Accession Number : ADP006000

Title :   Strength Analysis of Mechanically Fastened Composite Structures,

Corporate Author : NORTHROP CORP HAWTHORNE CA AIRCRAFT DIV

Personal Author(s) : Ramkumar, R. L. ; Saether, E. S. ; Appa, K.

Report Date : MAR 1988

Pagination or Media Count : 22

Abstract : An analysis is presented for the strength prediction of bolted composite structures, based on the average stress failure criterion. The analysis incorporates analytically derived special finite elements (loaded hole, unloaded hole, plain and effective fastener elements) into the SAMCJ (Strength Analysis of Multifastener Composite Joints) computer code. The loaded hole, unloaded hole and plain elements are derived from a doubly-connected laminate analysis that accounts for the effects of finite plate dimensions via a least squares boundary collocation solution procedure. The effective fastener element is derived from a fastener analysis that accounts for fastener shear and bending effects and through-the-thickness effects in the bolted laminates. The bolted plates are modeled using these elements, a conventional solution procedure yields the fastener loads and the stress state in each plate, and average stress failure criteria are used for strength prediction. SAMCJ predictions account for the effects of fastener spacing, adjacent cut-outs, through-the-thickness effects at the fastener location, and taper in the bolted plate thickness. SAMCJ predictions of fastener loads, joint failure loads and failure modes demonstrate excellent correlation with available test results from single and double shear tests on graphite/epoxy-to-aluminum joints. (SDW)

Descriptors :   *COMPOSITE STRUCTURES, *STRENGTH(MECHANICS), BENDING, BOUNDARIES, COMPUTER PROGRAMS, FAILURE, FAILURE(MECHANICS), FASTENINGS, FINITE ELEMENT ANALYSIS, JOINTS, LEAST SQUARES METHOD, LOADS(FORCES), POSITION(LOCATION), PREDICTIONS, SHEAR PROPERTIES, SHEAR TESTS, SOLUTIONS(GENERAL), STRESSES, TEST AND EVALUATION, THICKNESS, YIELD.

Subject Categories : Laminates and Composite Materials
      Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE