The variability of results concerning cold fusion, together with the difficulty of explaining the observations, suggests that some nonstandard processes may be occurring. One such possibility is that nuclear reactions occur in defects of a deuterated lattice as a result of transient motions that momentarily bring deuterium atoms into close proximity. A mechanism involving shear of a one-dimensional lattice is described that illustrates this possibility. Order-of-magnitude estimates indicate that the expected fusion rate is not inconsistent with some experiments.