Patent for Sale:

Cost-effective Nodal Construction System for Load-bearing Lattice Structures    

Assembly is fast and simple; it does not require any tools, bolts, gusset plates, welding, or glue. The bars or tubes become self-clamped upon assembly to maximize buckling resistance.

Overview

The patent pending technology consists of a node part and a simple general method for lattice structures construction. Upon assembly, the bars or tubes become quickly self-clamped at the nodal positions without sacrificing structural performance, thanks to the ingenious holes and grooves in the node part.

The EP and PCT applications have just obtained positive search reports (EESR and ISR+WO), indicating that the technology is new, inventive, and with industrial applications.

It provides the following strategic and cost-effective innovations:
-- Versatile assembly; tools, bolts, gusset plates, glue, or welding are not required. Ideal for fast and simple submarine or in-orbit construction.
-- Using hollow cross-sections for both metal and composite lattice designs. Any kind of bar or profile can be employed.
-- Full utilization of the outstanding strength and stiffness of unidirectional carbon fibre composites.

These innovations may achieve up to 4 fold mass reductions in the anisogrid structures of modern rocket interstages or up to 2 fold in lattice towers for wind power generation.

Primary Application of the Technology

The offered nodal technology would reduce costs and improve performance in the following fields:

Construction:
-- Tower structures for wind power generation, electricity transport, and telecommunications industries.
-- Columns, pillars, trusses, 2D/3D frames, bridges, domes, barrel vaults, etc., in permanent architecture.
-- Portable towers, scaffolds, scenarios, tents, sheds, or bridges in ephemeral architecture.
-- Anti-seismic and vibrations/shock attenuation.

Aerospace:
-- Primary structures for space launcher systems or aircrafts, e.g. payload adapters and dispensers, interstages, satellite central tubes, shear webs, stiff instrument benches, payload fairings, fuselages, trusses, etc.
-- In-orbit assembly of truss structures.
-- Zero thermal expansion structures, e.g. for orbital telescopes or trusses.

Maritime:
-- Underwater assembly for offshore structures, e.g. oil or wind energy platforms.
-- Hull reinforcements and lighter structures for ships and submarines.

Automotive:
-- Chassis frame structures and equipment frames for automotive industry.

Other fields:
-- Ready-to-assemble furniture
-- Constructive toys

The Problem Solved by the Technology

-- Jointing two or more non-parallel bars: The invention provides a cost-effective solution to the general engineering or constructive problem of jointing two or more non-parallel bars at the nodal positions of lattice structures. This problem has been traditionally tackled by bolting or welding, using or not using gusset plates. Although such methods are reliable and well developed, the material, time, and labour costs represents a high fraction of the total. Bolting requires periodic tension checks, gusset plates must be cut for the specific application, and welding is comparatively expensive and does not perform well for thick sections. In most cases, specific tooling and operations at workshop are required. Besides these traditional methods, there exist node-based technologies for the general fabrication of lattice structures. However, although the assembly is faster than with traditional methods, these nodal connectors usually require bolts and bar ends modifications, which leads to overall cost increases and reduces structural efficiency.

-- Using hollow cross-sections for both metal and carbon/glass fibre lattice designs: For example, most of the lightweight and high-load bearing structures for space launch systems (e.g. cryo-tanks, interstages or payload adaptors) rely on a lattice system of rib stiffeners frequently closed by a skin, e.g. the iso-, ortho-, or anisogrid design concepts. Hollow ribs are generally preferred to solid ribs because their higher specific stiffness increases the buckling resistance of these wide and thin-walled cylinders. Unfortunately, the available fabrication methods are only capable of producing solid ribs. For example, the metallic structures are generally machined from flat or curved aluminium panels that are then stir welded into cylinders (e.g. cryo-tanks of Falcon or SLS launchers), and the carbon fibre structures are competitively fabricated by filament winding (e.g. interstages and payload adaptors of Proton-M).

-- Full utilization of the outstanding strength and stiffness of unidirectional carbon/glass fibre composites: The main drawback that prevents taking full advantage of the outstanding properties of unidirectional carbon fibre composites in lattice structures is the material built-up at nodal positions. In such locations, two or more ribs running in different directions cross each other one on top of another and lead to material built-up. The important deviation from the optimal fibre/resin proportion at these positions dramatically reduces the effective strength and thus the overall lattice weight performance. Apparently, the solution would be cutting the fibres running in one direction at crossing positions to avoid material built-up, but this also reduces the strength.

-- In-orbit or submarine assembly of lattice structures: Another remarkable motivation for the technology is the improvement of the in-orbit or submarine assembly of lattice structures. It is well known that the simple task of using screws, bolts, nuts, or locks to fasten the structural members in Space or submarine trusses may be cumbersome and time consuming because of the space or diving suit gloves thickness and pressurization.

-- Assembly of zero thermal expansion lattices: Structures that do not change their length as temperature changes are highly desirable or even mandatory for dimension critical applications, like measurement equipment frames and orbital trusses.

How the Technology Solves the Problem

Lattice structures are generally the most weight-efficient choice for load-bearing structures since their bars are axially loaded in compression or tension, where their mechanical properties are most favourable. The contributions of bending and shearing, with worst properties, are usually much lower.

Assembly is fast and simple; it does not require any tools, bolts, gusset plates, welding, or glue. The bars or tubes become self-clamped upon assembly to maximize efficiency, thanks to the ingenious arrangement of node holes and grooves. The node is manufactured economically by standard methods.

Besides solving the aforementioned problems, the technology leads to important savings, mainly provided by the outstanding performance improvement and drastic reductions in weight, assembly time, labour, and infrastructure. For example, rough estimations predict around 50% savings in total lattice towers cost upon development and adoption of the technology.

Furthermore, adoption of the technology is easy since the node part is simple and can be manufactured economically by standard methods, e.g. casting, machining, injection moulding, or 3D printing. Node geometry can be optimized to achieve the best performance for each application domain, thanks to the offered knowhow and optimization software.

Competitive Advantage

-- Jointing two or more non-parallel bars: The new system considerably reduces construction times and labour, and preserves full structural performance using nothing but integral nodes and bars with unmodified ends. Furthermore, bar ends can be considered as clamped upon structure assembly, rotations and traslations are tightly fixed in the node holes without any tool. This achieves lighter designs than other nodal methods where the ends are modelled as pinned.

-- Using hollow cross-sections for both metal and carbon/glass fibre lattice designs: By contrast to machining and filament winding fabrication methods, the offered technology easily enables using the stiffer hollow ribs to increase buckling resistance and provide a cost-effective solution for reducing weight in primary launcher structures, which represents an important fraction of the total empty mass.

-- Full utilization of the outstanding strength and stiffness of unidirectional carbon/glass fibre composites: The offered construction system does not reduce the strength at nodal positions of carbon/glass fibre lattice structures because the node part effectively reinforces the cut-weakened joint and the ribs become self-clamped at crossings positions without losing structural performance and with very little weight penalty. Furthermore, the ribs can be efficiently fabricated by pultrusion, one of the most cost-effective and highest quality production methods for unidirectional composites.

-- In-orbit or submarine assembly of lattice structures: The technology is a cost-effective solution to facilitate the zero gravity or submarine assembly of lattice structures that does not require screws, bolts, welding or any kind of bonding agent for coupling the structural members.

-- Assembly of zero thermal expansion lattices: Zero longitudinal thermal expansion lattices can be easily fabricated by selecting the adequate node geometry and the bars materials.

Comments on Deal Structure, Potential Terms and Restrictions

Besides obtaining license/acquisition agreements, this technology offer also soughts finding entities interested in the knowhow and the technology for its development or even for academic collaborations. Venture building is also an interesting option for developing and commercializing the technology.

Additional Information

The applications domain is so broad because the invention provides a cost-effective and weight-efficient solution to the general problem of jointing two or more non-parallel bars at the nodal positions of lattice structures. To illustrate the huge economic potential of the offered technology for Earth and Space application domains, some figures are given:

General estimations predict around 50% savings in the total cost of lattice towers for electricity transport or wind energy production markets upon development and adoption of the offered technology. For example, between 2014 and 2035 around $56B/year will be invested in new electricity transport networks. Taking into account that the majority of the overhead electricity transmission lines are suspended by lattice towers, which represent between 10 and 50% of the total cost, nodal technology potential savings would range between $2B and $10B per year. In addition, around $13B from the $98B/year spent in wind energy in 2015 correspond to new towers. In this market, the annual potential savings would reach $7B. Furthermore, both growing markets will benefit from the upcoming drastic restructuring of the global energy system towards renewable alternatives.

Every kilogram sent to space using the modern launch vehicles (e.g. Ariane 5, Atlas V, Proton-M, Soyuz 2, or Falcon 9) costs around $5K for LEO and $20K for GEO. Thus, improving the weight efficiency and reducing the fabrication costs of the load-bearing lattice structures in modern space launcher systems is crucial for the sustainable development of Space industry.