Fiber-optic sensors are increasingly used if special requirements avoid the application of electrical sensors, or economic benefit is promised. The scientific background is well developed; however, there are some restrictions with respect to long-term reliable use. For a widespread practical use, sensor products must be manufactured, characterized and validated according to standards. Guidelines on how to apply sensors and evaluate their operation on-site including special facilities to evaluate applied sensors are needed. The paper will present validation methods to evaluate the quality of sensor systems function. It will also indicate lacks of knowledge and methods to be filled to promote the use of FOS.
Currently, fibre-optic sensors (FOSs) are commonly used if special requirements make the application of electrical sensors impossible, or economic benefit is promised. The scientific background of FOS technology is well developed; however, there are still some restrictions with respect to long-term reliable use. For widespread practical use, sensor products must be manufactured, characterized and validated according to standards. Guidelines on how to apply sensors and evaluate their operation on-site including special facilities to evaluate applied sensors are needed. This paper will focus on important aspects, such as when FOSs may be used under real practical conditions, and will present validation methodologies to evaluate the overall quality of the sensor system's function. It will also indicate the lack of knowledge and methods to be elaborated to promote the use of FOS.
Fiber optic sensors are increasingly used because of their outstanding performance or if special requirements avoid the application of conventional electrical sensors. The scientific background for optical fiber sensors is well developed; however, the characteristic of sensors applied in rather harsh environment are almost always different from characteristics determined in laboratory or before its installation. In order to achieve long-term stable function and reliable measurement data after application and under harsh environmental conditions, guidelines for characterization and specification of sensor components are needed as well as methodologies for testing the sensor performance must be developed. Performance tests carried out revealed that there are still some restrictions with respect to long-term reliable use: first, some sensor products available on the market are not very often appropriately characterized, described and validated; second, application procedures are not always defined due to a lack of understanding the micromechanical issues in the interface zone between sensor and measuring object. Application procedures and profound knowledge of materials behaviour are necessary to get results from the sensor that can be reliably used. The paper describes first guidelines to prove the quality of fiber optic strain sensors, a testing facility developed for unbiased tests and certification of surface-applied sensors as well as result from comparison of commercially available strain sensors.
Fibre-optic sensors need to be more established in the sensor market. Their advantages have unquestionably been verified by numerous demonstrations. However, there are some open questions leading now and then to restraints in the user's community. The paper dicusses examples where fibre-optic sensors provide outstanding knowledge about the structure's behaviour, but application is often challenging. Requirements are listed and open questions to be solved are discussed. Short outlook to standards useful for better design, characterization and application is given. Standards are the basis for establiching SHM systems, especially for safety-critical structural diagnostics.
Standardization in fibre-optic sensing for structural safety - activities in the ISHMII and IEC
(2015)
Fiber-optic sensors are increasingly established in the sensor market. Their advantages have unquestionably been verified by numerous demonstrations to enhance the operational performance of aged structures or to monitor the structural behavior of safety-relevant structures or their components. However, there are some barriers in use due to a lack of extensive standardization of fiber-optic sensors. This leads very often to restraints in the users community. The paper shows the status in international standardization of fiber-optic sensors as well as current activities in leading institutions such as IEC and ISHMII and others with the purpose of providing relevant standards for a broader use of selected fiber-optic sensor technologies.
Sensors for assessment of the structure’s behaviour must work durably and reliably. Even if the performance of produced and delivered sensor is well specified, the sensor's strain characteristics and the performance of an applied sensor can significantly differ from the virgin sensor’s performance. The quality and appropriateness of installation decides over the long-term operability and getting reliable measurement results. The paper shows how important a clear terminology is, which problems might occur when sensor are not well characterized according to Standards or guidelines. Short outlook to experimental methods providing clear knowledge and appropriate Validation of the sensor’s performance for a defined measurement task is given. Finally, the state of-the-art in fibre-optic sensor Standardization is given.