The effect of specimen size on the four-point flexural response of ply-leve
l and sublaminate-level scaled composites was investigated. Two laminates w
ere studied, namely, [+45/-45/+45/-45], and [+45/-45/0/90](x). The material
system used was AS4/3502 graphite/epoxy. Enhanced x-ray radiography and ed
ge photomicroscopy were used to examine damage development in specimens loa
ded to various fractions of their ultimate load. This nondestructive examin
ation was coupled with observations of the load/deflection response to try
to correlate scaling effects with the damage development in the specimens.
Results were compared to previous studies involving tensile scaling effects
. It was found that the strength of ply-level scaled laminates decreased as
specimen size increased, and that this effect was modeled well using the t
ypical fracture mechanics scaling law. Sublaminate-level scaled specimens d
id not show a pronounced scaling effect. Although there seemed to be a slig
ht decrease in strength with increased specimen size, the effect was small
and may not be statistically significant.