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Key Safety Systems Vice President of Engineering Robert Block takes measurements using his firm's crash simulation software. The simulation system can cut down on the number of crash tests needed, which may cost up to $250,000.Software cuts out test dummy
Key Safety's programs reduce the need for costly fed crash simulations.
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As the cost of conducting crash tests rises along with the number of federally mandated tests designed to ensure that new safety products provide maximum protection, automakers are looking for ways to design air bag and restraint systems with fewer trials.
Key Safety Systems Inc., an auto supplier based in Sterling Heights, offers crash simulation software called AutoDOE that uses statistical analysis to simulate crash tests.
The software helps engineers evaluate a variety of designs for new safety products by demonstrating the effect during a crash of variables such as occupant size, restraint type, air bag and seat characteristics and vehicle impact speed.
Thousands of potential combinations can be evaluated using a relatively few number of experiments.
The approach is meant to save money and significantly increase the odds of identifying hard-to-find solutions to nagging quality problems.
"It's a strong and effective program and it would be nice if it could be used across the board," said Fred Daris, supervisor of the minivan restraints group at DaimlerChrysler AG's Chrysler Group, which used the Key Safety Systems software tool for nearly five years in a minivan crash-testing program.
"It could eliminate about half of the crash sled tests needed if it is used effectively," Daris said, "especially in the early stages of restraint system development."
AutoDOE, which stands for Automotive Design of Experiments, is a software analysis program based on Key Safety's crash testing methodology, which details the design point parameters that are involved in developing a vehicle's safety restraint system.
AutoDOE helps engineers identify valid product design alternatives by suggesting different experimental designs based on specific objectives.
The goal is to be able to control as many variables as possible, resulting in a fewer number of trials needed to predict the performance of the system being studied.
The need for crash simulation software has grown as federal testing requirements have become more demanding amid the growing number of occupant safety systems available in today's cars and trucks.
All of these systems must be tested to see how they protect drivers, as well as front and rear seat passengers. Automakers must meet safety guidelines for seat belts; driver- and passenger-side air bags; and side air bags and inflatable curtains for occupants, including those who, for whatever reason, may not be in a normal, belted position.
In May 2000, the National Highway Traffic Safety Administration introduced more stringent restraint criteria for children under 12, and detailed the severity of head, neck and chest injuries that restraint systems must protect against.
Two types of crash tests are typically used to test safety systems -- sled tests and barrier tests.
In a sled test, a crash test dummy mounted in a test frame is pushed by a hydraulic piston. The sled duplicates the same forces that occur during an actual vehicle crash.
In a barrier test, an actual vehicle is crashed into a wall or other obstruction.
In both types of tests, critical measurements are made before and after for the wide number of variables that affect occupants during a crash.
Key Safety Systems calculates that between 200 and 300 sled-type crash tests are needed to develop and validate the average vehicle's entire restraint system.
The cost to run these tests is staggering, according to Chrysler's Daris. A single sled test, with all the associated prototype parts, is about $10,000 for a new program, while a barrier crash could cost up to $250,000, he said. Car companies normally run about 30 barrier tests to validate a vehicle's restraint system.
King H. Yang, a professor of biomedical and mechanical engineering at Wayne State University, has studied computer modeling as it relates to vehicle crashworthiness and occupant injuries for over 27 years. Yang believes that numerical simulations will eventually replace conventional crash testing.
"The more we get data from crashes, the more we can make corrections in the computer software," he says. "There is a lot of information about injuries that we cannot get from using crash dummies, but is readily available from the computer simulations."
Kang believes that as engineers continue to develop computer models, they will one day be able to pinpoint the type of injuries that will occur as a result of a given crash.
"Hypothetically, if I know in detail what kind of injury will result from a crash," Kang said, "I might be able to deliver medicine stored in the air bag during deployment, providing a medical first response before the ambulance arrives."
AutoDOE is used in conjunction with the industry standard restraint design and optimization software, called MADYMO, which is made by TNO Automotive, an independent research company based in the Netherlands.
TNO Automotive will market AutoDOE as an add-on module to its flagship program, said Joe Massa, Key Safety's director of engineering systems performance.
"We will still continue to develop and update AutoDOE," Massa said. "TNO will be responsible for offering it to other companies."
Barrett Kalellis is a Metro Detroit freelance writer.
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