by Robert Dinan Accomplishment: The Air Force Research Laboratory (AFRL) has entered into a Cooperative Research and Development Agreement (CRADA) that will further the research of blast protection technologies. Under this CRADA, Dlubak Technologies Inc., of Freeport, Pa., provides cutting-edge window frames and glazings requested by AFRL researchers for full-scale trials at the AFRL-operated Sky Ten Range at Tyndall AFB, Fla. Payoff: Developing and validating blast mitigation technologies, specifically blast-resistant window and glazing technologies developed under this CRADA, has become one of many research and development activities that the Department of Defense and private industry are pursuing as a result of recent terrorist attacks. In the future, these technologies are expected to provide one more line of defense and protection for military personnel and civilians. This CRADA provides the Air Force with the opportunity to accelerate the transition of these technologies for future use and application. Background: During recent conflicts, the United States has seen a dramatic increase in the use of improvised explosives as a method of warfare and terrorism. The AFRL Materials and Manufacturing Directorate’s (ML) Force Protection Branch, located at Tyndall AFB, is pursuing blast mitigation technologies for buildings and expeditionary structures that will minimize the casualties caused by a terrorist explosive attack. This type of technology is particularly important because the vast majority of injuries and fatalities caused by an explosive are the result of flying glass and wall debris.
At Sky Ten Range, ML’s Range Operations and Support Group have two reaction structures with the capability to expose up to eight windows and/or wall systems at one time to a 1,000-pound TNT charge. The Range Control building onsite is a hardened concrete structure that protects researchers, visitors and data acquisition equipment during detonations. Range Control is a two minute walk from the detonation site, and has multiple live video feeds with vantage points outside and inside the reaction structure. Trials executed at the range are monitored and controlled from a master control board with over 100 channels available for recording critical scientific data during and after explosive detonation. In addition, the trials are also visually recorded using high-speed digital and traditional video, which is edited to provide researchers with another tool by which to analyze results. Research under this CRADA has already yielded the only successful blast-resistant windows using glazing with perimeter-anchored laminate. For these state-of-the-art windows, Dlubak Technologies fabricates glass with the polymer laminate layer(s) extending beyond the glass edges. These “laminate tails” are then anchored in the window frame using one of several techniques. Dlubak’s LAMLOK system, a patent-pending laminate-locking method, is already being marketed for commercial sale due in part to performance demonstrated during AFRL research trials under this CRADA. Different LAMLOK systems have been studied, including a hinged LAMLOK polyvinylbutyral (PVB) for post-blast emergency exit and a LAMLOK system for use in a standard window frame with either flat or curved glass. Based on the research results, a new and improved version of the interlocking mechanism was created for standard window frames. The CRADA allows for further blast-resistant window research, as well as other technologies, in the future. In addition to the blast resistant window research, ML engineers and scientists at Tyndall AFB are investigating several systems to prevent wall fragments from penetrating to the building interior. As a part of this wall research, AFRL pioneered blast-resistant polymer retrofit techniques for concrete block walls. Polymer application can be accomplished using spray-on or trowel-on methods and panels. The best application method can be matched to the specific need and is normally dependent on the wall area to be retrofit, skills or equipment available, and budget. The benefits of polymers for blast protection in new construction (as a stay-in-place concrete form) are also being evaluated as part of a project to evaluate the blast resistance of insulated concrete products widely used in concrete construction. Dlubak Technologies Inc. is a 50-year-old glass manufacturing company that has been involved in several high-profile projects, such as restoration of the Statue of Liberty, the Liberty Bell Pavilion, and the Sears Tower in Chicago . In 1997, Dlubak received the honor of special merit in the residential category of the annual DuPont Bendictus Awards for innovation in architectural glass.
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