Krishna Kannan

This paper presents the tractive performance of different grouser shapes in extremely soft seabed soil using finite element analysis (FEA). Consequently, the deformation characteristics and pattern of shear failure in the seabed soil can be predicted, eliminating expensive full-scale experiments. A three-dimensional FEA with the incorporation of geometric nonlinearity of shear rheometry is performed using coupled Eulerian–Lagrangian (CEL) technique in ABAQUS Explicit. The Mohr–Coulomb criterion is used to define the constitutive behaviour of the seabed soil sample used. To validate the model, the CEL simulation results are corroborated with experimental observations. The study reveals that the Mohr–Coulomb model with the governing parameters is able to capture the maximum rotational moment obtained from the experimental results with a maximum error of 3.5%. The Mohr–Coulomb model is therefore used to determine the maximum traction developed from two distinct grouser profiles to evaluate their tractive efficiency. It is observed that a triangular grouser offers better traction than an involute grouser.

This paper stems from the interest in the numerical study of the evolution of Boulder Clay Glacier in Antarctica, whose morphological characteristics have required the revision of the basis for most of the recent mathematical models for glacier dynamics. Bearing in mind the need to minimize the complexity of the mathematical model, we have selected the constitutive equation of rock glacier ice recently presented by two of the authors. Here, this model is extended in order to include temperature effects. In addition to the effects of climate change, it is also necessary to take into consideration the non-negligible level of melting due to temperature changes induced by normal stresses arising from the interactions of ice and the rock fragments that are within the rock glacier. In fact, local phase transition that occurs leading to the release of water implies significant modifications of ice viscosity, the main intrinsic factor driving the flow. In this paper we derive the model that describes the flow of rock glaciers that takes into consideration the effects of temperature and the normal stresses generated by the ice and rock fragments interactions.