  A powerful technique is introduced for simulating mechanical and
electromechanical properties of one-dimensional nanostructures under arbitrary
combinations of bending, twisting, and stretching. The technique is based on a
novel control of periodic symmetry, which eliminates artifacts due to
deformation constraints and quantum finite-size effects, and allows transparent
electronic structure analysis. Via density-functional tight-binding
implementation, the technique demonstrates its utility by predicting novel
electromechanical properties in carbon nanotubes and abrupt behavior in the
structural yielding of Au7 and MoS nanowires. The technique drives simulations
markedly closer to the realistic modeling of these slender nanostructures under
experimental conditions.
