Strength Analysis of Mark III Cargo Containment System using Anisotropic Failure Criteria

Abstract

Membrane type Mark III cargo containment system (CCS) is considered in this study to investigate its strength capability under applied loads due to liquefied natural gas (LNG) cargo. A rectangular plated structure supported by inner hull structure is exemplified from Mark III CCS according to classification society's guidance and it is assumed as multi-layered structure by stacking plywood, triplex, reinforced polyurethane (PU) foam and series of mastic upon inner hull structure. Commercially available general purpose finite element analysis package is used to have reliable FE models of Mark III CCS plate. The FE models and anisotropic failure criteria such as maximum stress, Hoffman, Hill, Tsai-Wu and Hashin taking into account the direction dependent material properties of Mark III CCS plate components and their material properties considering a wide variation of temperature due to the nature of LNG together form the strength analysis procedure of Mark III CCS plate. Strength capability of Mark III CCS plate is understood by its initial failure and post-initial failure states. Results are represented in terms of failure loads and locations when initial failure and post-initial failures are occurred respectively. From the results the basic design information of Mark III CCS plate is given.

A reduced order model for structural response of the Mark III LNG cargo containment system

“…4. The material model is isotropic linear and properties are chosen after [16,25] and similar to [24], and displayed in Table 1. The top plywood is free at both ends, and continuously supported by the foam.…”

“…This model combines the square of the hydrostatic and Von Mises (mean and deviatoric) stress linearly to a failure locus. However, other failure laws can also be considered [16], and show a large influence on the capacity, which is why this choice is not made here.…”