INFLUENCE OF PHYSICAL AND MECHANICAL PROPERTIES OF POLYMER COMPOSITS ON THE STRENGTH INDICATORS OF CAR PARTS

Аннотация

In this article, the influence of the physical and mechanical properties of polymer composite materials obtained by adding local fillers on the strength indicators of automotiveparts was studied. Keywords:Polymer, composite, physical-mechanical, part, strength, property, filler. Introduction. From the beginning of the 20th century, polymeric materials replaced metallic and ceramic materials. Today, polymer parts are used in friction pairs as an alternative material to metals or other materials [1-4]. Their normal tribological properties and low friction are beneficial for their operation in various processes, including parts of vehicles, aircraft components, and other machines and mechanisms. Research [2-6] shows that the reason for the loss of operability of machines and mechanisms is 80-90% wear due to friction. Around the world, 100 million tons of lubricants are used annually to reduce friction. In developed countries, the failure of machine-building equipment duetofriction and wear accounts for4-5% ofthenational income[5]. Most of the current research on polymer tribology [3-6] is focused on engineering polymers. However, most of them are simple and simple tribo-systems, in which relatively less load-bearing parts (bushing, shaft, pins, pulley) are involved. Until now, the tribological properties of polymers and their compositions in these tribosystems have not been thoroughly studied,but attention tothesematerials is increasing due to theemergence ofproblems. Objectand method ofresearch Research Method. The study of tribotechnical properties was carried out on the "Micron- tribo" tribometer, operating in mini and nano sizes. For the experiment, a SHX steel ball with a hardness of 38-40 was used. The diameter of the steel ball is 3-5 mm. The roughness of the polypropylene sample with a diameter of 40-50 mm and a thickness of 4 mm was measured usinga profilometer. The experiments were conducted at a contact pressure of 1-20 N, a rotational speed of 0.5 and 1 m/s. Changes in the surface and surface parameters formed on the surface and in the sampleofa steel ballwere observed and studied usingaprofilometer. Results andtheirdiscussion. The coefficient of friction and wear are significantly influenced not only by the type of filler, but also by its content in the composite. For this, their optimal amounts are determined experimentally. It is difficult to achieve the necessary properties by adding fillers to the polymer compositionseparately, therefore amixture ofseveral fillers is used. https://ijmri.de/index.php/jmsi volume 4,issue5,2025 320 Physical andmechanical properties of polypropylene Table1 JM380UZ No Properties Trial methods Measure unit CORGAS 1. Elasticity modulus,28mm/min, ASTMD 790 MPa 1682.53 2. Density ASTMD 1505 g/cm3 0.85-0.95 3. Relativeelongation, min ATSMD 638 % 30-50 Impact toughness IZOD(+23), min 4. ASTMD 256 kgfcm/cm2 6-9 Figure1.Dependenceof wearonaverage load Wear is directly proportional to the normal load, i.e., the greater the load, the greater the wear. The reason for this is that the increase in load brings the surfaces closer together, as a result of which their mechanical (penetration) and molecular attraction increases (Fig. 1). It has been shown that the degree of wear varies depending onthe average load, the slidingspeed is 0.5 l and 3.0 m/s. The maximum value of the degree of wear reaches 2-2.5 mg/min at a load of 5 N at a speed of 3 m/s, for 1 m/s this value is 0.4-0.5 mg/min, the minimum value is 1.4; 0.35 and 0.25 mg/min. Relatively small changes were observed at a speed of 0.5 m/s. The higher the material's velocity, the higher the temperature in the friction zone, resulting in softening of the material's surface and increased wear. To reduce wear, the optimal values of surface roughness forthis pairare determined experimentally. When a polypropylene sample is rubbed with a steel ball, it leaves a trace on the surface of the sample due to the normal load and sliding speed, the size and value of which depend on the friction modes and the type of material. These images are taken using a Micron- tribo"microscope mounted onatribometer and are calculated based ontrace measurements. RESULT Thefriction and wear of composites are significantly influenced by thenormal loadand the https://ijmri.de/index.php/jmsi volume 4,issue5,2025 321 slidingspeed. The degree ofwear varies depending onthe average load. Themaximum value of the degree of wear reaches 2-2.5 mg/min at a load of 5 N at a speed of 3 m/s, for 1 m/s this value is equal to 0.4-0.5 mg/min, the minimum value is 1.4; 0.35 and 0.25 mg/min at a load of 1 N. Relatively smallchanges were observed at aspeed of0.5m/s.