DETERMINATION OF DYNAMIC STRENGTH PARAMETERS OF ENGINE SILENCER

The forms of natural oscillations and their corresponding frequencies are referred to the parameters of dynamic strength, the determination of which allows us to recommend safe operating modes of the studied part, to identify dangerous zones formed as a result of the action of dynamic loads, and the forms of natural oscillations are the basis for further calculations on strength. The work is devoted to determining the parameters of dynamic strength of the element of the diesel engine noise reduction system. The studied element is a cylindrical part with a diameter of 117 mm with 8 holes in the side surface, each of which has a diameter of 21.6 mm, a cylinder height of 86 mm, a wall thickness of 2.48 mm. The holes are made in two rows of four in each at an equal angular distance, the rows are offset by 45˚ along the circumference relative to each other. To determine the forms of natural oscillations, a virtual model was first created in the SolidWorks software package and compared with the data of experimental studies. At the same time, experimental studies were conducted using the real-time speckle interferometry method, the optical circuit and equipment that implement this method are protected by patents of Ukraine. In the frequency range of 0...7 kHz, 12 forms of natural oscillations were obtained. The comparative analysis between the calculated and experimental data indicates the correctness of the modeling: the root mean square deviation is 3.42 Hz or 0.14%. A comparative analysis was performed for the forms of oscillations, and it was determined that the number of axial (breathing) lines in the specified range varies from 4 to 12, circular (flexural) from 0 to 2. For the studied object, the nature of the distribution of stresses and displacements under static and dynamic loads was determined. When an external load of 1 MPa is applied to the inner surface, the maximum value of the stresses (Von Mises) reaches 112 MPa for node No. 16796, when adding a dynamic component for the same element, the value of the stresses increases to 609 MPa for the same element, with the oscillation frequency being 2910 Hz. The maximum value of displacements along the axis perpendicular to the axis of rotation under static loading is 0.02 mm for node No. 8969, and 0.44 mm under dynamic loading.