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There is now a CONTENT FREEZE for Mercury while we switch to a new platform. It began on Friday, March 10 at 6pm and will end on Wednesday, March 15 at noon. No new content can be created during this time, but all material in the system as of the beginning of the freeze will be migrated to the new platform, including users and groups. Functionally the new site is identical to the old one. webteam@gatech.edu
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Ph.D. Thesis Defense Announcement
EXPERIMENTAL METHODS FOR UNDERSTANDING THE PERFORMANCE OF IMPULSIVELY LOADED CROSS-LAMINATED TIMBER PANELS
Noel R. Flores
Dr. Lauren K. Stewart (CEE)
Dr. T. Russell Gentry (SoA)
Dr. Lauren K. Stewart (CEE), Dr. T. Russell Gentry (SoA), Dr. Laurence J. Jacobs (COE), Dr. Lawrence F. Kahn (CEE), Dr. Karl F. Meyer (CEE)
Date & Time: 2-4PM EST Friday, August 12
Location: SEB122
Cross-laminated timber (CLT) is an innovative multi-layered engineered wood product with proven performance as a structural material in extreme events, including earthquake, wind, and fire. Although research is limited, CLT has shown great potential for application in the force protection of structures. This research bridges the gap between the quasi-static and intermediate strain rate loading regimes by investigating two areas that have remained unstudied or elusive, i.e., rolling shear failure of CLT under impulsive, blast-like loading and intermediate strain rates in CLT. A novel center-point testing system and methodology was developed that permits the application of impulsive loading in a highly controlled and repeatable manner. The testing system is highly adaptable and is capable of testing a variety of materials of variable widths, lengths, and thicknesses. The impactor is interchangeable to permit changes to the load condition. Realistic boundary conditions can be simulated empirically via changes to the boundary condition rotational rigidity. The testing system was validated and calibrated through a series of validation tests, finite element simulations, and via the development of a new experimental method. The Direct Force Method (DFM) is a new experimental method for empirically determining the force history applied to a specimen that controls for inertial effects that arise during testing. Experiments featured multiple test phases: quasi-static testing of undamaged CLT specimens, impulsive testing of undamaged CLT specimens, and residual capacity testing of damaged CLT specimens. Low span-to-depth ratio CLT specimens are used throughout testing to encourage the development of shear modes of failure. As verified by the test results, the testing system consistently produced shear modes of failure and facilitated the observation of CLT panel behavior under impulsive loading. The testing programs validated several hypotheses including the conditions that elicit shear modes of failure, strain-rate enhancement of CLT mechanical properties in the impulsive loading regime, and the role of boundary condition rigidity in affecting change in CLT panel behavior. The conclusions made on CLT panel behavior under impulsive loading and CLT panel residual capacity and survivability provide validation for CLT’s implementation as a structural material in force protection applications.
