LASCOR panels offer the potential for significant weight and cost reductions. Applied Thermal Sciences photo
The objective of this project was to complete LASer-welded corrugated-CORe (LASCOR) structural / closeout validation testing, complete material / corrosion testing and implement the technology into shipyard applications while incorporating material, design and manufacturing improvements to reduce cost. This was accomplished by optimizing the LASCOR design for materials, manufacturability, joining, structural and protection performance, and cost.
Future naval vessels must reduce weight to improve combat effectiveness and maneuverability, while remaining affordable. Improvements in manufacturing and process technology have made the use of laser-welded metallic sandwich panels more feasible and economical for naval applications. Laser-welded metallic sandwich panels are stiff, lightweight structures that offer the Navy corrosion resistance, reduced weight, less distortion and cost effectiveness. The design is similar to corrugated cardboard and consists of two sheets of metal that are joined to a corrugated metal core via laser welding. Efforts involving the panels have spanned more than 20 years, including work by the Naval Surface Warfare Center Carderock Division (NSWCCD) and ARL-Penn State under the Office of Naval Research’s (ONR) Manufacturing Technology Program. Today the technology is geared toward Navy implementation and manufacturing efficiency. Sandwich panels have seen limited use on various applications for the U.S. Navy, including DD-981, CV-41, LC 19/20, and DDG-51 as well as antenna platforms for the USS Mt. Whitney (LCC 20). Even after extensive development work, issues such as uniform design parameters; joining techniques; attachment practices, materials, repair and modification methods; and availability have prevented opportunistic growth in the use of laser-welded metallic sandwich panels for naval and other defense and commercial applications.
The project established a lightweight, stiff, flexible, adaptable and modular structural steel system to reduce weight with reduced distortion, improved corrosion resistance and improve performance while evaluating and demonstrating cost reduction for CVN 21 and DDG 1000 applications. Laser-welded metallic sandwich panels provide an opportunity for shipyards to reduce weight while enhancing performance in applications where an economical metallic solution is needed. By optimizing thickness, materials, geometry, and joint designs, the flexible sandwich panel designs can be tailored to a wide variety of shipyard applications that meet various performance requirements. As more applications for this technology are successfully implemented, additional opportunities will follow. It is expected that LASCOR structures will result in a weight reduction of between 15% and 30% over conventionally fabricated structures.
LASCOR is being evaluated for future applications on CVN 78 Class in parallel with fabrication of various prototype panels to demonstrate manufacturability. Provided that LASCOR designs offer the shipyard improved performance or cost reduction, LASCOR may be incorporated into baseline designs for future construction. Also, LASCOR is being considered for other ship platform use, and this project helped to streamline future shipyard implementation efforts.
Based on the work conducted under this project, a competitive bid initiated by General Dynamics Bath Iron Works (BIW) resulted in a multi-million dollar contract to develop, test, and manufacture ship sets of Deck Edge Safety Berms and Personnel Safety Barrier Panels for DDG 1000 using hybrid laser-welded metallic sandwich panel technology, with approximately 84 panels per hull. This technology was selected as the low-cost, technically compliant solution to meet weight, structural, heat, and other requirements while offering corrosion resistance, reduced weight, and less distortion. The first two ships of the DDG 1000 class are being built by BIW; the two ship sets of panels are scheduled for delivery by October 2011.