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Frank Nabarro developed the theory of dislocations and their role in plastic deformation. His work connected microscopic defects to macroscopic resistance to deformation, and his monograph Theory of Crystal Dislocations helped organize the subject. A scientific obituary by a colleague describes both the theoretical contributions and his long influence on materials science.^[ref]

A lattice-friction stress for dislocation glide, associated with Rudolf Peierls and Frank Nabarro. A simple model gives ${\tau }_P\sim 3G\exp (-2\pi w/b)$, where $w$ is core width and $b$ the Burgers vector magnitude. Spreading slip over many atomic rows reduces the periodic energy barrier; narrower cores are harder to move in this model.