Scaling Effects in Composite Laminates Under Tensile, Flexural, and Compressive Loading

It has been demonstrated by several researchers that composite materials exhibit scaling effects both in unidirectional and multidirectional specimens. This has an important impact on the design and manufacture of full scale structures. In the current work, the authors present a wide range of experimental data for scaled composite laminates under tensile, flexural and compressive loading. Data for both blocked ply (so-called ply-level) and distributed ply (so-called sublaminate-level) thickness scaling are presented. Laminates studied include the following stacking sequences: [45/-45/45/-45]s, [45/-45/0/90]s, [45/-45/90/0]s, [45/90/-45/0]s, [45/-45/45/-45/0]s, [45/-45/0/0]s, [90/0/90/0]s. In general, ply-level scaling leads to degraded performance with increased specimen size in all stacking sequences, under all loading conditions. Sublaminate-level scaling also leads to a lowering of strength and strain to failure, although the effect is much less pronounced than in ply-level scaling. Typically, the strength of these specimens decreases by about 5% as the size of the specimens is quadrupled.