cgb MacroComb: Highly rigid sandwiched honeycomb panels

CGB MacroComb are highly rigid CFC sandwich panels with plane surfaces and extremely light-weight hexagonal comb structures of carbon inside. They are ideally suited for spanning large areas.

Hexagonal combs: the ideal form designed by nature

Nature has found a nearly perfect shape for rigid structures: the honeycomb with its hexagonal cavities. Of all possible connected cell-structure the honeycomb displays the smallest ratio of wall-material to volume and thus enables highly-stressable structures. Upon load tension is distributed through the comb walls and not punctually through the body.

CGB MacroComb – modular concept of carbon

CGB pursues a variable and modular design concept: two types of panels may be freely positioned and finally connected to each other by holohedrally gluing the comb surfaces and the edges. This ensures maintaining as great stability as possible - even at mountings between MacroComb panels. Computationally 80 % of mechanical performance of the panel can be achieved even if point-loads on seams. Combs and cover panels are manufactured in wrapping method with load-optimizes fibre orientation. Further optimisation of stability can be achieved by foaming in pack of the comb cells.

3-point bending test of the ITKE regarding loading capacity

The ITKE (Institut für Tragkonstruktionen und Konstruktives Entwerfen) of the TU Stuttgart has examined CGB's CFRP-combs in a 3-point bending test regarding bearing strengths and obtained outstanding results:

Configuration of the comb structure:

• Length: 146cm
• Width: 107.5cm
• Height: 25cm
• Width across flats: 30.0cm
• Wall thickness top panel: 2mm
• Wall thickness combs: 2x1mm

By the way, such comb structures have a weight of only 15kg/m².

The test results display shear-force capabilities of 66.5kN, equivalent to 6,6 tons on that surface. The chargeable shear force without consideration of safety factors amounted to 30.93kN/m. For the tested comb structure this means that failure occurs at a surface load of more than 6.6 tons.

Equivalent to the load-case of a single-span girder, such as a pedestrian bridge with an assumed traffic load of 5kN/m² this calculates to a maximum span of 6.30 meters under consideration of the safety factors on the effect side and material side.

Application of CGB MacroComb

CGB MacroComb is in consequence an ideal high-tensile and light-weight CFRP-sandwich-panel. With its comb-structure it can be used among others in the following fields:

• Aerospace and astronautics
• Ship-building
• Vehicle construction and superstructures
• Building industry
• Stage and exhibition stand construction
• Hoisting technology
• Manufacture of reservoirs, tanks and containers