Encapsulation of Fiber Optic Sensors in 3D Printed Packages for Use in Civil Engineering Applications: A Preliminary Study

Abstract

Fiber optic sensors have considerable potential for measuring strains in the challenging environment posed by today’s civil engineering applications. Their long-term reliability and stability are particularly important attributes for assessing, with confidence, effects such as cracking and response to normal (and abnormal) loads. However, given the fragile nature of the bare fiber, the sensors must be packaged to achieve adequate robustness but the resulting increased cost of installation can frequently limit the number of sensors which can be installed or their use may have to be ruled out altogether due to these financial constraints. There is thus potential for the development of a more affordable type of packaging and this paper describes work undertaken to produce a cost-effective and easy-to-use technique for encapsulating fiber optic sensors in resin, taking advantage of 3D printing techniques which are widely available and at low cost. This approach can be used to produce a robust, inexpensive packaged sensor system which is seen as being suitable to be extended to a wider range of uses including installation in concrete structures prior to casting. To evaluate this approach, several such 3D printed package types and geometries are described and their behavior is assessed from a programme of laboratory trials, the results of which are presented in this paper. This proof-of-concept testing has demonstrated the considerable potential which 3D printed packages have and the scope for further development and consequent use in civil engineering applications. Areas showing promise and potential, which have been identified from the work undertaken, are discussed.

Smart Textiles for Electricity Generation

“…Admittedly, traditional encapsulating layers in smart textiles, e.g., hermetic plastic packages, might not only impair breathability but also undermine their energy performance by impeding, for instance, stress transport within TENGs and PENGs, 439 heat flow in TEGs, 228 body fluids absorption in EBFCs, 607 and translucency of solar cells. 180 Therefore, to achieve robustness without sacrificing wearability and output power of smart textiles, developing innovative encapsulant materials and technologies, 783 such as fully biobased films, 784 ultrathin White-EVA film, 785 and 3D printing packages, 786 are highly desired to stamp out this predicament.…”

Lead (Pb2+) ion sensor development using optical fiber gratings and nanocomposite materials

“…An in-house laser-based fiber grating inscription facility [40,41] was used to manufacture both the LPGs and FBGs, writing these into boron-doped photosensitive silica-clad single-mode fiber (PS1250/1500 from Fibercore, UK). LPGs and FBGs of 30 mm and 10.16 mm length, respectively, were inscribed into the fiber core by using a deep-UV KrF excimer laser operating at 248 nm with a pulse energy of 10 mJ and frequency of 100 Hz.…”

Laboratory Investigation of Fiber Bragg Grating Strain Sensors for Semirigid Base Asphalt Pavements

“…Different types of FBG strain sensors used for asphalt pavement monitoring have been developed, and the limited application sections have revealed exciting prospects [7,[17][18][19][20][21][22][23][24][25]. However, in the pavement structure, the naked optical FBG is difficult to directly install with the harsh pavement construction and service conditions because of the risk of optical fiber breakage.…”

“…However, in the pavement structure, the naked optical FBG is difficult to directly install with the harsh pavement construction and service conditions because of the risk of optical fiber breakage. erefore, reasonable encapsulation or packaging becomes a necessary process [17,20,[26][27][28]. Regardless of the encapsulation form used, there is a multi-stage strain-transfer process when the stress is transmitted, and the problem of strain loss exists [29][30][31].…”