Fiber microbuckling, a compressive failure mechanism in unidirectional
fiber-reinforced composites, was studied in a model system composed o
f a single polyamide fiber in a silicone matrix. The transparent matri
x permitted direct observation of fiber microbuckling during compressi
on. In all instances the shape of the microbuckling was planar and sin
usoidal. The effects of fiber diameter, fiber modulus, and matrix modu
lus on the critical wavelength were observed. Excellent agreement with
predictions from the stability analyses of Sadowsky et al. and Darby
and Kanellopoulos was obtained.