Fracture toughness micromechanics by energy methods with a photocure fiber-reinforced composite

Academic Article

Abstract

  • A fracture toughness analysis for discontinuous fiber reinforcement was evaluated as a function of fiber volume percent (V ) using advanced flexural bend tests. Fully articulated fixtures with 40-mm spans were used to examine specimens (2 × 2 × 50 mm ) under conditions of Euler-type bending to reduce shearing effects. Testing for fracture toughness in standardized international units (kJ/m ) using fundamental mechanics-of-materials energy methods by strain energy was then applied for assessment of resilience and work of fracture (WOF). Fracture toughness was also measured as strain energy release (SER ) for the condition of unstable fracture between peak load and 5% maximum deflection past peak load. Energies were calculated by numerical integration using the trapezoidal rule from the area under the load-deflection curve. Fracture depths were normalized using sample dimensions from microscopy imaging for a combined correlation matrix analysis of all mechanical test data. V significantly correlated with resilience, WOF, and SER , but negatively correlated with degree of crack depth with p < 0.0000005. All measured interrelated properties also significantly correlated with one another (p < 0.000001). Significant fracture toughness differences between particulate-filled and fiber-reinforced composites began when adding fiber reinforcement at 10.3 V for resilience, 5.4 V for WOF, and 5.4 V for SER (p < 0.05). © 2007 Society of Plastics Engineers. f IC 1 IC f f f IC 3 2
  • Published In

  • Polymer Composites  Journal
  • Digital Object Identifier (doi)

    Author List

  • Petersen RC; Lemons JE; McCracken MS
  • Start Page

  • 311
  • End Page

  • 324
  • Volume

  • 28
  • Issue

  • 3