For a self-made tube-packaged FBG(fiber Bragg grating) strain sensor,the influencing factors of strain transfer ratio and the corresponding error transfer law with finite element method are studied.

Based on dynamic interaction analysis between soil mass and a underground structure,from the consideration of displacement response characteristics of the underground structure against earthquake action, a new concept-shear strain transmission ratio(SSTR)was introduced.

The key factors which have influence on the photonic weigher s accuracy are introduced in this paper from three points:the manufacturing of the fiber grating sensors,the packaging of the fiber grating sensors,the average strain transfer rate of the fiber grating sensors.

The strain transfer factor, k , is proposed for the characterization of the deformation transfer from the material measured to the sensor.

The measuring accuracy of FBG strain sensor is mainly determined by the physical and mechanical performance of bare fiber,protective coating,adhesive layer and host material;namely the interface strain transfer characteristics between these layers.

Optic fiber Bragg grating sensor requires a strain transfer coefficient when it is embedded in or adhered to the structure due to an interlayer between structure and sensor.

The concept of strain transferring coefficient was proposed through analysis of principle of fiber Bragg Grating sensors.