（调研报告）
Ultrasonic emission detection
Introduction
Ultrasonic emission detection is a non-destructive method used to detect defects and internal abnormalities in materials. The technique utilizes ultrasonic waves, typically produced with a transducer, to detect soft and hidden defects within a material. Ultrasonic emission detection is a technique extensively used in the aerospace, automotive, and power industries. It is commonly used during the inspection of materials such as metals, composites, and reinforced plastics.
Application
Ultrasonic emission detection is used for detecting soft and hard-to-detect damage in materials. This type of damage is typically undetectable through visual or physical tactile inspection and is only revealed, through the reflection of ultrasonic waves. This type of inspection is usually conducted to check for hard-to-detect internal defects and assess the quality of the materials. The detection of flaws and internal damage can help in preventing and identifying potential safety issues that may arise from a defective product. There are numerous techniques used for ultrasonic emission detection, such as immersion testing, contact testing and pulse-echo techniques.
Immersion testing is an advanced technique used to detect and assess damage in materials. This technique involves immersing the part being inspected in a liquid and using an ultrasonic transducer to send sound waves through the material. The sound waves travel through the material and create an ultrasonic map, which is then analyzed and used to identify potential damage. This technique is commonly used to inspect large areas - such as pipelines and large structures - in order to detect and assess damage.
Contact testing utilizes an ultrasonic transducer to inspect a material in direct contact with the material. The transducer sends sound waves into the material, which reflects when it detects a flaw. This reflection is then used to detect the presence of flaws within the material. This technique is usually used to inspect smaller areas in comparison to immersion testing, and is efficient in detecting very small defects.
The pulse-echo technique is similar to contact testing, however it utilizes an acoustic transducer in order to send and receive ultrasonic signals. This technique is often used for inspection of curved surfaces, or large areas that cannot be inspected with a contact transducer. The signal which is generated allows the technician to detect flaws within the material and pinpoint their exact location.
Advantages
Ultrasonic emission detection is a non-destructive method of testing and is used to detect hidden or soft defects in materials. By using this type of testing, manufacturers can identify and rectify potential problems with their products before they enter the market. Additionally, this type of testing is highly efficient at detecting very small defects and does not require physical contact with the material - minimising the risk of any additional damage. Another advantage of this type of testing is that it is relatively inexpensive and quick to execute.
Conclusion
In conclusion, ultrasonic emission detection is an efficient non-destructive technique used to detect hard-to-find damage and defects in materials. Its use is extensive in many industries, such as the aerospace, automotive and power industries, where it is utilized to ensure the quality of its products. There are several techniques used for ultrasonic emission detection, depending on the size and complexity of the material. Furthermore, this type of testing is relatively inexpensive and efficient, making it preferable over destructive testing methods.
