Advanced Composite Sandwich Panel Architecture for Improved Performance at Reduced Weight and Cost

The Navy is currently developing advanced surface combatants like DD(X), LPD-17, LCS and CVX to meet challenges of the 21st century. The desire to reduce maintenance cost and weight makes the use of composite structures very attractive, but cost of manufacturing large composite structures remains a significant technology barrier. KaZaK and UMass Lowell propose to develop pultrusion technology of balsa cored carbon fiber epoxy composite panels with unique reinforcement architecture with the goal of significantly reducing weight and cost of ship composite structures. Composites manufactured from carbon fiber preforms similar to the ones proposed here have been shown to exhibit surprising improvements in mechanical properties over conventional composites, including 30% increase in tensile strength, greater than an order of magnitude improvement in fatigue life, increase in stiffness, and reduction in delamination damage. A revolutionary feature of the proposed technology is the ability to manufacture thin wall composite parts with mechanical properties equivalent to regular thickness conventional composites, leading to super lightweight structural components. Significant cost savings are anticipated from material property improvements. An ancillary advantage will be the ability to pultrude epoxy matrix composites instead of being limited to vinyl ester resin as is the case with current VARTM techniques.BENEFITS: The primary anticipated benefits of the proposed novel carbon fiber epoxy balsa core pultruded panels are significant improvements in mechanical properties leading to direct weight and cost savings. These savings will stem from performance improvements due to novel carbon fiber reinforcement geometry and the use of epoxy matrix combined with pultrusion, by far the lowest cost composite manufacturing technology. The NGSS DD(X) design is the targeted beneficiary of the proposed technology development effort, although the technology will be generically applicable to all future composite ship structure. The same basic technology can be applied to the production of composite piers, bridge decks and other large civil engineering structures. Other potential Navy applications include LCS, LPD, CV(x) and other future combatants. The simplicity and versatility of the proposed technology will allow cost-effective implementation into new lightweight composite systems and easy retrofit into many existing ones. The high strength to weight properties will make these materials excellent candidates for metal replacement applications.