Control of the Structural Rigidity of Agricultural Machinery During its Operation

Introduction. A promising approach to the machine design is the development of adaptive design structures compensating for external influences by changing the stress-strain state of their elements. However, these structures have not been widely used in agricultural machinery design because of the type of loading and the specific of transported loads that cause intense corrosion and abrasive damage. Aim of the study. The study is aimed at analyzing the methods for changing the strength characteristics of the structures of parts and assembly units of agricultural machinery during their operation and at developing methods for determining their stress-strain state to use in the design control algorithm. Materials and methods. As an example, we have examined the side of a vehicle body. Based on the principles of automatic control theory, the load-carrying structure is designed as a multilayer rectangular plate made of a polymer composite material. The inner layers are honeycomb filled with a non-Newtonian dilatant fluid. The filler performs the function of a compensator for external impacts. There were used the methods of mathematical modeling based on the constructing boundary value problems of the statics of multilayer thin plates, and plates on an elastic foundation, and studying their stress-strain state by solving analytically differential equations expressed in displacements. Results. There was developed an algorithm for determining the stress-strain state of a multilayer rectangular composite plate with discrete support under a normal distributed load taking into account impact disturbances. There were determined maximum bending stresses and the stresses arising from the braking of a rigid body moving with acceleration by the inner part of the plate. Discussion and Conclusion. In the study, there have been analyzed existing structural materials, technologies and technical means used to compensate for control action arising from the machine operation. There has been developed the methodology for transitioning from traditional designs to advanced models featuring adaptive elements, which change their stress-strain state depending on changes in external load. There has been theoretically substantiated a multilayer composite vehicle body side structure, which can withstand not only distributed forces but also impacts. Its material consumption is significantly reduced (several times) compared to steel, and its service life is increased due to the chemical resistance of the materials used in its manufacture. This design approach allows the proposed methodology to be used for a wide range of applications in the production of new agricultural equipment.