Phone: +44 (0) 1425 655027 email: info@epsilonoptics.com

website: www.epsilonoptics.com

Surface Bonded Sensor Patches

Often the simplest way to install fibre-optic sensors on a composite structure is by surface bonding. It is also the only practical method of installing sensors on an existing structure and can equally be applied to metal and concrete structures.

Typically the sensors are prepared in the form of pre-cured composite patches. These patches can be made in a suitably clean and controlled environment and then delivered fully tested and ready to fit, complete with cabling and connectors. This has the significant advantage that the sensors are rugged and easy to handle in a typical composite production environment. Many patches can be linked together on a single optical fibre cable, making installation very quick with minimum disruption to other production activities. Several Fibre Bragg Gratings can be combined in a single patch, for example to form a strain rosette, or to include temperature

compensation. Patches can also be produced in custom shapes to conform accurately to the surface of the structure. Surface bonded patches are usually made from relatively lightweight, low-modulus laminate, typically 0.5mm thick. This helps to ensure that the shear stress through the bond is very low, leading to longer service life and more accurate strain measurement. Epsilon have developed a range of methods for bonding sensor patches to structures, depending on the required service life, service conditions, and the surface properties of the structure. We can supply sensors suitable for either Time Division Multiplexing or Wavelength

Division Multiplexing interrogation systems. Sensor patches are manufactured to order ensuring that they are optimised for your specific

application. The following examples give some idea of the typical design options.

Standard Type “A” strain sensing patch Compact Type “E” temperature sensing patch

Compact strain sensing patches 60 X 8mm with 1.8mm aerospace cable

Phone: +44 (0) 1425 655027 email: info@epsilonoptics.com

website: www.epsilonoptics.com

Extended multi-sensor patches These can be produced to custom shapes, as sensor rosettes and can include temperature sensors as required.

Custom sensor patch for a marine application • Conformal shape • Combined temperature and strain

sensing

• Waterproof armoured fibre optic tails.

Patches can also be manufactured for bonding to aerodynamic or hydrodynamic surfaces.

They have a maximum thickness of about 0.6mm and are designed to be extremely smooth to blend into the surface. If the patch is going to be over coated with paint or High Build we can add a brightly pigmented abrasion resistant coating to the patch in order to reduce the risk of damage due to sanding down.

Sensor patches can be supplied with a wide variety of connectors types including telecoms. aerospace and sub-sea. Typical cable options include:

• 1.8mm High temperature Aerospace cable

• 3mm PVC jacket, Kevlar armoured

• 6mm PU jacket, Military break-out cable

• 6mm PU jacket, stainless steel armoured