Device and method for measuring sectional forces

Patent metadata

Field	Value
Publication number	US-9274015-B2
Application number	US-201414182854-A
Country	US
Kind code	B2
Filing date	Feb 18, 2014
Priority date	Feb 19, 2013
Publication date	Mar 1, 2016
Grant date	Mar 1, 2016

Abstract

A device and a method are disclosed for measuring sectional forces on a single-piece structural element in respect of a sectional plane by strain gauges, wherein a first and a second strain gauge of the plurality of strain gauges are arranged on a first outer wall, and a third and a fourth strain gauge are arranged on a second outer wall, with the result that, when the structural element is loaded with a first force, the change in length of the first and third strain gauges is opposite to the change in length of the second and fourth strain gauges, wherein the first outer wall and the second outer wall have, in the region of a cavity, at least three openings, which are separated from each other by webs, and wherein the first, second, third and fourth strain gauges are arranged on the webs.

First claim

The invention claimed is:

1. A device for measuring sectional forces on a single-piece structural element in respect of a sectional plane by a plurality of strain gauges,
wherein the structural element comprises a first and a second outer wall, which extend perpendicular to the sectional plane, extend in a mirror-symmetrical manner in relation to each other about a first mirror plane of symmetry and are connected by further outer walls, wherein the first mirror plane of symmetry extends perpendicular to the sectional plane,
wherein each strain gauge has at least one associated measurement direction as well as a nominal length and electrical resistance, and the electrical resistance of the strain gauge depends on the length of the strain gauge in the measurement direction,
wherein a first and a second strain gauge of the plurality of strain gauges are arranged on the first outer wall, and a third and a fourth strain gauge of the plurality of strain gauges are arranged on the second outer wall,
wherein the strain gauges are arranged such that, when the structural element is loaded with a first force acting parallel to the sectional plane and parallel to the first mirror plane of symmetry, the first and third strain gauges undergo an identically oriented change in length in the measurement direction, the second and fourth strain gauges undergo an identically oriented change in length in the measurement direction, and the change in length of the first and third strain gauges is opposite to the change in length of the second and fourth strain gauges,
wherein,
the structural element comprises a cavity,
the first outer wall comprises, in a region of the cavity, at least three openings, which are separated from each other by webs and connect the cavity to an exterior of the structural element, the second outer wall comprises, in a region of the cavity, at least three openings, which are separated from each other by webs and connect the cavity to an exterior of the structural element, and the openings and webs of the first outer wall are arranged in a mirror-symmetrical manner about the first mirror plane of symmetry in relation to the openings and webs of the second outer wall,
the first, second, third and fourth strain gauges are each arranged on one of the webs, and
the webs of each outer wall extend away from a common point.

2. The device according to claim 1 , wherein a fifth and a sixth strain gauge of the plurality of strain gauges are arranged on the first outer wall, and a seventh and an eighth strain gauge of the plurality of strain gauges are arranged on the second outer wall, in such a manner that, when the structural element is loaded with a torque acting perpendicular to the first force and parallel to the first mirror plane of symmetry, the fifth and seventh strain gauges undergo an identically oriented change in length in the measurement direction, the sixth and eighth strain gauges undergo an identically oriented change in length in the measurement direction, and the change in length of the fifth and seventh strain gauges is opposite to the change in length of the sixth and eighth strain gauges, and
wherein the fifth, sixth, seventh and eighth strain gauges are each arranged on one of the webs.

3. The device according to claim 2 , wherein the strain gauges are arranged such that, when the structural element is loaded with the first force, the fifth and eighth strain gauges undergo an identically oriented change in length in the measurement direction, the sixth and seventh strain gauges undergo an identically oriented change in length in the measurement direction, and the change in length of the fifth and eighth strain gauges is opposite to the change in length of the sixth and seventh strain gauges.

4. The device according to claim 1 , wherein the strain gauges are arranged such that, when the structural element is loaded with the torque, the first and fourth strain gauges undergo an identically oriented change in length in the measurement direction, the second and third strain gauges undergo an identically oriented change in length in the measurement direction, and the change in length of the first and fourth strain gauges is opposite to the change in length of the second and third strain gauges.

5. The device according to claim 1 , wherein the first outer wall comprises four openings, between which four webs extend, of which a first and a third web extend in a first direction, and a second and a fourth web extend in a second direction, and
wherein the second outer wall comprises four openings, between which four webs extend, of which a first and a third web extend in the first direction, and a second and a fourth web extend in the second direction.

6. The device according to claim 5 , wherein the first direction extends inclined at an angle of 30° to 60° in relation to the sectional plane, and
wherein the second direction extends inclined at an angle of −30° to −60° in relation to the sectional plane.

7. The device according to claim 5 , wherein the first direction and the second direction are inclined at opposite angles in relation to the sectional plane.

8. The device according to claim 1 , wherein the further outer walls comprise a third and a fourth outer wall, which extend in a mirror-symmetrical manner in relation to each other about a second mirror plane of symmetry and perpendicular to the sectional plane, wherein the second mirror plane of symmetry extends perpendicular to the first mirror plane of symmetry and perpendicular to the sectional plane,
wherein a ninth and a tenth strain gauge of the plurality of strain gauges are arranged on the third outer wall, and an eleventh and a twelfth strain gauge of the plurality of strain gauges are arranged on the fourth outer wall, in such a manner that, when the structural element is loaded with a second force acting parallel to the sectional plane and parallel to the second mirror plane of symmetry, the ninth and eleventh strain gauges undergo an identically oriented change in length in the measurement direction, the tenth and twelfth strain gauges undergo an identically oriented change in length in the measurement direction, and the change in length of the ninth and eleventh strain gauges is opposite to the change in length of the tenth and twelfth strain gauges,
wherein the third outer wall comprises, in the region of the cavity, at least three openings, which are separated from each other by webs and connect the cavity to the exterior of the structural element, the fourth outer wall comprises, in the region of the cavity, at least three openings, which are separated from each other by webs and connect the cavity to the exterior of the structural element, and the openings and webs of the third outer wall are arranged in a mirror-symmetrical manner about the second mirror plane of symmetry in relation to the openings and webs of the fourth outer wall,
the ninth, tenth, eleventh and twelfth strain gauges are each arranged on one of the webs formed by the third and fourth outer walls, and
the webs of the third and fourth outer walls each extend away from a common point.

9. The device according to claim 8 , wherein the strain gauges are arranged such that, when the structural element is loaded with the torque, the ninth and twelfth strain gauges undergo an identically oriented change in length in the measurement direction, the tenth and eleventh strain gauges undergo an identically oriented change in length in the measurement direction, and the change in length of the ninth and twelfth strain gauges is opposite to the change in length of the tenth and eleventh strain gauges.

10. The device according to claim 8 , wherein the third outer wall comprises fo

Assignees

• Airbus Operations Gmbh

Inventors

• Schlipf Bernhard
• Giese Matthias

Classifications

• G01L5/161 Primary

  using variations in ohmic resistance · CPC title

• G01L1/2287 Primary

  constructional details of the strain gauges (adjustable resistors H01C10/00) · CPC title

• G01L5/1627

  of strain gauges (using piezoresistors G01L5/162) · CPC title