Author(s): E. Appolonov; N. Klementeva; K. Sazonov; A. Tumashik
Linked Author(s):
Keywords: No Keywords
Abstract: In accordance with recommendat ions of ITTC and IAHR committees the main method for determinat ion o f ice bending strength is the failure of cant ilever beams that were cut out from the ice floe simulated in the ice tank. For bending strength calculat ions equat ion is used for cant ilever beam obtained for elast ic bodies. During studies of ice physical & mechanical properties in the ice tanks measurements are made for the force that init iated the beam failure and dimensions o f the obtained fragment are taken. It is customary to take the maximum (peak) value of the measured force. In the ice tank o f KSRI the study was per formed aimed at definit ion of the cantilever failure behavior and the changes in breaking force versus time were examined more thoroughly than it is usually done. This study has made it possible to identify the “fine structure” of failure pattern for the beams. It was shown that independent of the beam end loading rate, thickness of ice floe and ice structure (FG or columnar ice) the two processes are observed at beam failure. In the beginning the beam demonstrates elast ic properties. This process ends with crack init iat ion that propagates along the thickness but not through. After crack init iation the process observed is quite long and at that time the beam material should not be considered as elast ic. It shows plast ic, duct ile properties or it is subjected to creep. For more precise definit ion addit ional studies are required. In any case, the maximum value o f breaking force that is usually used for ice bending strength calculat ions is governed by the non-elast ic behavior of the beam. Therefore, it is not correct to use equation obtained for elast ic cantilever beam. Its applicat ion requires introduction of correction factors.
Year: 2010