structural health testing
Structural Health Monitoring (SHM) is able to detect damage of an engineering structure and provides means of analyzing acquired data. SHM is characterized by monitoring an engineering structure such as bridges, dams, buildings, etc. over long periods of time by the use of a number of sensors. Because of the large amount of acquired data a statistical approach to data analysis is necessary.
The result of SHM shall provide an operator or owner of engineering structure reliable information regarding the integrity of a structure. SHM is based on the assumption that assessment of damage requires a comparison between two (time separated) system states.
advantages of acoustic emissions sensors for SHM
- The AE method can detect actively growing flaws while other methods require periodic inspection to make sure whether a crack is active or not. Since repair of existing cracks can sometimes do more harm than good to a structure, it is necessary to determine whether a defect is benign or active before repairs are made [A Study on the Application of the Acoustic Emission Method for Steel Bridges. Kazuo Endo, B.E.2000]
- The AE method can locate remote or hidden flaws. This excludes the need for direct and close access to the locations of defects. [A Study on the Application of the Acoustic Emission Method for Steel Bridges. Kazuo Endo, B.E.2000]
- The AE method is one of the few NDE (nondestructive examination) methods which are appropriate for long-term continuous monitoring of flaws. The AE method is more sensitive than other NDE and can detect even incipient flaws. Other methods, which are highly dependent on defect size or surface opening, are only able to detect defects reliably after they have progressed beyond a certain size. [A Study on the Application of the Acoustic Emission Method for Steel Bridges. Kazuo Endo, B.E.2000]
For SHM purposes reliably working equipment is needed which can acquire, analyze and issue warning or alarms in real time and autonomously for 24 hours a day, 7 days a week. Vallen Systeme delivers measurement equipment which fulfills the requirements of SHM.
typical system configuration
- Chassis: MB19 in single chassis or multi chassis configuration
- AE-signal processor board: ASIP-2/S and TR-2/512 (transient recorder mudules)
- AE-sensors: VS30-SIC-46dB, VS75-SIC-34dB or VS150-RIC
- Analysis software: VisualAE, VisualTR and VisualClass
- Location modules: Linear location, planar location and 3D location
- Additional modules: ECP to program own analysis routines or license routines of others