On reliability of engineering computations

and computer calculations

V.B.Orlov, Yu.P.Petrov

Saint-Petersburg State University

35, Universitetsky Prospect, Saint-Petersburg, Petershof, Russia

Research results and statements are discussed that enable to reveal unreliability of some conventional and widely used calculation approaches. Mistakes are discussed that occur when stability problems are solved by using of second Lyapunov method, when a theorem on continual dependence of solutions of differential equation systems on parameters is used, when stability margin is estimated by the roots of characteristic polynomial. Application of obtained results will enable to avoid mistakes in computation and design of engineering objects, hence decreasing probability of emergencies and catastrophes originated from these mistakes.