EXPERTISE

A new dawn in the use of advanced composite materials

THE NEED

There exists in Industry a market for low cost, lightweight, stiff, high strength engineering tubes. ​Performance tubes/struts are used within satellites, aircraft, bridges, buildings, vehicles and process plants. They have many different applications, such as structural supports, actuators, robotic arms and manipulators, as load transferring links in high speed machinery and pipework systems .

The need to reduce the mass of structures has in recent years, led to considerable interest in the use of advanced composite materials (i.e. FRP’s, MMC’s and Ceramics) which possess a greater specific strength and stiffness than metals, and thus offer performance gains over traditional tubes in compression and flexure. However, members made from such special materials can present problems in the method of their attachment to the rest of the overall structure.

THE SOLUTION

The innovative Smart-Tube product meets this challenge by exploiting an elegant and simple design assembly concept, giving it distinct pricing and technical advantages over both conventional all-metallic, and advanced all composite tubes.

In order to improve on current lightweight strut technology, the Smart-Tube product offers increased buckling/flexure resistance by utilising the benefits of both metals and advanced composite materials but without connection and thermal mismatch problems. The Smart-Tube design is unique and is based on sound mechanical engineering principles and established materials and manufacturing techniques.

HOW?

The main feature of the Smart-Tube product is the way joint difficulties are overcome by utilising the most useful properties of the materials comprising the strut assembly: the high strength and stiffness to weight ratio of the advanced material, together with the ductility of metals. The degree of innovation lies in the unique way the advanced material is incorporated into, and worked by the tube assembly, without having to rely on either mechanical fastening or adhesive bonding, thus eliminating the major problem usually associated with the implementation of materials of this kind.

The tensile performance of the sleeved tube assembly is streamlined by the fact that only the inner metallic tube is directly supporting axial loads. The tensile strength of the tube is thus calculated ignoring the outer composite sleeve, whereas during compressive loading the presence of the outer composite sleeve is of significance: the composite contributes to resisting any tendency of the assembly to flex, thereby increasing the maximum compressive buckling load that the tube can sustain.

KEY BENEFITS

piggy

Low cost

strut

No composite-metal fasteners or adhesive joints

fire

Elimination of assembly thermal mismatch

compression

Bespoke tension/compression capacities

jigsaw

Simple assembly /
dis-assembly

hammer

Repairable and upgradeable

TO SUMMARISE

The Smart-Tube offers significant performance gains over tubes composed of traditional materials (with respect to specific strength and stiffness ie weight), and over tubes composed entirely of advanced materials (with respect to cost, simplicity, replaceability, and integrity of connections).

The Smart-Tube is novel on an international basis and has the potential to be exploited across a wide range of application industries including low cost spacecraft vehicle applications within the Access to Space market, civil and military aerospace, robotic arm and manipulator fields, high speed machinery, progressive civil engineering structures and plant process piping systems.