Impact Biomechanics

Dr. Duane Cronin builds virtual human body models that give insight into what happens in accidents, what types of injuries occur, and how to prevent them.

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Duane Cronin

Dr. Duane Cronin
Professor, Department of Mechanical Engineering, Waterloo University; Executive Director, Waterloo Centre for Automotive Research

Research area
In his lab at the University of Waterloo, Dr. Duane Cronin is bent on building a better crash-test dummy, or, as he calls it, “a crash test genius.” He doesn’t diminish the original crash-test dummy, which is an anthropometric test device that he acknowledges has advanced science and saved lives, but he wants to make one that pushes the boundaries. With the help of Compute Canada’s advanced research computing resources, he’s doing just that by building virtual human body models that will give insight into what happens in accidents, especially with events that occur in fractions of a second.

As he describes it: “The goal of our research is to protect humans in injurious situations and to do that, we use numerical models of the human body. After all, we simply can’t test crashworthiness with live humans.”

What is the industrial relevance to the research?
The industrial relevance isn’t, at first glance, very intuitive, but safety is one essential element for auto manufacturers to remain competitive and sustainable. Twenty years ago, consumers didn’t consider the safety aspect as much when making their purchases, but today it’s front and centre. Every vehicle has undergone compliance testing, which means it has to meet a certain safety standard, but the standards are much higher today.

The New Car Assessment Program (NCAP) also provides a star rating for vehicles, so once manufacturers pass the compliance test, the program then provides further information to determine how much better it does relative to other vehicles.

One important element, he says, is that the current vehicle design cycle for an auto manufacturer is about five years, but manufacturers are trying to reduce it from five to three years. To do that, however, requires advanced design and engineering methods.

“If they want to do it all in a computer-aided engineering environment, they need to have methods of assessing safety systems,” Dr. Cronin says. “To reduce the vehicle design cycle, they have to continue moving more towards the virtual side. It’s estimated that it will save them millions of dollars and it could even approach billions of dollars in savings globally.”

The level of detail in these biofidelic human models has only been made possible through advances in high performance computing, and in this case the ability to access world-class computing resources through SHARCNET and Compute Canada. This essential resource is enabling advanced finite element human body models (HBM) to make significant contributions to the field of injury biomechanics.

Can you describe the environmental benefits of this technology?

There’s a mandate to reduce C02 emissions and improve what’s known as the corporate average fuel economy (CAFE).

“The CAFE requirement is to achieve 34 miles per gallon by 2015 and 54.5 miles per gallon by 2025,” Cronin says. “In 2014, we were at 28.8. In Canada, the government wants to reduce greenhouse gas emissions by 50 per cent in 2025, compared to the 2008 number, which means a dramatic improvement in fuel economy.”

In Ontario last year, light truck surpassed passenger vehicle sales. Given that consumers want big vehicles, and manufacturers have to provide the products customers want, their challenge is to make these vehicles even more fuel efficient, likely by making them out of lighter materials.

“Instead of stamped sheet metal that’s spot-welded together, the next generations will be ultra high-strength steel, aluminum and even materials such as magnesium,” Cronin says. To ensure the crash-worthiness and vehicle-occupant safety of these new materials is a monumental challenge that can be addressed through his computer-aided engineering and biofidelic human models.

What is the current focus of Dr. Cronin’s research?
First, he’s been working with 3M on structural adhesives. If you want to make vehicles lighter, you have to join dissimilar materials such as steel and aluminum. There are some methods that work, but not many. The obvious alternative is structural adhesives that glue materials together and to create an electrical isolation between the components, reducing corrosion issues.

Crash-worthiness, again, is important, so researchers and manufacturers initially work with a virtual design on the computer. From there, they take the virtual model of the vehicle and create a finite element model. Inside the computer, they can crash that car and determine its performance, provided they understand and model it correctly.

To assess the occupant safety in a crash, they must be able to move to biofidelic human models. Current crash-test dummies work for uni-directional impacts. The next step is to introduce a biofidelic human model, which can predict response in omni-directional loading. This research has been undertaken in collaboration with the Global Human Body Models Consortium (GHBMC) and six centres of expertise at universities around the world, including the University of Waterloo. The GHBMC is a consortium of original equipment manufacturers (OEMs) and suppliers including: Fiat Chrysler Automobiles, General Motors, Ford, Honda, Hyundai, Nissan, PSA Peugeot Citroen, Renault, Partnership for Dummy Technology and Biomechanics, and Takata. “If you’re in a side-impact accident, but there’s a frontal component to it, our model should be able to predict response and the level of safety in those cases,” Cronin says.

In addition to seat belts and crush structures, vehicle manufacturers are moving towards active safety systems. Airbags came into the equation as standard equipment in the 1990s and now, automatic braking is being considered, but that system needs a crash-tester because when you choose to brake, you brace yourself, but if you don’t know it’s coming, you might react differently. “Active musculature in human models is important,” Dr. Cronin says. ‘’It will allow us to effectively design and evaluate active safety systems.”

Finally, he’s been working to understand injury in more aggressive environments, such as those in which the Canadian Forces find themselves.

“We’ve used models to understand what’s happening, what types of injuries are occurring, and how to prevent them,” he says. He’s been working with the Canadian Forces, through Defence Research and Development Canada, on landmine protection for the leg, blast protection for the head, as well as advanced body armour to protect the thorax from ballistic threats. He’s also had a couple of patents on a new design for the latter.

How does Dr. Cronin use Compute Canada resources in his research?
Compute Canada is an essential component of his work because it’s all done virtually, on a computer.

“We have grown to be one of the top groups in the world in this area and a lot of that is directly attributable to the fact that we have Compute Canada’s resources available,” he says. “If we didn’t have them, we couldn’t be competitive internationally.”

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