Challenges and Responses of Acoustic Emission Testing Technology
- Challenges Brought by the Development of Special Applications in Various Industries
(1) Challenges from Advances in Acoustic Emission Testing Methods
Currently, most acoustic emission testing systems are effective instruments for periodic and inspection testing, and they have been widely applied in various industries. This testing method is characterized by its ability to quickly complete the entire testing process within a few hours through manually controllable loading. Once the testing is completed, no further testing is performed until the next scheduled cycle. This approach, suitable for periodic testing, is not applicable for equipment that cannot be subjected to manual loading or requires long-term monitoring. Particularly in applications requiring remote long-term real-time monitoring, there has been a lack of suitable products. For example, in long-term monitoring applications such as mines, tunnels, wind power generation, bridges, and complete sets of equipment in enterprises, monitoring operations need to be conducted from monitoring rooms that are far away from the measurement points, typically over 1,000 meters away. In these long-term real-time monitoring applications, the existing methods mainly rely on a computer acting as the main unit for the acoustic emission device, using the internet or other remote networks, with another computer acting as a client for operation. This method requires placing a computer on-site, and frequent manual operations on the client computer are necessary. Although this dual-computer communication solution can address some issues, its usage is limited in many scenarios. For instance, environments such as mines, bridges, tunnels, and those with radioactive, high-temperature, or toxic conditions are unsuitable for personnel operation. Additionally, some on-site environments may lack power supply or stable locations, making it impractical to place computers. Faced with these application challenges, there is an urgent need for the market to quickly develop a suitable remote acoustic emission monitoring system for long-term monitoring.
Response Measures: Government and industry management agencies should provide necessary policy encouragement and financial investment. Research institutions and instrument manufacturers should increase manpower and financial investment to develop applicable technologies and equipment for remote long-term monitoring.
(2) Challenges from the Diversity of Physical Conditions of Testing Objects
For acoustic emission testing of superconducting materials, research needs to be conducted in ultra-low temperature environments, while high-temperature environments in petrochemical and metallurgy testing also pose challenges to testing instruments. For the testing of micro devices, miniaturization of sensors is essential. For high-speed particles, bullets, and other strong impact sources, low-sensitivity sensors are required. Instruments used in underwater or oil-immersed environments need to have enhanced protection levels. For holes or tanks deeper than 100 meters, the main unit of the instrument must meet the necessary intrinsic safety and explosion-proof standards. In applications involving high-voltage equipment, electrical isolation is required between the equipment operated by personnel and the on-site testing equipment to ensure operator safety. For some machining equipment, high-speed fluid devices, and equipment with rapidly changing loads, the inherent mechanical or electromagnetic noise levels are already very high, making it extremely difficult to separate effective signals related to internal defect propagation. These special application requirements cannot be fulfilled using traditional acoustic emission testing technologies and general instruments.
Response Measures: Develop specialized testing equipment for different applications and strengthen technical exchanges within the industry. After classifying and summarizing similar industry applications, research shared acoustic emission testing technologies to avoid isolated efforts in various applications and promote communication through technical exchanges to enhance testing technology in related industries.
2. Challenges from the Lack of Application Standards
In the field of non-destructive testing, acoustic emission is a unique passive testing method characterized by its principles. The vast differences in signal source conditions across various industries make it difficult to adopt a unified standard for different applications. This has led to a significant lack of necessary standards for acoustic emission testing in various industries, which has become a major obstacle to the widespread application of acoustic emission technology. Currently published acoustic emission testing standards primarily focus on special inspection industries, covering only pressure vessels, gas cylinders, atmospheric storage tanks, and composite materials. The research conducted by universities and research institutions on various testing and evaluation methods is mostly limited to theoretical studies, with few that can be applied in engineering.
Response Measures: For applications in various industries, relevant experts should be organized by industry associations to summarize commonalities in all applications and classify them, then develop standards based on these classifications. As the number of standards increases, efforts should be made to enhance the effective coverage of standards across industries with fewer standards. The aim should be to quickly improve testing standards for various applications to pave the way for the engineering application of acoustic emission testing technology across industries.
3. The Conflict Between Testing Costs and Popularization
The cost of acoustic emission testing systems has been difficult to reduce effectively, resulting in high instrument prices that have not allowed for the same scale effects seen in other non-destructive testing instruments. This has hindered the widespread adoption and affordability of acoustic emission technology in various sectors. Moreover, for periodic and inspection testing, extensive time is required for setting up instruments, including scaffolding and wiring, which occupies much of the testing process, leading to prolonged downtime for operations and increased time costs for companies. Additionally, the substantial investigation and analysis required before and after testing needs to be managed by certified technical personnel, which adds to labor costs as many staff members must be involved in the process.
Response Measures: To mitigate these costs, enterprises can adopt long-term monitoring systems where an initial setup covers multiple monitoring points, thus reducing the cost per unit. Specifically, integrating acoustic emission monitoring systems with other monitoring equipment during the design and manufacturing stages can streamline operations. By building in automated detection and alarm systems, routine operations can be managed by a single staff member.
4. Awareness and Popularization Challenges of Acoustic Emission Technology
As of now, the Special Equipment Non-Destructive Testing Personnel Qualification Examination Committee of the General Administration of Quality Supervision, Inspection and Quarantine of China has conducted multiple training sessions for Level II and III acoustic emission testing personnel since 2002, with nearly 700 individuals obtaining Level II and III certification. However, these professionals contribute only minimally to the overall awareness and dissemination of acoustic emission technology.
In universities, while there are research projects related to acoustic emission, most focus on core technologies that are not inherently acoustic emission based. Instead, acoustic emission is often used merely as a supplementary tool for enhancing project evaluation. The number of researchers focusing directly on acoustic emission technology in higher education institutions and research organizations is very limited, with scarce funding allocated to such research.
Currently, within enterprises and testing institutions, most technical personnel engaged in acoustic emission testing research lack formal training and educational background in relevant fields, leading to many research efforts being basic and still in the learning phase. These issues hinder the effective promotion of acoustic emission testing technology in China.
Response Measures: Address these challenges at the foundational level by incorporating acoustic emission testing into the educational curriculum. Reform educational materials to include acoustic emission testing as an essential component of non-destructive testing, placing it on par with radiography, ultrasonics, and other disciplines in higher education. Furthermore, increasing government and corporate investments in acoustic emission-related testing projects will stimulate research and development efforts in institutions and colleges.
Key Players in the Acoustic Emission Testing Equipment Market in China
Qawrums Ltd. https://www.aendt.com
Leading manufacturer of acoustic emission testing equipment.
Offers a range of AE testing equipment, including sensors, amplifiers, and data acquisition systems.
Applications include materials testing, non-destructive testing (NDT), and structural health monitoring.
China Representative of Physical Acoustics Corporation (PAC)
Provides AE sensors, instruments, and software for various applications.
Applications include materials testing, structural health monitoring, and leak detection.
PAC is a globally recognized company in the AE testing equipment market, and the representative office in China likely provides localized support and services.
QingCheng Ltd. https://ae-ndt.com
Provides AE testing equipment and services for various applications.
Applications include materials testing, structural health monitoring, and NDT.
Vallen Systeme
Develops and manufactures AE testing equipment, including sensors, instruments, and software for various industries, including aerospace, automotive, and energy.