Study On Vibration Reduction Of Helicoptor Sensitive Equipment’s Surporting Structure With Damping Technology

The vibration is inherent characteristics of the helicopter during normal workinghours. The helicopter will often have a broadband random vibration phenomena causeddue to vibration modes excited at the same time out. The harm to sensitive equipmenton the helicopter is very large, in particular, is likely to cause equipment malfunction orreducing reliability. Taking into account the sensitive equipment and helicopters areconnected together through the support structure, the damping on the support structureto reduce the helicopter vibration energy transfer will be a very effective way for theprotection of sensitive equipment vibration.First of all, establishing a finite element model of the helicopter sensitiveequipment support structure, which modal and modal effective mass analysis areapplied upon. After incentive load is applied to the random vibration response analysis,combined with modal and modal effective mass analysis results, we can get the fewmodes which have greater impact on the vibration of sensitive equipment. By the modalstrain energy analysis of the support structure, it can easily to find out the optimumlocation of the laying of constrained damping.It has studied on the calculation method of constrained damping structureparameters and effects of changes in structural parameters of its damping performance.The results show that the damping layer thickness、constrained layer thickness, andmodulus parameters have a major impact on the damping performance of theconstrained damping structure. Under the weight limit of constrained damping structure,the presence of the damping effect has a lot to do with the thickness of constrainedlayer.In order to achieve the goal of the best damping performance of the constraineddamping structure, using the basic principles of experimental optimization to carry outthe orthogonal combination of test and approximate fitting1,2,3,5-order modal lossfactor quadratic response surface model. The optimum design parameters are obtainedby the use of the optimization toolbox to optimize the fitted response surface model.The results show that the fitted response surface model can reflect the functionalrelationship between the1,2,3,5-order modal loss factor and constrained damping layer.What’s more, with the optimized structural parameters to applied the constraineddamping structure to the support structure, the vibration of the center mass of sensitiveequipment has greatly reduced.