FUNDAMENTALS AND APPLICATIONS OF MICRO-RAMAN SPECTROSCOPY TO STRAIN-MEASUREMENTS IN FIBER-REINFORCED COMPOSITES

Micro Raman spectroscopy (MRS) can be used to measure strain in crysta lline and semicrystalline materials with mu m scale spatial resolution . It has been employed as a tool for measuring micromechanical behavio ur in composites, and has contributed significantly to understanding o f composite behaviour. An overview of the fundamentals of Raman spectr oscopy and strain measurements using Raman spectroscopy as well as the instrumentation required is given. Studies using MRS to gain insight into the structure, elastic moduli, and failure modes of several types of fibres are presented. The micromechanical behaviour of single fila ment model composites is examined in detail including: residual stress es caused by processing; the stress transfer behaviour from the matrix to the fibre during loading; and the interfacial behaviour as a funct ion of tensile and compressive loading, interface surface treatment, a nd environmental exposure. Finally, recent studies using MRS to study the fibre-fibre interaction and hence the fracture characteristics of full composites are discussed. (C) 1995 The Institute of Materials and ASM International.