Yu S. Increasing the workability of sucker rods made of polymeric composite materials.

The thesis is devoted to the issue of increasing the workability of sucker rods made of polymer composites by developing new designs of connections, evaluating their stress-strain state and choosing conditions to ensure the dissipation of the energy of its vibrations, and at the same time prevent resonance. The influence of defects in new and worn sucker rods made of composite on their stress-strain state is investigated. This assessment of the stress-strain state of the connection of the fiberglass body and the steel head under the conditions of the combined action of bending and axial load was studed. According to the results of analytical and experimental research, the design of sucker rod joints has been improved in order to increase the efficiency of their operation. To confirm the adequacy of the proposed mathematical model and the correctness of the obtained theoretical results, fatigue tests of sucker rods were carried out on a laboratory bench with rotation with a circular cantilever bending. The use of the wedge joint design of a fiberglass body with a steel head was justified and tested. A continuous rotator has been improved, which makes it possible to continuously rotate the string of sucker rods, which reduces the value of torque when it is working in the well. Based on the processing of laboratory data for the first time, the dependence of the number and length of cracks on the magnitude of bending stress was obtained during fatigue testing of fiberglass and hybrid sucker rods and the fatigue characteristics during cyclic bending of rods were obtained. The evaluation of the endurance characteristics of fiberglass sucker rods materials in various environments has been further developed.