Cellulose Core Sandwich Hull for Puncture-Resistant Buoyancy
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Solution Overview
Problem
Existing marine hulls face challenges such as puncture vulnerability, high weight, complex assembly, reduced interior space, and compromised speed and maneuverability, while requiring attachment mechanisms that can withstand large forces and torque.
Innovation Solution
A deep-drawn marine hull with a sandwich structure featuring a cellulose-based core and fiber-reinforced thermoplastic skins, bonded by thermoplastic adhesives, which provides stiffness, buoyancy, and allows for a lightweight, low-cost design with integrated fasteners for securing cargo and passengers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single-layer metal or plastic hull is used, then the hull is simple in structure and easy to manufacture, but it is vulnerable to punctures and sinks when punctured
Solution Approach 1:
The hull is divided into multiple functional layers: an outer skin for puncture resistance, a cellular core for buoyancy and energy absorption, and an inner skin for structural support. This segmentation allows each layer to perform its specific function, resolving the contradiction between structural simplicity and puncture resistance.
Solution Approach 2:
The cellular core material is positioned between the outer and inner skins to provide beforehand cushioning. When the outer skin is punctured, the cellular core absorbs the impact energy and prevents water from reaching the inner skin, maintaining buoyancy and preventing sinking.
2Strength
If rigid or hard shell hulls are used, then the hull provides structural strength and stiffness, but the weight makes them difficult to transport
Solution Approach 1:
The hull uses a composite sandwich structure combining a cellular core material with outer and inner skins. This composite construction provides high stiffness-to-weight ratio, delivering the required structural strength while keeping the overall weight low for easy transport.
Solution Approach 2:
The cellular core provides localized stiffness and strength where needed, particularly in areas subject to impact or bending moments, while the thin outer and inner skins maintain low weight. This local quality approach optimizes the strength-to-weight ratio throughout the hull structure.
3Weight of moving object
If foldable hulls with many parts are used, then the hull is lightweight and easy to transport, but the large number of parts complicates assembly and reduces interior space
Solution Approach 1:
The outer skin, cellular core, and inner skin are merged into a single integrated sandwich structure that can be manufactured as one piece or pre-assembled units. This merging eliminates the need for multiple separate parts and complex assembly procedures while maintaining lightweight construction.
Solution Approach 2:
The cellular core serves multiple functions simultaneously: providing buoyancy, absorbing impact energy, and contributing to structural stiffness. This multi-functionality reduces the need for additional structural elements, simplifying the overall design and assembly.
4Strength
If foldable hulls with interior flanges or ribs are used, then the hull provides structural support, but the flanges reduce the amount of space for passengers and gear
Solution Approach 1:
The cellular core provides distributed structural support throughout the hull volume rather than requiring concentrated ribs or flanges. This local quality approach maintains structural integrity while preserving maximum interior space for passengers and gear.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution results in a lightweight, stiff, and aerodynamically smooth hull that maintains buoyancy even with punctures, offers ample interior space, and secure attachment options, enhancing the performance and safety of watercraft.
Implementation Method 1
an outer skin of a fiber-reinforced thermoplastic material and having a waterproof outer surface, a first sheet of thermoplastic adhesive, an inner skin of fiber-reinforced thermoplastic material
Implementation Method 2
The cells absorb energy of an impact at the outer surface of the outer skin by deformably crushing
Implementation Method 3
Air trapped within cells which are not completely crushed or punctured by the impact provide the hull with buoyancy to allow the hull to float at the surface of a body of water
Data Source
AI summary
A deep-drawn, marine hull having a sandwich structure with a cellulose-based core and watercraft utilizing same are provided. The hull includes an outer skin of a fiber-based thermoplastic and having a waterproof outer surface, a first sheet of thermoplastic adhesive, an inner skin of a fiber-reinforced thermoplastic material and having a compartment-defining outer surface, a second sheet of thermoplastic adhesive and a shock absorbing, cellular core of a cellulose-based material and positioned between the skins The skins are bonded to the core by the first and second sheets and by press molding. Cells of the cellular core absorb energy of an impact at the outer surface of the outer skin by deformably crushing. Air trapped within cells which are not completely crushed or punctured by the impact provide the hull with buoyancy to allow the hull to float at the surface of a body of water.