Arunjunairaj Mahendran^1*, Günter Wuzella¹, Thomas Hardt-Stremayr¹, Wolfgang Gindl-Altmutter²

Journal of Renewable Materials, Vol.4, No.3, pp. 215-224, 2016, DOI:10.7569/JRM.2016.634110

Abstract Woven natural fiber-reinforced composites were fabricated using four different flax fabrics and two biobased epoxy resin matrices. The reinforced composites were prepared using resin infusion technique and fiber volume fractions of between 28–35% were achieved using this method. The fiber matrix interaction and the failure mechanism in the composite were observed using scanning electron microscopy. The flexural strength and modulus on the warp and weft directions were characterized and it was found that based on yarn count and yarn thickness change in the flexural strength was observed. Dynamic water absorption and thickness swelling were observed for a certain period of… More >

D. Puglia^1*, F. Dominici¹, M. Badalotti², C. Santulli³, J.M. Kenny¹

Journal of Renewable Materials, Vol.4, No.3, pp. 199-205, 2016, DOI:10.7569/JRM.2016.634102

Abstract In this work, cocoa bean shells (CBS), which were ground, then sieved to less than 150 μm and dried in a vacuum oven, have been introduced in a polycaprolactone (PCL) matrix in three different amounts, 10, 20 and 30% wt. The obtained composites were tested under tensile loading, which indicated an enhanced rigidity with a slight decrease of strength with respect to the neat polymer and a reduced elongation, particularly evident for composites with 30 wt% CBS, where final collapse took place for strains only slightly exceeding the yielding point. Differential scanning calorimetry (DSC) indicated a rather negligible variation of… More >

Estefanía Lidón Sánchez-Safont¹, Jennifer González-Ausejo¹, José Gámez-Pérez¹, José María Lagarón², Luis Cabedo^1*

Journal of Renewable Materials, Vol.4, No.2, pp. 123-132, 2016, DOI:10.7569/JRM.2015.634127

Abstract Novel biodegradable composites based on poly(3-hydroxybutirate-co-3-hydroxyvalerate) (PHBV) and different contents of purifi ed alpha-cellulose fi bers (3, 10, 25 and 45%) were prepared by melt blending and characterized. The composites were characterized by scanning electron microscopy (SEM), wide-angle X-ray scattering (WAXS) experiments, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), dynamic mechanic analysis (DMA) and Shore D hardness measurements. Disintegrability under composting conditions was studied according to the ISO 20200 standard. Morphological results showed that high dispersion of the fi bers was achieved during mixing. Good adhesion on the fi ber-matrix interface was also detected by SEM. The addition of low… More >

Estela Krause Sammartino^1,2,3†, María Marta Reboredo⁴, Mirta I. Aranguren^*,4

Journal of Renewable Materials, Vol.4, No.2, pp. 101-112, 2016, DOI:10.7569/JRM.2014.634144

Abstract Composites made from polypropylene (PP) and local South American fibers traditionally used in yarnderived craftsmanships, Caranday Palm, were studied regarding the effect of fiber addition, concentration and characteristics of the coupling agent (molecular weight and percentage of grafted maleic anhydride), as well as type of processing. A laboratory-scale intensive mixing followed by compression, and pilot plant twin extrusion followed by injection, were the two processes investigated. The use of the first one allowed the selection of processable formulations with high fiber concentration and a percentage of coupling agent below the surface fiber saturation. In fact, it was found that there… More >

Mengyue He¹, Zhifang Zhang^1,*, Karthik Ram Ramakrishnan²

Structural Durability & Health Monitoring, Vol.12, No.4, pp. 213-256, 2018, DOI:10.32604/sdhm.2018.05122

Abstract Fibre reinforced polymer (FRP) composite laminates are now commonly used in many structural applications, especially in the aerospace industry, where margins of safety are kept low in order to minimise weight. Timely detection and assessment of damage (in particular delaminations) in composite laminates are therefore critical, as they can cause loss of structural integrity affecting the safe operation of the composite structures. The current trend is towards implementation of structural health monitoring (SHM) systems which can monitor the structures in situ without down time. In this paper, first, the current available SHM techniques for delamination detection in FRP composites are… More >

G. Lasko^∗, I. Schäfer^∗, Z. Burghard^†, J. Bill^†, S. Schmauder^∗, U. Weber^∗, D. Galler^‡

Molecular & Cellular Biomechanics, Vol.10, No.1, pp. 27-42, 2013, DOI:10.3970/mcb.2013.010.027

Abstract Owing to the apparent simple morphology and peculiar properties, nacre, an iridescent layer, coating of the inner part of mollusk shells, has attracted considerable attention of biologists, material scientists and engineers. The basic structural motif in nacre is the assembly of oriented plate-like aragonite crystals with a ’brick’ (CaCO₃ crystals) and ’mortar’ (macromolecular components like proteins) organization. Many scientific researchers recognize that such structures are associated with the excellent mechanical properties of nacre and biomimetic strategies have been proposed to produce new layered nanocomposites. During the past years, increasing efforts have been devoted towards exploiting nacre’s structural design principle in… More >

Kunigal N.Shivakumar¹, Shivalingappa Lingaiah², Robert Sadler², Matthew Sharpe²

CMC-Computers, Materials & Continua, Vol.1, No.4, pp. 309-318, 2004, DOI:10.3970/cmc.2004.001.309

Abstract The exfoliation and dispersion of nanoclay (2% by weight) and nanovermiculite (2% by weight) particles in a polymer matrix is analyzed using the Scanning Electron Microscope (SEM) after a low temperature air plasma etch. The plasma etch preferentially removes the polymer to expose the nanoparticles. Both Argon and air have been used as the etching media to study the etching process. SEM analysis illustrate the results of the etching in flat and edge surfaces of both nanoclay (MMT) and nanovermiculite (VMT) filled polymer. Both the MMT and VMT were dispersed using a IKA high shear mixer and a Sonicator. More >

B. Kriegesmann¹, R. Rolfes¹, E. L. Jansen¹, I. Elishakoff², C. Hühne³, A. Kling³

CMC-Computers, Materials & Continua, Vol.32, No.3, pp. 177-200, 2012, DOI:10.3970/cmc.2012.032.177

Abstract Four different approaches for the design of axially compressed cylindrical shells are presented, namely (1) the knockdown factor (KDF) concept, (2) the single perturbation load approach, (3) a probabilistic design procedure and (4) the convex anti-optimization approach. The different design approaches take the imperfection sensitivity and the scatter of input parameters into account differently. In this paper, the design of a composite cylinder is optimized considering the ply angles as design variables. The KDF concept provides a very conservative design load and in addition an imperfection sensitive design, whereas the other approaches lead to a significantly less conservative design load… More >

Luiz F. Kawashita¹, Alexandre Bedos², Stephen R. Hallett³

CMC-Computers, Materials & Continua, Vol.32, No.2, pp. 133-158, 2012, DOI:10.3970/cmc.2012.032.133

Abstract A methodology is proposed for modelling transverse matrix cracks in laminated composites in a three-dimensional explicit finite element analysis framework. The method is based on the introduction of extra degrees of freedom to represent the displacement discontinuity and the use of a cohesive zone model to determine damage evolution and crack propagation. The model is designed for the analysis of matrix cracks in laminates made of uni-directional fibre-reinforced plies, allowing several assumptions to be made which greatly simplify the algorithm. This was implemented in the commercial software Abaqus/Explicit as a user-defined element subroutine (VUEL). The methodology was verified via the… More >

M. Pankow¹, A.M. Waas², C.F. Yen³

CMC-Computers, Materials & Continua, Vol.32, No.2, pp. 81-106, 2012, DOI:10.3970/cmc.2012.032.081

Abstract The compression response of 3D woven textile composites (3DWC) that consist of glass fiber tows and a polymer matrix material is studied using a combination of experiments and finite element based analyses. A previous study reported by the authors consisted of an experimental investigation of 3DWC under high strain rate loading, Pankow, Salvi, Waas, Yen, and Ghiorse (2011). Those experimental results were explained by using the finite element method to analyze the high rate deformation response of representative volume elements (RVEs) of the 3DWC, Pankow, Waas, Yen, and Ghiorse (2012). In this paper, the same modeling strategy is used to… More >