Device for determining strains on fiber composite components
AssigneeHottinger Baldwin Messtechnik GmbH
InventorsKarl-Heinz Haase, Carsten Hecker, Sebastian Klein, Sigmund Glaser
Life of this patent
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Abstract
In an apparatus for determining loads on fiber composite components (1), especially of vehicle and aircraft parts, strain gages (3) are integrated in the components (1) for determining strains. The strain gages (3) are connected with an evaluating apparatus (4), for monitoring and determining loads that tend to cause damage. The strain gages (3) are preferably integrated into the fiber composite component (1) such that the measuring grids (5) thereof are laid between individual fiber layers (2) and are guided out of the component (1) ready for connection via special connecting pins (8) to the associated evaluating apparatus (4) via loose cable connections (12).
Claims16
An arrangement for determining loads on a fiber composite component, comprising:
- a fiber composite component including plural fiber layers comprising a fiber composite material;
- and
- at least one strain sensor unit, which strain sensor unit comprises a foil strain gage including a measuring grid covered with insulating layers on both opposite sides of said measuring grid, and which strain sensor unit further comprises electrical connecting pins electrically conductively connected to and extending perpendicularly from said measuring grid;
- wherein:
- said at least one strain sensor unit is respectively integrated into said fiber composite component in that said strain gage is sandwiched between at least one of said fiber layers on a first side of said strain gage and at least one of said fiber layers on a second side of said strain gage opposite said first side, and said connecting pins extend perpendicularly through and protrude outwardly from said at least one fiber layer on at least one of said sides of said strain gage so that respective contact portions of said connecting pins are externally accessible for making electrical contact therewith outside of said fiber layers of said fiber composite component.
A sensor element for determining strains in a fiber composite component, comprising a foil strain gage with a measuring grid, arranged between a carrier layer and an upper cover layer, connecting pins extending perpendicularly to the measuring grid and serving as electrical connection points, and strain relief elements formed of a material of the measuring grid respectively connected between ends of the measuring grid and the connecting pins, wherein the upper cover layer is formed of a same material as the carrier layer, and wherein the strain relief elements are adapted to relieve material strains from a fiber composite material of the fiber composite component so as to be adapted to prevent falsification of a resistance value measurement of the measuring grid by a strain-varied resistance influence of an electrical supply connection through the connecting pins and the strain relief elements to the measuring grid.
A sensor element for determining strains in a fiber composite component, comprising a foil strain gage with a measuring grid, arranged between a carrier layer and an upper cover layer, and connecting pins extending perpendicularly to the measuring grid and serving as electrical connection points, wherein the upper cover layer is formed of a same material as the carrier layer, and wherein outer surfaces of the carrier layer and of the upper cover layer are roughened by irradiation to be adapted to improve an adhesion of the outer surfaces with respect to fiber layers of the fiber composite component.
A method of producing an arrangement for determining loads on a fiber composite component, comprising the steps:
- a) laying at least one fiber layer comprising fiber material into a mold;
- b) providing a polymeric material in or on said at least one fiber layer;
- c) placing onto said at least one fiber layer, at least one sensor unit that comprises a foil strain gage including a measuring grid and that further comprises connecting pins electrically conductively connected to and extending perpendicularly from said foil strain gage;
- d) covering said measuring grid respectively of said at least one sensor unit with at least one further fiber layer comprising fiber material such that said connecting pins protrude outwardly above said at least one further fiber layer;
- e) providing a peel-off film on said at least one further fiber layer;
- f) arranging a stamping pad of soft porous material above said peel-off film so as to receive respective outwardly protruding portions of said connecting pins;
- g) pressing a layered stack including said stamping pad, said peel-off film, said at least one further fiber layer, said at least one sensor unit, said polymeric material, and said at least one fiber layer against said mold, wherein said pressing is achieved by a vacuum process or a pressure process, so as to form a solidified or rigidified fiber composite component having said foil strain gage integrated therein and having portions of said connecting pins protruding outwardly therefrom;
- and
- h) removing said stamping pad.
Dependencies are inferred from the claim text.