Method for testing of products on vibration strength
Mihails Zakrževskis, Vitālijs Beresņevičs, Vladislavs Jevstigņejevs

The present invention can be used for testing of thin-walled structures and units of airplanes and ships on durability due to the action of continuous vibration spectrum. Its objective is to approach the excited vibration spectrum to the operation conditions of testing object in order to increase the reliability of experimental results and reduce expenses on realization of vibration test. The proposed method lies in placing of testing object (1) on working table (2) of vibration test bench which is mounted on stationary base (6) through elastic elements (springs 4 an 5) applying to the working table an external harmonic excitation by vibro-exciter (3). Elastic system of test bench is made from main elastic supports (4) and additional elastic limiters (5). The ends of main elastic supports are connected with stationary base and working table. One end of every elastic limiter is attached to the stationary base, but the other one remains free. In static equilibrium position of the system a clearance (7) between free end of elastic limiter and working table is set to zero. Degree of elastic nonlinearity (k1+k2)/k1 of the system is taken within interval: 11 is less or equal to (k1+k2)/k1 that is less or equal to 18, where k1 is resulting stiffness coefficient of main elastic supports (4), and k2 is resulting stiffness coefficient of elastic limiters (5). Frequency omega of harmonic excitation force is taken within interval from 0.91 to 0.950 multiplied by natural frequency both of working table (2) and testing object (1) supported on main elastic elements (4).



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