Optimal design of shell constructions taking into account the evolution of corrosion damage

Abstract

An algorithm for computer modeling of the evolution of corrosion wear of the surface material of shell elements in the conditions of joint action of mechanical external loads and the impact of aggressive environments has been developed.
 A mathematical model of deformation of shells of rotation with variable as a result of corrosion of external and internal components of wall thickness is constructed.
 The proposed algorithm allows to trace in time the process of corrosion degradation of the surface material of the shells in accordance with arbitrary (existing) mathematical models of corrosion from the initial moment of time to complete destruction due to corrosion loss of material.
 An original algorithm for selecting the optimal parameters of the rotation shells and the study of their durability taking into account the corrosion degradation of the surface material has been developed.The essence of the algorithm is to optimize the design parameters at the end of its durability, further reverse bilateral build-up of the "sacrificial" layer of material and rational refinement of the project according to technological requirements.
 The solution of the problem of weight optimization of the shell under conditions of asymmetric bilateral non-uniformto the surface material, as a result of corrosion damage, is carried out using the necessary conditions of optimality in the form of the principle of maximum L. S. Pontryagin with phase constraints.The problem of satisfying technological requirements at the initial moment of time is formulated as the problem of the best quadratic approximation of the obtained continuous controls in the form of optimally variable thickness of the shell wall with a piecewise constant function.
 Numerical results of computer modeling of corrosion degradation of surface material and selection of optimal parameters of a cylindrical reservoir for storage of petroleum products under conditions of simultaneous action of force loading and influence of aggressive environment are given.