Sikulskyi V. Scientific basis for formation of large-size cargo aircraft monolithic panels by successive local deformation

The object of study is the blank and die production of aircraft structures; the purpose of the study is to increase the productivity of formation processes and bring complex shapes of monolithic panels with ribs in terms of computer-integrated technologies that provide high precision of the parts, industrial efficiency with low equipment and tool cost; research methods – theoretical studies are based on the principles of the minimum potential energy of the mechanical system, the study of the formation of the panels was carried out using computer finite element method (FEM), the experimental study of strain and stress – strain measurement method, the study of the process zone of deformation in real time using 3D-scanner and test machines; the result is a scheme of sequential zonal deformation of panels with ribs to achieve high precision as a result of the iterative process and program control of the distribution of local actions; devices have been developed for straightening, modifying and shaping profiles and monolithic panels of complex shapes that allow working both in standalone mode and as part of a robotic complex based on computer program control; the algorithm of forming panels of complex shapes with a two-stage scheme is proposed, which allows achieving deviations from the specified contour for panels of double curvature not more than 0.3 mm; novelty – for the first time, the scientific foundations of forming large-size cargo aircraft monolithic panels by sequential local deformation have been developed; for the first time, the concept of forming large-size monolithic panels by zonal deformation was developed, the essence of which is to use special re-adjustable devices associated with software tools to ensure the distribution of deformation zones and a software method to control the required surface shape in real time using information methods of designing the deformation process based on the application of finite element method; for the first time, a method of changing the parts of a complex form by zonal addition of moments and stretching (compressive) forces was proposed and scientifically substantiated, and rational schemes of the sequence of application of local actions were proposed for producing panels with unified surface shapes; for the first time, the problem of forming large-sized double-curvature panels was solved by sequential local deformation; degree of implementation – the results of the research are implemented at the Antonov State Enterprise, at Kharkov State Enterprise of Industrial Entrepreneurship, Kharkiv, and in the educational process of National Aerospace University “Kharkiv Aviation Institute”; scope of application – forming panels of complex shapes in aircraft and shipbuilding.