Buckling is possible with loads close to limit ones in case of composite wing high lift device thin skins design. This project suggests engineering approach to postbuckling state assisted design of composite thin-walled devices taking into account life time boundary conditions. Fatigue life and residual strength boundary conditions in case of damages such as dents have been examined. Boundary conditions with specified barely visible impact damages in case of ultimate loading and with visible impact damages in case of increased limit loading have been taken into account. Postbuckling state assisted design complex methodology for thin panels based on analytic solutions of geometrically non-linear problems has been suggested. It is also supplemented with fatigue life and residual strength boundary conditions. Analytic dependences have been obtained which make it possible to calculate minimal composite panel thickness with damages of specified type and with given device dimensions, known potentially critical areas, restricted damages (dents), known composite design performances and given loading. Panels combined loading cases taking into account thermal effect have been examined. Developed methodology may be used at early stages of composite thin-walled devices design in order to define skin minimal thicknesses taking into account specified damages (dents)