Lightweight support structure, method of producing a lightweight support structure, composite sandwich panel and method of producing a composite sandwich panel

1. A lightweight support structure ( 1 ) comprising:

a composite sandwich panel ( 5 ) comprising:

a first face sheet ( 10 );

a lightweight core ( 15 ) attached to the first face sheet ( 10 );

an optional second face sheet ( 20 ) attached to the lightweight core ( 15 ) opposite the first face sheet ( 10 ) when present; and

an essentially rotationally symmetric cut-out ( 30 ) extending through the first face sheet ( 10 ) and into said lightweight core ( 15 );

a rotationally symmetric insert ( 50 ) fitted into said cut-out ( 30 ) for at least one of load application and anchorage of components to the composite sandwich panel ( 5 ),

characterized in that:

the cut-out ( 30 ) comprises an essentially rotationally symmetric inner cut-out ( 31 ) and an essentially rotationally symmetric outer cut-out ( 32 ) arranged essentially concentric with respect to each other, providing for a support ( 40 ) there between; and

said support ( 40 ) comprises a core support ( 41 ) cut from said lightweight core ( 15 ) and a support face sheet disc ( 42 ) on top, cut from of said first face sheet ( 10 ).

2. A lightweight support structure ( 1 ) according to claim 1 ,

characterized in that said insert ( 50 ) comprises:

an inner insert ring ( 51 ) configured to be receivable within the inner cut-out ( 31 ) of the composite sandwich panel ( 5 );

an outer insert ring ( 52 ) configured to be receivable within the outer cut-out ( 32 ) of the composite sandwich panel ( 5 ),

wherein said outer insert ring ( 52 ) is arranged with respect to said inner insert ring ( 51 ) so as to provide an insert trench ( 54 ) there between for receiving the support ( 40 ) of the composite sandwich panel ( 5 );

an insert connecting portion ( 53 ) connecting said inner insert ring ( 51 ) with said outer insert ring ( 52 ), configured to be restable on the support face sheet disc ( 42 ) of the support ( 40 ); and

an insert receiving area ( 55 ) for receiving a fixture ( 100 ) for at least one of attaching and anchoring of components at least one of into and onto the composite sandwich panel ( 5 ).

3. A lightweight support structure ( 1 ) according to claim 2 , characterized in that an adhesive ( 56 ) is provided in said insert trench ( 54 ) and the insert ( 50 ) comprises at least one channel ( 57 ) extending from said trench ( 54 ) through the outer insert ring ( 52 ), configured such that upon fitting of the insert ( 50 ) into the cut-out ( 30 ) of the composite sandwich panel ( 5 ), the support face sheet disc ( 42 ) forces said adhesive ( 56 ) through said at least one channel ( 57 ).

4. Method of producing a lightweight support structure ( 1 ) according to claim 3 ,

characterized in that said inner cut-out ( 31 ) and outer cut-out ( 32 ) are self-cut into the composite sandwich panel ( 5 ) by rotation of the insert ( 50 ) around its symmetry axis, wherein the inner insert ring ( 51 ) and outer insert ring ( 52 ) of the insert ( 50 ) are at least partially provided with at least one of an abrasive coating and a saw-tooth geometry.

5. A lightweight support structure ( 1 ) according to claim 1 characterized in that the insert ( 50 ) is a self-cutting insert, its inner insert ring ( 51 ) and outer insert ring ( 52 ) being provided with at least one of an abrasive coating and a saw-tooth geometry configured such that—by rotation of the insert ( 50 ) around its symmetry axis—at least one of said inner cut-out ( 31 ) and said outer cut-out may be cut.

6. A lightweight support structure ( 1 ) according to claim 1 , characterized in that the insert ( 50 ) is fixed into the cut-out ( 30 ) of the composite sandwich panel ( 5 ) by at least one of: form-fitting, force-fitting, soldering, brazing, welding, and an adhesive.

7. A lightweight support structure ( 1 ) according to claim 1 , wherein the core support ( 41 ) is compressed so as to allow said insert ( 50 ) to lie flatly inside the composite sandwich panel ( 5 ).

8. A lightweight support structure ( 1 ) according to claim 1 , characterized in that said insert ( 50 ) comprises:

an inner insert ring ( 51 ) configured to be receivable within the inner cut-out ( 31 ) of the composite sandwich panel ( 5 );

an outer insert ring ( 52 ) configured to be receivable within the outer cut-out ( 32 ) of the composite sandwich panel ( 5 ),

wherein said outer insert ring ( 52 ) is arranged with respect to said inner insert ring ( 51 ) so as to provide an insert trench ( 54 ) there between for receiving the support ( 40 ) of the composite sandwich panel ( 5 ); and

an insert connecting portion ( 53 ) connecting said inner insert ring ( 51 ) with said outer insert ring ( 52 ), configured to be restable on the support face sheet disc ( 42 ) of the support ( 40 ).

9. Method of producing a lightweight support structure ( 1 ) comprising the steps:

providing a composite sandwich panel ( 5 ) comprising:

a first face sheet ( 10 ), and

a lightweight core ( 15 ) attached to the first face sheet ( 10 ),

cutting an essentially rotationally symmetric inner cut-out ( 31 ) and an essentially rotationally symmetric outer cut-out ( 32 ) into said composite sandwich panel ( 5 ) by cutting through the first face sheet ( 10 ) and into said lightweight core ( 15 ), wherein the inner cut-out ( 31 ) and the outer cut-out ( 32 ) are arranged essentially concentric with respect each other,

characterized by the steps of:

by cutting said inner cut-out ( 31 ) and outer cut-out ( 32 ), providing a support ( 40 ) inbetween, said support ( 40 ) comprising a core support ( 41 ) cut from said lightweight core ( 15 ) and a support face sheet disc ( 42 ) on top, cut from of said first face sheet ( 10 );

fitting a rotationally symmetric insert ( 50 ) into said cut-out ( 30 ) for at least one of load application and anchorage of components to the composite sandwich panel ( 5 ),

wherein said cut-out ( 30 ) is configured for receiving a rotationally symmetric insert ( 50 ) for at least one of load application and anchorage of components to the composite sandwich panel ( 5 ); and wherein said support ( 40 ) is configured for stabilizing said insert ( 50 ) within the composite sandwich panel ( 5 ).

10. Method of producing a lightweight support structure ( 1 ) according to claim 9 ,

characterized in that the step of fitting said insert ( 50 ) into said cut-out ( 30 ) comprises:

fitting an inner insert ring ( 51 ) of the insert ( 50 ) into the inner cut-out ( 31 ) of the composite sandwich panel ( 5 );

fitting an outer insert ring ( 52 ) of the insert ( 50 ) into the outer cut-out ( 32 ) of the composite sandwich panel ( 5 );

resting an insert connecting portion ( 53 ) connecting said inner insert ring ( 51 ) with said outer insert ring ( 52 ) on the support face sheet disc ( 42 ) of the support ( 40 ) wherein upon being fitted, the insert ( 50 ) being self-aligned with the cut-out ( 30 ).

11. Method of producing a lightweight support structure ( 1 ) according to claim 10 , characterized in that the step of fitting said insert ( 50 ) into said cut-out ( 30 ) further comprises the following steps:

a) compressing said core support ( 41 ) by means of said insert connecting portion ( 53 ) exercising pressure on the support face sheet disc ( 42 ), the core support ( 41 ) being compressed by a compression (Δ) equal to a thickness (D) of said insert connecting portion ( 53 );

b) measuring an unevenness (U) between a top surface of the insert ( 50 ) and a top surface of the first face sheet ( 10 );

c) increasing said a compression (Δ);

d) repeating steps a) to c) until said unevenness (U) is below a predetermined unevenness tolerance.

12. Method of producing a lightweight support structure ( 1 ) according to claim 10 , characterized in that the step of fitting said insert ( 50 ) into said cut-out ( 30 ) further comprises the following steps:

a) compressing said core support ( 41 ) by means of said insert connecting portion ( 53 ) exercising pressure on the support face sheet disc ( 42 ), the core support ( 41 ) being compressed by a compression (Δ) equal to a thickness (D) of said insert connecting portion ( 53 );

b) measuring an unevenness (U) between a top surface of the insert ( 50 ) and a top surface of the first face sheet ( 10 );

c) increasing said compression (Δ); and

d) repeating steps a) to c) until the insert ( 50 ) lies flatly inside said composite sandwich panel ( 5 ).

13. Method of producing a lightweight support structure ( 1 ) according to claim 9 ,

characterized in that said rotationally symmetric insert ( 50 ) is fixed into the cut-out ( 30 ) of the composite sandwich panel ( 5 ) by at least one of: form-fitting, force-fitting, soldering, brazing, welding, and an adhesive.

14. Method of producing a lightweight support structure ( 1 ) according to claim 9 ,

characterized in that said inner cut-out ( 31 ) and outer cut-out ( 32 ) are cut into the composite sandwich panel ( 5 ) by means of a cutter tool ( 70 ) comprising an inner cutting ring ( 71 ) and an outer cutter ring ( 72 ) corresponding respectively to said inner cut-out ( 31 ) and said outer cut-out ( 32 ).

15. Method of producing a lightweight support structure ( 1 ) according to claim 9 ,

characterized in that the step of fitting said insert ( 50 ) into said cut-out ( 30 ) comprises:

fitting an inner insert ring ( 51 ) of the insert ( 50 ) into the inner cut-out ( 31 ) of the composite sandwich panel ( 5 );

fitting an outer insert ring ( 52 ) of the insert ( 50 ) into the outer cut-out ( 32 ) of the composite sandwich panel ( 5 );

resting an insert connecting portion ( 53 ) connecting said inner insert ring ( 51 ) with said outer insert ring ( 52 ) on the support face sheet disc ( 42 ) of the support ( 40 ) wherein upon being fitted, the insert ( 50 ) is self-aligned with the cut-out ( 30 ) by one of a tapered conical section ( 51 . 5 ) of the inner insert ring ( 51 ) and a tapered conical section ( 52 . 5 ) of the outer insert ring ( 52 ).

16. A composite sandwich panel ( 5 ) comprising:

a first face sheet ( 10 );

a lightweight core ( 15 ) attached to said first face sheet ( 10 ); and

an optional second face sheet ( 20 ) attached to the lightweight core ( 15 ) opposite the first face sheet ( 10 ) when present;

wherein:

the composite sandwich panel ( 5 ) is provided with rotationally symmetric cut-out ( 30 ) extending through the first face sheet ( 10 ) and into said lightweight core ( 15 );

the insert cut-out ( 30 ) comprises a rotationally symmetric inner cut-out ( 31 ) and a rotationally symmetric outer cut-out ( 32 ) arranged concentric with respect to each other, providing for a support ( 40 ) inbetween, comprising a core support ( 41 ) cut from said lightweight core ( 15 ), and a support face sheet disc ( 42 ) cut from of said first face sheet ( 10 );

said cut-out ( 30 ) is configured for receiving a rotationally symmetric insert ( 50 ) for at least one of load application and anchorage of components to the composite sandwich panel ( 5 ); and

said support ( 40 ) is configured for stabilizing said insert ( 50 ) within the composite sandwich panel ( 5 ).

17. Method of producing a composite sandwich panel ( 5 ) comprising the steps:

providing a composite sandwich panel ( 5 ) comprising:

a first face sheet ( 10 );

a lightweight core ( 15 ) attached to the first face sheet ( 10 );

an optional second face sheet ( 20 ) attached to the lightweight core ( 15 ) opposite the first face sheet ( 10 ) when present;

cutting an essentially rotationally symmetric inner cut-out ( 31 ) and an essentially rotationally symmetric outer cut-out ( 32 ) into said composite sandwich panel ( 5 ) by cutting through the first face sheet ( 10 ) and into said lightweight core ( 15 ), wherein the inner cut-out ( 31 ) and the outer cut-out ( 32 ) are arranged essentially concentric with respect each other,

by cutting said inner cut-out ( 31 ) and outer cut-out ( 32 ), providing a support ( 40 ) inbetween, said support ( 40 ) comprising a core support ( 41 ) cut from said lightweight core ( 15 ), and a support face sheet disc ( 42 ) on top cut from of said first face sheet ( 10 );

shaping the inner cut out ( 31 ) and the outer cut-out ( 32 ) for receiving a rotationally symmetric insert ( 50 ) for at least one of load application and anchorage of components to the composite sandwich panel ( 5 ); and

shaping said support ( 40 ) for stabilizing said insert ( 50 ) when present within the composite sandwich panel ( 5 ).

18. Method of producing a composite sandwich panel ( 5 ) according to claim 17 , characterized in that said inner cut-out ( 31 ) and outer cut-out ( 32 ) are self-cut into the composite sandwich panel ( 5 ) by an inner insert ring ( 51 ) and an outer insert ring ( 52 ) of an insert ( 50 ) for at least one of load application and anchorage of components to the composite sandwich panel ( 5 ), by rotation of said insert ( 50 ) around its symmetry axis,

wherein at least one of said inner insert ring ( 51 ) and said outer insert ring ( 52 ) are provided with at least one of an abrasive coating and a saw-tooth geometry.

19. Method of producing a composite sandwich panel ( 5 ) according to claim 17 , characterized in that said inner cut-out ( 31 ) and outer cut-out ( 32 ) are cut into the composite sandwich panel ( 5 ) by means of a cutter tool ( 70 ) comprising an inner cutting ring ( 71 ) and an outer cutter ring ( 72 ) corresponding, respectively, to said inner cut-out ( 31 ) respectively and said outer cut-out ( 32 ).

20. The method of claim 17 , further comprising:

providing said rotationally symmetric insert ( 50 ), and

anchoring at least part of the insert ( 50 ) in at least one of the inner cut-out ( 31 ) and the outer cut-out ( 32 ) by at least one of form-fitting and force-fitting.