Not so dummy

Japanese work on a new breed of crash test dummy will help designers develop safer vehicles and save lives.

Created by engineers at Toyota in Japan, THUMS (total human model for safety) is a virtual representation of the human body that can provide engineers with precise data about the injuries people might sustain in various accidents.

Traditional dummies replicate the outward impact on the body. But the virtual ones, using complex computer modelling, take into account bone strength and skin flexibility — even ligaments and tendons.

According to Toyota, this new emphasis on detail will make it possible to predict more accurately the physical damage that different impacts will cause, to vehicle occupants and pedestrians. A company spokesman claimed that the accuracy of the system has been ascertained by comparing the results of THUMS simulations with X-rays taken from accident victims.

An advantage of this system, besides its inherent accuracy, is that it will allow car designers to identify elements that are responsible for injury during an accident and enable the effects of any adjustments to be evaluated.

THUMS has its roots in a Toyota product and technology development programme called ‘Maximise and Zeronise’ which has at its core the boldly stated ambition to ‘eliminate all traffic accidents’.

Other technology to stem from this includes an adaptive front-lighting system (AFS) that allows headlights to swivel in line with vehicle speed and steering angle, and pre-crash safety (PCS) which detects imminent collisions and automatically tightens the front seat belts and initiates an emergency stop.

In the UK, researchers at Loughborough University are working on the development of virtual pregnant crash test dummies. This work is building on EPSRC-funded research carried out by the university’s Dr Serpil Acar.

Her project concluded that a number of factors must be considered when optimising car safety for pregnant women. They are bigger and heavier, and the extra progesterone in the body loosens the muscles, ligaments and joints.

It will build on earlier work at Volvo’s safety centre in Sweden which applied computer science to crash test dummies and developed the world’s first pregnant crash test dummy.

Researchers used this to explore the impact of a seat belt and airbag on a mother and unborn baby in car accidents. Biomechanics engineer Laura Thackery explained that while the uterus is flexible, the less-resilient placenta is at risk of detaching in the event of an accident.

It is this uncertainty which drives such computer studies to find better ways of protecting the unborn child.  

A BRIEF HISTORY OF THE CRASH TEST DUMMY

The crahs test dummy, or anthropomorphic test device as it was originally known, has evolved significantly since its inception at the end of the 1940s.

While at first nothing more than a mannequin-style figure, today it is a highly advanced instrumentation tool. First developed by Californian inventor Samuel Alderson under contract with the USAF, ‘Sierra Sam’ was used for evaluation of pilot restraint and aircraft ejection systems.

The military used crash test dummies and crash sleds to test a variety of applications and human tolerance to injury. Though originally using human volunteers, higher safety standards required higher speed tests, which was not safe for human subjects.

Following the Motor Vehicle Safety Act (1966), General Motors began developing crash test dummies and today GM’s Hybrid III is the industry standard. Hybrid III accurately represents the way drivers and passengers sit in vehicles.

A head is designed to respond like a human head — from its symmetry to the forehead deflecting as it would if struck in a collision. The chest cavity has a steel rib cage to simulate the mechanical behaviour of a human chest in a crash. It is equipped with vinyl skin and consists of electronic tools such as accelerometers, potentiometers and load cells. These measure the acceleration, deflection and forces that various body parts would experience during crash detection.

However, with the steady advance of computer power leading to virtual systems, the days of the physical crash test dummy may be numbered.