Hybrid Ship Hulls

Hybrid Ship Hulls provides an overview of cutting-edge developments in hybrid composite-metal marine ship hulls, covering the critical differences in material processing and structural behavior that must be taken into account to maximise benefits and performance.Supporting the design of effective hybrid hulls through proper consideration of the benefits and challenges inherent to heterogenic structures, the book covers specific details of quality control, manufacturing, mechanical and thermal stress, and other behavioral aspects that need to be treated differently when engineering hybrid ship hulls. With a particular focus on heavy-duty naval applications, the book includes guidance on the selection of composite part configurations, innovative design solutions, novel hybrid joining techniques, and serviceability characterization. Addresses the engineering requirements specific to hybrid structure engineering that are essential for optimization of hybrid hull design and maximization of material benefits. Covers methodology, techniques and data currently unavailable from other sources, providing the essential base knowledge to support robust design, reliable manufacturing, and proper serviceability evaluation. Includes MATLAB codes, enabling engineers to easily apply the methods covered to their own engineering design challenges.

A hull is the watertight body of a ship or boat. Above the hull is the superstructure and/or deckhouse, where present. The line where the hull meets the water surface is called the waterline. The structure of the hull varies depending on the vessel type. In a typical modern steel ship, the structure consists of watertight and non-tight decks, major transverse and watertight members called bulkheads, intermediate members such as girders, stringers and webs, and minor members called ordinary transverse frames, frames, or longitudinal, depending on the structural arrangement. The shape of the hull is entirely dependent upon the needs of the design. Shapes range from a nearly perfect box in the case of scow barges, to a needle-sharp surface of revolution in the case of a racing multihull sailboat. The shape is chosen to strike a balance between cost, hydrostatic considerations (accommodation, load carrying and stability), hydrodynamics (speed, power requirements, and motion and behavior in a seaway) and special considerations for the ship's role, such as the rounded bow of an icebreaker or the flat bottom of a landing craft. The book Hybrid Ship Hulls, Engineering Design Rationales provides an overview of cutting-edge developments in hybrid composite-metal marine ship hulls, covering the critical differences in material processing and structural behavior that must be taken into account to maximise benefits and performance. Supporting the design of effective hybrid hulls through proper consideration of the benefits and challenges inherent to heterogenic structures, the book covers specific details of quality control, manufacturing, mechanical and thermal stress, and other behavioral aspects that need to be treated differently when engineering hybrid ship hulls.

The sandwich panel materials are chosen for the skin and the core with consideration given to the joint with steel. Their advantages are highlighted over the other common alternatives.

The project dealt with mechanical issues related to hybrid ship hulls made with composite panels attached to a steel truss. The steel truss was designed to carry the bending loads of the hull girder, whereas the composite skins were designed to carry shear and water pressure loads. Experimental and numerical evaluations of the concept were performed. A six meter (20 ft) model, which had been built and initially tested in 2004 under a separate grant, was turned upside-down and tested to verify performance under hogging loads. After these hogging tests, the model was turned back and tested to failure after simulated internal blast by removal of select panels. Material tests and elastic-plastic analyses were performed. Four journal papers describing the work on the present hybrid ship hull concept have been submitted for publication (three have been published and the last one has been accepted).

In recent years compelling reasons for using a combination of steel and composites in a so-called hybrid ship hull have been voiced. A high speed boat is presently being built to evaluate performance of a hybrid hull under real sea loads. In this paper the manufacturing of the steel truss for this boat hull is described. The truss consists of bulkheads, longerons, etc. made in welded thin-walled closed stainless steel sections. Due to the small thickness of the steel, mostly 2 mm, various bungs and reinforcements were added wherever higher loads were introduced. Measures were taken to reduce fatigue issues and to make the stiff steel share loads appropriately with the compliant glass and carbon fiber reinforced composite panels.

A hybrid ship structure could potentially combine the benefits of both steel and composites to obtain possible superior characteristics. In this dissertation, a hybrid ship hull made of a steel truss and composite sandwich skins was investigated. The steel truss was designed to carry the bending loads, whereas the composite skins were designed to carry shear and water pressure loads. A 142 meter ship hull, similar to a destroyer in terms of size, weight and speed, was designed, finite element analyzed and optimized. A 6 meter model was subsequently developed, finite element analyzed, manufactured and tested under sagging loads. The model was loaded to 36% above the design load, at which point there was substantial yielding and residual deformation of the steel truss. However, there was no indication of failure in any of the composite sandwich panels, nor in the bonds between the panels and the steel truss. Joints in hybrid structures were also investigated in the dissertation, including joints between a steel hull and a composite superstructure, and between a stainless steel Advanced Double Hull and a composite bow/stern. Joints were designed and specimens were manufactured and tested mechanically and environmentally.

A finite element tool has been developed to design and investigate a multi-hull composite ship structure, and a hybrid hull of identical length and beam. Hybrid hull structure is assembled by Titanium alloy (Ti-6Al-4V) frame and sandwich composite panels. Wave loads and slamming loads acting on both hull structures have been calculated according to ABS rules at sea state 5 with a ship velocity of 40 knots. Comparisons of deformations and stresses between two sets of loadings demonstrate that slamming loads have more detrimental effects on ship structure. Deformation under slamming is almost one order higher than that caused by wave loads. Also, Titanium frame in hybrid hull significantly reduces both deformation and stresses when compared to composite hull due to enhancement of in plane strength and stiffness of the hull. A 73 m long hybrid hull has also been investigated under wave and slamming loads in time domain for dynamic analysis.

Forest trees cover 30% of the earth's land surface, providing renewable fuel, wood, timber, shelter, fruits, leaves, bark, roots, and are source of medicinal products in addition to benefits such as carbon sequestration, water shed protection, and habitat for 1/3 of terrestrial species. However, the genetic analysis and breeding of trees has lagged behind that of crop plants. Therefore, systematic conservation, sustainable improvement and pragmatic utilization of trees are global priorities. This book provides comprehensive and up to date information about tree characterization, biological understanding, and improvement through biotechnological and molecular tools.