The damage assessment of a buckling plate using the zero strain trajectory method and digital image correlation measurements represents an approach to monitor and control structural lightweight components during operation over their entire lifetime. From an analytical point of view, a differential equation for the model to calculate plates under external loads can be derived. Based on this partial differential equation, the equilibrium conditions at an infinitesimal element of the buckled plate can be used to determine the buckling differential equation and solve it for different boundary conditions. Imperfections and defects, such as geometric or physical imperfections, have a big influence on the buckling behaviour and the critical buckling load of a plate. Predeformations, thickness changes, eccentric load initiation and non-ideal boundary conditions influence the deformation state of the plate under load in different ways. Thus, it is important to modify the numerical model similar to the real geometric and physical conditions for further analyses and calculations. By means of the numerical analysis or digital image correlation measurements the strain state of the plate under specific load and boundary condition, the reference configuration is known. The so called zero strain trajectories can be determined from these directions. If the stress state of the plate changes, the strains along the reference trajectory no longer disappear and strains are measurable. The effects of a load change, changing imperfections and also the influence of damage with increasing diameter on the strain curve along the zero strain trajectories are analysed in detail. By means of a characteristic change in strain, it is possible to deduce an existing damage and with the help of further trajectories also the location of the damage on the plate can be found. Measurement results from buckling tests with a plate test bench are analysed using the finite element method. Plates made of the aluminium 2024-T3 as well as PMMA are used. The displacements and strains on the surface of the plate are measured contactless and non-destructive by digital image correlation. Furthermore, the zero strain trajectories are determined, the influence of load changes and damages on the strain trajectory is shown in the test and the concept of damage assessment is verified by using the zero strain trajectory method.