SubscribeWhen a warhead, or similar fragmenting device is detonated, it is necessary to analyse the pattern of fragment dispersion.
This is done typically by assembling large pieces of card into ‘stacks’ of up to 40 and positioning these stacks around the detonation area. The resulting hole patterns in a given piece of card may be analysed to measure dispersion. However an analysis of the stack provides even more detailed information.
Factors such as depth of penetration, angular dispersion and an indication of energy can be derived from this 3-dimensional analysis. Fragments removed from the card are logged at their respective positions and the mass of the fragments may be recorded automatically by use of electronic scales.
Each card is placed on a reference light source and viewed by a digital camera. The image from the camera is used to measure the hole shape parameters, area and positions. Due to the complex mathematical algorithms being used, sub-pixel accuracy is possible, giving precision measurement over the entire area.
The data from successive cards in the stack is assimilated into a 3-dimensional plot showing the track of each fragment.
In the past, a typical trial would take between 3 and 6 months to analyse. With the Strawboard Imager type 600, such analysis is reduced to a matter of hours.
The unit shown above illustrates the supplied calibration plate that is used to ensure optimum accuracy.
The imager systems have been supplied in various forms to Government research establishments in the UK. Variants for analysis of target plates and other removed-mass situations have also been supplied. X-ray plate analysis is another area of application.
