N102-173 TITLE: Fire Simulation and Residual Strength Prediction Tool for Aluminum Ship Structures During and After Fire

TECHNOLOGY AREAS: Ground/Sea Vehicles, Materials/Processes

OBJECTIVE: The Navy has a requirement for a validated analysis tool to predict fire growth, fire spread, heat transfer through structure boundaries, time dependent material softening, structural stability, and residual strength of advanced aluminum structure during and after fire. This SBIR is seeking proposals for modules which address an aspect of this problem, and a system integrator to integrate the modules into a prediction tool.

DESCRIPTION: The use of aluminum alloys and their extruded structural components in marine construction has a great advantage in minimizing a vessel�s weight. Given its one-third density of steel and 70% of the tensile strength of steel, the resulting weight of aluminum high speed craft is much lower than a similar vessel constructed from steel. The reduction of hull structural weight allows for increased payload, top speed, and operation range at lower operational and total ownership cost. Protection of aluminum structure from fire is a key issue in aluminum structural design as aluminum�s properties are quickly reduced when the temperature exceeds 150 degree Celsius. In addition, the material properties of aluminum are permanently modified by elevated temperature causing the structure to be weakened following a fire event. Given a larger (more than two times) coefficient of thermal expansion than steel, the resulting large thermal stress/strains in an aluminum hull during a local fire could lead to failures elsewhere in the vessel. A strong technical fire modeling and residual strength assessment capability is very important to replace the current prescriptive approach to a performance-based analysis procedure that will allow designers greater freedom and flexibility in laying out designs and making structural fire protection decisions to ensure adequate fire safety.

PHASE I: Demonstrate feasibility of proposed analysis approach. Perform a preliminary validation study using test data. Propose a conceptual design for a prototype software/tool to define a fire scenario, construct structural model, and perform prediction.

PHASE II: Fully develop all the solution modules and integrate them into a tool that can be commercialized. The tool should capture the key events including fire growth, fire spread, smoke movement, heat transfer to structural boundaries, fire and structure coupling, time and temperature dependent material response, softening, structural stability, post-fire strength assessment. Validate that the prototype software provides appropriate results by correlating it to well defined test data at component and structure level.

PHASE III: Prepare a user-friendly package that can be used by engineers in the naval, shipyard, and aerospace industries in collaboration with a potential software vendor for commercialization. Expand the experimental data base collected from Navy, DOD, and commercial industries. Conduct validation for the specific area of interest.

PRIVATE SECTOR COMMERCIAL POTENTIAL/DUAL-USE APPLICATIONS: Damage and collapse in an aluminum structure from a fire event is not unique to naval vessels and military aircraft; it is equally prevalent in the civilian sector. Outside the ship industry, the aerospace, oil and power industry are increasingly using aluminum construction. The validated and user-friendly toolkit developed in this program has great potential for optimizing the placement and configuration of structural fire protection during the design stage, providing guidance to the crew in a fire situation, and performing the post-fire damage evaluation for decision making.

REFERENCES:
1. SNAME (1974), "Aluminum fire protection guidelines", SNAME T&R Bulletins 2-21, New York: Society of Naval Architects and Marine Engineers, 1974.

KEYWORDS: Aluminum Structure; Fire Simulation; Thermal-Mechanical Coupling; Material Softening; Structural Instability

** TOPIC AUTHOR (TPOC) **

DoD Notice:   Between April 21 and May 19, 2010, you may talk directly with the Topic Authors to ask technical questions about the topics. For reasons of competitive fairness, direct communication between proposers and topic authors is not allowed starting May 19, 2010, when DoD begins accepting proposals for this solicitation.

However, proposers may still submit written questions about solicitation topics through the DoD's SBIR/STTR Interactive Topic Information System (SITIS), in which the questioner and respondent remain anonymous and all questions and answers are posted electronically for general viewing until the solicitation closes. All proposers are advised to monitor SITIS (10.2 Q&A) during the solicitation period for questions and answers, and other significant information, relevant to the SBIR 10.2 topic under which they are proposing.

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