Orthotropic sandwich structure

Abstract

The present invention relates to an orthotropic sandwich structure (1) having different bending rigidities, the orthotropic sandwich structure (1) comprises a first membrane (21) and a second membrane (22) spaced apart by a distance H, and a shear structure (3) consisting of a plurality of shear elements (4) connecting them, each having a generatrix (G) of curve length L. The first and second ends (I1, I2) of the generatrix are positioned at a first distance d1 from the first membrane (21) and a distance d2 from the second membrane (22), respectively. According to the present invention, the generatrix (G) has a curve length L of at least 1.25*(H-(d1+d2)), and the straight lines (D) passing through the orthogonal projections (J1, J2) on the membranes (21, 22) at the ends (I1, I2) form an angle (B) of up to 45° with the direction (ZZ') perpendicular to the intermediate surface (Sm) of the shear structure (3).

Claims

1. An orthotropic sandwich structure (1) comprising a first membrane (21), a second membrane (22), and a shear structure (3) connecting the first and second membranes (21, 22), The orthotropic sandwich structure (1) has an intermediate surface (Sm) that is equidistant from the first and second films (21, 22), The shear structure (3) is composed of a plurality of shear elements (4) distributed in a first direction (XX') tangential to the intermediate surface (Sm), Each of the shear elements (4) has a section (40) that is perpendicular to the intermediate plane (Sm) and has a generatrix (G) that extends between the first and second ends (I1, I2) in some plane (XZ) including a first direction (XX'), and is not perpendicular to the intermediate plane (Sm). The aforementioned busbar (G) has a curve length L measured between the first and second ends (I1, I2), The first and second ends (I1, I2) each have a first orthogonal projection (J1) on the first film (21) located at a distance d1 from the first end (I1), and a second orthogonal projection (J2) on the second film (22) located at a distance d2 from the second end (I2). The first and second orthogonal projections (J1, J2) are separated by a distance H. An orthotropic sandwich structure (1) characterized in that the generatrix (G) of the section (40) of the shear element (4) has a curve length L of at least 1.25*(H - (d1 + d2)), and the straight lines (D) passing through the first and second orthogonal projections (J1, J2), respectively, form an angle (B) of up to 45° with a third direction (ZZ') perpendicular to the intermediate surface (Sm).

2. The orthogonal anisotropic sandwich structure (1) according to claim 1, wherein the distance d1 between the first end (I1) and the first orthogonal projection (J1) is a maximum of 0.5 times the distance H between the first and second orthogonal projections (J1, J2).

3. The orthogonal anisotropic sandwich structure (1) according to claim 1 or 2, wherein the distance d1 between the first end (I1) and the first orthogonal projection (J1) is 0.

4. The orthogonal anisotropic sandwich structure (1) according to any one of claims 1 to 3, wherein the distance d2 between the second end (I2) and the second orthogonal projection (J2) is up to 0.5 times the distance H between the first and second orthogonal projections (J1, J2).

5. The orthogonal anisotropic sandwich structure (1) according to any one of claims 1 to 4, wherein the distance d2 between the second end (I2) and the second orthogonal projection (J2) is 0.

6. The orthogonal anisotropic sandwich structure (1) according to any one of claims 1 to 5, wherein the tangent (T1) at the first end (I1) to the generatrix (G) forms an angle (A1) of at least 45° with the third direction (ZZ') perpendicular to the intermediate surface (Sm).

7. The orthogonal anisotropic sandwich structure (1) according to any one of claims 1 to 6, wherein the tangent (T2) at the second end (I2) to the generatrix (G) forms an angle (A2) of at least 45° with the third direction (ZZ') perpendicular to the intermediate surface (Sm).

8. The orthogonal anisotropic sandwich structure (1) according to any one of claims 1 to 7, wherein the generatrix (G) of each section (40) of the shear element (4) has a shape in which the curvature direction is reversed once.

9. The orthotropic sandwich structure (1) according to any one of claims 1 to 8, wherein each section (40) of the shear element (4) has a non-uniform thickness E0.

10. The orthogonal anisotropic sandwich structure (1) according to any one of claims 1 to 9, wherein the shear elements (4) are dispersed at a constant pitch in the first direction (XX').

11. The orthogonal anisotropic sandwich structure (1) according to any one of claims 1 to 10, wherein each of the shear elements (4) of the plurality of shear elements is made of a material having a tensile modulus of at least 20 MPa, preferably at least 30 MPa, at a 4% elongation.

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