Integral assessment of stress-defomated condition of metal structures of machines under the action of static and dynamic loads

Abstract

The article considers a system that combines the influence of static on dynamic loads on the example of the support-rotary circuit of a truck construction crane. The position of the system and its elements with the highest loads is revealed, the method of creating steel structures is investigated, each element, depending on the average load, experiences a stress-strain state. The basic laws of the theory of elasticity and plasticity were used to build a calculated mathematical model of the loaded support-rotary circuit. Equations of motion were compiled taking into account the behavior of structural elements and the machine as a whole under the simultaneous action of different loads. The calculation scheme was taken in the form of a structure consisting of rods rigidly connected to each other in nodes. As a method of calculation the method of finite elements with definition of displacements (deformations), efforts (stresses) in nodes of a grid of constructive elements of a design of a basic-rotary contour is applied. The stress distribution in each structural element depending on the type of load was obtained. This distribution allowed to choose rational parameters of a design in each its section. The proposed approach allowed to create a solid structure that provides reliability and economy of material. Thus, the results obtained allowed to fully analyze and decide on the simultaneous provision of strength, rigidity and minimum material consumption of the structure.