Accession Number : AD0771795

Title :   A Synthesis Procedure for Mechanically Fastened Joints in Advanced Composite Materials. Volume II.

Descriptive Note : Final rept. 1 Nov 71-31 Aug 73,


Personal Author(s) : Waszczak,J. P. ; Cruse,T. A.

Report Date : SEP 1973

Pagination or Media Count : 203

Abstract : The purpose of this study is to provide the composites designer with an automated preliminary design capability for weight minimized mechanically fastened joints and to identify the common characteristics of such minimum weight designs. The problem of a single column of fasteners loaded in simple tension is considered. The main plate can be made of either graphite-epoxy or boron-epoxy and is loaded by double shear metal splice plates. Independent linear variations in plate widths and thicknesses, including individual ply orientation thicknesses, are permissible along the length of the joint. An optimization algorithm based on the variable metric method is used to solve the unconstrained minimization problem which is formulated using an interior penalty function. The development of an extremely efficient approximate stress analysis package based on lamination theory and the theory of anisotropic elasticity made the development of the automated synthesis procedure possible. A first failure analysis, based on the maximum ply stress failure criterion, used in conjunction with a simple joint modeling procedure and bolt load partitioning analysis is shown capable of conservatively predicting the failure characteristics of several multiple fastener joints. A combination of failure modes has been identified which is common to all the minimum weight designs achieved in this limited study. (Author-PL)

Descriptors :   *Composite materials, *Bolted joints, Boron, Epoxy resins, Carbon fibers, Graphite, Laminates, Stresses, Weight, Holes(Openings), Optimization, Numerical analysis, Synthesis, Failure(Mechanics)

Subject Categories : Laminates and Composite Materials
      Couplers, Fasteners, and Joints

Distribution Statement : APPROVED FOR PUBLIC RELEASE