Sirenko M. Development and improvement of the technology of layer-by-layer synthesis of products from polymer composite materials for aviation and rocket and space technology

The dissertation proposes a new scheme, method and technology for obtaining products from polymer composite materials in the process and using layer-by-layer synthesis technologies. The new technology aims to improve the strength characteristics of parts and products. The influence of technological parameters on the operational properties of products from polymer composite materials obtained by layer-by-layer synthesis methods has been studied. It has been established that the distance between the reinforcement layers is a significant and main factor influencing the final characteristics of the obtained products. A direct relationship has been established between reducing the distance between the reinforced layers and increasing the strength properties of the product. Rational schemes for obtaining products from polymer composite materials using the 3D printing method have been developed. A reinforcement scheme has been developed that allows maintaining the integrity of the fiber not only within the layer, but also at the transition between layers. The reinforcement scheme allows for a positive influence on the properties of the material, taking into account the direction of the operational loads, and the printing modes ensure reliable and sufficient fixation and adhesion of the reinforcing fiber to the main polymer of the polymer composite material. Approximation equations were constructed for the results, and the results were compared with the base (reference) sample. These approximation function equations allow for the prediction of the operational properties of the product in the specified ranges. The use of a complex of modern and complementary methods for studying the structure and properties of materials, research of technological methods and modes ensure the reliability of the results obtained. The scientific provisions, conclusions and recommendations developed in the dissertation are substantiated by the conducted complex of experimental studies and the implementation of the results of the work. The conclusions formulated in the work do not contradict the classical ideas regarding the formation of the structure and properties of composite materials. The practical significance of the work lies in the development of a new scheme and method of reinforcing products with fiber when using FDM/FFF 3D printing, with a description of the influence of technological printing parameters and recommendations for their selection, technological equipment for reinforcement installed on a 3D printer with Delta-type kinematics and methods for performing reinforcement have been developed. A method for mechanical testing of polymer composite materials with a layered structure obtained by 3D printing has been proposed and substantiated. The obtained research results have been implemented in the educational process and can be used for the development and manufacture of parts and products with improved specific strength properties.