A comprehensive review of the mechanical characterisation and modelling of randomly oriented strand material architecture and their hybrids with laminates is presented. Randomly oriented strand composites are long discontinuous fibre systems that exhibit excellent formability characteristics and stiffness properties comparable to quasi-isotropic laminates, allowing their use in the manufacture of intricate geometric parts for automotive and aerospace industries. Randomly oriented strand architecture complements out-of-autoclave methods such as compression moulding, thermostamping and resin-transfer moulding leading to cost-reduction. Their applicability is limited to non-structural and low-load bearing applications due to their low strength properties. Continuous fibre aerospace preforms exhibiting excellent mechanical performance possess low formability characteristics and are confined to simple shell-like geometries with minimal curvatures, while incurring high-costs and long manufacturing times. Hybridisation of randomly oriented strand and with other material architectures represents trade-off solutions of formability and performance characteristics often yielding synergistic effects. Seemingly simple, randomly oriented strand architecture is a complex material system that poses several structural and process challenges. This work categorises the pertinent research work from the literature on the mechanical characterisation into the framework of a formal characterisation environment of composite structures that includes the coupon, the part and structural levels. The manufacturing, dispersion methods and measurement techniques are qualitatively assessed with reference to the mechanical properties. The discussion on modelling involves the identification of crucial characteristics of significant analytical and numerical modelling techniques devised for the prediction of the mechanical behaviour of randomly oriented strand composites and their hybrids. Emphasis is on the methods of stiffness and strength prediction. Our perspectives on the effective use of randomly oriented strand composites and their hybrids are discussed. Process characterisation and process modelling of randomly oriented strand composites and their hybrids are beyond the scope of this article.
LessardHet al.
Influence of process parameters on the thermostamping of a [0/90]12 carbon/polyether ether ketone laminate. Compos Part A: Appl Sci Manuf2015;
70: 59–68.
4.
SodenPD, HintonMJH and KaddourAS.
A comparision of the predictive capabilities of current failure theories for composite laminates. Compos Sci Technol1998;
58: 1225–1254.
5.
KellyA andTysonWR.Tensile properties of fibre-reinforced metals: Copper/tungsten and copper/molybdenum. J Mech Phys Solids1965;
13: 329–350.
SeleznevaM and LessardL.Characterization of mechanical properties of randomly oriented strand thermoplastic composites. J Compos Mater2015;
50: 2833-2851.
13.
VisweswaraiahSB, LessardL and HubertP.Tensile behaviour of hybrid fibre architectures of randomly oriented strands combined with laminate groups. J Compos Mater2016; (Accepted).
14.
WakemanMDet al.
Compression moulding of glass and polypropylene composites for optimised macro- and micro-mechanical properties. 4: Technology demonstrator – a door cassette structure. Compos Sci Technol2000;
60: 1901–1918.
15.
WakemanMet al.
Stamp forming of carbon fibre/PA12 composites – A comparison of a reactive impregnation process and a commingled yarn system. Compos Sci Technol2006;
66: 19–35.
BourbanP-Eet al.
Material phenomena controlling rapid processing of thermoplastic composites. Compos Part A2001;
32: 1045–1057.
18.
BernetNet al.
Commingled yarn composites for rapid processing of complex shapes. Compos Part A: Appl Sci Manuf2001;
32: 1613–1626.
19.
BernetNet al.
An integrated cost and consolidation model for commingled yarn based composites. Compos Part A: Appl Sci Manuf2002;
33: 495–506.
20.
JanssonNet al.
Finite element modelling and testing of an injection moulded generic tow reinforced structure. Compos Part B: Eng2005;
36: 487–495.
21.
JanssonNWakemanMD andMånsonJAE.Optimization of hybrid thermoplastic composite structures using surrogate models and genetic algorithms. Compos Struct2007;
80: 21–31.
22.
SwolfsYGorbatikhL andVerpoestI.Fibre hybridisation in polymer composites: a review. Compos Part A: Appl Sci Manuf2014;
67: 181–200.
23.
MaromGet al.
Hybrid effects in composites: conditions for positive or negative effects versus rule-of-mixtures behaviour. J Mater Sci1978;
13: 1419–1426.
24.
VisweswaraiahSB, LessardL and HubertP.Interlaminar shear behaviour of hybrid fibre architectures of randomly oriented strands combined with laminate groups. Compos Struct2017;
176: 823–832.
25.
VisweswaraiahSBet al.
Flow-control and hybridization strategies for thermoplastic stiffened panels of long discontinuous fibers. J Reinf Plastics Compos2017;
0: 0731684417707585.
26.
VisweswaraiahS, et al. Conditions for notch sensitivity in hybrid fibre architectures of randomly oriented strands combined with laminate groups. In: COMPTEST 2017. 20–25 August 2017. S.L. Lomov, L. Gorbatikh, Y. Swolfs, Belgium.
27.
VisweswaraiahS, et al. Effects of hybridization of laminates with randomly oriented strands at coupon and part levels. In CANCOM 2017. 17–20 July 2017, Ottawa.
28.
CorbridgeDMet al.
Compression moulding of composites with hybrid fibre architectures. Compos Part A: Appl Sci Manuf2017;
95: 87–99.
29.
HanJH, et al. Effect of fabric reinforcement on failure response of discontinuous long fiber composite bolted joints. In: SAMPE, Long Beach, CA, 23–26 May 2011.
30.
EvansAD, et al. Joint design of continuous/discontinuous hybrid carbon fibre composites. In: 21st International conference on composite materials. 20–25 August, 2017, Xi'an, China.
ThomasGP. Compression molded composites: processes, benefits and applications – an interview with TenCate, in AZoM.
33.
RoyS, et al. Compression molding of composite tailboom frames. In: AHS 70th Annual forum. Montreal: American Helicopter Society International, Inc, 20–25 May, 2014. Montreal, Canada.
34.
USA, D.o.D.–. Composite materials handbook: polymer matric composites guidelines for characterization of structural materials. 2002.
35.
YamashitaSet al.
Experimental characterization of the tensile failure mode of ultra-thin chopped carbon fiber tape-reinforced thermoplastics. J Reinf Plastics Compos2016;
35: 1342–1352.
36.
EguémannN. Study on the mechanical behaviour of carbon fibre reinforced PEEK polymer with a layered discontinuous architecture. 2013, L’U.F.R. des sciences et techniques de l'Université de Franche-Comté.
37.
FortinGY. Process-induced shape distortions in aerospace thermoplastic composites. In: Materials engineering.
Vancouver, Canada: University of British Columbia, 2016.
38.
HarperLT, et al. Automated spray deposition for net-shape carbon/epoxy compression moulding in ICCM-17.
Edinburgh, UK:
ICCM, 2009.
39.
QianCet al.
Notched behaviour of discontinuous carbon fibre composites: comparison with quasi-isotropic non-crimp fabric. Compos Part A: Appl Sci Manuf2011;
42: 293–302.
40.
JohansonK, et al. Studying the heterogeneity of discontinuous fiber composites using a new full-field strain measurement system. In: The 19th international conference on composite materials, Montreal, Canada, July 28-August 2, 2013.
41.
HexMC® user guide. Hexcel Corporation, 2013.
42.
WanY andTakahashiJ.Tensile properties and aspect ratio simulation of transversely isotropic discontinuous carbon fiber reinforced thermoplastics. Compos Sci Technol2016;
137: 167–176.
43.
JinBCet al.
Optimization of microstructures and mechanical properties of composite oriented strand board from reused prepreg. Compos Struct2017;
174: 389–398.
44.
LessardHet al.
Influence of process parameters on the thermostamping of a [0/90]12 carbon/polyether ether ketone laminate. Compos: Part A2015;
70: 59–68.
JohansonKet al.
Heterogeneity of discontinuous carbon fibre composites: damage initiation captured by digital image correlation. Compos Part A: Appl Sci Manuf2015;
68: 304–312.
47.
KilicMH. A nonlinear 3D micromechanical and structural framework for analysis of discontinuous long-fiber thermoplastic composites. In: CAMX – the composites and advanced materials expo, Orlando, FL. 13–16 October 2014.
48.
LandryB. Experimental study and numerical simulation of defect formation during compression moulding of discontinuous long fibre carbon/PEEK composites. In: Mechanical Engineering. Montreal: McGill University, Thesis, 2016.
49.
CollinsC and HubertP. Dimensional stability in compression moulded discontinuous long fibre carbon/PEEK composites. In: CANCOM. Ottawa, 17–20 July 2017.
50.
BernasconiACosmiF andHinePJ.Analysis of fibre orientation distribution in short fibre reinforced polymers: a comparison between optical and tomographic methods. Compos Sci Technol2012;
72: 2002–2008.
51.
TuttleM, ShifmanT and BoursierB. Simplifying certification of discontinuous composite material forms for primary aircraft structures. In: SAMPE, Seattle, Washington DC, 17–20 May 2010.
52.
FernandesHet al.
Carbon fiber composites inspection and defect characterization using active infrared thermography: numerical simulations and experimental results. Appl Opt2016;
55: D46–D53.
53.
CosmiF andBernasconiA.Micro-CT investigation on fatigue damage evolution in short fibre reinforced polymers. Compos Sci Technol2013;
79: 70–76.
54.
WanYet al.
Micro-CT analysis of internal geometry of chopped carbon fiber tapes reinforced thermoplastics. Compos Part A: Appl Sci Manuf2016;
91: 211–221.
55.
FeraboliPet al.
Defect and damage analysis of advanced discontinuous carbon/epoxy composite materials. Compos Part A: Appl Sci Manuf2010;
41: 888–901.
56.
Denos BR. CT Scan Analysis for the Characterization of Fiber Orientation in Long Discontinuous Fiber Composite Materials – Thesis, in Department of Aeronautics and Astronautics, Purdue University: West Lafayette, Indiana, 2014.
57.
Cutting RA. Considerations for non-destructive evaluation of discontinuous fiber composites using dynamic analysis – Thesis, in Aeronautics and Astronautics. Purdue University: West Lafayette, Indiana, 2015.
58.
LyuX, et al.
Determination of transverse flexural and shear moduli of chopped carbon fiber tape-reinforced thermoplastic by vibration. J Compos Mater2017;
0(0). 1–10: 0021998317707815.
59.
EguémannN, et al. Processing of characterisation of carbon fibre reinforced PEEK with discontinuous architecture. In: ECCM16 – 16th European conference on composite materials, Seville, Spain. 22–26 June 2014.
60.
WanY andTakahashiJ.Tensile and compressive properties of chopped carbon fiber tapes reinforced thermoplastics with different fiber lengths and molding pressures. Compos Part A: Appl Sci Manuf2016;
87: 271–281.
61.
BenvenisteY.A new approach to the application of Mori-Tanaka's theory in composite materials. Mech Mater1987;
6: 147–157.
62.
HanJH, AlexanderWB and GodwinA. Characterization of milled carbon fiber added random discontinuous long fiber composites. In: SAMPE, Seattle, WA, 17–20 May 2010.
63.
LandryB andHubertP.Experimental study of defect formation during processing of randomly-oriented strand carbon/PEEK composites. Compos Part A: Appl Sci Manuf2015;
77: 301–309.
64.
NakashimaYet al.
Analytical modelling of the behaviour and scatter of the flexural modulus of randomly oriented carbon fibre strand thermoplastic composites. Compos Struct2017;
178: 217–224.
65.
BoursierB and LopezA. Failure initiation and effect of defects in structural discontinuous fibre composites. In: SAMPE Fall technical conference, 11–14 October, Salt Lake City, 2010.
66.
FeraboliPet al.
Notched behavior of prepreg-based discontinuous carbon fiber/epoxy systems. Compos Part A: Appl Sci Manuf2009;
40: 289–299.
67.
GuoQ, et al. Numerical and experimental study of the mode i interlaminar failure of chopped carbon fiber tape reinforced thermoplastics. In: 21st International conference on composite materials, 20–25 August 2016. ICCM: Xi’an, China.
68.
LyuX, TakahashiJ and Y.Wan Analysis of viscoelastic behaviour of ultra-thin chopped carbon fiber tape reinforced thermoplastics with different tape lengths. In: ECCM17 – 17th European conference on composite materials, 26–28 June 2016. ECCM: Munich, Germany.
69.
JacobGCet al.
Crashworthiness of various random chopped carbon fiber reinforced epoxy composite materials and their strain rate dependence. J Appl Polym Sci2006;
101: 1477–1486.
70.
MengL, et al. Failure analysis of ultra-thin chopped carbon fiber tape reinforced thermoplastic in mechanical joints. In: ECCM17 – 17th European conference on composite materials, 26–28 June 2017. ECCM: Munich.
71.
YamashitaSet al.
Residual mechanical properties of carbon fibre reinforced thermoplastics with thin-ply prepreg after simulated lightning strike. Compos Part A: Appl Sci Manuf2017;
101: 185–194.
72.
YamashitaSet al.
Volume resistivity of ultra-thin chopped carbon fiber tape reinforced thermoplastics. Compos Part A: Appl Sci Manuf2016;
90: 598–605.
NilakantanG andNuttS.Reuse and upcycling of aerospace prepreg scrap and waste. Reinf Plastics2015;
59: 44–51.
75.
RasheedMIA.Compression molding of chopped woven thermoplastic composite flakes – a study on processing and performance. PhD thesis, University of Twente, Netherlands, 2016.
76.
EguémannN, et al. Compression moulding of complex parts for the aerospace with discontinuous novel and recycled thermoplastic composite materials. In: The 19th International conference on composite materials, Montreal, Canada, July 28–Aug 2, 2013.
77.
FeraboliP, et al. Lamborghini “forged composites(R)” technology for the suspension arms of the Sesto Elemento. In: The 26th American Society for Composites (ASC) technical conference, Montreal, Canada, 26–28 September 2011.
78.
HowellDD andFukumoteS. Compression molding of long chopped fiber thermoplastic composites. In: The compoistes and advanced materials expo (CAMX), Orlando, FL, 2014.
79.
KilicMH. Multi-scale modeling of discontinuous long-fibre composites. In: SAMPE conference proceedings, Seattle, WA, 2–5 June 2014.
80.
LeBlancDet al.
Study of processing conditions on the forming of ribbed features using randomly oriented strands thermoplastic composites. J Am Helicopter Soc2015;
60: 1–9.
81.
LeBlancD.Compression moulding of complex parts with randomly-oriented strand thermoplastic composites. Montreal: McGill University, 2014.
82.
LeblancDet al. Compression moulding of stiffened brackets using randomly-oriented strands thermoplastic composites. In: CAMX 2014 – Composites and advanced materials expo: combined strength. Unsurpassed Innovation, 2014.
83.
RouxMet al. Recycling of high performance thermoplastic composites with high voltage fragmentation. In: The 19th international conference on composite materials. Montreal, Canada, 2013.
84.
EguemannNet al. Manufacturing and recycling of complex composite thermoplastic parts for aerospace applications. In: SAMPE Europe 7th SETEC 12. Lucerne, Switzerland, 2012.
85.
FujitaM, NakashimaY and TakahashiJ. Influence of strand dispersion method on mechanical properties of hollow-S-shaped member made of randomly-oriented CFRTP strands. In: 21st International conference on composite materials. 20–25 August 2017: Xi'an, China.
86.
ToyodaH, et al. Influence of strand dimension and dispersion method on rigidity and its scatter of hat shaped specimens made of randomly-oriented CFRTP strands. In: 21st International conference on composite materials. 20–25 August 2017: Xi'an, China.
87.
Kravchenko SG. Failure Analysis in Platelet Molded Composite Systems – Thesis, in Department of Aeronautics and Astronautics. Purdue University: West Lafayette, Indiana, 2017.
88.
LuoY andVerpoestI.Compressibility and relaxation of a new sandwich textile preform for liquid composite molding. Polym Compos1999;
20: 179–191.
89.
WakemanMDet al.
Compression moulding of glass and polypropylene composites for optimised macro- and micro- mechanical properties 3. Sandwich structures of GMTs and commingled fabrics. Compos Sci Technol1999;
59: 1153–1167.
90.
WakemanMDet al.
Robotic tow placement for local reinforcement of glass mat thermoplastics (GMTs). Compos Part A: Appl Sci Manuf2002;
33: 1199–1208.
91.
LeeS-Het al.
A toughening and strengthening technique of hybrid composites with non-woven tissue. J Mater Process Technol2008;
207: 21–29.
92.
SelmyAIet al.
Monotonic properties of unidirectional glass fiber (U)/random glass fiber (R)/epoxy hybrid composites. Mater Des2011;
32: 743–749.
93.
SelmyAIet al.
Interlaminar shear behavior of unidirectional glass fiber (U)/random glass fiber (R)/epoxy hybrid and non-hybrid composite laminates. Compos Part B: Eng2012;
43: 1714–1719.
94.
SelmyAIet al.
In-plane shear properties of unidirectional glass fiber (U)/random glass fiber (R)/epoxy hybrid and non-hybrid composites. Compos Part B: Eng2012;
43: 431–438.
95.
Cabrera-RíosM andCastroJM.An economical way of using carbon fibers in sheet molding compound compression molding for automotive applications. Polym Compos2006;
27: 718–722.
96.
WulfsbergJet al.
Combination of carbon fibre sheet moulding compound and prepreg compression moulding in aerospace industry. Proc Eng2014;
81: 1601–1607.
97.
MallickPK.Effect of fiber misorientation on the tensile strength of compression molded continuous fiber composites. Polym Compos1986;
7: 14–18.
98.
DuaneE and Daniel GrauerBH. Manfred Reif & Frank Henning, Andreas Martsman, Simon Tage Jespersen, Using unidirectional glass tapes to improve impact performance of thermoplastic composites in automotive applications. 11–12 September 2012. 12th annual SPE automotive composites conference and exhibition, Troy, MI.
99.
ThattaiparthasarthyKB, et al. Continuous fibers tailored long fiber reinforced thermoplastics in ICCM-17.
Edinburgh, UK:
ICCM, 27–31 July 2009.
100.
GhasemnejadHHadaviniaH andAboutorabiA.Effect of delamination failure in crashworthiness analysis of hybrid composite box structures. Mater Des2010;
31: 1105–1116.
101.
Fette M, et al. Automated and cost-efficient production of hybrid sheet moulding compound aircraft components. Procedia Manufacturing 2016; 6: 132–139.
102.
Fette M, et al. New methods for computing and developing hybrid sheet molding compound structures for aviation industry. Procedia CIRP 2017; 66: 45–50.
103.
CabaAC. Characterization of carbon mat thermoplastic composites: flow and mechanical properties. In: Engineering mechanics. Blacksburg: Virginia Polytechnic Institute and State University, Thesis, 2005.
104.
PanYLorgaL andPelegriA.Numerical generation of a random chopped fiber composite RVE and its elastic properties. Compos Sci Technol2008;
68: 2792–2798.
105.
Tucker IiiCL andLiangE.Stiffness predictions for unidirectional short-fiber composites: review and evaluation. Compos Sci Technol1999;
59: 655–671.
106.
KirupananthamG.Characterisation of discontinuous carbon fibre preforms for automotive applications, Thesis.
UK:
University of Nottingham, 2013.
MoriT andTanakaK.Average stress in matrix and average elastic energy of materials with misfitting inclusions. Acta Metallurg1973;
21: 571–574.
109.
JainAJinBC andNuttS.Mean field homogenization methods for strand composites. Compos Part B: Eng2017;
124: 31–39.
110.
JainAet al.
Non-symmetric stiffness tensor prediction by the Mori–Tanaka scheme – comments on the article “Effective anisotropic stiffness of inclusions with debonded interface for Eshelby-based models” [Composite Structures 131 (2015) 692–706]. Compos Struct2015;
134: 1118–1119.
111.
LielensGet al.
Prediction of thermo-mechanical properties for compression moulded composites. Compos Part A: Appl Sci Manuf1998;
29: 63–70.
112.
SatoYet al. Elastic modulus estimation of chopped carbon fiber taper reinforced thermoplastics using the Monte Carlo simulation. In: The 19th international conference on composite materials, Montreal, Canada, 2013.
113.
SeleznevaMet al.
Analytical model for prediction of strength and fracture paths characteristic to randomly oriented strand (ROS) composites. Compos Part B: Eng2016;
96: 103–111.
114.
BekahSRabieiR andBarthelatF.The micromechanics of biological and biomimetic staggered composites. J Bionic Eng2012;
9: 446–456.
115.
PimentaS andRobinsonP.An analytical shear-lag model for composites with ‘brick-and-mortar’ architecture considering non-linear matrix response and failure. Compos Sci Technol2014;
104: 111–124.
116.
HarbanK andTuttleM.Certification of discontinuous fiber composites via stochastic modeling.
NJ:
FAA, 2017.
117.
JinBCet al. Nondestructive testing and evaluation of conventional and reused carbon fiber epoxy composites using ultrasonic and stitched MicroCT. In: SAMPE, Long Beach, CA, 2016.
118.
HarperLTet al.
Representative volume elements for discontinuous carbon fibre composites – Part 1: Boundary conditions. Compos Sci Technol2012;
72: 225–234.
119.
HarperLTet al.
Representative volume elements for discontinuous carbon fibre composites – Part 2: Determining the critical size. Compos Sci Technol2012;
72: 204–210.
120.
QianCet al. Determination of the size of representative volume elements for discontinuous fibre composites. In: 18th International conference on composite materials, Jeju, Korea, 2011.
FeraboliPet al.
Stochastic laminate analogy for simulating the variability in modulus of discontinuous composite materials. Compos Part A: Appl Sci Manuf2010;
41: 557–570.
123.
HeadBH.Analysis methods for discontinuous fiber composites.
Washington:
University of Washington, 2013.
124.
SeleznevaMet al.
Modelling of mechanical properties of randomly oriented strand thermoplastic composites. J Compos Mater2017;
51: 831–845.
125.
LiYet al.
Experimental investigation of randomly-oriented tow-based discontinuous composites and their equivalent laminates. Compos Part A: Appl Sci Manuf2017;
102: 64–75.
126.
DaiC andSteinerPR.Spatial structure of wood composites in relation to processing and performance characteristics. Part 2. Modelling and simulation of randomly-formed flake layer network. Wood Scitechnol1994;
28: 135–146.
127.
PainterGBudmanH andPritzkerM.Prediction of oriented strand board properties from mat formation and compression operating conditions. Part 1. Horizontal density distribution and vertical density profile. Wood Sci Technol2005;
40: 139–158.
128.
LuCSteinerPR andLamF.Simulation study of wood-flake composite mat structures. Forest Product J1998;
48: 89–93.
129.
HarperLTet al.
3D geometric modelling of discontinuous fibre composites using a force-directed algorithm. J Compos Mater2016;
51: 2389–2406.
130.
JinBCet al. Prediction of the stiffness of reused carbon fiber/epoxy composite oriented strand board using finite element methods. In: SAMPE, Long Beach, CA, 2016.
131.
ShahSZHet al. Three dimensional modeling & progressive damage analysis of discontinuous fibers composites (DFC) material. In: 21st International conference on composite materials. Xi'an, 2017.
132.
QianCCet al.
Structural optimisation of random discontinuous fibre composites: Part 1 – Methodology. Compos Part A: Appl Sci Manuf2015;
68: 406–416.
133.
QianCCet al.
Structural optimisation of random discontinuous fibre composites: Part 2 – Case study. Compos Part A: Appl Sci Manuf2015;
68: 417–424.
134.
SalmiM. Stiffness and failure modeling of discontinuous long fiber composites. Exstream Engineering, 2014.
135.
WazzikiEl, Ngo AD, Leblanc D, Modelling of compression moulding process cycle time and application of DFMA concept to evaluate the tooling costs for carbon fiber reinforced thermoplastic composites T-Shape parts. In: 20th International conference on composite materials. 19–24 July, 2015, ICCM: Copenhagen.
