Slow crack growth in laminate composites via in-situ X-ray tomography and simulations

To assist in damage tolerant analyses for composites, a compact tension T650/5320 laminate composite was characterized via in-situ X-ray tomography during cyclic loading. A 3D image processing analysis of the fatigue crack growth illustrated the various damage mechanisms, including intralaminar cracking (dominant) and delamination facilitating ply cross-over. A finite element analysis was conducted to compute the change in stored energy per cycle, dU/dN, which showed that the experimentally observed intralaminar crack growth rates, per ply, collapsed to a single dU/dN curve, where direct observations of fiber bridging were associated with a reduction in crack growth rate for the influenced ply.

Automated summary

A compact tension T650/5320 laminate composite was characterized using in-situ X-ray tomography to analyze the damage mechanisms during cyclic loading. The 3D image processing analysis revealed the presence of intralaminar cracking and delamination facilitating ply cross-over. A finite element analysis was conducted to compute the change in stored energy per cycle, dU/dN, which showed that the observed intralaminar crack growth rates collapsed to a single curve.