ICF100316OR DYNAMIC FRACTURE BEHAVIOR OF COMPOSITES S.Ravi 1 , N.G.R. Iyengar 1 , N.N. Kishore 1 and A. Shukla 2 1 Indian Institute of Technology, Kanpur 208 016, India 2 University of Rhode Island, Kingston, RI 02881, USA Presently at RIAM, Kyushu University, Kasuga 816-8580, Japan ABSTRACT Dynamic fracture behavior of glass-polyester composites subjected to dynamic loads has been studied. Theaimistostudythee ectofreinforcementtype, bervolumefraction,initialnotchorientation and berorientation.Cranz-Schardintypemulti-sparkhighspeedrecordingsystemhasbeenused to record the initiation and propagation history at a pre-determined short intervals of time. It has been observed that the damage grows normal to the loading direction irrespective of the type of reinforcement,initialnotchorientationand berorientation.Thedamagepropagatesathighervelocity than in the unreinforced polyester matrix. Further, for a given energy input, the damage area reduceswithincreasein bervolumefraction. KEYWORDS Dynamic fracture, stress waves, high speed recording, damage zone, glass-polyester composite. INTRODUCTION Thefracturebehaviorofcompositematerialsundervariousloadsisofsigni cantpracticalimportance in terms of its service performance. It is known that the fracture process in composites precedes with the formation of a zone, often referred to as damage zone, ahead of the crack tip. The damage zone consistsofmanymicromechanismslike berfracture,matrixcracks,interfacefailureetc.Further, as the damage propagates, these failure modes may interact with each other resulting in a complex fractureprocess. ShuklaandKhanna[1,2]haveinvestigatedthee ectof ber-matrixinterfaceon dynamic crack growth and associated fracture energy in a brittle matrix material reinforced with discrete bers.Theresultsindicatethatthe berreinforcementreducesfractureenergyavailableat the crack tip as calculated from the instantaneous stress intensity factor and results in small crack jump distance. Agarwal et al. [3] used Cranz-Schardin camera to study the dynamic damage growth in glass/polyester composites. Their results show that the dynamic damage in composite, propagates with a slightly lower velocity than the crack propagation velocity in a polyester resin. In the present study, we attempt to study the fracture behavior in glass-polyester composites having reinforcements in the form of cloth and chopped strand mat loaded with stress waves.
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