The Acoustic Emission Identification Technology Of Signal Characteristic Under Various Loading Hoisting Machinery General Defects

With the rapid development of national economy in our country,the hoisting machinery as the important basis of modern production equipment,is widely used in all kinds of material lifting,transportation,loading and unloading,installation of occasions,has a huge market demand.However,due to the characteristics of metal fatigue,hoisting machinery steel structure often occurred in large stress concentration and welding defects in the expansion of the crack,resulting in tower crane scrap or even break,fall the occurrence of major accidents,etc.Therefore,in view of the hoisting machinery general defects nondestructive identification study,it is of great theoretical and practical significance.Acoustic emission testing technology,as one kind of nondestructive testing technology is sensitive to defects,detection with high efficiency,the overall detection without shutdown of equipment can be a unique advantage.Has now been widely due to pressure vessels and detection in the field of aerospace.However,in view of the hoisting machinery of nondestructive testing is still in the early exploration stage,did not formulate relevant national standards,widely used in the industry pressure vessel standards to test the hoisting machinery.Acoustic emission instrument with fatigue testing machine is adopted in this article,the hoisting machinery general defects specimen of acoustic emission signal acquisition and analysiS?The tasks finished are as follows:(1)Based on acoustic emission testing fixture features of relevant standards and testing machine,the preparation of the corresponding specimen without defects,crack defects and welding defects.And according to the load characteristics of the testing machine made the corresponding reasonable loading scheme.(2)Based on zero defect,crack defects of two kinds of specifications and welding defects specimens under the action of tensile load of the acoustic emission test.Got in the process of the acoustic emission signal characteristic parameters of the frequency spectrum characteristics of the corresponding range were analyzed.Special crack defects of two kinds of different specifications of the corresponding summary and comparative analysis.(3)Collected in the torque load crack defects and welding defects of specimens under the action of the acoustic emission signal characteristic parameters.On the positioning features analysis,characteristic parameter analysis and spectrum analysis.Concluded that two kinds of defects corresponding signal of specimen under torsion load characteristics.