A variable shape three-dimensional structure includes: an upper frame; a lower frame; and a longitudinal coupling member that couples the upper and lower frames. Each of the frames includes cross units and an end coupling portion. Each cross unit is formed by two rigid members crossing each other and pivotally coupled together. The end coupling portion pivotally couples the ends of the rigid members of the cross units. The longitudinal coupling member includes a bent unit comprising a first and second bent rigid members, and a bent portion coupling shaft. The first and second bent rigid members are bent in a V-shape. The bent portion coupling shaft pivotally couples the bent portions of the first and second bent rigid members. The upper end of the bent unit is coupled to the upper frame and the lower end of the bent unit is coupled to the lower frame.

A shape-morphing space frame (SMSF) utilizing the linear bistable compliant crank-slider mechanism (LBCCSM). The frame's initial shape is constructed from a single-layer grid of flexures, rigid links and LBCCSMs. The grid is bent into the space frame's initial cylindrical shape, which can morph because of the inclusion of LBCCSMs in its structure. The design parameters include the frame's initial height, its tessellation pattern (including the unit cell bistable elements' placement), its initial diameter, and the resulting desired shape. The method used in placing the unit cell bistable elements considers the principle stress trajectories. Two different examples of shape-morphing space frames are presented herein, each starting from a cylindrical-shell space frame and morphing, one to a hyperbolic-shell space frame and the other to a spherical-shell space frame, both morphing by applying moments, which shear the cylindrical shell, and forces, which change the cylinder's radius using Poisson's effect.

What is presented is a unit cell comprising a cellular geometry that comprises cell walls and cell edges arranged into a combination of a cubic cell geometry and a tetrahedral cell geometry arranged to have a coincident central vertex. The cubic cell geometry comprises three orthogonal cell faces that intersect at its central vertex. The tetrahedral cell geometry comprises an arrangement of eight tetrahedral cells that share its central vertex such that each tetrahedral cell shares three coincident edges with three other tetrahedral cells in a cubically symmetric arrangement. The tetrahedral cell geometry is combined with the cubic cell geometry such that all vertices of the tetrahedral cell geometry are coincident with the vertices of the cubic cell geometry.

What is presented is a unit cell comprising a cellular geometry that comprises cell walls and cell edges arranged into a combination of a cubic cell geometry and a tetrahedral cell geometry arranged to have a coincident central vertex. The cubic cell geometry comprises three orthogonal cell faces that intersect at its central vertex. The tetrahedral cell geometry comprises an arrangement of eight tetrahedral cells that share its central vertex such that each tetrahedral cell shares three coincident edges with three other tetrahedral cells in a cubically symmetric arrangement. The tetrahedral cell geometry is combined with the cubic cell geometry such that all vertices of the tetrahedral cell geometry are coincident with the vertices of the cubic cell geometry.

The invention concerns a method for installing a hatch (34) to a subsea structure (10) by connecting the hatch to the subsea structure by at least one hinge (20) having a first mounting portion (21), a second mounting portion (22), a flexible portion (23) interconnecting the first and second mounting portion allowing a pivot connection between the first and second mounting portion. The installation steps comprise •—inserting a protrusion (23) of the first mounting portion (21) into an installation hole arranged in the subsea structure (10), •—inserting a protrusion (24) of the second mounting portion (22) into an installation hole arranged in the hatch (34), thereby •—engaging the first mounting portion (21) of the hinge (20) for anchorage with the subsea structure (10) and engaging the second mounting portion (22) for anchorage with the hatch (34) thereby arranging for the hatch to pivot between a closed and an open position about a pivot axis provided by the flexible portion of the hinge. The invention also concerns a hinge and an assembly for subsea use.

The invention concerns a method for installing a hatch (34) to a subsea structure (10) by connecting the hatch to the subsea structure by at least one hinge (20) having a first mounting portion (21), a second mounting portion (22), a flexible portion (23) interconnecting the first and second mounting portion allowing a pivot connection between the first and second mounting portion. The installation steps comprise •—inserting a protrusion (23) of the first mounting portion (21) into an installation hole arranged in the subsea structure (10), •—inserting a protrusion (24) of the second mounting portion (22) into an installation hole arranged in the hatch (34), thereby •—engaging the first mounting portion (21) of the hinge (20) for anchorage with the subsea structure (10) and engaging the second mounting portion (22) for anchorage with the hatch (34) thereby arranging for the hatch to pivot between a closed and an open position about a pivot axis provided by the flexible portion of the hinge. The invention also concerns a hinge and an assembly for subsea use.

An assembly for integrating an elongate structural member is provided. The elongate structural member includes a first end portion, a second end portion, and an elongate mid-portion that extends between the first and the second end portions. The first end portion is within a first plane and the second end portion within a second plane, and the first and the second planes are offset and parallel to each other. The elongate mid-portion is sloped between the first and the second planes. each of the first and the second end portions defining therein a polygonal hole. Multiple elongate structural members may be used to assemble a lattice structure.

An assembly for integrating an elongate structural member is provided. The elongate structural member includes a first end portion, a second end portion, and an elongate mid-portion that extends between the first and the second end portions. The first end portion is within a first plane and the second end portion within a second plane, and the first and the second planes are offset and parallel to each other. The elongate mid-portion is sloped between the first and the second planes. each of the first and the second end portions defining therein a polygonal hole. Multiple elongate structural members may be used to assemble a lattice structure.

A lattice structure according to an embodiment of the invention comprises a plurality of struts integrally connected to one another at a plurality of nodes, wherein the plurality of struts are arranged into at least a first region comprising a first repeating strut arrangement, a second region comprising a second repeating strut arrangement, the first repeating strut arrangement being different to the second repeating strut arrangement, and a boundary region disposed between the first region and the second region, the boundary region comprising a plurality of struts configured to connect nodes in the first region to nodes in the second region, a strut arrangement in the boundary region being different to the first and second repeating strut arrangements. The first repeating strut arrangement and/or the second repeating strut arrangement may be configured based on a crystallographic lattice, including but not limited to the Bravais lattices. Such an arrangement of lattices can mimic the polygrain structure in crystals so as to enhance the strength and ductility of the lattice structure, using strengthening mechanisms analogous to those in crystalline alloys. Methods and apparatus for designing a lattice structure are also disclosed.

What is presented is a unit cell comprising a cellular geometry that comprises cell walls and cell edges arranged into a combination of a cubic cell geometry and a tetrahedral cell geometry arranged to have a coincident central vertex. The cubic cell geometry comprises three orthogonal cell faces that intersect at its central vertex. The tetrahedral cell geometry comprises an arrangement of eight tetrahedral cells that share its central vertex such that each tetrahedral cell shares three coincident edges with three other tetrahedral cells in a cubically symmetric arrangement. The tetrahedral cell geometry is combined with the cubic cell geometry such that all vertices of the tetrahedral cell geometry are coincident with the vertices of the cubic cell geometry.