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Lightweight Materials for a Changing Automotive Industry

Ed Bernardon
Contributor: Ed Bernardon
Posted: 05/27/2014

Automotive IQ editor Will Hornick had the opportunity to speak with Ed Bernardon who is the VP of Strategic Automotive Initiatives at Siemens PLM Software. The discussion focused around the future of lightweight materials in the automotive industry in light of some of the exciting vehicles that have debuted around the world.

"In the short term we are going to see more lightweight body in white assemblies that do not fully rely on steel/welded structures, as in the body of the new Ford F150."

Lightweight Materials discussion on aluminum and composite in the auto industry

I understand that your company has quite an interesting story.

Our company Vistagy was acquired by Siemens just over 2 years ago. Vistagy developed specialized engineering software including Fibersim for engineering composites and lightweight structures. Prior to the founding of VISTAGY, three of the four founders were at the MIT Draper Labs where we initially developed production robotic machinery in the 80’s to make men’s suits, blue jeans, sweatpants and other apparel items. The idea was to reduce the cost of labor to keep apparel companies competitive in the US.

We then took this flexible material handling expertise and applied it to manufacturing composite structures. Early on, we had a major project with Dow United Technologies, where we built automated preforming equipment, such as pick and place machines, double diaphragm forming stations. This included a manufacturing line for the Dodge Viper which had carbon fiber parts in the transmission. To avoid trial and error development methods we looked for software to simulate draping and forming of composites and there wasn’t any to be found. That is when we founded VISTAGY at the time called Composite Design Technologies.

The demand for lighter weight structures in automotive of the early 90’s went away when fuel prices went down. So we built the company on aerospace and high performance automotive applications like Formula 1 that used hand lay-up and thermosets.

Seven years ago, we started a group that specifically focused on high volume automotive application as we felt the need for better fuel economy would drive the demand for composites and lightweight structures.

Leveraging our past experience at MIT-Draper as well as the experience we built delivering software to leading composites programs in other industries for the last 20 years, put us ahead of the game and well positioned to pursue the automotive composite market which is growing quickly and becoming a significant portion of what we do.

In your view, what are some of the challenges that the industry is dealing with regarding weight reduction?

We were with an OEM director for light weighting late last year that was starting a new vehicle program and we asked what the greatest challenges are for his engineering staff who for the first time will be designing even lighter weight automotive structures.

He felt that composite engineering is a top concern, since composites is an additive manufacturing process, where you build up a part in layers. As a result, you have to think about design of structures in a different way. This is a new and significant challenge for engineers who are used to working with steel.

Another challenge he indicated is the engineering of joints that are not welded, especially where a mixed materials is required. Should you use adhesives, rivets or welds, how do you engineer a joint to avoid mixed material corrosion while at all times taking cost and cycle time into consideration?

Those are the big issues.

In your view will it be an abrupt change to all composites?

The i3 was a big step for composites in automotive, in a sense like the 787 was in aerospace in that the new design went from an all-aluminum structure to an all carbon composite one. In automotive though the greater emphasis on cost will drive designs to a mix of materials and where carbon is combined with lower cost materials.

Is the i3 full carbon body a cost-effective approach? It will be interesting to see what BMW and other OEM’s will do in upcoming models as an indicator of how the use of carbon alone and in a mix will evolve.

Do you see aluminum as a bridge technology?

Aluminum is a proven alternative as demonstrated recently by the introduction of aluminum into the 2015 Ford F150 body. Ford has taken 450 pounds out of the body, which then results in 750 pounds out of the truck. Since Ford is going into production with aluminum on the largest volume production vehicle in the USA, this is a strong indicator that a glued/riveted aluminum body is a cost effective alternative to a steel welded structure.

Carbon fiber especially in a continuous form is a more expensive raw material relative to aluminum. But if you put it only where it can be most effective in combination with other lower cost materials such as fiberglass, plastic, or metals, the opportunities for cost effective use of carbon fiber composites will increase. Also the substitution of a composite component at the assembly level will be a lot easier with a riveted and glued body in white made of aluminum rather than a traditional welded steel structure, this should help speed the introduction of composites.

How will this impact the nature of engineering tools used in the automotive industry?

Engineering software providers must provide tools that help engineers make the trade-offs needed to design a cost effective lighter-weight mixed material vehicle. As the material mix changes, engineers will no longer be able to rely on experience built up over the last 50 or 60 years on steel-welded structures to make needed design trade-offs. Engineering software must help designers make these trade-offs, and help build expertise faster with less reliance on costly trial and error prototyping.

For instance, engineers will need to trade off cost against the requirement for reduced weight at a specific performance level. For a high performance Formula One car, the high cost of hand laid up uni tape is acceptable. At the other end where cost is king over performance, a steel-welded structure will work. But in between, the right choice depends in part on how much you are willing to pay for the required performance level at a lower weight.

Engineering software must efficiently provide the engineer with the data needed to make more informed decisions about these trade-offs. It might be a highly accurate simulation or a tool that facilitates access to the data needed to make the trade-off. In the end, the goal is to reduce engineering time and reduce reliance on prototypes.

Determining what software features will save our customers time though in not necessarily straight forward. In our software development efforts we do ask what features a customer wants to see in our software, but more importantly we identify issues our customers have in their engineering processes that create difficulties or reduce design quality. We uncover details about any struggles they encounter as we work "at elbow" with our customer, that is how we learn things that don’t come out in discussions about software features. We actually consider every customer as more of a partner from which we can learn as well as teach. Our history of innovation comes from working closely with to our customers. As a result, our customers feel we truly understand their challenges, how those challenges will evolve, and that we can reliably provide the appropriate software initially and in the future.

Many times we do uncover issues that cannot be solved by our own software products so we maintain an open architecture that allows us to interface directly to numerous software applications that are provided by our partners.

There is a certain amount of engine technology improvement as well needed to take advantage of the lighter weight bodies.

That is a good point, since as you make the body lighter, then the chassis can also be lighter, the engine can be smaller, smaller fuel tank or fewer batteries, smaller brakes etc., this is the weight reduction spiral. So you get a lot of additional weight reduction by making the body in white lighter. In addition of course to smaller engines, more fuel efficient technologies and drives as well as anything that can be done to reduce parasitic losses are also being employed. It is not just about light-weighting.

Have you guys done a study on the development time that you have managed to save customers?

In our Fibersim software we developed a laminate definition interface specifically for automotive that lets the designer as we say, "work like you think". The approach to laminate design in automotive applications differs significantly from aerospace composites due to shorter design cycle time and more complex shapes that change often.

We have released a new automotive laminate design interface that saves automotive engineers as much as 90% of the time required for composite laminate definition in comparison to interfaces used in traditional aerospace applications. Aerospace engineers have also embraced this new technology as it seems to save time in aero design as well, this is an initial example (with many more to come) of how the automotive industry will influence composites design tools in the aerospace industry.

Another time savings our customers have seen is the ability to reduce reliance on prototypes. Without engineering software, when developing designs and even the manufacturing process itself, you are more reliant on building and testing prototypes, especially when developing forming processes for complex shapes. We have seen a 66% to 75% reduction on the number of prototypes required to arrive at a suitable part/process design when our software is used to weed out less desirable alternatives and to more quickly hone in on optimal design features and processing parameters.

How do you see the market for lightweight materials evolving in the short to midterm?

In the short term we are going to see more lightweight body in white assemblies that do not fully rely on steel/welded structures, as in the body of the new Ford F150. We’ll see more and more aluminum, non-welded structures that take advantage of alternative assembly methods like riveting and gluing. These changes will result in big gains in fuel economy.

Composites will also make gains in the short term, initially in structures like hoods, doors, seat structures and roof panels. Over time composites will make their way more and more into the body in white, initially in higher priced models then working their way down to cars in lower price ranges.

Looking farther ahead is more difficult. I’m not sure we will see another "i3" like vehicle with a full continuous fiber composites passenger compartment in lower to mid-price ranges. BMW learned a lot from the i3, both what is cost-effective and more importantly what isn’t cost-effective for future models. It’s more likely we will see body assemblies with a mix of materials combining composites with high strength steel, aluminum, magnesium, lower performance composites and plastics. Alternative assembly methods based on rivets and glue will enable the introduction of alternative materials if all relevant joining issues such as corrosion can be addressed for the life cycle of the vehicle.

I mentioned earlier the use of composites in a mixed materials assembly, but you will also see a mixing of materials at the part level. Carbon fiber may not be needed everywhere in a body structure especially in areas where you don’t need the stiffness carbon fiber provides. For such an application you could use carbon fiber tows only in areas required to provide stiffness and with the remainder of the part made of lower cost materials such as chopped carbon or glass or SMC.

The interior is another interesting area, especially seating. Four or five years ago composites were rarely a design alternative except for the most expensive models. Now we are starting to see composite being considered in areas such as seat frames in even lower cost vehicles.

As we all know change takes time, but the fact that alternatives to steel/welded car body technologies pioneered many years ago by Lotus have been adopted by Tesla, Jaguar and Ford, indicates that we will see more alternative material and assembly methods for the body in white in the near as well as long term.

We are still in the early stages of this market transformation, going forward it will be very important that manufacturers work closely with the tools and solution vendors. This is an exciting time for the automotive industry – you could even say a major upheaval and opportunity to re-invent, the likes of which haven’t been seen in over 50 years.

Thank you for such an interesting conversation.

Ed Bernardon
Contributor: Ed Bernardon
Posted: 05/27/2014