Modal Analysis on Working Parts of Vertical Helical Ditcher

The dynamic characteristics of the working parts of a helical ditcher was analyzed.The low modes natural frequency of the working parts under free state were determined by OMA(operational modal analysis) test and FEA(finite element analysis) modal analysis method respectively.Then the natural frequency tested by OMA was compared with the results of FEA to verify the correctness of FEA method.Constraint modal analysis of the working parts was taken for further research.The purpose of reducing vibration and noise was achieved by changing inner diameter,pitch and thickness of the helical blades.The influence of different structural parameters on natural frequency was ensured.The results showed that the correctness of FEA was varified.The natural frequency of working parts increased with the increase of the inner diameter and distance between pitches.Low order natural frequency decreased with the increase of thickness,while the high order natural frequency increased with the increase of thickness.