Membrane Hull Technology Implemented into a D-Collar Work Boat

Abstract

Membrane Hull Technology (MHT) was initially developed for the United States Navy Rigid-Hull Inflatable Boats (RHIB) as an alternative structure design to provide weight savings and shock mitigation. MHT accomplishes this by veering away from traditional hull design and utilizing a grid like system with an increased number of longitudinal stringers and transverse frames with a significantly lower moment of inertia when compared to traditional stringers and bulkheads. The decrease in stiffness allows for increased deflection in the hull during high load events with the added benefit of shock absorption. This technology, developed by Structural Composites Inc., has been successfully implemented into multiple Navy RHIBs. To date, this technology has not been applied into a D-Collar work boat that has various design differences when compared to RHIBs. The main design difference examined will be converting the large, structural freeboard away from traditional cored structure to a thin walled framed structure. Other design differences examined include the integration of an Armstrong bracket, the hull to deck interaction and the various workloads and equipment seen on the D-Collar workboat. Finite Element Analysis was conducted to optimize the structural laminate while conforming to design standards to decrease the structure mass by greater than 40%. Analysis showed hull deflections greater than 4 cm which validated the theory of Membrane Hull Technology as a shock mitigation structure by increasing the time and distance over which accelerations are applied to the craft.