scope:

The present guideline is concerned with optical strain sensors (OSS) where the strain sensitive element is a fibre Bragg grating (FBG).

It is the purpose of the guideline to define the most important features and characteristics, to name the procedures for their determination and also to define the coupling and testing conditions necessary for the demonstration of these features and characteristics.

The aims are the following:

• the unambiguous and complete description of the relevant performance parameters of optical strain sensors using consistent terminology

• to facilitate the communication between manufacturers and users

• compatibility, to specify limitations or the unequivocal and well-founded assessment of products from different manufacturers

• the promotion of the competent choice of OSS for the best solution of the respective measurement objectives

The details in the guideline refer to the measurement of static and dynamic values of strain with OSS based on FBG, whereby measurements are typically made in the continuous range from 0 Hz up to several kHz.

The OSS can be used in various ways in diverse structural forms:

• structurally integrated, closely embedded, with all-round homogeneous enclosure by the material to be measured

• surface or boundary-surface bonding by glueing or laminating

• locally attached to the object of measurement

The measuring equipment for the determination and verification of the OSS characteristics will be separately described with regard to their performance parameters and characteristics. When applied to tasks in accordance with this guideline, the chosen measuring equipment must be subjected to calibration, initially and at regular intervals, in conformity with the standard DIN EN ISO/IEC 17025:2000. This calibration is the necessary requirement for the statement: "tested according to VDI/VDE 2660".