Composite-material part joining

Determination of Permissible Stresses along the Stiffened Hole Outline in Designs of Anisotropic Composite Materials

“…Gluing in is proposed as the main method of sleeve installation. At the same time, conducted research has shown that as a result of exertion of radial tensile stresses on the hole edge, an adhesive layer and a slab work together until the load does not exceed 15-20% of breaking load [9,22]. In [11,16] it is noted that tensile stresses value and its coverage can be reduced by means of preliminary ( at the stage of inserting of the sleeve into the hole) creating in their coverage alternating field of compressive stresses due to combined radial stretch of the stiffening element and the hole of billet walls in the local areas.…”

“…At the same time, main issue is to decrease stress concentration as much as possible along the hole outline [4,7,8,13,16,17,19,20,23]. One of the ways reducing stress concentration and obtaining their uniform distribution is installation of intermediate metal sleeve between a composite material slab and a bolt transferring loads [2,9,14,15,22]. Installation of intermediate metal sleeve without clearance reduces stress concentration: circumferential stress 4-5 times, radial stress 2-3 times.…”