Mechanical Behavior and Mechanisms of Damage in Carbon/Epoxy Laminates with Traditional Layup and Double-Double Layup under Low Speed Impact
Double-double, Quad, Impact, Mechanical properties, Damage
The improvement and optimization of composite materials is something sought after in several researches; reducing manufacturing time and costs, improving material characteristics and properties, among other things, is extremely important for its use to be even more widespread. Therefore, this work evaluates the possibility of replacing traditional quadriaxial composite laminates (QUAD) by a new layup configuration, called double-double (DD), without losses in its mechanical properties. For this, two carbon fiber/epoxy laminates were developed, both with twelve layers of AS4/8552 prepreg, with equivalent properties and different configurations (stacking sequence): the QUAD [0°3/90°/±45°]S and the DD [±0°/±55°]3T. These materials were submitted to uniaxial compression, low velocity impact tests with energies of 30J, 45J and 74J, and compression after impact (CAI), in order to evaluate the material resistance with and without different types of damage, observing its properties. mechanics and residuals, in addition to their damage mechanisms, mathematically modeling this behavior. The results obtained showed that the two laminates, conventional and double-double, presented similar values, both in the compression behavior of the laminate and in its tolerance to damage. propagation of cracks and delamination, however, the total values obtained for delaminated area are similar for the two laminates for all impact energies studied, this demonstrates that, if the impact behavior is considered, a conventional laminate can be replaced by a laminate DD.