Deep seabed polymetallic nodule mining machines have to operate in extremely soft ocean floor having soils of shear strength in the order of 1-3 kPa. The extent of sinkage and pullout force or breakout force required to lift the mining machine from the seafloor bottom needs to be evaluated for the successful operation and retrieval of the mining machine. In most of the cases the breakout force exceeds the submerged weight of object. Most of the empirical equations for estimating breakout forces are based on the bearing capacity phenomena. In the present study experimental investigations have been carried for obtaining undrained or immediate breakout forces on flat plates, plates with involute grousers and single track unit of Undercarriage unit. The magnitude of forces so obtained from the experiments has been compared to those calculated from the empirical equations. Studies on the extent of sinkage in soft sediments is critical for quantification of resistances encountered by the mining machine which influences the maneuverability of the mining machine. Experimental investigations have been carried out on flat plates, flat plates with grousers and single track of undercarriage unit as a part of sinkage studies. Sinkage has also been studied by Finite Element Methods using MohrCoulomb material model neglecting angle of internal friction angle as soils were fully cohesive and solving through explicit methods.
The maturity of sophisticated numerical tools for predicting damage in composite materials has become a priority research area in aero- and underwater structures. This paper proposes a modeling approach to endeavor achieving high fidelity of mechanical behavior of composite materials subjected to high pressure applications. The strategy begins with numerical methods to design an alternative material for high pressure applications and to build a ladder with experimental observations when these composites are deployed for 600 bar pressure which take into account the relevant deformation, effective estimation of mechanical properties and failure mechanisms at different length scales. Coupon-shaped specimens with different hardener-epoxy ratios were manufactured to investigate the uniaxial tensile performance and the morphological studies were carried out in order to have a picture regarding the delamination and debonding behavior of the aforementioned composites. The further scope of this work involves a review of some notable micromechanic models and to establish the state-of-art together with insights for future development. Analytical models based on the mechanics of materials (MOM) approach and Mori-Tanaka (M-T) methods are shown to estimate the elastic response of composite materials. An attempt has been made to validate these finite-element predictions with experimental observations in order to secure the capability of a numerical framework. The outcome of our study also assures that these composites can be used in advanced structural applications under different conditions.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.