| The Armored Vehicle Launch Bridge (AVLB) is subjected to cyclic loading during its launching as well as tank crossing. The cyclic loading causes cracks to initiate in critical bridge components, and to propagate.; According to the Preventive Maintenance Checks and Services (PMCS) from the U.S. Army, three AVLB components, the splice doubler angle, the splice plate, and the bottom chord, are susceptible to fatigue damage. In the present study, the laboratory fatigue tests on the materials used for the components, aluminum 2014-T6, aluminum 7050-T765, and ASTM A36 steel, were conducted along with the acoustic emission (AE) fatigue crack monitoring technique. A total of fourteen compact-tension specimens were prepared in this study. These specimens were six aluminum 2014-T6, four aluminum 7050-T76511, and four ASTM A36 steel specimens. The aluminum 2014-T6 specimens were subjected to four combination sets of loading frequency and ratio (R), the aluminum 7050-T76511 specimens to two combination sets, and the ASTM A36 steel specimens to two combination sets. (Abstract shortened by UMI.)... |
