EP0031378B1 - Structural element, tetrahedral truss constructed therefrom and method of construction - Google Patents
Structural element, tetrahedral truss constructed therefrom and method of construction Download PDFInfo
- Publication number
- EP0031378B1 EP0031378B1 EP80901524A EP80901524A EP0031378B1 EP 0031378 B1 EP0031378 B1 EP 0031378B1 EP 80901524 A EP80901524 A EP 80901524A EP 80901524 A EP80901524 A EP 80901524A EP 0031378 B1 EP0031378 B1 EP 0031378B1
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- Prior art keywords
- hexagonal
- struts
- tetrahedral
- truss
- ring
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- E—FIXED CONSTRUCTIONS
- E04—BUILDING
- E04B—GENERAL BUILDING CONSTRUCTIONS; WALLS, e.g. PARTITIONS; ROOFS; FLOORS; CEILINGS; INSULATION OR OTHER PROTECTION OF BUILDINGS
- E04B1/00—Constructions in general; Structures which are not restricted either to walls, e.g. partitions, or floors or ceilings or roofs
- E04B1/18—Structures comprising elongated load-supporting parts, e.g. columns, girders, skeletons
-
- E—FIXED CONSTRUCTIONS
- E04—BUILDING
- E04B—GENERAL BUILDING CONSTRUCTIONS; WALLS, e.g. PARTITIONS; ROOFS; FLOORS; CEILINGS; INSULATION OR OTHER PROTECTION OF BUILDINGS
- E04B1/00—Constructions in general; Structures which are not restricted either to walls, e.g. partitions, or floors or ceilings or roofs
- E04B1/18—Structures comprising elongated load-supporting parts, e.g. columns, girders, skeletons
- E04B1/19—Three-dimensional framework structures
-
- E—FIXED CONSTRUCTIONS
- E04—BUILDING
- E04B—GENERAL BUILDING CONSTRUCTIONS; WALLS, e.g. PARTITIONS; ROOFS; FLOORS; CEILINGS; INSULATION OR OTHER PROTECTION OF BUILDINGS
- E04B1/00—Constructions in general; Structures which are not restricted either to walls, e.g. partitions, or floors or ceilings or roofs
- E04B1/18—Structures comprising elongated load-supporting parts, e.g. columns, girders, skeletons
- E04B1/19—Three-dimensional framework structures
- E04B1/1903—Connecting nodes specially adapted therefor
- E04B1/1906—Connecting nodes specially adapted therefor with central spherical, semispherical or polyhedral connecting element
-
- E—FIXED CONSTRUCTIONS
- E04—BUILDING
- E04B—GENERAL BUILDING CONSTRUCTIONS; WALLS, e.g. PARTITIONS; ROOFS; FLOORS; CEILINGS; INSULATION OR OTHER PROTECTION OF BUILDINGS
- E04B1/00—Constructions in general; Structures which are not restricted either to walls, e.g. partitions, or floors or ceilings or roofs
- E04B1/18—Structures comprising elongated load-supporting parts, e.g. columns, girders, skeletons
- E04B1/19—Three-dimensional framework structures
- E04B2001/1924—Struts specially adapted therefor
- E04B2001/1927—Struts specially adapted therefor of essentially circular cross section
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- E—FIXED CONSTRUCTIONS
- E04—BUILDING
- E04B—GENERAL BUILDING CONSTRUCTIONS; WALLS, e.g. PARTITIONS; ROOFS; FLOORS; CEILINGS; INSULATION OR OTHER PROTECTION OF BUILDINGS
- E04B1/00—Constructions in general; Structures which are not restricted either to walls, e.g. partitions, or floors or ceilings or roofs
- E04B1/18—Structures comprising elongated load-supporting parts, e.g. columns, girders, skeletons
- E04B1/19—Three-dimensional framework structures
- E04B2001/1957—Details of connections between nodes and struts
-
- E—FIXED CONSTRUCTIONS
- E04—BUILDING
- E04B—GENERAL BUILDING CONSTRUCTIONS; WALLS, e.g. PARTITIONS; ROOFS; FLOORS; CEILINGS; INSULATION OR OTHER PROTECTION OF BUILDINGS
- E04B1/00—Constructions in general; Structures which are not restricted either to walls, e.g. partitions, or floors or ceilings or roofs
- E04B1/18—Structures comprising elongated load-supporting parts, e.g. columns, girders, skeletons
- E04B1/19—Three-dimensional framework structures
- E04B2001/1957—Details of connections between nodes and struts
- E04B2001/1972—Welded or glued connection
-
- E—FIXED CONSTRUCTIONS
- E04—BUILDING
- E04B—GENERAL BUILDING CONSTRUCTIONS; WALLS, e.g. PARTITIONS; ROOFS; FLOORS; CEILINGS; INSULATION OR OTHER PROTECTION OF BUILDINGS
- E04B1/00—Constructions in general; Structures which are not restricted either to walls, e.g. partitions, or floors or ceilings or roofs
- E04B1/18—Structures comprising elongated load-supporting parts, e.g. columns, girders, skeletons
- E04B1/19—Three-dimensional framework structures
- E04B2001/1981—Three-dimensional framework structures characterised by the grid type of the outer planes of the framework
-
- E—FIXED CONSTRUCTIONS
- E04—BUILDING
- E04B—GENERAL BUILDING CONSTRUCTIONS; WALLS, e.g. PARTITIONS; ROOFS; FLOORS; CEILINGS; INSULATION OR OTHER PROTECTION OF BUILDINGS
- E04B1/00—Constructions in general; Structures which are not restricted either to walls, e.g. partitions, or floors or ceilings or roofs
- E04B1/18—Structures comprising elongated load-supporting parts, e.g. columns, girders, skeletons
- E04B1/19—Three-dimensional framework structures
- E04B2001/1981—Three-dimensional framework structures characterised by the grid type of the outer planes of the framework
- E04B2001/1984—Three-dimensional framework structures characterised by the grid type of the outer planes of the framework rectangular, e.g. square, grid
Definitions
- This invention relates generally to structural trusses and other articulated supporting structures and specifically to three-dimensional structural trusses, i.e. supporting structures whose primary load-bearing capacity is attributable to extension of the structure in three dimensions.
- a structural truss may generally be considered to be an open, skeletal assembly of struts joined at nodes to achieve a supporting structure of high load-bearing capacity relative to its weight, i.e. high specific structural strength.
- Fundamentally trusses are based on the geometric triangle to take advantage of the inherent rigidity of the skeletal-triangle in supporting a coplanar load.
- conventional trusses are essentially two dimensional (2D) (planar) structures, i.e. they are not freestanding.
- Three dimensional (3D) stability is achieved by providing lateral support, e.g. by cords or other cross-linking members between parallel trusses.
- Complex, quasi-3D trusses may be built up with a grid-like network of 2D truss members; however, such complex networks are not fundamentally 3D trusses, since the base member of the network is not repeated periodically in three dimensions.
- U.S. Patent No. 3,139,959 for "Construction Arrangement” issued July 7, 1964 to R. W. Kraft discloses a tetrahedral truss in a diamond cubic arrangement and in a distorted diamond cubic arrangement. Kraft further discloses linear and zig-zag ("W" shaped) construction elements for the trusses.
- U.S. Patent No. 3,333,349 for "Framework Molecular Orbital Model Assembly" issued August 1, 1967 to G. C. Brumlik discloses a model for representing the physical and geometric relationships of molecular and atomic orbitals, including a tetrahedral geometric relationship.
- the present invention provides a truss that is fundamentally periodic in three dimensions and therefore has three-dimensional stability without dependence on lateral stabilizing members or complex networking.
- the truss may be built up simply in regular fashion by "repeating" a fundamental unit in the three dimensions to the extent desired.
- the truss design continues to take advantage of the inherent rigidity of the basic skeletal triangle.
- the truss design achieves these advantages with maximum geometric efficiency, i.e. the minimum number of struts per node (four) that is required for stability of an articulated, periodic 3D structure.
- a three-dimensional tetrahedral truss in the pattern of cubic diamond characterized by:
- the truss may be a graded structure wherein the characteristic dimension of said skeletal-tetrahedral units varies layer-wise within said truss by an integer power of the fraction one-half (Fig. 12).
- the "characteristic dimension" is defined as the length of a side of the conceptual reference cube enclosing the tetrahedral unit.
- the invention also relates to a structural element for forming a three-dimensional, tetrahedral truss in the pattern of cubic diamond, characterized by:
- the invention also relates to a hexagonal structural element for constructing a three-dimensionally periodic skeletal tetrahedral truss in the pattern of cubic diamond, characterized by:
- the invention also relates to a method for constructing a three-dimensionally periodic, skeletal tetrahedral truss in the pattern of cubic diamond, characterized by the steps of:
- equilateral tetrahedron 10 (having equal faces) and its complementary skeletal-tetrahedron 12 are shown for definitional purposes.
- the equilateral tetrahedron may conceptually be thought of as a three-dimen- tional triangle, extending spatially the exceptional two-dimensional (planar) rigidity of the equilateral triangle.
- the skeletal-tetrahedron 12 may be thought of as consisting of four struts 14 joined at a node 16 and externally terminating at the four apexes respectively of the phantom reference tetrahedron 10 enclosing the skeletal assembly 12.
- the skeletal equilateral tetrahedron is the most geometrically stable articulated structure of line elements, having maximum symmetry (i.e. cubic), with the minimum number of struts per node (i.e. four) for a stable 3D articulated structure, while utilizing the rigidity of the basic triangle.
- a skeletal-tetrahedral unit 20 is shown wherein four struts 14 are received and joined onto four protrusions 23 respectively of a male-node 22, the assembly forming a skeletal equilateral tetrahedron.
- the struts and the nodes may optionally be hollow to minimize the weight of the unit, as shown for example in the male-node 22 by channels 24 within protrusions 23.
- 3A and 3B another skeletal-tetrahedral unit 30 is shown wherein four struts 14 are received into the four receptacles 33 of a female-node 32.
- Joining of the struts to the node may be by conventional means such as fusion joining (welding or brazing), mechanical joining (pins, clamps, and the like), or adhesive joining. Further, the unit may be formed as a continuous (jointless) element.
- the struts may be tubes or rods of oriented or pyrolytic graphite, a material having exceptional specific stiffness and low thermal expansion, and the nodes of a structural alu- minimum alloy having exceptionally toughness properties.
- the composite structure would have ultra-stiff struts (though of low though- ness) joined at high toughness nodes (plastically deformable upon the unit being excessively loaded).
- a phantom reference cube 40 of characteristic dimension "a” which as shown in Fig. 5 may be inserted into any of the eight cubic (sub-cell) positions of a phantom unit-cell 50 having characteristic dimension "2a".
- Four tetrahedral units 42 of like orientation are joined in alternating sub-cells 40 of the unit-cell 50, as shown in the exploded view of Fig. 6, to form the completed unit-cell 50, as shown in Fig. 7.
- This unit-cell may be repeated simply in any or all of the three dimensions to the extent desired, thereby obtaining a three-dimensionally periodic, tetrahedral truss.
- a fundamental bilateral-element 80 is shown having equal sides 82 and having an included angle 84 of about 109° 28', i.e. the angle between the struts of a skeletal equilateral tetrahedron.
- Optional features may be included to facilitate joining of a plurality of bilateral-elements, such as a structural pin 86 at one extremity and a complementary, close fitting receptacle 88 at the other extremity.
- the bilateral-elements may be made of conventional alloys, preferably those having high specific strength.
- FIG. 9A, 9B and 9C an exploded plan view, a plan view, and a side view are shown respectively of the triplanar-ring of Fig. 9.
- Each of the six bilateral-elements 80 is comprised of two straight side members connected at one end with an included angle therebetween of about 109° 28'.
- the bilateral-elements are arranged and connected to form ring 90 which delimits three pairs of facing, opposite elements such as 80 and 80', the cross-opposing sides, such as 82 and 82', of each pair being substantially parallel with each other and coplanar with one of the three characteristic planes of the ring.
- these triplanar-ring elements are exceptionally rigid under torsional loading. Joining may be secured by conventional fusion joining means or by adhesive joining means and the like.
- the hexagonal triplanar-ring of the invention is equivalently comprised of three pairs of equilateral strut members.
- Each pair of struts connect at one end to form interconnecting struts having an included angle therebetween of about 109° 28', and the three strut pairs are cooperatively arranged and connected into the ring.
- the mating strut ends thereof connect to form included angles therebetween of about 109° 28', and the resultant ring thereby delimits three pairs of parallel struts, the struts being coplanar with one of the three characteristic planes of the ring.
- Figs. 10 and 10A Four hexagonal triplanar-rings 90 are assembled into the closed skeletal-tetrahedral unit 100 as shown in Figs. 10 and 10A.
- Rigid joining of the unit may be by conventional mechanical means such as bolting, riveting, strapping, clamping, and the like or by conventional fusion joining.
- Fig. 7 The sixteen struts 44 making up the unit-cell 50 may be classified into two categories, i.e. corner struts and face struts.
- a corner strut has its external extremity terminating at a corner of the unit-cell. There are four of these corner struts 72 per unit-cell.
- a face strut has its external extremity terminating at a face of the unit-cell. There are twelve of these face struts 74 per unit-cell.
- the closed skeletal-tetrahedral unit 100 (Fig. 10) is of the pattern formed by the face struts of the cubic-diamond unit-cell 50 shown in Fig. 7.
- the closed tetrahedral unit 100 is preferred over the articulated tetrahedral unit 42 (Fig. 7) because points of stress concentration at strut-node joints are eliminated.
- a plurality of tetrahedral units 100 are co- operatively stacked (nested), as shown in Figs. 11 and 1 1A, to build up a tetrahedral truss 110.
- Rigid joining of neighboring tetrahedral units 100 may be accomplished by conventional means as discussed above. Note that a skeletal equilateral tetrahedron is completed at each juncture of neighboring units 100, thereby obtaining the cubic-diamond structure of the first node of the invention (Fig. 7).
- tetrahedral truss 1 10 of Fig. 11 is shown with further three-dimensional extension 123, i.e. repeated units 10. Additionally the simplicity is shown with which a graded truss 120 (e.g. having layers 122 and 123) may be built up. By varying the characteristic dimension of adjacent layers by an integer power of the fraction one-half, adjacent layers may be co- operatively stacked, as shown in the exploded perspective view of Fig. 12A. Thus, a tetrahedral truss may readily be constructed having a relatively "smooth" (close) supporting surface with an open structure in the interior portions of the truss.
- the hexagonal triplanar-ring 90 (Fig. 9), having the advantage that a jointless element is obtained.
- the ring may be mechanically shaped from a linear member of a structural alloy and fusion joined to close the ring, with perhaps subsequent heat treatment, e.g. precipitation hardening.
- the material may be a fiber reinforced composite.
- the ring may be constructed of oriented graphite according to conventional methods, e.g. by pyrolyzing a shaped winding or organic fiber under orienting tension.
- FIG. 13 an optional feature is shown for promoting the rigidity at the juncture between neighboring closed skeletal-tetrahedral units 100 (Fig. 11).
- a cross-sectional cut is taken through such a junc4ure.
- the hexagonal triplanar-rings 90 may be of hexagonal cross-section, rather than of circular cross-section as shown in the preceding drawings.
- a linear, close fiting filler rod 132 also of hexagonal cross-section, is inserted into the void between neighboring rings 90.
- the members are shown as being hollow to minimize weight.
Abstract
Description
- This invention relates generally to structural trusses and other articulated supporting structures and specifically to three-dimensional structural trusses, i.e. supporting structures whose primary load-bearing capacity is attributable to extension of the structure in three dimensions.
- A structural truss may generally be considered to be an open, skeletal assembly of struts joined at nodes to achieve a supporting structure of high load-bearing capacity relative to its weight, i.e. high specific structural strength. Fundamentally trusses are based on the geometric triangle to take advantage of the inherent rigidity of the skeletal-triangle in supporting a coplanar load. However, being based on the two dimensional triangle, conventional trusses are essentially two dimensional (2D) (planar) structures, i.e. they are not freestanding. Three dimensional (3D) stability is achieved by providing lateral support, e.g. by cords or other cross-linking members between parallel trusses. Complex, quasi-3D trusses may be built up with a grid-like network of 2D truss members; however, such complex networks are not fundamentally 3D trusses, since the base member of the network is not repeated periodically in three dimensions.
- U.S. Patent No. 3,139,959 for "Construction Arrangement" issued July 7, 1964 to R. W. Kraft discloses a tetrahedral truss in a diamond cubic arrangement and in a distorted diamond cubic arrangement. Kraft further discloses linear and zig-zag ("W" shaped) construction elements for the trusses. U.S. Patent No. 3,333,349 for "Framework Molecular Orbital Model Assembly" issued August 1, 1967 to G. C. Brumlik discloses a model for representing the physical and geometric relationships of molecular and atomic orbitals, including a tetrahedral geometric relationship.
- The present invention provides a truss that is fundamentally periodic in three dimensions and therefore has three-dimensional stability without dependence on lateral stabilizing members or complex networking. As a result of this periodicity, the truss may be built up simply in regular fashion by "repeating" a fundamental unit in the three dimensions to the extent desired. Further, the truss design continues to take advantage of the inherent rigidity of the basic skeletal triangle. Still further, the truss design achieves these advantages with maximum geometric efficiency, i.e. the minimum number of struts per node (four) that is required for stability of an articulated, periodic 3D structure.
- According to the present invention there is provided a three-dimensional tetrahedral truss in the pattern of cubic diamond, characterized by:
- (a) a three-dimentionally periodic, skeletal array of an interconnected plurality of closed skeletal tetrahedral units;
- (b) each of said closed tetrahedral units comprising four hexagonal triplanar rings arranged and connected along cooperatively mating strut sides thereof to form said unit; and
- (c) each of said hexagonal rings comprising six equilateral struts the intersections of which form equal included angles therebetween of about 109° 28', each ring thereby delimiting three pairs of parallel struts with each of said struts being coplanar with one of said three planes.
- The truss may be a graded structure wherein the characteristic dimension of said skeletal-tetrahedral units varies layer-wise within said truss by an integer power of the fraction one-half (Fig. 12). The "characteristic dimension" is defined as the length of a side of the conceptual reference cube enclosing the tetrahedral unit.
- The invention also relates to a structural element for forming a three-dimensional, tetrahedral truss in the pattern of cubic diamond, characterized by:
- (a) a closed skeletal tetrahedral unit (100);
- (b) said tetrahedral unit comprising four hexagonal triplanar rings (90) arranged and connected along co-operatively mating strut sides thereof to form said unit;
- (c) each of said hexagonal rings (90) comprising six equilateral struts the intersections of which form equal included angles (84) therebetween of about 109° 28', each ring thereby delimiting three pairs of parallel struts with each of said struts being coplanar with one of said three planes; and
- (d) each ring (90) having strut sides adapted to co-operatively mate along the lengths thereof with the strut sides of adjacently located and similarly configured hexagonal triplanar rings.
- The invention also relates to a hexagonal structural element for constructing a three-dimensionally periodic skeletal tetrahedral truss in the pattern of cubic diamond, characterized by:
- (a) six equilateral struts arranged and connected to form a hexagonal triplanar ring (90) the intersecting struts of which form equal included angles therebetween of about 109° 28';
- (b) said hexagonal ring (90) thereby delimiting three pairs of parallel struts, each of said struts being coplanar with one of said three planes; and
- (c) said ring (90) having strut sides adapted to co-operatively mate along the lengths thereof with the strut sides of adjacently located and similarly configured hexagonal triplanar rings to form a closed skeletal tetrahedral unit (100) of said tetrahedral truss.
- The invention also relates to a method for constructing a three-dimensionally periodic, skeletal tetrahedral truss in the pattern of cubic diamond, characterized by the steps of:
- (a) adjacently locating four hexagonal triplanar rings (90) to form a closed skeletal tetrahedral unit (100), each of said hexagonal rings comprising six equilateral struts the intersections of which form equal included angles therebetween of about 109° 28', each ring (90) thereby delimiting three pairs of parallel struts, and each of said struts being coplanar with one or said three planes;
- (b) connecting said hexagonal rings (90) to one another along co-operatively mating struts thereof; and
- (c) interconnecting a plurality of said closed tetrahedral units (100) along co-operatively mating strut sides thereof to form said tetrahedral truss.
- Further details are given below with reference to the drawings wherein:
- Figs. 1 and 1A show respectively an equilateral tetrahedron and its complementary skeletal-tetrahedron.
- Figs. 2, 2A and 2B show respectively a skeletal-tetrahedral unit, its component struts being received onto a male-node, and the male-node.
- Figs. 3, 3A and 3B show respectively another skeletal-tetrahedral unit, its component struts being received in a female-node, and the female-node.
- Fig. 4 shows a skeletal-tetrahedral unit enclosed in a conceptual reference cube of characteristic dimension "a".
- Fig. 5 shows the placement of a skeletal-tetrahedral unit in a unit-cell of characteristic dimension "2a".
- Figs. 6 and 7 show respectively placement and joining of four skeletal-tetrahedral units into the pattern of cubic-diamond.
- Fig. 8 begins a sequence of drawings and shows a bilateral-element having equal sides about an included-angle of about 109° 28'.
- Figs. 9, 9A, 9B and 9C show respectively a hexagonal triplanar-ring element in perspective, an exploded plan view of its assembly from six bilateral-elements, a plan view, and a side view.
- Figs. 10 and 10A show respectively a closed skeletal-tetrahedral unit and its assembly from four hexagonal triplanar-rings.
- Figs. 11 and 11 A show respectively a. perspective view and an exploded view of three closed skeletal-tetrahedral units stacked in cooperative fashion.
- Figs. 12 and 12A show respectively a perspective view and an exploded view of a graded truss built up from a plurality of closed skeletal-tetrahedral units and having layers of different characteristic dimensions.
- Fig. 13 shows an optional cross-sectional configuration at the juncture of adjacent, closed tetrahedral units.
- Figs. 2 to 7 relate to embodiments of skeletal-tetrahedral units found in the prior art.
- Referring specifically to the drawings, in Figs. 1 and 1A an equilateral tetrahedron 10 (having equal faces) and its complementary skeletal-
tetrahedron 12 are shown for definitional purposes. The equilateral tetrahedron may conceptually be thought of as a three-dimen- tional triangle, extending spatially the exceptional two-dimensional (planar) rigidity of the equilateral triangle. The skeletal-tetrahedron 12 may be thought of as consisting of fourstruts 14 joined at anode 16 and externally terminating at the four apexes respectively of thephantom reference tetrahedron 10 enclosing theskeletal assembly 12. The skeletal equilateral tetrahedron is the most geometrically stable articulated structure of line elements, having maximum symmetry (i.e. cubic), with the minimum number of struts per node (i.e. four) for a stable 3D articulated structure, while utilizing the rigidity of the basic triangle. - In Figs. 2, 2A and 2B a skeletal-
tetrahedral unit 20 is shown wherein fourstruts 14 are received and joined onto fourprotrusions 23 respectively of a male-node 22, the assembly forming a skeletal equilateral tetrahedron. The struts and the nodes may optionally be hollow to minimize the weight of the unit, as shown for example in the male-node 22 bychannels 24 withinprotrusions 23. In Figs. 3, 3A and 3B another skeletal-tetrahedral unit 30 is shown wherein fourstruts 14 are received into the fourreceptacles 33 of a female-node 32. The latter arrangement is preferred due to the increased resistance to bending loads at the joint between a strut and the node. Joining of the struts to the node may be by conventional means such as fusion joining (welding or brazing), mechanical joining (pins, clamps, and the like), or adhesive joining. Further, the unit may be formed as a continuous (jointless) element. - Conventional structural alloys, preferably those having high specific strength, may be used to construct the units. However, it is preferred to utilize complementary materials to achieve a composite with a blend of exceptional individual material properties. For example, the struts may be tubes or rods of oriented or pyrolytic graphite, a material having exceptional specific stiffness and low thermal expansion, and the nodes of a structural alu- minimum alloy having exceptionally toughness properties. Thus, the composite structure would have ultra-stiff struts (though of low though- ness) joined at high toughness nodes (plastically deformable upon the unit being excessively loaded).
- In Fig. 4, an articulated skeletal-
tetrahedral unit 42 oftruss 44 andnode 46 is shown enclosed in aphantom reference cube 40 of characteristic dimension "a", which as shown in Fig. 5 may be inserted into any of the eight cubic (sub-cell) positions of a phantom unit-cell 50 having characteristic dimension "2a". Reference is made to these phantom volumes only to facilitate description of the invention as they do not comprise tangible structure. Fourtetrahedral units 42 of like orientation are joined inalternating sub-cells 40 of the unit-cell 50, as shown in the exploded view of Fig. 6, to form the completed unit-cell 50, as shown in Fig. 7. This unit-cell may be repeated simply in any or all of the three dimensions to the extent desired, thereby obtaining a three-dimensionally periodic, tetrahedral truss. - An embodiment of the tetrahedral truss of the present invention and its method of construction is shown in Figs. 8 to 12. In Fig. 8, a fundamental bilateral-
element 80 is shown havingequal sides 82 and having an includedangle 84 of about 109° 28', i.e. the angle between the struts of a skeletal equilateral tetrahedron. Optional features may be included to facilitate joining of a plurality of bilateral-elements, such as astructural pin 86 at one extremity and a complementary, closefitting receptacle 88 at the other extremity. The bilateral-elements may be made of conventional alloys, preferably those having high specific strength. - Six bilateral-
elements 80 are assembled into the hexagonal triplanar-ring 90 as shown in Fig. 9. In Figs. 9A, 9B and 9C an exploded plan view, a plan view, and a side view are shown respectively of the triplanar-ring of Fig. 9. Each of the six bilateral-elements 80 is comprised of two straight side members connected at one end with an included angle therebetween of about 109° 28'. The bilateral-elements are arranged and connected to formring 90 which delimits three pairs of facing, opposite elements such as 80 and 80', the cross-opposing sides, such as 82 and 82', of each pair being substantially parallel with each other and coplanar with one of the three characteristic planes of the ring. It is noted that these triplanar-ring elements are exceptionally rigid under torsional loading. Joining may be secured by conventional fusion joining means or by adhesive joining means and the like. - As shown in Figs. 7, 9, 9A, 9B and 9C the hexagonal triplanar-ring of the invention is equivalently comprised of three pairs of equilateral strut members. Each pair of struts connect at one end to form interconnecting struts having an included angle therebetween of about 109° 28', and the three strut pairs are cooperatively arranged and connected into the ring. The mating strut ends thereof connect to form included angles therebetween of about 109° 28', and the resultant ring thereby delimits three pairs of parallel struts, the struts being coplanar with one of the three characteristic planes of the ring.
- Four hexagonal triplanar-
rings 90 are assembled into the closed skeletal-tetrahedral unit 100 as shown in Figs. 10 and 10A. Rigid joining of the unit may be by conventional mechanical means such as bolting, riveting, strapping, clamping, and the like or by conventional fusion joining. To clarify the derivation of the unit and to emphasize that it is in fact a skeletal-tetrahedral structure, reference is again made to Fig. 7. The sixteen struts 44 making up the unit-cell 50 may be classified into two categories, i.e. corner struts and face struts. A corner strut has its external extremity terminating at a corner of the unit-cell. There are four of these corner struts 72 per unit-cell. A face strut has its external extremity terminating at a face of the unit-cell. There are twelve of these face struts 74 per unit-cell. The closed skeletal-tetrahedral unit 100 (Fig. 10) is of the pattern formed by the face struts of the cubic-diamond unit-cell 50 shown in Fig. 7. The closedtetrahedral unit 100 is preferred over the articulated tetrahedral unit 42 (Fig. 7) because points of stress concentration at strut-node joints are eliminated. - A plurality of
tetrahedral units 100 are co- operatively stacked (nested), as shown in Figs. 11 and 1 1A, to build up atetrahedral truss 110. Rigid joining of neighboringtetrahedral units 100 may be accomplished by conventional means as discussed above. Note that a skeletal equilateral tetrahedron is completed at each juncture of neighboringunits 100, thereby obtaining the cubic-diamond structure of the first node of the invention (Fig. 7). - In Fig. 12, the
tetrahedral truss 1 10 of Fig. 11 is shown with further three-dimensional extension 123, i.e. repeatedunits 10. Additionally the simplicity is shown with which a graded truss 120 (e.g. having layers 122 and 123) may be built up. By varying the characteristic dimension of adjacent layers by an integer power of the fraction one-half, adjacent layers may be co- operatively stacked, as shown in the exploded perspective view of Fig. 12A. Thus, a tetrahedral truss may readily be constructed having a relatively "smooth" (close) supporting surface with an open structure in the interior portions of the truss. - There are alternative methods for forming the hexagonal triplanar-ring 90 (Fig. 9), having the advantage that a jointless element is obtained. For example, the ring may be mechanically shaped from a linear member of a structural alloy and fusion joined to close the ring, with perhaps subsequent heat treatment, e.g. precipitation hardening. As another alternative, the material may be a fiber reinforced composite. As a further alternative, the ring may be constructed of oriented graphite according to conventional methods, e.g. by pyrolyzing a shaped winding or organic fiber under orienting tension.
- In Fig. 13, an optional feature is shown for promoting the rigidity at the juncture between neighboring closed skeletal-tetrahedral units 100 (Fig. 11). A cross-sectional cut is taken through such a junc4ure. As shown, the hexagonal triplanar-
rings 90 may be of hexagonal cross-section, rather than of circular cross-section as shown in the preceding drawings. A linear, closefiting filler rod 132, also of hexagonal cross-section, is inserted into the void between neighboring rings 90. The members are shown as being hollow to minimize weight. - Although the present invention has been described in conjunction with preferred embodiments, it is to be understood that modifications and variations may be utilized without departing from the scope of the invention as claimed.
Claims (14)
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
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US5449779A | 1979-07-03 | 1979-07-03 | |
US54497 | 1979-07-03 |
Publications (3)
Publication Number | Publication Date |
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EP0031378A1 EP0031378A1 (en) | 1981-07-08 |
EP0031378A4 EP0031378A4 (en) | 1981-07-16 |
EP0031378B1 true EP0031378B1 (en) | 1984-03-28 |
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Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP80901524A Expired EP0031378B1 (en) | 1979-07-03 | 1981-01-26 | Structural element, tetrahedral truss constructed therefrom and method of construction |
Country Status (5)
Country | Link |
---|---|
EP (1) | EP0031378B1 (en) |
CA (1) | CA1157219A (en) |
DE (1) | DE3067251D1 (en) |
IT (1) | IT1193541B (en) |
WO (1) | WO1981000130A1 (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2020068194A3 (en) * | 2018-06-15 | 2020-05-28 | Ogre Skin Designs, Llc | Structures, systems, and methods for energy distribution |
Families Citing this family (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2556757B1 (en) * | 1983-12-14 | 1987-04-10 | Bouygues Sa | THREE-DIMENSIONAL CONCRETE CARRIER MESH AND PROCESS FOR MAKING THIS MESH |
DE3913474A1 (en) * | 1989-04-24 | 1990-10-25 | Siemens Ag | PHOTOTHERMAL EXAMINATION METHOD, DEVICE FOR IMPLEMENTING IT AND USE OF THE METHOD |
CA2180638C (en) * | 1994-11-14 | 2007-07-31 | Charles R. Owens | Structural frame |
US5615528A (en) * | 1994-11-14 | 1997-04-01 | Owens; Charles R. | Stress steering structure |
GB2490767A (en) * | 2012-04-16 | 2012-11-14 | Alexander Owen David Lorimer | Structural geometric framework |
CN102912852B (en) * | 2012-10-18 | 2014-12-24 | 东南大学 | Regular tetrahedral symmetrical deployable mechanism unit |
US20190055729A1 (en) * | 2017-08-15 | 2019-02-21 | Jon Dietz | Unitary hubs for domes or spheres |
CN113581398B (en) * | 2021-09-07 | 2022-08-16 | 哈尔滨工业大学(深圳) | But rapid Assembly's bull stick node |
Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3333349A (en) * | 1964-04-01 | 1967-08-01 | George C Brumlik | Framework molecular orbital model assembly |
Family Cites Families (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3148539A (en) * | 1959-01-20 | 1964-09-15 | Charles E Cook | Ideal spherical hinge for analytical framework |
US3139959A (en) * | 1961-06-12 | 1964-07-07 | United Aircraft Corp | Construction arrangement |
US3354591A (en) * | 1964-12-07 | 1967-11-28 | Fuller Richard Buckminster | Octahedral building truss |
DE1810434C3 (en) * | 1968-11-22 | 1975-06-19 | Richard Dipl.-Ing. 8000 Muenchen Dietrich | Building structure |
US3722153A (en) * | 1970-05-04 | 1973-03-27 | Zomeworks Corp | Structural system |
US3707813A (en) * | 1971-06-30 | 1973-01-02 | J Mudgett | Modular structure |
US3853418A (en) * | 1973-02-28 | 1974-12-10 | Celanese Corp | Safety support for use adjacent a vehicular trafficway |
DE2316141C3 (en) * | 1973-03-29 | 1979-08-16 | Conrad Roland 1000 Berlin Lehmann | Spatial network for climbing |
US4207715A (en) * | 1978-09-14 | 1980-06-17 | Kitrick Christopher J | Tensegrity module structure and method of interconnecting the modules |
-
1980
- 1980-06-25 DE DE8080901524T patent/DE3067251D1/en not_active Expired
- 1980-06-25 WO PCT/US1980/000809 patent/WO1981000130A1/en active IP Right Grant
- 1980-07-02 IT IT23203/80A patent/IT1193541B/en active
- 1980-07-02 CA CA000355252A patent/CA1157219A/en not_active Expired
-
1981
- 1981-01-26 EP EP80901524A patent/EP0031378B1/en not_active Expired
Patent Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3333349A (en) * | 1964-04-01 | 1967-08-01 | George C Brumlik | Framework molecular orbital model assembly |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2020068194A3 (en) * | 2018-06-15 | 2020-05-28 | Ogre Skin Designs, Llc | Structures, systems, and methods for energy distribution |
US11371576B2 (en) | 2018-06-15 | 2022-06-28 | Ogre Skin Designs, Llc | Structures, systems, and methods for energy distribution |
US11898619B2 (en) | 2018-06-15 | 2024-02-13 | Ogre Skin Designs, Llc | Structures, systems, and methods for energy distribution |
Also Published As
Publication number | Publication date |
---|---|
DE3067251D1 (en) | 1984-05-03 |
EP0031378A1 (en) | 1981-07-08 |
IT8023203A0 (en) | 1980-07-02 |
EP0031378A4 (en) | 1981-07-16 |
IT8023203A1 (en) | 1982-01-02 |
IT1193541B (en) | 1988-07-08 |
WO1981000130A1 (en) | 1981-01-22 |
CA1157219A (en) | 1983-11-22 |
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