The effects of glass-fiber sizings on the strength and energy absorption of the fiber/matrix interphase under high loading rates

• Published in: Composites science and technology Vol. 61; no. 2; pp. 205 - 220
• Main Authors: Tanoglu, M, McKnight, S.H, Palmese, G.R, Gillespie Jr, J.W
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01-01-2001; Elsevier
• Subjects: A. Coupling agents; A. Polymer-matrix composites (PMCs); Applied sciences; B. Impact behavior; B. Interphase: B. Fiber/matrix bond; Composites; Exact sciences and technology; Forms of application and semi-finished materials; Polymer industry, paints, wood; Technology of polymers; A. Polymer-matrix composites (PMCs); B. Interphase: B. Fiber/matrix bond; B. Impact behavior; A. Coupling agents; Textile oiling; Interphase; Fiber reinforced material; Testing speed; Mechanical properties; Epoxy resin; Shear strength; Experimental study; Property processing relationship; Composite material; Surface treatment; Coupling agent; Impact strength; Ballistics; Measurement method; Glass fiber; Energy absorption; Fracture mode
• ISSN: 0266-3538; 1879-1050
• DOI: 10.1016/S0266-3538(00)00195-0

The interphases of various sized E-glass-fiber/epoxy-amine systems were tested at displacement rates in the range 230–2450 μm/s by a new experimental technique (dynamic micro-debonding technique). By this method, the rate-dependent interphase properties, apparent shear strength and absorbed energies due to debonding and frictional sliding, were quantified. The systems include unsized, epoxy-amine compatible, and epoxy-amine
incompatible glass fibers. The high displacement rates that induce high-strain-rate interphase loading were obtained by using the rapid expansion capability of piezoelectric actuators (PZT). The results of dynamic micro-debonding experiments showed that the values of interphase strength and specific absorbed energies varied in a manner that is dependent on the sizing and exhibited significant sensitivity to loading rates. The unsized fibers exhibit greater frictional sliding energies that could provide better ballistic resistance, while the compatible sized fibers show higher strength values that improve the structural integrity of the polymeric composites. In addition, significantly higher amounts of energy are absorbed within the frictional sliding regime compared to debonding. By using the experimental data obtained, a case study was performed to reveal the importance of the interphase related micro damage modes on energy absorption (and therefore ballistic performance) of glass/epoxy composite armor.