Prediction of the elastic moduli of chicken-feather-reinforced PLA and a comparison with experimental results

Abstract

The purpose of this study is to obtain the elastic moduli, the key material property, of random discontinuous fiber composites with experiments and micromechanical models and to compare them. The proposed study makes it possible to assess the elastic moduli of chicken-feather fiber (CFF)/PLA green composites with different CFF mass fractions and to determine the feasibility of the micromechanical models for the CFF/PLA composites. For this purpose, initially, CFF/PLA composites including 2, 5 or 10 % chicken-feather mass fractions were extruded and standard tensile specimens for ISO 527 were formed with the injection-molding method. Tensile tests were carried out in accordance with the standards and the elastic moduli were calculated using the stress-strain curve. Then, using six different micromechanical models, the elastic moduli of the CFF/PLA composites with different mass fractions were calculated and compared with the experimental results. The results of the experiments and the models indicated that the presence of chicken feather increased the elastic moduli of all the composites in comparison with the pure PLA. According to the experimental data, the maximum increase in the elastic moduli of the composites with the presence of CFF was found to be 5.4 %. The maximum error in the prediction is about 16.8 % for the composite with a chicken-feather rate of 10 % when Manera's model is used. Among the micromechanical models, the ones that gave more converging results for the prediction of the elastic moduli of the CFF/PLA composites are Pan's 2-D, IROM (the inverse rule of mixtures), Nielsen-Chen and Halpin-Tsai models. A comparison of the results of these six models shows that the maximum deviation (the percentage error in prediction) is the smallest (1.4 %) for the Nielsen-Chen model. Therefore, the Nielsen-Chen model is the most appropriate model for the prediction of the elastic moduli of the CFF/PLA composites. Keywords: chicken feather, PLA, green composite, micromechanical models Namen te {tudije je dobiti module elasti~nosti kot glavne lastnosti materiala, kompozitov z naklju~nimi vlakni, z eksperimenti in z mikromehanskimi modeli ter njihova primerjava. Predlagana {tudija bo omogo~ila dolo~itev modula elasti~nosti kompozita iz vlaken pi{~an~jega perja (CFF)/PLA, z razli~nim masnim dele`em CFF in ugotoviti izvedljivost mikromehanskih modelov za CFF/PLA kompozite. V ta namen so bili najprej kompoziti CFF/PLA z 2 %, 5 % in 10 % pi{~an~jih peres, ekstrudirani in izdelani so bili standardni natezni preizku{anci po ISO 527, z metodo brizganja v formo. Natezni preizkusi so bili izvr{eni v skladu s standardom in modul elasti~nosti je bil izra~unan iz krivulje napetost-raztezek. Nato so bili izra~unani moduli elasti~nosti kompozita CFF/PLA, z uporabo {estih razli~nih mikromehanskih modelov in primerjani z rezultati preizkusov. Rezultati preizkusov in modelov so pokazali, da prisotnost pi{~an~jih peres pove~a modul elasti~nosti vseh kompozitov, v primerjavi s~istim PLA. Eksperimentalni podatki so pokazali, da j...

Measuring the flexibility matrix of an eagle’s flight feather and a method to estimate the stiffness distribution*

“…The elastic moduli of chicken-feather fibers including mass fractions of 2%, 5%, and 10% were tested during tensile tests; thereby, six different micro-mechanical models were tested to confirm that the Nielsen-Chen model gives the best predictions of the elastic modulus. [30] Generally, the cortex material was reported to have an elastic modulus of 2.5-6.5 GPa, [31][32][33] whereas the foam's modulus is 0.01-0.03 GPa. [31,32] Four bending tests of pigeon feathers were carried out by Corning and Biewener to find that bending-induced bulking was the main cause of failures.…”