Shape memory polymers (SMPs) with variable stiffness properties become the most promising candidate materials for morphing skins. Due to the influence of external environment, electric-driven composite skin is becoming the trend of development. In this paper, rubber toughed hydro-epoxy morphing skins filled with conductive carbon black (CB) and short-cut carbon fiber (SCF) were prepared. The total mass fraction of CB and SCF was fixed at 2.6 wt %. By adjusting the content ratio of CB and SCF (CB/SCF), the in-plane mechanical property, fracture morphology, thermal-mechanical behavior, electronic resistivity, and out-of-plane shape memory behavior of five types of skin were investigated. These results showed that the addition of CB and SCF had a synergistic effect on skin performance. When CB/SCF was 5:5, the composite skin had the highest tensile strength and the lowest glass transition temperature (Tg). In the thermo-active shape memory test, the composite skin presented good shape fixity rate (Rf) and shape recovery rate (Rr). Due to the bridging effect of SCFs on CB particles, the composite skin with CB/SCF ratio of 5:5 has the minimum resistivity and can return to its initial shape within 29 s at 60 V.
PeterFStumpfECarossaGM, et al. Morphing Value Assessment on Overall Aircraft Level. In: WölckenPPapadopoulosM (eds) Smart Intelligent Aircraft Structures (SARISTU). Cham, Switzerland: Springer, 2016, pp. 859–871.
2.
AjajRMParancheerivilakkathilMSAmoozgarM, et al. Recent developments in the aeroelasticity of morphing aircraft. Prog Aerosp Sci2021; 120: 29, doi:10.1016/j.paerosci.2020.100682.
3.
RothBCrossleyW. Application of optimization techniques in the conceptual design of morphing aircraft. In: AIAA’s 3rd Annual Aviation Technology, Integration, and Operations (ATIO) Forum, Denver, CA, 17-19 November 2003, Reston, VA: AIAA.
4.
ThillCEtchesJBondI, et al. Morphing skins. Aeronaut J2008; 112: 117–139, doi:10.1017/s0001924000002062.
5.
KikutaMT. Mechanical properties of candidate materials for morphing wings. MPhil Thesis, Blacksburg, VA: Virginia Polytechnic Institute and State University, 2003.
6.
GriffinC. Pressure deflection behavior of candidate materials for a morphing wing. MPhil Thesis, Morgantown, WV: West Virginia University, 2007.
7.
KeihlMMBortolinRSSandersB, et al.Mechanical properties of shape memory polymers for morphing aircraft applications. In: Proceedings of SPIE smart structures and materials 2005: industrial and commercial applications of smart structures technologies USABellingham, WA: SPIE, 2005, pp. 143–151.
8.
ZhuGWeiKWangK. Shape memory polymers for aeronautic & space applications. Polym Mater Sci Eng2010; 26: 168–171.
9.
TianGZhuGXuS, et al.Photodirected 2D-to-3D morphing structures of shape memory polycaprolactone/W18O49 nanowires composite film. Sci China Mater2021; 64: 1495–1506. DOI: 10.1007/s40843-020-1538-6.
10.
TianGZhuGXuS, et al. A polycaprolactone/polydopamine nanocomposite with sunlight-induced shape memory effect and solid state plasticity. Smart Mater Struct2020; 29: 105019, doi:10.1088/1361-665X/aba53e.
11.
WeiKMaBLiuY, et al.An investigation on shape memory behaviors of epoxy resin system. J Mater Res2015; 30: 2179–2187. DOI: 10.1557/jmr.2015.180.
12.
WeiKZhuGTangY, et al. Shape-memory effects of a hydro-epoxy resin system. J Polym Res2013; 20: 123, doi:10.1007/s10965-013-0123-7.
13.
ByeDMcClureP. Design of a Morphing Vehicle. 48th AIAA/ASME/ASCE/AHS Structures, structaral dynamics, and materials conference. Honolulu, HI: AIAA, 2007.
14.
ChenYSunJLiuY, et al. Variable stiffness property study on shape memory polymer composite tube. Smart Mater Struct2012; 21, doi:10.1088/0964-1726/21/9/094021.
15.
YuKYinWLSunS, et al.Design and analysis of morphing wing based on SMP composite. In: Proceedings of SPIE Industrial and Commercial Applications of Smart Structures Technologies 2009, San Diego, CA, 1 April 2009. Bellingham, WA: SPIE, pp.1–8.
SunJOunaiesZXuY, et al.Mechanical and electrical properties of spandex reinforced GMWNT/epoxy shape memory composites. In: Proceedings of SPIE Behavior and Mechanics of Multifunctional Materials and Composites 2012, San Diego, CA, 28 March 2012, Bellingham, WA: SPIE.
18.
McKnightGDotyRKeefeA, et al. Segmented reinforcement variable stiffness materials for reconfigurable surfaces. J Intel Mat Syst Str2010; 21: 1783–1793, doi:10.1177/1045389x10386399.
19.
ChenYYinWLiuY, et al. Structural design and analysis of morphing skin embedded with pneumatic muscle fibers. Smart Mater Struct2011; 20: 085033, doi:10.1088/0964-1726/20/8/085033.
20.
PerkinsDReedJHavensE. Morphing wing structures for loitering air vehicles. In: 45th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics & Materials Conference. Palm Springs, CA, 19–22 April 20042004, p. 4006–4015.
21.
YinWLSunQJZhangB, et al.Seamless Morphing Wing with SMP Skin. Adv Mater Res2008; 47–50: 97–100.
22.
HenryACMolinariGRivas-PadillaJR, et al.Smart morphing wing: optimization of distributed piezoelectric actuation. AIAA J2019; 57: 2384–2393. DOI: 10.2514/1.J057254.
23.
Barcala-MontejanoMARodríguez-SevillanoÁABardera-MoraR, et al. Smart materials applied in a micro remotely piloted aircraft system with morphing wing. J Intel Mat Syst Str2018; 29: 3317–3332, doi:10.1177/1045389x18783893.
24.
SunJDuLScarpaF, et al. Morphing wingtip structure based on active inflatable honeycomb and shape memory polymer composite skin: a conceptual work. Aerosp Sci Technol2021; 111: 106541, doi:10.1016/j.ast.2021.106541.
25.
WeiKZhuGTangY, et al. An investigation on shape memory behaviours of hydro-epoxy/glass fibre composites. Compos Part B-Eng2013; 51: 169–174, doi:10.1016/j.compositesb.2013.03.036.
26.
WeiKZhuGTangY, et al. The effects of carbon nanotubes on electroactive shape-memory behaviors of hydro-epoxy/carbon black composite. Smart Mater Struct2012; 21: 085016, doi:10.1088/0964-1726/21/8/085016.
27.
WangKZhuGRenF, et al. The effects of carbon fiber on electroactive shape memory behaviors of cyanate/polybutadiene epoxy/carbon black composites. J Reinf Plast Comp2015; 35: 556–565, doi:10.1177/0731684415624021.
28.
WangKZhuGMYanXG, et al. Electroactive shape memory cyanate/polybutadiene epoxy composites filled with carbon black. Chinese J Polym Sci2016; 34: 466–474, doi:10.1007/s10118-016-1766-8.
29.
LiangJZ. Electrical conductivities of high‐density polyethylene composites reinforced with carbon fiber and nanometer carbon black. Polym Composite2018; 40: E1801–E1807, doi:10.1002/pc.25166.
30.
LuHYuKSunS, et al.Mechanical and shape-memory behavior of shape-memory polymer composites with hybrid fillers. Polym Int2010; 59: 766–771. DOI: 10.1002/pi.2785.
31.
LengJLvHLiuY, et al. Electroactivate shape-memory polymer filled with nanocarbon particles and short carbon fibers. Appl Phys Lett2007; 91: 144105, doi:10.1063/1.2790497.
32.
LengJLvHLiuY, et al.Synergic effect of carbon black and short carbon fiber on shape memory polymer actuation by electricity. J Appl Phys2008; 104: 104917. DOI: 10.1063/1.3026724.
33.
RenXZhuG. A variable stiffness morphing skin: preparation and properties. Smart Mater Struct2021; 30: 125016, doi:10.1088/1361-665X/ac32e8.
34.
WeiKZhuGTangY, et al.Electroactive shape-memory effects of hydro-epoxy/carbon black composites. Polym J2012; 45: 671–675. DOI: 10.1038/pj.2012.185.
35.
RenXZhuG. An electric‐driven variable stiffness morphing skin: Preparation and properties. Polym Composite2022; 1: 12, doi:10.1002/pc.26491.
36.
WangJNiLLiQ, et al. The synergistic effects of carbon black and carbon fibre on the thermal conductivity of silicone rubber. Polym Polym Compos2015; 23: 271–276.
37.
RothBPetersCCrossleyW. Aircraft Sizing with Morphing as an Independent Variable: Motivation, Strategies and Investigations. In: AIAA’s Aircraft Technology, Integration, and Operations (ATIO) 2002 Technical Forum, Los Angeles, California, 1–3 October 2002, Reston, VA: AIAA.
38.
BarbarinoSBilgenOAjajRM, et al. A review of morphing aircraft. J Intel Mat Syst Str2011; 22: 823–877, doi:10.1177/1045389x11414084.
