COLOGNE, Germany – Ford is developing one of the world’s first digital human child body models as part of a pioneering programme to make car travel safer for young people.
“We study injury trends in the field, and we know that traffic crashes are the leading cause of death for people from age 4 to 34,” said Dr. Stephen Rouhana, senior technical leader for safety, Ford Research and Advanced Engineering. “We want to better understand how injuries to younger occupants may be different.
“Our restraint systems are developed to help reduce serious injuries and fatalities in the field, and they have proven to be very effective. But crash injuries still occur. The more we know about the human body, the more we can consider how to make our restraint systems even better.”
Building a digital model is no simple task. The work on Ford’s adult human body model took 11 years to complete. Digital models are used in research, not in vehicle development. They don’t take the place of crash dummies, which measure the effect of forces on the body. Instead, they are used as a way to understand how to further improve restraint system effectiveness through better understanding of injury mechanisms.
The digital model is constructed component by component – brain, skull, neck, ribcage, upper and lower extremities, etc – with extensive research included on each part.
“Building the model of a person is just like building a model of a car,” said Rouhana. “You start with your surface geometry for each component and any subcomponent it contains – in this case the geometry of the human body and its internal organs.”
After gathering such data through medical scans as well as anatomical texts, the researchers build a model section by section, creating regions of the body. The brain in Ford’s adult human digital model was constructed as a separate component, detailed down to the brain stem, the gray matter and the fluid between the layers.
The components are then joined into a virtual human body, which is extensively validated. Then, using mathematical and analytical tools combined with available data on the properties of human tissues from the medical and engineering literature, researchers are able to determine the effects of a crash – and the pressure of a restraint system – on the body.
“A child’s body is very different from an adult’s,” Rouhana said. “Building a digital human model of a child will help us design future systems that offer better protection for our young passengers.”
Rouhana’s research work in the area of human response to impact recently led to him being awarded the prestigious Award of Merit from the Association for the Advancement of Automotive Medicine. This is the highest honor that can be awarded to an individual in the field and was presented to him in Paris, last month.
Conventional Crash Test Dummy History
Ford has been using conventional crash test dummies for the past seven decades to help enhance occupant protection in its vehicles.
The world’s first crash test dummy was conceived in 1949 for the US Airforce. Codenamed Sierra Sam, it was designed to test jet fighter ejector seats.
In the mid-1950s, Ford’s Engineering and Research Department in the US developed its own life-like plastic crash test dummies called FERD 1 and FERD II. Complete with electronic instruments for brains, they had steel skeletons with tough plastic parts to simulate muscle and softer plastic to simulate skin.
In 1971, Ford introduced the world’s first standardized automotive crash test dummy, the Hybrid I, followed by an updated Hybrid II design. The current Hybrid III model has a spine made out of metal discs, a movable neck, a steel ribcage, vinyl skin, and knees that are designed to respond to impact like the human counterpart.
Ford also uses specially developed dummies for side-impact crashes. The WorldSID and EuroSID 2 models contain more than 220 different sensors to record crash injuries and impact forces.
“Today’s crash test dummies are very complex devices,” explained Ford body and safety senior engineer Jake Head. “A Hybrid III costs approximately €34,000 but with full instrumentation this can rise to more than €50,000.”
Ford uses child-sized and adult-sized dummies in crash tests to ensure that the safety and restraint systems are suitable for occupants of different sizes and weights.
The company has also become a leader in the world of virtual safety research. Ford engineers in Germany and the US crash-tested the current Focus more than 12,000 times in virtual situations to prove out new technologies designed to protect occupants in crashes. These virtual simulations have become so effective that the number of physical vehicle crash tests has been significantly reduced.