The transmitting properties of acoustic emission(AE) signal is investigated in order to provide experimental basis for application of AE technique. In the paper, the influences of the geometric shape and material prop...The transmitting properties of acoustic emission(AE) signal is investigated in order to provide experimental basis for application of AE technique. In the paper, the influences of the geometric shape and material properties of the mediums and the bearing type on AE transmission are analyzed for providing the theoretic foundation for selecting the transmission route of AE signal and the fixing location of the AE sensor reasonably. According to the transmitting properties of AE, an apparatus of detecting AE signal for the tool breakage monitoring system has been set up. Its application results show that it is of benefit to improving the sensitivity of the tool breakage monitoring system.展开更多
Tool condition is one of the main concerns in friction stir welding （FSW）, because the geometrical condition of the tool pin including size and shape is strongly connected to the microstrueture and mechanical perfor...Tool condition is one of the main concerns in friction stir welding （FSW）, because the geometrical condition of the tool pin including size and shape is strongly connected to the microstrueture and mechanical performance of the weld. Tool wear occurs during FSW, especially for welding metal matrix composites with large amounts of abrasive particles, and high melting point materials, which significantly expedite tool wear and deteriorate the mechanical performance of welds. Tools with different pin-wear levels are used to weld 6061 Al alloy, while acoustic emission （AE） sensing, metallographic sectioning, and tensile testing are employed to evaluate the weld quality in various tool wear conditions. Structural characterization shows that the tool wear interferes with the weld quality and accounts for the formation of voids in the nugget zone. Tensile test analysis of samples verifies that both the ultimate tensile strength and the yield strength are adversely affected by the formation of voids in the nugget due to the tool wear. The failure location during tensile test clearly depends on the state of the tool wear, which led to the analysis of the relationships between the structure of the nugget and tool wear. AE signatures recorded during welding reveal that the AE hits concentrate on the higher amplitudes with increasing tool wear. The results show that the AE sensing provides a potentially effective method for the on-line manitoring of tool wear.展开更多
基金Supported by the Laboratory of Robotics, Chinese Academy of Sciences
文摘The transmitting properties of acoustic emission(AE) signal is investigated in order to provide experimental basis for application of AE technique. In the paper, the influences of the geometric shape and material properties of the mediums and the bearing type on AE transmission are analyzed for providing the theoretic foundation for selecting the transmission route of AE signal and the fixing location of the AE sensor reasonably. According to the transmitting properties of AE, an apparatus of detecting AE signal for the tool breakage monitoring system has been set up. Its application results show that it is of benefit to improving the sensitivity of the tool breakage monitoring system.
文摘Tool condition is one of the main concerns in friction stir welding （FSW）, because the geometrical condition of the tool pin including size and shape is strongly connected to the microstrueture and mechanical performance of the weld. Tool wear occurs during FSW, especially for welding metal matrix composites with large amounts of abrasive particles, and high melting point materials, which significantly expedite tool wear and deteriorate the mechanical performance of welds. Tools with different pin-wear levels are used to weld 6061 Al alloy, while acoustic emission （AE） sensing, metallographic sectioning, and tensile testing are employed to evaluate the weld quality in various tool wear conditions. Structural characterization shows that the tool wear interferes with the weld quality and accounts for the formation of voids in the nugget zone. Tensile test analysis of samples verifies that both the ultimate tensile strength and the yield strength are adversely affected by the formation of voids in the nugget due to the tool wear. The failure location during tensile test clearly depends on the state of the tool wear, which led to the analysis of the relationships between the structure of the nugget and tool wear. AE signatures recorded during welding reveal that the AE hits concentrate on the higher amplitudes with increasing tool wear. The results show that the AE sensing provides a potentially effective method for the on-line manitoring of tool wear.
