Headforms

About Headforms

Headforms have specialized the testing of vehicles where information can be more readily gained by using a modified head alone or in conjunction with a dummy. This is done to provide more varied information than is normally derived from reading the response of the head in a standard impact test. Headforms have helped in the development of safer vehicle interiors and exteriors in pedestrian impacts. They also have been used to test personal safety gear. These devices indicate the extreme importance of protecting the head from injury in accidents.

Why We Test With Headforms

The eyeglass dummy heads are specified in ASTM standards for testing of protective eyewear. They allow the tester to insure that a proper level of protection will be afforded in sports and industrial eyewear. Projectiles are launched at the head to run these tests.
 
The deformable face headform is mounted on a dummy in use. It was the result of SAE papers and is used to tailor the impact response of the head when the nose area hits the steering wheel. The deformation also leaves a record of the contact. This allows the vehicle developer to test steering wheel designs to minimize facial injury and head acceleration caused by contact.
 
Free motion headforms launched by robot arms are used to impact many interior surfaces in the car. They give the test engineer the ability to impact many areas of the vehicle interior in a controlled method. Controlled impacts in these areas would be impossible if the head were mounted on the dummy. They help the vehicle developer to tailor the interior surfaces of the vehicle to prevent or reduce head injury.
 
The ejection mitigation headform, 18KG head, is used to test the ability of side curtain airbags to restrain the vehicle occupant’s head within the vehicle in a roll-over accident. This aids in the design and development of side curtain airbags. The head weighs 4 to 5 kg, 18 kilograms refers to the total moving mass of the headform and its impactor when in use to impact the car from the side.
 
Spherical headforms are launched at the windshield in American, European, and Asian vehicle tests to simulate a pedestrian head strike. The impact locations are more controllable than they would be using a full pedestrian dummy. Better design of the windshield for pedestrian protection is the result.

History of Headforms

The eyeglass dummy heads are a result of the development in the 1950’s and 60’s of the VIP dummies by Alderson Research Laboratories. The heads of these dummies were modified to make the eyeglass dummies in the 1970’s and were written into ASTM code Z87.1.
 
The deformable face headform was based on a Hybrid III head with a modified skull and facial area. It was developed by GM and ARL in 1989.
 
The free motion headform based on a Hybrid III head modified to be launched from a robot arm accelerator was developed in 1992 by General Motors and Alderson Research Labs (Smrcka).
 
The 18 KG head was developed by the Vehicle Research and Test Center (VRTC) and Humanetcis in 2007 using a head originally designed in 1991 for pedestrian impacts.
 
The spherical headforms were developed in Europe by TNO followed by Humanetcis in the last decade of the 20th century and the first decade of the 21st century.

Headforms and Their Use in the US Code of Federal Regulations

1
Free Motion Headform  92041-001:
U.S. Code of Federal Regulations Title 49 “Transportation” 49CFR Part 572. “Anthropomorphic Test Devices”.
Subpart L
1995
2
Federal Motor Vehicle Safety Standards
U.S. Code of Federal Regulations Title 49 “Transportation” 49CFR Part 571.201 “Occupant protection in interior impact
(where used)
1997

Other Regulations

The spherical headforms are incorporated into European and Asian testing protocols for normal and New Car assessment programs (JNCAP).

Future Headforms

As dummies are pushed further toward measuring non-contact, closed head injuries there may be development in the area of simulating the soft tissue in the head. This will require the application of clinical research and tissue characterization to the development of the heads.

Headform Review

Headforms are used on dummies, launched by various accelerators and are used statically for testing vehicle interiors, exteriors and unrelated protective devices (eyewear). Their use has been instrumental in increasing the level of protection both in and out of the vehicle as well as for the development of general safety gear.