Therefore, as a first step, a team now led by DERA's Graham Meeks, produced a knife handle, crammed with electronic sensors and capable of accepting a range of blades. This was then linked to a computer before being given to a large number of volunteers, who were invited to stab a target dummy designed to recoil as much like a human as possible. Each stabbing action was digitally recorded for its degree of force, velocity and direction.
"In the initial stages we wanted to produce a force/ velocity curve to understand the impact event," said Graham Meeks. "But there was little to be gained from stabbing an object that did not respond as a human would do. Stabbing actions alter according to the resistance offered. A person stabbing a piece of solid wood acts differently than one stabbing a piece of plasticine or another human being and it was therefore important that we created, as closely as possible, the same conditions for the tests as would be met in real life."
The absence of high-tech instrumentation and materials able to respond to the threat in the same way as human skin and tissue has meant that it has not, until recently, been possible to accurately measure the physical effects on the human body of an impact- at least until after the event. Major advances, closely based on military-defense-related technology, have not produced the skin and tissue simulates, making a substantial difference to the research into a better level of body projection.
"In a sense, the origin of the trauma is unimportant," said Dr. Sandy Bell, the leader of the team looking at the effects of blunt trauma. "The shock waves set up by an explosive charge are generically similar to those set up by a knife or a bullet striking the body armor."
"What we have found is that some types of body armor actually make the trauma effect worse and it is important that we understand how much the human body is capable of withstanding."
Computer Assistance Critical
But it was still necessary to know the exact form and distribution of the energy (or shock wave) and it was the third of the recent advances that has made this possible. Computer- based analytical methods now allow snapshots of the effect that a blow is having on the human dummy. In the split- second of time being covered, the analysis shows the distribution and form of the shock waves and the effect that, at each moment in time, the trauma is having on the "body."
It will, according to Scotland Yard's Dr. Taylor, be another year, at least, before the results of the present research begin to bear fruit. The level of technical knowledge is not yet advanced enough to convert the latest, manmade, laminates into a form capable of creating a woven material. Even when it is possible, it will still be necessary to achieve the correct geometry in the weave that retains and preferably enhances the existing properties of the substances. He and the DERA scientists, however, remain optimistic that, in the fullness of time, a way will be found to build armor that will offer substantial improvements in the level of protection of officers.
Looking to the Future
There is little doubt that improvements are necessary and overdue. Research in the United States and in the U.K. show that officers will not wear body armor if it was too hot, too heavy, restricts movement or cannot be concealed. Perhaps because of this, current body armor tends to be issued on the basis of the threat being faced. Officers dealing with an armed situation will, for short periods, wear armor that would be wholly unsuitable for routine patrol work. On the other hand, the search for comfort has inevitably reduced the level of protection offered to the officer on the street.
There is no question that the existing American NIJ standard of a 44 mm "backface deformity" for ballistic protection, i.e. the depth of the dent caused by the bullet hitting the armor, has saved a great number of lives in the states but complaints about wearability continue and there is mounting medical evidence of the substantial, if nonfatal, risks inherent in the blunt trauma effect occasioned by a 44 mm backface deformity.
With growing levels of violence being faced by officers the world over, society owes them an obligation to produce the best protection of which technology is capable. The DERA research is a valuable contribution to this effort.
Patrick Hook retired in 1994 after a varied and distinguished 31-year career with the Metropolitan Police in London, rising to the rank of chief inspector. His last four years of law enforcement service were spent at the famed Scotland Yard where he was involved in planning and developing policy on a wide range of issues. Hook, who resides in England, is a prolific freelance writer in Europe often on police matters. This is his first contribution to POLICE.