque frames without any carbon fiber dis-continuity so it can be made to order for each cyclist.
“The key to economic sustainability in bike production is the cost of tooling,” says Alessandro Giusto, who is the co-founder of the company and the innovation and simulation manager. “A mold may cost up to €50,000 to 60,000, therefore only the big brands can reach volumes large enough to make a mold for each size. Instead, we have developed an innovative technology to build all sizes with one adjustable mold.”
The biggest Italian brand makes 15,000 high-end bikes a year, while EXEPT’s business plan calls for producing up to 3,000 pieces annually in five years.
All-round expertise
The movable mold concept was developed by the three founders and reflects their passion for bicycles. Giusto previously worked at Continental, a global leader in tire manufacturing, and also had experience in aerospace and the design of car-bon components for the sporting goods business. The second business partner, Alessio Rebagliati, is a colleague from Continental, while the third founder, Wolfgang Turainsky, is a German engineer who used to work for a Spanish manufacturer of bike components.
It took two years and two prototyping cycles to make prototypes that proved the feasibility of the custom monocoque process. Prior to being analyzed with simulation and finite element method (FEM) tools, the first frame was given to a former cycling professional for testing. Once the firm received his technical approval, EXEPT presented the project to an investment fund (Focus Futuro), which provided the necessary resources to move on to detailed design, testing and certification.
“The bike was designed from the very start according to the new concept,” Giusto says. “However, we did not focus on car-bon fiber initially, as composite material design is a complex activity that is a full-time job. Once we got the funds to finance our innovative idea, we could quit our previous jobs and plunge into the new enterprise.”
The pretest on the first prototype in May 2018, which was developed with just three months of design, confirmed the results of simulation and reassured Giusto and his partners they were ready to launch the bicycle at the Eurobike show in July, 2018.
Foolproof decision
In his experience in engineering companies in the aerospace and sporting goods industries, Giusto had the opportunity to learn and appreciate Simcenter™ Nastran® software, specifically the finite element modeling, and the pre- and postprocessing environment of Simcenter Femap™ software from Siemens.
“In aerospace, Simcenter Nastran is a de facto choice and we also used Simcenter Femap in our company,” Giusto remembers. “In six years, from 2007 to 2013, I acquired advanced skills with these tools, then I was in charge of the calculation department at Continental, where nonlinear analysis is performed using totally different tools.”
As a result, when the EXEPT project began, Giusto immediately reactivated his contacts with Siemens. “We did not need comparative analysis or benchmarking,” he says. “I knew we needed Simcenter Nastran, and the quality/price tradeoff for Simcenter Femap was excellent. All I had to do was call Siemens to explain our requirements and get an adequate offer, which we accepted immediately.”
EXEPT purchased a node locked bundle that incorporates Simcenter Femap with Nastran Basic in a single, integrated solution.
The EXEPT team initially worked with pencil and paper, proceeding by increasing levels of complexity to identify the loads that acted on the structure. The next stage was the development of the first simplified FEM model.
“We made a very simple model; in aero-space, they call it Global FEM, which is made up of one-dimensional elements (bars), and we investigated the load properties of these tubes in different riding, braking and impact conditions,” Giusto explains. “This approach is very useful as it provides quick feedback for each frame section. Then we moved on to a model of isotropic material, simulating an aluminum frame with constant thick-ness, and using the information from the Global FEM, we identified where we should decrease or increase the cross sections to optimize stiffness and weight. Finally, we worked on the geometry, which was re-meshed with four modifications to increase stiffness by 27 percent. This was done by just addressing the geometry!”
The carbon challenge
After optimizing the frame stiffness, the EXEPT’s engineers focused on carbon design. To define the ply book, also known as the lamination sequence, Giusto adjusted the structure 82 times, achieving extraordinary results.
“Compared to the initial stiffness of the nonoptimized prototype, we increased torsional stiffness by 150 percent while increasing the monocoque weight by only 12 percent,” Giusto says. “In this phase, Simcenter Femap offered huge benefits in terms of time and costs, enabling us to test and analyze the layering and direction of fibers only in the virtual domain, without increasing the quantity of material used.”
EXEPT executed an in-depth comparative analysis of the performance of more than 800 stock frames (in stan-dard sizes) developed and sold in the past three to four years in order to identify and achieve high-end stiffness and weight targets.
“The first nonoptimized frame we made was the third-best in terms of stiffness out of 800 frames we analyzed,” Giusto says. “We pushed stiffness so far that we decided to reduce it afterwards for road tests, to find the best tradeoff between stiffness and rideability. You know, reducing an optimized parameter is much easier than increasing it.”
At the end of June 2018, the excellent performance of EXEPT’s custom monocoque and the reliability of Simcenter Femap simulations was confirmed and certified with tests by an independent German laboratory: The deviation between real test and simulation was below 5 percent.
Giusto highlights how using Simcenter Femap accelerated the development of new frames: “We purchased Simcenter Femap with Nastran in September 2017 and started to laminate carbon in January 2018, delivering the ply book at the end of March. With Simcenter Femap, it took less than three months for over 80 iteration cycles. Just consider the average lead time for a brand bike is two years. We launched our model in July, having started to work on it less than one year before.
“All of this was possible only thanks to simulation; we made no physical iterations. No one in the cycling industry in Italy currently has comparable tools. At the beginning we contacted the engineering departments of big brands to present our concept; they have a conventional approach because they never develop a frame from scratch. They start with the expertise of their carbon supplier and rely on external partners for the subsequent development.”
Combining software and services
Giusto has no doubts when asked to list the key benefits of Simcenter Femap: “The key success factor is postprocessing. Simcenter Femap is definitely the best of all postprocessing engines I have used in my career. Simcenter Femap with Nastran has a complete environment for linear stress analysis of composites structures, which is suitable for our tasks. The Siemens software allows us to query the model and extract as much information as possible from structures like our frames; for instance, using free-body analysis to identify the interplay of forces inside the structure.”
The clear and intuitive visual display of Simcenter Femap helps the user under-stand the model better and provides advanced reporting tools for data extraction. As a result, the model construction is intuitive, fast and lean. “When I started to work full time with Simcenter Femap and Simcenter Nastran to simulate our frames, I did not start from scratch, but still I needed some training to refresh my memory after seven years using different software. Anytime I have a problem, I just have to pick up the phone and the engineers are always ready to answer questions to my full satisfaction. They can indicate the best way to approach analysis with a limited budget while using the best-fitting software configuration for our needs, regardless of the situation.”
With the advanced FEM capabilities of Simcenter Femap, EXEPT can execute sophisticated and critical simulations, static and dynamic tests, and simulations of complex mechanical events like falling and impact.