Cost-effective nodal construction system for load-bearing lattice structures

Ref-Nr:

Lattice structure example

Technology abstract

A simple node and the assembly method to build 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 efficiency thanks to the ingenious arrangement of node holes and grooves. The node is manufactured economically by standard methods.

 

Technology Description

The offered technology consists of a node part and a simple method to assembly lattice structures. 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 knowhow behind the offer includes design equations and in-house software to obtain the geometry of the node parts for the efficient fabrication of, for example, cylindrical lattice shells or geodesic domes.
 
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. 
 
This aerospace-native experimental technology allows the efficient manufacture of primary lattice structures in modern space launch systems (e.g. payload adaptors, interstages, satellite central tubes, or cryo-tanks). For example, up to 4-fold mass reductions are expected in interstages of heavy load rockets.
 
In addition, the absence of tooling and the minimal manipulation requirements for assembly provides an ideal technique for in-orbit of lattice structures like those forming the International Space Station. Furthermore, zero longitudinal thermal expansion lattices can be easily fabricated by selecting the adequate node geometry and the bars materials.
 
The number of Earth applications is almost unlimited since lattice structures are extensively used for their economy and outstanding performance in architecture and engineering fields.

Innovations & Advantages

The technology provides the following strategic and cost-effective innovations for lattice structures construction:

  • Using hollow cross-sections for both metal and composite lattice designs. Any kind of bar or profile can be employed (Figure 3).
  • Full utilization of the outstanding strength and stiffness of unidirectional carbon fibre composites. 
  • Versatile assembly; tools, bolts, gusset plates, glue, or welding are not required. Ideal for fast and simple in-orbit (or submarine) construction.

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

Current and Potential Domains of Application

The lattice structures that can be efficiently fabricated with the offered nodal technology would reduce costs and improve performance in the following domains:
In Space:

  • Payload adapters and dispensers, launcher interstages and skirts, satellite central tubes, booms and shear webs, stiff instrument benches, payload fairings, trusses, etc. for space launcher systems.
  • In-orbit assembly of lattice or truss structures.
  • Zero thermal expansion structures, e.g. for orbital telescopes.

On Earth:

  • Lattice tower structures for wind power generation, electricity transport, and telecommunications industries.
  • Columns, pillars, trusses, space frames, bridges, domes, barrel vaults, etc., in common permanent architecture.
  • Portable towers, scaffolds, scenarios, tents, sheds, or bridges in ephemeral architecture, for civil and military applications.
  • Chassis frame structures and equipment frames for automotive industry.
  • Fuselages and panels for aircraft industry.
  • Hull reinforcements and lighter structures for ships and submarines in maritime and offshore industries.
  • Underwater assembly of lattice structures, e.g. oilrigs.
  • Ready-to-assemble furniture, like IKEA´s shelving, chairs, tables.
  • Constructive toys, like Mecano or Lego.
  • Zero thermal expansion structures, e.g. for telescopes or measurement equipment.