1104 KB39 KB199920252015Khoshravan, MohammadrezaMoslemi, Mohsenletnik:61številka:9str. 507-516, SI 95ISSN:0039-2480COBISSID:14183707URN:URN:NBN:SI:doc-7L8VKDAIenZveza strojnih inženirjev in tehnikov Slovenije et al.Strojniški vestnikdelaminacijamodel kohezivne conenapovedovanje s končnimi elementinormalna kohezijska trdnostCohesive zone parameters selection for mode-I prediction of interfacial delamination|In order to determine the normal cohesive strength of composite laminates, a new test methodology was proposed. The values of cohesive zone parameters (the cohesive strength and the separation energy) for mode I interlamiar fracture of E-glass/epoxy woven fabrication were computed from a series of experimental tests. Cohesive zone model simulation based on interface finite elements was conducted. A modified form of the Park-Paulino-Roesler (PPR) traction-separation law together with a bilinear mixed-mode damage model was used to simulate the damage processes, using Abaqus cohesive elements. The numerical results were compared with experimental tests and confirmed the adequacy of normal cohesive strength. To ensure the sufficient dissipation of energy that successfully predicts delamination onset and propagation, cohesive zone length and minimum number of cohesive elements at cohesive zone length were determined. Interfacial penalty stiffness and the resistance curve of the composite specimen were also computed. The results show that the modified PPR model accurately simulates the fracture process zone ahead of the crack tip as compared to the bilinear modelDelaminacija je vrsta napake, ki se pogosto pojavlja pri laminiranih kompozitih in jo opisujemo kot ločevanje plasti ali skupine plasti od sosednjih plasti zaradi delovanja zunajravninskih strižnih obremenitev. Za napovedovanje zmogljivosti ter izboljšanje zanesljivosti in varnosti konstrukcij je pomembno, da zaznavamo in analiziramo progresivno rast delaminacije. Predstavljena raziskava je bila namenjena pripravi primerne metodologije za karakterizacijo loma pri delaminaciji tkanih kompozitnih laminatov v pogojih čistih obremenitev tipa I. Simulacija loma materialov s kohezivnimi elementi zahteva obsežne izkušnje za določanje mreže, točne vrednosti parametrov za karakterizacijo zakona trakcije-ločevanja in tudi ustrezno obliko trakcije-ločevanja. Predlagana je nova metodologija preizkusov za določanje normalne kohezivne trdnosti (NCS) kompozitnih laminatovTEXTznanstveno časopisjejournalsSlovenian National E-content AggregatorNational and University Library of SloveniaUniverza v Ljubljani, Fakulteta za strojništvo