AE(声发射无损检测)

Mild steel strain-stress and strain - acoustic emission curve

2.1.2 Surface layer brittleness evaluation
2.1.4 Detection of the Fatigue Crack Growth Materials and Components in alternating loads destruction is one of the common failure. Using acoustic emission monitoring of fatigue fracture process can be found early fatigue crack. It can predict the fatigue life of components, according to combining with fracture mechanics calculation.
Evaluation Of Quality of layer principle diagram

2.1.3 Fracture toughness test for acoustic emission Using acoustic emission technique can achieve AE starting load, and can infer the critical load of crack propagation and material fracture toughness K .
IC
Crack tip of AE in the region
7075 aluminum alloy unilateral notched specimen of acoustic emission of fracture toughness test results
The basic principle is to establish a relationship between the AE and Materials Characterization. This is also the basis of application of AE in actual production .
Acoustic Emission Detection
Contens
1 2
The Notion of AE Technique
Application of Acoustic Emission TechAcoustic Emission Detectiong of Basic Physics

Acoustic Emission Technique Principle

2.The Application of AE Technique
Acoustic emission testing technique applies on ceramics, rock and concrete, timber, bones and other solid materials Material and structure, expecting common metal and composite materials.
Location of the Acoustic Emission Signals' source
Acoustic Emission Signal Collection System Analysis of Acoustic Emission Signals
1.The Notion of AE technique
Typical Results Representation of AE Testing
d. Nuclear reactor pressure vessels e. Monitoring of aircraft structural integrity

In addition to these, acoustic emission technology can also be used to test stress corrosion and hydrogen embrittlement crack and fracture analysis of composite and rock mechanics and so on.
At present, the application of this technique has already covered aerospace, ships, weapons, nuclear energy, petrochemicals, construction, geology, power, medicine, mines, and various other industries.
In order to raise some wear and fatigue strength of steel structure , surface chemical treatment is an effective method, such as carburizing and nitriding. Component surface in the heat treatment process of carbides and nitrides, a high hardness, often leading to the surface of brittle, in the course of using peel. We can also use the methods of AE detection and mechanical properties experiment to evaluate the layer properties.

2.2 Structural Integrity Assessment
Many structures, such as pressure vessels, oil pipelines and so on, need structural integrity assessment. This is also the main applications of acoustic emission technique fields. The following are some of the concrete application instance.
The scene of spherical tank AE testing

Pressure Policy for a New Vessel
Example of Transducers Distribution on Vessel's Surface
Main Application: (1) Materials Characterization; (2) Structural Integrity Assessment; (3) Monitoring the Process of Running and Technology; (4) Leak Detection.

2.1 Materials Characterization
This application attempt to establish a sort of relationship between the AE and micromechanism、mechanical characteristics by materials characterization experiment of AE monitoring. It can normally achieve two objectives : (1) Analysis and evaluation of deformation and fracture Mechanism and mechanics behavior; (2) Establishing a extensive AE characteristics of the database. 2.1.1 Plastic deformation of acoustic emission Typical examples of metal plastic deformation in this application.Through the acoustic emission monitoring of tensile test, we can get a strain-acoustic emission curve.
AE is a kind of nondestructive examination technique. It is based on the energy of the part of the material quickly releasing and emitting instantaneous elastic wave. Most of materials of deformation and fracture can produce acoustic emission. If the release of strain energy is large enough, our ears be able to hear these voices. But singles of AE emitted by most of materials are too feeble to directly hear by our ears, and need the help of electronic instruments to detect. The technique useing detecting devices to record and analysis of acoustic emission signals and utilization of acoustic emission signal to infer the location and type of acoustic emission source is called acoustic emission testing.
a. Titanium alloy gas cylinder inspection

b. Vehicle seamless gas cylinder
Detection of steps

c. Metal pressure container
Metallic pressure vessels, as the number, safety , cost and routine determination problem, has always been the focus of AE testing at home and abroad in particular chemical, petroleum and nuclear industry in service container.