Static And Dynamic Properties Of Needle Punched Chopped Strand Mats Composite With Open Hole

Needle punch process was widely used in textile area provided remark performance. The introduced thickness-direction fibers via needle punched process play an important role that provides excellent z-directional properties that minimizes delamination problem. In previous study, it was found after needle punch process the tensile strength and mode-I interlaminar fracture toughness of nonwoven composite was increased with increasing punching density due to the increased fiber entanglement. The flexural impact, fatigue and wear properties were decreased with punching densities because of the damage to fiber during the punching process which resulted in the reduction of fiber length.In this study, needle punch process was applied on chopped glass fiber mat in order to improve the properties of glass mat composite with circular holes. Normal glass mat and needle punched glass mat were employed to fabricate composite with same volume fraction of glass fiber. Circular holes were drilled on the specimens. Decreasing of notched strength of drilled specimens from unnotched strength was compared between needle punched glass mat composite and glass mat composites. The tensile results and fracture behavior were analyzed and discussed. Cross-sectional observation was used to analyze combination of z-directional fibers with matrix. Furthermore, effect of needle punching density on fatigue properties and fracture behavior for normal specimens and specimens with circular holes also investigated.