• Flexural cracks were observed in all ice types under study.
• In the natural sea ice case, the maximum load was produced by compression
process, while in the model ice this process was not so well pronounced.
• Diagonal shear cracks were observed during the beam tests in the natural sea ice
and in the columnar model ice.
• As the relative length of the beams (
L
h ) decreased to values 3–4, the growth of the
failure force was observed: in the sea ice it was due to compression, in the model
ice due to bending.
• In the shorter beams of the sea ice we can expect shear failure: the shear force as
given in formula (4) is independent of the relative ice length; it is governed by
the shear strength of ice and cross-sectional area, i.e. remains constant (Fig. 17).
The same is valid for the model columnar ice beams (Fig. 19). In the
fine-grained ice case, the ice crushing under indenter forcing is growing as the
relative beam length is reduced, and this force becomes the governing factor of
the ice beam failure.
Conclusions
Our investigations have shown that the test on loading of floating ice beam with
fixed ends is representative in the terms of study of the ice failure mechanisms at
various relations of its strength parameters (crushing, compressive, flexural, shear
strength). The ice types used for the described tests (sea ice, model ice of the FG
type, and columnar model ice) have different relationships of the strength parameters, primarily, the ratio of the ice flexural strength to crushing strength. This, in
turn, causes various ice failure patterns when loading geometrically similar beams.
The tests in the Ice Basin were performed only with two model ice sheets (one of
the FG type and one of the columnar type), which were prepared according to the
technology used in the Krylov Centre. It is interesting to spread the number of the
ice sheets, as well to carry out the similar tests of ice beams with fixed ends in the
other Ice Basins with their specific technology of model ice preparation.
In the current analysis the effects of indentation rate, the Young modulus, and ice
inhomogeneity as functions of ice thickness were not considered. Additional tests
are required to study these factors.
Acknowledgements The authors acknowledge the support from UNIS and the Research Council
of Norway through the Centre for Research-based Innovation (SAMCoT project).
References
1. Vershinin, S. A. (1988). Ice action on offshore structures. In Results of science and
technology, issue: Water Transport (Vol. 13). Moscow.
2. Sanderson, T. J. O. (1988). Ice mechanics—Risks to offshore structures. Graham and
Trotman.
Experimental Studies of Sea and Model Ice Fracture Mechanics
609
• In the natural sea ice case, the maximum load was produced by compression
process, while in the model ice this process was not so well pronounced.
• Diagonal shear cracks were observed during the beam tests in the natural sea ice
and in the columnar model ice.
• As the relative length of the beams (
L
h ) decreased to values 3–4, the growth of the
failure force was observed: in the sea ice it was due to compression, in the model
ice due to bending.
• In the shorter beams of the sea ice we can expect shear failure: the shear force as
given in formula (4) is independent of the relative ice length; it is governed by
the shear strength of ice and cross-sectional area, i.e. remains constant (Fig. 17).
The same is valid for the model columnar ice beams (Fig. 19). In the
fine-grained ice case, the ice crushing under indenter forcing is growing as the
relative beam length is reduced, and this force becomes the governing factor of
the ice beam failure.
Conclusions
Our investigations have shown that the test on loading of floating ice beam with
fixed ends is representative in the terms of study of the ice failure mechanisms at
various relations of its strength parameters (crushing, compressive, flexural, shear
strength). The ice types used for the described tests (sea ice, model ice of the FG
type, and columnar model ice) have different relationships of the strength parameters, primarily, the ratio of the ice flexural strength to crushing strength. This, in
turn, causes various ice failure patterns when loading geometrically similar beams.
The tests in the Ice Basin were performed only with two model ice sheets (one of
the FG type and one of the columnar type), which were prepared according to the
technology used in the Krylov Centre. It is interesting to spread the number of the
ice sheets, as well to carry out the similar tests of ice beams with fixed ends in the
other Ice Basins with their specific technology of model ice preparation.
In the current analysis the effects of indentation rate, the Young modulus, and ice
inhomogeneity as functions of ice thickness were not considered. Additional tests
are required to study these factors.
Acknowledgements The authors acknowledge the support from UNIS and the Research Council
of Norway through the Centre for Research-based Innovation (SAMCoT project).
References
1. Vershinin, S. A. (1988). Ice action on offshore structures. In Results of science and
technology, issue: Water Transport (Vol. 13). Moscow.
2. Sanderson, T. J. O. (1988). Ice mechanics—Risks to offshore structures. Graham and
Trotman.
Experimental Studies of Sea and Model Ice Fracture Mechanics
609