JUSTIFICATION OF THE MODERNIZED CONSTRUCTIVE
The work is devoted to the search for the causes of failures of the OP-2000 sprayer frame with the use of CAE-system APM WinMachine and the development of a constructive scheme to prevent such failures. The aim of the study was to identify causes of damage and residual deformations of the side members of the frame and finding constructive solutions to avoid detected failures. The problem is solved by constructing a finite element model of the problem structure and analyzing its stress-strain state under different loading conditions using the structure 3D CAE module-APM WinMachine system and comparing the results with the analysis of full-scale samples. To determine the geometric parameters of the key structural elements, as well as adequate modeling of the fasteners of the product under consideration and the correct load distribution, a 3D model of the sprayer frame was used. For numerical experiments, a complex plate-rod model was developed, which allows to accurately reflect the features of the geometry of the structure and the location of the support surfaces, and the parameters of the partition grid were selected in such a way as to adequately simulate the application of loads. As a result of the calculations, it was found that the reason for the destruction of the frame spars is an insufficient margin of safety and stability under dynamic loading, which was modeled by the acceleration of gravity along the vertical axis taking into account the intrinsic mass of all elements of the model. Comparison of the calculated stress-strain state of the structure with a full-scale object shows sufficient convergence of the results. The areas with maximum stress and strain values coincide with the actual fracture zones and residual deformations of the sprayer frame. For the development of engineering solutions aimed at preventing the identified failures, a series of numerical experiments was conducted, in which the optimal configuration of the repair design scheme was determined. In the course of these calculations, decisions were made on the form and location of additional structural elements that increase the strength, stiffness and stability of the frame. Pilot operation of the sprayer repaired according to the proposed constructive scheme in the conditions of the economy, where failures were previously observed, in the field seasons of 2017 and 2018, no new failures were revealed.