Abstract: The invention is of a basic nature, the entire technical disclosure is new in the art of design. The new method is based on a new concept of strength and elastic stability. Classical mechanics views a body to be formed of small units of material. Such fundamental characteristic of a body as an elastic limit is identified with limit of material unit. It is scientific conclusion supported with facts that every structure has its own limit which, in general, is different from the limit of material. New basic equation of elastic deformation establishes deformation--elastic force--geometrical stiffness relations. Geometrical stiffness characterizes the resistance to deformation, based on geometry of the whole body. New method suggests a different approach to using mathematical equations and procedures. In order to obtain valid and verifiable inferences from an equation, attention should be paid to physical meaning of the variables.