Accession Number : ADA322773

Title :   Mechanical Tests and Failure Analysis on Selected Components of the Class 60 Armored Vehicle Launched Bridge (AVLB) During the Class 70 Modification Program.

Descriptive Note : Final rept. Feb 93-Jun 96,

Corporate Author : ARMY RESEARCH LAB FORT BELVOIR VA

Personal Author(s) : Horner, Howard E.

PDF Url : ADA322773

Report Date : DEC 1996

Pagination or Media Count : 138

Abstract : The current Class 60 armored vehicle launched bridge (AVLB), with an overall length of 63 ft, is capable of carrying Class 60 (military load classification MLC - 60 tons) tracked and wheeled loads over a 60-ft-wide gap. The heavier, wider M1A1 main battle tank (Class 70 load) can cross the AVLB over a 50-ft-wide gap with precautions. Several modifications were proposed to upgrade a number of AVLBs from Class 60 to Class 70 for the 60-ft clear span crossings. The objective of the work was to conduct necessary mechanical tests on selected AVLB components to obtain pertinent data to verify their load carrying capability and the proposed modifications. Various AVLB components were cut or removed from several AVLBs as samples for a variety of mechanical and special tests. Special test jigs were designed and built to test the samples of the components on the testing machine. Failure analyses were performed on the components that failed during the special tests or the fatigue tests of the modified AVLBs undergoing the simulated crossings. Two Class 60 AVLBs were converted to Class 70, with extensive modifications to the bottom chords, and then were tested. One of them was deliberately tested to failure by static overloading to observe the mode of failure. The bridge buckled in the top chords at about 190 tons. The modified bottom chords did not fail by cracking, indicating the success of the Class 70 modification program to upgrade the AVLB.

Descriptors :   *ALUMINUM ALLOYS, *MILITARY BRIDGES, *TRAFFICABILITY, LOAD DISTRIBUTION, TENSILE STRENGTH, MILITARY REQUIREMENTS, CRACKING(FRACTURING), BEARING STRENGTH, BENDING, OPERATIONAL EFFECTIVENESS, FRACTURE(MECHANICS), FLEXURAL STRENGTH, BUCKLING, FATIGUE(MECHANICS), CONNECTORS, FAILURE(MECHANICS), CROSSINGS, OVERLOAD, TANKS(COMBAT VEHICLES), FATIGUE TESTS(MECHANICS), PULL TESTS, SHEAR STRENGTH.

Subject Categories : Properties of Metals and Alloys
      Civil Engineering

Distribution Statement : APPROVED FOR PUBLIC RELEASE