Abstract: The present invention provides an apparatus for distributed pressure sensing. The apparatus comprises a series of Bragg gratings, a light guide incorporating the series of Bragg gratings and a plurality of moveable wall portions. The moveable wall portions are coupled to respective Bragg gratings so that the movement of one of the moveable wall portion causes a force on the respective Bragg grating resulting in a change in strain of the respective Bragg grating. The apparatus also comprises at least one rigid member that is attached at attachment regions between which a sensing region of at least one Bragg grating is defined. The rigid member is arranged so that a strain in the sensing region is not directly influenced by a change in strain of the light guide outside the sensing region.

Abstract: The present invention provides an apparatus for pressure sensing. The apparatus comprises a light guide, a Bragg grating incorporated into the light guide and a moveable wall portion. The moveable wall portion has opposite first and second sides and is being positioned so that a change in pressure at one of the sides relative to a pressure at the other side will move the moveable wall portion. The moveable wall portion is coupled to the Bragg grating so that the movement of the moveable wall portion causes a force on a side of the Bragg grating. The force has a component that is transversal to the Bragg grating and effects a change in strain of the Bragg grating and thereby a change in an optical period of the Bragg grating.

Abstract: The invention relates to blind rivets and to methods of joining therewith. The method of the invention is suitable for joining two or more workpieces with a blind rivet. The method includes the first step of positioning a blind rivet at a point of overlap of two or more workpieces, the blind rivet including a rivet body and a mandrel. The next step involves rotating the mandrel about a longitudinal axis thereof and contacting the mandrel with the overlapping workpieces, wherein the mandrel is rotated at a speed to cause plasticization of the overlapping workpieces. The method then involves causing the mandrel to penetrate through the plasticized overlapping workpieces and form an aperture therethrough. A further step of the method involves capturing a portion of the overlapping workpieces that is displaced upon the penetration of the mandrel and securing the rivet body within the aperture to join the overlapping workpieces. The invention also includes a workpiece penetrating and joining blind rivet.

Abstract: The present invention provides an optical device which comprises a light guide incorporating a Bragg grating. The apparatus also comprises a moveable wall portion which is coupled to the Bragg grating so that a movement of the wall portion causes a force that effects a change in strain of the Bragg grating and thereby effects a change in an optical period of the Bragg grating. A temperature related change in the optical period of the Bragg grating is reduced by a temperature related change in the force on the Bragg grating by the moveable wall portion.

Abstract: The present invention provides an apparatus for pressure sensing. The apparatus comprises a light guide, a Bragg grating incorporated into the light guide and a moveable wall portion. The moveable wall portion has opposite first and second sides and is being positioned so that a change in pressure at one of the sides relative to a pressure at the other side will move the moveable wall portion. The moveable wall portion is coupled to the Bragg grating so that the movement of the moveable wall portion causes a force on a side of the Bragg grating. The force has a component that is transversal to the Bragg grating and effects a change in strain of the Bragg grating and thereby a change in an optical period of the Bragg grating.

Abstract: The present invention provides an apparatus for distributed pressure sensing. The apparatus comprises a series of Bragg gratings, a light guide incorporating the series of Bragg gratings and a plurality of a moveable wall portion. The moveable wall portions have opposite first and second sides and each moveable wall portion is positioned so that a change in pressure at one of the sides relative to a pressure at the other side will move the moveable wall portion. The moveable wall portions are coupled to respective Bragg gratings so that the movement of one of the moveable wall portion causes a force on the respective Bragg grating resulting in a change in strain of the respective Bragg grating. The apparatus also comprises at least one rigid member that is attached at attachment regions between which a sensing region of at least one Bragg grating is defined.