  We perform {\textit ab initio} calculations for the strain-induced formation
of non-hexagonal-ring defects in graphene, graphane (planar CH), and graphenol
(planar COH). We find that the simplest of such topological defects, the
Stone-Wales defect, acts as a seed for strain-induced dissociation and
multiplication of topological defects. Through the application of inhomogeneous
deformations to graphene, graphane and graphenol with initially small
concentrations of pentagonal and heptagonal rings, we obtain several novel
stable structures that possess, at the same time, large concentrations of
non-hexagonal rings (from fourfold to elevenfold) and small formation energies.
