Composite laminate and load-introduction component for a load-introduction joint

Patent metadata

Field	Value
Publication number	US-11274688-B2
Application number	US-201916359480-A
Country	US
Kind code	B2
Filing date	Mar 20, 2019
Priority date	Oct 8, 2014
Publication date	Mar 15, 2022
Grant date	Mar 15, 2022

Abstract

A composite laminate for connection to at least one attachment component in a load-introduction joint, said composite laminate comprising an opening that is adapted to receive a load-introduction component of said load-introduction joint, wherein a prefailure indication element is provided in the region of said opening, said prefailure indication element being modifiable by said load-introduction component in a prefailure mode of said load-introduction joint for indication of an impending function-affecting failure of said composite laminate. The invention is further related to a corresponding load-introduction component.

First claim

What is claimed is:

1. A composite laminate for connection to an attachment component in a load-introduction joint, the composite laminate comprising:
an opening that comprises an inner peripheral sidewall and extends between opposing sides of the composite laminate, the opening being adapted to receive a load-introduction component of the load-introduction joint therethrough such that the load-introduction component comes at least partly in direct contact with the inner peripheral sidewall of the opening in a normal operation mode of the load-introduction joint; and
a prefailure indication element that is arranged inside the opening on a portion of the inner peripheral sidewall of the opening, the prefailure indication element being modifiable by the load-introduction component in a prefailure mode of the load-introduction joint from a first condition in the normal operation mode of the load-introduction joint to a second condition in the prefailure mode for indication of an impending function-affecting failure of the composite laminate, wherein the prefailure indication element is compressed or partially destructed by the load-introduction component of the load-introduction joint in the prefailure mode from the first condition in the normal operation mode to the second condition in the prefailure mode, wherein the prefailure indication element comprises at least one prefailure indication projection that is arranged on the inner peripheral sidewall of the opening, wherein the at least one prefailure indication projection is arc-shaped, and wherein the at least one arc-shaped prefailure indication projection is arranged between a first and a second arc-shaped axial recess provided inside the opening on the inner peripheral sidewall of the opening.

2. The composite laminate of claim 1 , wherein the opening comprises a first opening diameter when the prefailure indication element is in the first condition in the normal operation mode and a second opening diameter when the prefailure indication element is in the second condition in the prefailure mode, and wherein the first opening diameter is no more than 50% of the second opening diameter.

3. The composite laminate of claim 1 , wherein the prefailure indication element is provided inside the opening at least on a peripheral side of the opening that is arranged diametrically opposed to a main load direction of a main load that is applicable to the composite laminate in operation.

4. A load-introduction joint, comprising:
an attachment component;
a load-introduction component; and
a composite laminate that is mounted to the attachment component via the load-introduction component, the composite laminate comprising:
an opening that comprises an inner peripheral sidewall and extends between opposing sides of the composite laminate, wherein the opening accommodates at least partly the load-introduction component such that the load-introduction component is at least partly in direct contact with the inner peripheral sidewall of the opening in a normal operation mode of the load-introduction joint; and
a prefailure indication element that is arranged inside the opening on a portion of the inner peripheral sidewall of the opening, the prefailure indication element being modifiable by the load-introduction component in a prefailure mode of the load-introduction joint from a first condition in the normal operation mode of the load-introduction joint to a second condition in the prefailure mode for indication of an impending function-affecting failure of the composite laminate, wherein the prefailure indication element of the composite laminate is compressible or partially destructible by the load-introduction component in the prefailure mode from the first condition in the normal operation mode to the second condition in the prefailure mode and comprises at least one prefailure indication projection that is arranged on the inner peripheral sidewall of the opening of the composite laminate, wherein the at least one prefailure indication projection is arc-shaped, and wherein the at least one arc-shaped prefailure indication projection is arranged between a first and a second arc-shaped axial recess provided inside the opening of the composite laminate on the inner peripheral sidewall of the opening.

5. The load-introduction joint of claim 4 , wherein the opening of the composite laminate comprises a first opening diameter when the prefailure indication element is in the first condition in the normal operation mode and a second opening diameter when the prefailure indication element is in the second condition in the prefailure mode, and wherein the first opening diameter is no more than 50% of the second opening diameter.

6. The load-introduction joint of claim 4 , wherein the prefailure indication element of the composite laminate is provided inside the opening of the composite laminate at least on a peripheral side of the opening that is arranged diametrically opposed to a main load direction of a main load that is applicable to the composite laminate in operation.

7. A composite laminate for connection to at least one attachment component in a load-introduction joint, the composite laminate comprising:
an opening extending between opposing sides of the composite laminate and having a central axis thereof, the opening being adapted to receive a load-introduction component of the load-introduction joint; and
a prefailure indication projection defined in and extending along a portion of a peripheral sidewall of the opening, the prefailure indication projection having a first position and a second position, the projection being compressed or partially destructed by the load-introduction component when in the second position relative to when in the first position for indication of an impending function-affecting failure of the composite laminate,
wherein the prefailure indication projection comprises a projection defined between axially opposing first and second recesses that extend radially away from the central axis into the peripheral sidewall of the opening, and
wherein the prefailure indication projection extends radially toward the central axis between the first and second recesses.

8. The composite laminate according to claim 7 , wherein the prefailure indication projection has a thickness of 50% to 90% of a thickness of the composite laminate adjacent to the load-introduction component when the prefailure indication projection is in the first position.

9. The composite laminate according to claim 7 , wherein the prefailure indication projection is arranged diametrically opposed to a main load direction of a main load that is applicable to the composite laminate in operation.

10. The composite laminate according to claim 7 , wherein the prefailure indication projection is formed to reduce a given contact surface between the load-introduction component and the composite laminate when the prefailure indication projection is in the first position.

11. The composite laminate according to claim 7 , wherein the at least one prefailure indication projection is an arc-shaped prefailure indication projection that extends adjacent to the load-introduction component about less than an entire circumference of the load-introduction component when the arc-shaped prefailure indication projection is in the first position.

12. The composite laminate according to claim 11 , wherein the at least one arc-shaped prefailure indication projection extends in a thickness direction parallel to the central axis of the opening between the first and second recesses.

Assignees

• Airbus Helicopters Deutschland GmbH

Inventors

• Buesing Moritz

Classifications

• B64C27/473

  Constructional features · CPC title

• B64C27/48

  Root attachment to rotor head · CPC title

• F16B5/02

  by means of fastening members using screw-thread ({F16B5/0004 takes precedence}; construction of screw-threaded connections F16B25/00 - F16B39/00) · CPC title

• B29C66/43

  Joining a relatively small portion of the surface of said articles (B29C66/45 takes precedence) · CPC title

• F16B31/02

  for indicating {the attainment of a particular tensile load} or limiting tensile load {(apparatus for, or method of, determining value of torque or twisting moment for tightening a nut or other member similarly stressed G01L5/24)} · CPC title