In structural analysis, an imperfection is an assumed production-related deviation of structural components. It is assumed that, for example, a column has both a curvature and an inclination and this geometric imperfection significantly influences the buckling behavior.
Exemples are the standards EN 1993-1-1, EN 1993-1-6, and EN 1992-1-1. They include the information about the type and size of imperfections, which usually must be taken into account for the stability analysis.