Compression tests of castor oil biopolymer

Ferneda, Amauri Bravo; Costa, Romeu Rony Cavalcante da; Tita, Volnei; Proença, Sérgio Persival Baroncini; Carvalho, Jonas de; Purquerio, Benedito de Moraes

doi:10.1590/s1516-14392006000300013

Cited by 8 publications

(6 citation statements)

References 8 publications

(8 reference statements)

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“…They showed that when the PDL is subjected to a continuous loading, it shows an elastic behavior followed by a viscoelastic phase. Figure 16 shows the viscoelastic behavior of the PDL which is in good agreement with the investigation of Ferneda et al [84] who studied the behavior of a viscoelastic material. They revealed the stress behavior of a viscoelastic material with loading, unloading, and reloading cycles.…”

Section: Discussionsupporting

confidence: 87%

Mechanical responses of maxillary canine and surrounding tissues under orthodontic loading: a non-linear three-dimensional finite element analysis

Roostaie

Soltani

2017

J Braz. Soc. Mech. Sci. Eng.

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Section: Discussionsupporting

confidence: 87%

Mechanical responses of maxillary canine and surrounding tissues under orthodontic loading: a non-linear three-dimensional finite element analysis

Roostaie

Soltani

2017

J Braz. Soc. Mech. Sci. Eng.

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“…It is highlighted that in Fig. 9 the radial and the circumferential stresses vs time plots, shown the viscoplastic response generally displayed by polymers in compression [29,45,47], with the typical behavior of a softening after yield, followed by a plateau response, and an exponential increment of the stress for the low increment of strain.…”

Section: Viscoplastic Model Phenomenological Featuresmentioning

confidence: 89%

“…Figure 2 shows the representative Stress-strain experimental test curves. It is worth noting that until 20% strain no barreling effect was observed for the different strain rates used, i.e., the specimen deformed without displaying shearing and barreling [45].…”

Section: Compression Testmentioning

confidence: 94%

Computational modeling of viscoplastic polymeric material response during micro-indentation tests

O’Connor

Santos

Borges

et al. 2020

J Braz. Soc. Mech. Sci. Eng.

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The computational modeling of instrumented indentation tests used to characterize material properties is challenging. It is mainly due to the computational techniques demanded to couple the complex physical mechanisms involved, such as, for example, the time-dependent inelastic material response to loads during contact. Therefore, this work aims to simulate the mechanical response of the poly vinylidene fluoride (PVDF) during a micro-indentation test considering a viscoplastic material model, and a prescribed load approach, using the finite element method. Further, model validation is performed based on experimental data measured during the contact between the indenter and the PVDF. Numerical analyses were performed using COMSOL Multiphysics finite element software considering the loading scheme of the experimental tests of 800 mN/ min rate during loading and unloading, and a 400 mN constant load, held by 30 s. Finally, a viscoplastic Chaboche constitutive model is presented considering two cases: (1) a perfectly plastic behavior, and (2) a nonlinear isotropic hardening behavior based on Voce and Hockett-Sherby exponential laws. While the latter models exhibit some discrepancy in capturing the experimental behavior, the former one has shown excellent agreement with the load-depth curves obtained experimentally, achieving the best fitting for the set of Chaboche parameters: A = 1 s −1 , n = 4.62 and ref = 132 MPa. Moreover, several phenomenological features of viscoplastic behavior such as rate dependence, plastic flow (or creep) and stress relaxation were accurately provided by the Chaboche model when describing the behavior of the PVDF material. Keywords Viscoplasticity • Polymers • Microindentation • Finite elements Nomenclature E Young's modulus F y Yield function h max Maximum indentation depth h r Residual or final indentation depth h m , r m PVDF sample thickness and radius J 2 Second deviatoric stress invariant P Applied load P max Maximum applied load Q p Plastic potential r i Indenter radius S Deviatoric stress tensor t h Holding load time vpe Effective viscoplastic strain vp Viscoplastic strain tensor Cauchy's stress tensor Mises Effective von Mises stres ys Yield Stress ys0 Initial yield stress sat , Voce model parameters Technical Editor: João Marciano Laredo dos Reis.

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“…Entre as suas indicações clínicas incluem-se a fixação de próteses, a reconstituição e o preenchimento de espaços ósseos (Bioosteo, 2006), sendo em algumas situações uma alternativa ao polimetilmetacrilato. Ressalta-se que a maioria das publicações referentes ao emprego do polímero de mamona está associada a estudos in vivo, que analisaram biocompatibilidade, capacidade de estimulação na neoformação óssea, osteointegração e toxicidade (Kfuri et al, 2001;Rezende et al, 2001;Ignácio et al, 2002;Ziliotto et al, 2003;Laranjeira et al, 2004;Bolson et al, 2005;Pereira-Júnior et al, 2007), mas há poucos relatos sobre suas propriedades mecânicas (Claro Neto, 1997;Kfuri et al, 2001;Silva et al, 2001;Ferneda et al, 2006). Dessa forma, o objetivo deste trabalho foi avaliar o comportamento mecânico do polímero de mamona, quanto à carga máxima e à tensão à compressão, ao módulo e à resistência ao dobramento, tendo por variáveis o tempo de produção e a presença de catalisador, e utilizando como padrão comparativo o polimetilmetacrilato.…”

Section: Introductionunclassified

Propriedades mecânicas do cimento ósseo e da poliuretana de mamona com e sem catalisador

Lima

Rahal

Müller

et al. 2008

Arq. Bras. Med. Vet. Zootec.

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RESUMOAvaliou-se o comportamento mecânico do polímero de mamona, tendo por variáveis o tempo de produção e a presença de catalisador, e utilizando como padrão comparativo o cimento ósseo (polimetilmetacrilato). Foram estabelecidos três grupos experimentais, de acordo com o tipo de corpo de prova (cilindro ou barra) e polímero utilizado, que foram posteriormente subdivididos em subgrupos conforme o tempo após produção, ou seja, 24, 48 e 72 horas. O ensaio de compressão analisou a carga máxima e a tensão e o ensaio de dobramento estudou o módulo de dobramento e a resistência. Estatisticamente não houve diferenças nos valores de resistência à compressão ou ao dobramento às 24, 48 e 72 horas após a produção do polimetilmetacrilato e da poliuretana, com ou sem catalisador. A poliuretana com catalisador foi a mais resistente nos ensaios de compressão, apresentando módulo de dobramento semelhante ao do polimetilmetacrilato e resistência ao dobramento superior à da poliuretana sem catalisador. Conclui-se que: o tempo não alterou as propriedades mecânicas dos compósitos avaliados; o catalisador melhorou o desempenho mecânico da poliuretana de mamona; na resistência mecânica à compressão, a poliuretana com catalisador suportou mais carga que o polimetilmetacrilato.Palavras-chave: polímero de mamona, biomaterial, resistência mecânica, resina acrílica post-production time, namely, 24, 48, and 72 ABSTRACT The mechanical properties of castor oil-based polyurethane was evaluated considering post-production time and the presence of a catalyst as variables and using bone cement (polymethylmetacrylate) as a comparative pattern. According to proof body type (cylinders or bars) and the used polymer, three experimental groups were established. Such groups were later subdivided according to

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Compression tests of castor oil biopolymer

Cited by 8 publications

References 8 publications

Mechanical responses of maxillary canine and surrounding tissues under orthodontic loading: a non-linear three-dimensional finite element analysis

Mechanical responses of maxillary canine and surrounding tissues under orthodontic loading: a non-linear three-dimensional finite element analysis

Computational modeling of viscoplastic polymeric material response during micro-indentation tests

Propriedades mecânicas do cimento ósseo e da poliuretana de mamona com e sem catalisador

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