JEC COMPOSITES MAGAZINE - Issue #86 - January/February 2014 - 52

additive manufacturing
file format to convey precise material content information
between the CAD system and the printing machines [3] .
To make the products even lighter, stronger and more
competitive, the industry needs a more accurate, realistic
and reliable prediction of the strength and fatigue life
of composites in the design and manufacturing process.
Among the available methods, micromechanics-based
stress and fatigue analysis of fibre-reinforced composites
is a very efficient way to estimate structural stiffness,
strength and fatigue life under real loading conditions and
to study the effects of fibre content and layering direction
on the final products.

as an additive manufacturing technique to build largescale composite structures [16] . Cellular materials are
made of composites, and are assembled, disassembled and
reassembled as needed.
Theoretically, the resulting stiffness and strength per density can be 10 times higher than conventional composite
structures. This approach using assembled manufacturing
rather than layering or printing is truly disruptive. n

Robot-assisted continuous fibre
placement or tape layering manufacturing
Automated manufacturing of composites can also be
categorized as "additive manufacturing" since the fibres
are added or layered over configured moulds or tools as
in automated tape layering (ATL) or automated fibre placement (AFP). Similarly to AM, AFP/ATL programming
software also reads the CAD surface and ply boundary
information and adds material according to user-specified
manufacturing standards and requirements [11 - 13] . Depending on the complexity and size of structural geometry,
robots with the required motional axes are used, and are
programmed based on the CAD and laminate sequence.
In AFP/ATL, conventional fibre tows and unidirectional tapes are fed to the robot arm and the motion can be
very complex, depending on the configuration and layup
sequence. Using newly developed multidirectional tapes
(C-ply from Chomarat) [14] , the robot motion can be dramatically simplified and material usage can be reduced.
According to the size and layup sequence of the laminated
structures, users can specify the thickness of plies and
width of multidirectional tapes, affecting the mechanical
performance of the final product. It has recently become
possible to consolidate thermoplastics rapidly for pipes
and curved structures. Rapid consolidation of thermoplastic composites is expected to become a key technology for advanced AM of composites [15] . Multidirectional
tapes can be also utilized in laser-assisted processing of
fibre-reinforced thermoplastic composites [14 , 15] .
New disruptive 3D paths, instead of sliced 2D data used in
current AM, can be developed for depositing fibres, resins
and possibly a third material for backing. This approach
may eliminate tools, as noticed in metal laser deposition,
resulting in reduced material scrap, shorter design cycles
and significantly reduced part counts.

Cellular digital materials

More information:
http://composites.hanyang.ac.kr
References
[1] The future of additive manufacturing, http://machinedesign.com/3d-printing/future-additive-manufacturing/
[2] Additive manufacturing a new frontier for composites,
Terry Wohlers, http://www.compositesworld.com
[3] Product Information for Composite and Additive Manufacturing Project, http://www.nist.gov/el/msid/proceng/
picamproj.cfm
[4] Additive Manufacturing, next-generation of manufacturing, http://web.ornl.gov/sci/manufacturing/research/
additive_manufacturing.shtml
[5] Solid Concepts, http://www.solidconcepts.com/
[6] Laser Deposition Technology (LDT),
http://www.rpm-innovations.com
[7] Easy Composites, http://www.easycomposites.co.uk/
[8] Additive Manufacturing Trends in Aerospace: Leading
the Way, http://www.stratasys.com/
[9] SLS Material, Selective Laser Sintering Materials,
http://www.paramountind.com
[10] Additive Manufacturing in the USA, CRP USA, http://
www.crp-usa.net/3d-printing-for-the-usa.html
[11] Fiber placement system, MAG, http://www.mag-ias.
com
[12] Coriolis-composites, http://www.coriolis-composites.
com/
[13] Aeronautics, mtorres, http://www.mtorres.es/
[14] C-Ply, Chomarat, http://www.chomarat.com
[15] Laser assisted processing of fiber-reinforced thermoplastic composite, Fraunhofer, IPT, http://www.ipt.
fraunhofer.de
[16] New approach assembles big structures from small
interlocking pieces, MIT Technology Review, vol. 116, no 5,
Sept 2013 (http://www.technologyreview.com/)

Interlocking cellular digital materials have been proposed

52 jec composites magazine / No86 January - February 2014

http://composites.hanyang.ac.kr http://machinedesign.com/3d-printing/future-additive-manufacturing/ http://machinedesign.com/3d-printing/future-additive-manufacturing/ http://www.compositesworld.com http://www.nist.gov/el/msid/proceng/picamproj.cfm http://web.ornl.gov/sci/manufacturing/research/additive_manufacturing.shtml http://www.solidconcepts.com/ http://www.rpm-innovations.com http://www.easycomposites.co.uk/ http://www.stratasys.com/ http://www.paramountind.com http://www.crp-usa.net/3d-printing-for-the-usa.html http://www.crp-usa.net/3d-printing-for-the-usa.html http://www.mag-ias.com http://www.coriolis-composites.com http://www.mtorres.es/ http://www.chomarat.com http://www.ipt.fraunhofer.de http://www.technologyreview.com/

JEC COMPOSITES MAGAZINE - Issue #86 - January/February 2014

Table of Contents for the Digital Edition of JEC COMPOSITES MAGAZINE - Issue #86 - January/February 2014