| As a key component of the stability of the helicopter rotor system,the viscoelastic damper bears a huge amount of alternating load when the helicopter takes off and land,and the working environment is extremely bad.In addition to providing sufficient damping for the blade oscillating motion,the damper itself is required to have a simple structure,light weight and high reliability.Therefore,the high damping elastic silicone rubber is used as the elastic matrix for the alternating load,and the adhesive will be the elastic matrix and the aluminum.A new process for high temperature thermal vulcanization bonding of alloy inner cylinders.However,in the manufacturing process,there may be problems such as poor internal rubber pores and poor adhesion at the metal-rubber bonding layer;in the course of use,the metal-rubber bonding layer may debonded and the rubber interior may occur as the rubber is fatigued many times.Cracking and other issues.Regardless of the type of defect,the performance of the damper will be seriously affected,which will threaten the safety of the helicopter.Therefore,the corresponding technical research work on the quality inspection of viscoelastic dampers is of great significance for ensuring the take-off and landing safety of helicopters and extending the life of rotor systems.Firstly,based on the structural characteristics of the viscoelastic damper,the bonding process and the possible defect characteristics,on the basis of a large number of experiments,the industrial CT method and the ultrasonic characteristic scanning imaging method are selected from many non-destructive testing methods.These two methods have their own advantages and disadvantages,so they use complementary methods to complement each other.Subsequently,the damper is imaged and detected by using the existing industrial CT detection platform.After the image is reconstructed by FDK algorithm,the detection results are analyzed,and the internal defects of the elastic body and the specific position of the debonding defect at the metal-rubber interface are obtained.size.Then use the expansion module of VGstudio software to mark the whole defect part with color,make the defect display more intuitive,and then spread the whole damper from the three-dimensional graphic into a two-dimensional circular cut plane graphic,so that the bonding layer can be judged more accurately.The defects also laid the foundation for subsequent ultrasound experiments.Then analyze the difficulties of ultrasonic testing,propose corresponding solutions,make full use of the existing ultrasonic feature imaging detection technology and equipment to compare and test the outer tube bonding layer of the damper,analyze the experimental results,and compare with the ray detection results.Yes,some close-type debonding defects that may be missed by the radiation inspection are obtained.Finally,based on the prior art,a horizontal special ultrasonic imaging system was designed and developed.The system is used to detect the inner tube joint layer of the damper sample,which visually shows the distribution of the defect,and compares it with the ray detection result,and also obtains a weak combination defect that may be missed by the ray detection.The results show that industrial CT can detect both internal defects of elastomers and debonding defects of metal-rubber bonding layer with a resolution of up to 1 mm.Ultrasonic feature imaging technology can detect weak bonding defects that cannot be detected by industrial CT.The solution has high reliability and high repeatability,which is suitable for the mass production of viscoelastic dampers and in-service quality monitoring. |
