VESTNIK of Samara University. Aerospace and Mechanical EngineeringVESTNIK of Samara University. Aerospace and Mechanical Engineering2542-04532541-7533Samara National Research University16710.18287/2541-7533-2004-0-1 (5)-49-51UnknownProving theorems of changing structure rigidity11sadohina@ssau.ruSamara State Aerospace University1803200431495114052014Copyright © 2015, VESTNIK of the Samara State Aerospace University2015<p>We propose demonstration of theorems of structure deformation potential energy derivatives according to changing of the amount of the material it consist of using the principle of possible stress changes.</p>