Method for making mechanical links

1. A method for making a mechanical multishear link, the multishear link capable of coupling a composite part between a metal wing-fitting element and a metal back-fitting element, comprising the steps of:

providing the multishear link with a plurality of subassemblies so that attachment of each shear assembly to another is via simple shear interfaces between the subassemblies;

defining each subassembly for each of the shear interfaces and describing a shear for each of the shear interfaces by a stiffness measure;

determining the shear interfaces by applying a Huth method calculation to each of the shears to provide a mechanical relationship at each of the shear interfaces creating a system of equations for a computer-assisted resolution; and

wherein coupling pins for coupling the composite part to the metal wing-fitting element and the metal back-fitting element at the shear interfaces are based on a result of the Huth method calculation.

2. The method according to claim 1 , further comprising sizing each area of the multishear link around the shear interfaces through an iterative process by adding material when the iterative process indicates too much stress and by removing material when the iterative process indicates low stress.

3. The method according to claim 2 , wherein the subassemblies are represented by sets of springs, with each spring representing the stiffness measure of a respective composite or metal materials.

4. The method according to claim 2 , wherein with the iterative process is performed by keeping constant a thickness of the composite part and designing the metal fitting element with a progressive thickness in order to equally distribute stress over each row of the pins.

5. The method according to claim 1 , wherein the multishear link is broken down into a set of mesh type Huth subsystems, and adjacent links are connected by a spring that represents the same material being used by two separate shear areas.

6. The method according to claim 1 , wherein the stiffness measures are calculated based on properties of respective composite or metal materials, geometry of the parts being used, and stress being placed on the multishear link.

7. The method according to claim 6 , wherein the stiffness measures are transferred to a transfer of stress system matrix, which is reversed to obtain stresses (fij) crossing over the multishear link.

8. The method according to claim 1 , wherein, each pin and each material is accounted for independently.

9. The method according to claim 1 , further comprising applying a fourth order multishear link with two composite blades, three metal blades, and three rows of pins, wherein the fourth order multishear link is broken down into a set of eight mesh type Huth subsystems.

10. The method according to claim 9 , further comprising representing the subsystems by sets of four springs, with each spring representing a stiffness of a given material and sizing the fourth order multishear link using the subsystem.

11. The method according to claim 1 , further comprising sizing the multishear link by calculating an exact stress at each location of the multishear link for each shear, based on material, module, and thickness at the each location.

12. The method according to claim 1 , wherein said multishear link comprises a fitting, a back-fitting and a splitter to provide an assembly having a double mechanical shear perpendicular to attachments of the multishear link.

13. The method according to claim 1 , wherein one or several splitters are inserted in the multishear link, rows of pins are provided in number and position according to an amount of shear stress expected at each attachment and wherein thickness of composite material is kept constant while thickness of the fitting element, back-fitting element and splitters is gradually increased for equally distributing stress on each row of pins.