Some Mechanical and Structural Aspects of the Smolensk Crash
By Dr. Gregory Szuladzinski, Ph.D., MSME
SCND2014GS

Appendix II. Fragmentation

Imagine a container, such as a steel barrel, used for experimental purposes. The barrel is filled with water the internal pressure is growing. At some point the barrel breaks. If the pressure was growing slowly, the cracking is typically along one line. If the pressure rises rapidly, the barrel may disintegrate into several parts. If, instead of water, one puts an explosive into the barrel, then the more of this material that is used, the more fragments will result. With strong (or large) explosive charge, the barrel will disintegrate into an array of different size fragments. The smallest may have 2 cm², and the largest will be a significant part of the barrel. These small pieces are often called shrapnel. They are a characteristic trace of the use of explosives against metal containers.

The only other opportunity to produce fragments of aircraft structures is to strike a rigid barrier at high speed. There was no rigid obstacle in this case, whereas a speed of 270 km/h is insufficient to create a an abundance of shrapnel.

The mechanism of creation of multiple cracks due to large and sudden loads and the related process of formation of fragments, is described in Chapter 15 of book published by the author of this report, Formulas for Structural and mechanical shock and impact (CRC Press 2009).

Fig. 22a-g. Photographs of small fragments, found on 10 April 2010 around the streets Gubienki and Kutuzowa.^iv In some debris (Fig. 22a, b) the rivet holes are visible, which makes it unlikely that they were caused by the forces tangential to the shell.

Above: Fig. 22a		Above: Fig. 22b
Above: Fig. 22c		Above: Fig. 22d
Above: Fig. 22e		Above: Fig. 22f

Above: Fig. 22g

Above: Fig. 23 Tail section of the fuselage.