High Buckling Strength of Auxetic Carbon Fiber Composite Laminates

This research focused on testing the effect of the negative Poisson's ratio of a carbon fiber composite on its critical buckling load. A secondary goal was to determine the accuracy of simulation compared to the experimental results for carbon fiber composites. In order to accomplish these two goals, both simulation and experimental testing were employed. For the simulation, ABAQUS software was used to determine predicted values for the critical buckling loads of auxetic and non-auxetic composites as well as the respective nonlinear force behavior of these composites. These results were then compared to experimental results of four auxetic and four non-auxetic specimens each experiencing uniaxial compressive tests. The results of simulation and experimentation showed that the critical buckling loads, and force sustained in general, of the auxetic composites were about three times higher than those of non-auxetic composites. While it appears that the negative Poisson's ratio has a significant impact on the buckling strength of composite materials, further testing is required to determine the effects of other factors on the critical buckling loads. Along with this, the simulation was more accurate for the auxetic composites than for the non-auxetic composites. Therefore, further testing and simulation are required to determine the limits of simulation accuracy for composite structures.