Vibration Dynamic Characteristics Simulation for Helicopter Main Gear Box Test Bench

Abstract

New elements are usually used in developing promising products, and they are introduced to improve its characteristics. This study objective is aimed at making certain decisions to eliminate or reduce negative effects of design and technological solutions that are being identified only at the bench testing stage. Problem of resonant interactions between bench elements and main gear box units is connected to significant distortion of the product under development dynamic analysis results. Therefore, identifying resonant interaction conditions and obtaining reliable results in the course of developing any kind of units is relevant for the aviation industry enterprises. JSC "Reduktor--PM" created a universal bench, and it was involved in solving this task practically for the first time, since significant oscillation levels were registered significantly exceeding the calculated values in the process of testing the bench. To determine the bench element base frequencies, the modal analysis task was finalized to identifying natural frequencies of the bench structural elements and partial frequencies of these elements at installing the unit on the bench. Wave transformation pattern in complex structures significantly depends on the element base and the structural connection between its components. In fact, the wave field structure is n-dimensional. Nevertheless, general approaches to generating interaction conditions are possible on the basis of their expansion in coordinates. In this case, the algorithm for determining oscillation natural frequencies in the bench elements and in the structure as a whole is based on the modal analysis