Impact energy is generally assumed to equal the maximum kinetic energy that is due to the acceleration of the flyer plate.
Defining impact energy:
- Energy loss that is due to the bending strain energy in the flyer plate has been ignored in much of the earlier literature, because of its complexity.
- Recent estimates of energy partitioning suggest that only 15 to 20% of the flyer plate energy is used for cladding, whereas 66% is absorbed in flyer plate forming and 15% is dissipated as excess energy in the base plate.
- The flyer plate standoff distance is therefore a very important factor, because it physically limits the flyer plate acceleration and dynamic bend angle.
- Simple determinations of flyer plate standoff distance resulting from empirical testing are often used.
- Standoff distances that are twice the flyer plate thickness for thin components (up to 6.5 mm, or 0.26 in.) and are equal to the flyer plate thickness for thicker components (up to 13 mm, or 0.5 in.) are generally used (Ref 12).
- Other studies have indicated that a uniform flyer plate velocity is obtained with a separation distance equal to only a few multiples of the flyer plate thickness
Systematic evaluation of standoff distance and dynamic bend angle, which indicated that:
· A LAMINAR BOND WAS ACHIEVED AT DISTANCES EQUAL TO APPROXIMATELY HALF THE FLYER PLATE THICKNESS
· A STABLE WAVY BOND ZONE WAS PRODUCED AT INTERMEDIATE STANDOFF DISTANCES EQUAL TO 1.0 TO 1.5 TIMES THE FLYER PLATE THICKNESS
·DELAMINATION OCCURRED AT DISTANCES ABOVE TWO TIMES THE FLYER PLATE THICKNESS