Lepljeni in hibridni prekrovni spoji med polimernimi kompoziti ojačenimi z ogljikovimi vlakni in aluminijem AA7075-T651

S povečevanjem uporabe polimernih kompozitov v letalski industriji se je povečalo tudi zanimanje za hibridne lepljene spoje, kjer se s pomočjo epoksidnih lepil spajajo kompoziti in aluminij. Spoji so lahko dodatno varovani, kar je bilo v tej raziskavi izvedeno z uporabo različnih kompozitnih sornikov. Prednost hibridnih spojev je predvsem v lahki in kompaktni konstrukciji, sloj lepila pa služi tudi kot izolator med različnima materialoma in preprečuje pojav galvanske korozije. V nalogi je bila ugotovljena višja trdnost adhezijskega spoja brez varovanja od spoja z varovanjem s sornikom, razlog za to je v zmanjšani površini lepljenja in nesočasnem prenosu sile adhezijskega in oblikovnega spoja. Višjo trdnost smo dosegali pri spojih varovanih s sornikom iz ogljikovih vlaken, saj ima manjši modul elastičnosti kot aramid, kjer je posledično prišlo do zamika prenosa sile. Laminati, izdelani z vakuumsko infuzijo, so po trdnosti primerljivi s spoji z industrijskim lepilom. Na prelomnih površinah je bila ugotovljena delaminacija plasti ogljikovih vlaken v epoksidni matrici in variiranje debeline sloja lepila, industrijsko lepilo je zdržalo vse predpisane obremenitve. With increased use of polymer composites in the aerospace industry, there has also been increased interest in development of hybrid adhesive joints, such as composites and aluminum, bonded with epoxy adhesives. Joints can be additionally protected against detachment, in this study we used different composite bolts. The main advantage of such joints is in lightweight construction, a layer of adhesive also serves as an insulation between different materials, which prevents galvanic corrosion. In this paper we prove better strength of adhesive joints without pin that secures joints from breaking, the main reason for that is in reduced gluing surface and uneven transmission of force. Higher value of strength was obtained from joints with carbon fiber pin, because of its lower elastic module, than the aramid fiber pin, where there was a delayed transmission of force. Laminates that were made with vacuum infusion, are from the mechanical point of view comparable with glued joints. On the breaking surfaces we noticed mostly delamination of carbon fibers and uneven thickness of glue, the industrial glue withstood all the specified loads.