M. Uchida¹, N. Tada¹, Y. Tomita²

The International Conference on Computational & Experimental Engineering and Sciences, Vol.6, No.2, pp. 91-98, 2008, DOI:10.3970/icces.2008.006.091

Abstract Micro- to mesoscopic deformation behavior of semi-crystalline polymer with randomly distributed rubber particles is evaluated by numerical simulation. In this model, dimension of mesostructure is identified by volume fraction of interface region around the rubber particles. The effects of strain rate and size of mesostructure on macroscopic stress-strain relation and strain distribution in mesoscopic area are discussed. In the earlier stage of deformation, the slope of stress-strain relation changes by rubber particle size while stress in the following deformation is mainly affected by the tensile strain rate. The anisotropic deformation in lamellar oriented interface region causes change in the strain… More >

Fernanda Gentil¹, Renato Natal Jorge², António Joaquim Mendes Ferreira³, Marco Parente⁴, Pedro Martins⁵, Eurico de Almeida⁶

The International Conference on Computational & Experimental Engineering and Sciences, Vol.9, No.1, pp. 45-56, 2009, DOI:10.3970/icces.2009.009.045

Abstract The interest in finite element method (FEM) concerning biomechanics has been increasing, in particular, to analyze the mechanical behavior of the human ear. In this work, a finite element model of the middle ear was made. A dynamic study based on a structural response to harmonic vibrations, for different sound pressure levels, applied on the eardrum, is presented using the ABAQUS program. The model includes different ligaments and muscle tendons with elastic and hyperelastic behavior of these supportive structure. The non-linear behavior of the ligaments and muscle tendons was considered, being the connection between ossicles done by contact formulation. Harmonic… More >

Weijun Yang^1†, Xiaomin Zhao^2†, Elena Fortunati¹, Franco Dominici¹, Jose M. Kenny¹, Debora Puglia^1*, De-Yi Wang^2*

Journal of Renewable Materials, Vol.5, No.5, pp. 423-434, 2017, DOI:10.7569/JRM.2017.634146

Abstract Presented herein is a deep investigation of the fire, mechanical and thermal performances of poly(lactic acid) (PLA)-based nanocomposites, which were obtained by combining cellulose nanocrystals (CNC) with various contents of N,N’-diallyl-phenylphosphoricdiamide (P-AA) via a two-steps masterbatch melt extrusion process (glycidyl methacrylate grafting on PLA and CNC premixing with PLA). Results have shown that the value of the limiting oxygen index (LOI) increased to 28.8% and a V-0 rating in UL94 test was obtained when 2 wt% of P-AA was added in the presence of cellulose nanocrystals (3 wt%). The incorporation of CNC induced a decrease of both PHRR and THR… More >

Juan P. Correa^1,2*, Alejandro Bacigalupe^2,3, Jorge Maggi⁴, Patricia Eisenberg^2,3

Journal of Renewable Materials, Vol.4, No.4, pp. 258-265, 2016, DOI:10.7569/JRM.2016.634117

Abstract Poly(lactic acid)/poly(butylene adipate-co-terephthalate) (PLA/PBAT)-based nanocomposites were prepared by melt blending of PLA and PBAT with 5 wt% of unmodified (Cloisite Na) and modified (Cloisite 30B) montmorillonites. X-ray diffraction (XRD) revealed an intercalated structure in both nanocomposites. The extent of the intercalation was higher for nanocomposites based on modified clays (OMMT) with chemical affinity with the polymer matrix. Rheological measurements have shown an increase in viscosity and a better degree of clay dispersion for nanocomposites containing OMMT. Nanocomposites with OMMT showed lower PBAT separated phase particle size and improvements in thermal stability, mechanical properties and water vapor barrier when compared with… More >

Shengcai Li^1,*, Jun Tang^1,2, Lin Guo³

Structural Durability & Health Monitoring, Vol.13, No.1, pp. 61-84, 2019, DOI:10.32604/sdhm.2019.06058

Abstract The simplified mechanical model and finite element model are established on the basis of the measured results and analysis of the grouting pile deformation monitoring, surface horizontal displacement and vertical displacement monitoring, deep horizontal displacement (inclinometer) monitoring, soil pressure monitoring and seepage pressure monitoring in the lower reaches of Wuan River regulation project in Shishi, Fujian Province. The mechanical behavior and deformation performance of mould-bag pile retaining wall formed after controlled cement grouting in the silty stratum of the test section are analyzed and compared. The results show that the use of controlled cement grouting mould-bag pile technology is to… More >

Ying Xu¹, Shengping Shen^1,2

CMC-Computers, Materials & Continua, Vol.28, No.1, pp. 81-96, 2012, DOI:10.3970/cmc.2012.028.081

Abstract This paper considers the surface effect through the surface and bulk electric Gibbs free energy. The analytical expressions are derived for the effective elastic, dielectric and piezoelectric modulus for nano-structural elements in electromechanical coupling problems. Numerical examples for PZT are given to illustrate the size effects on the electromechanical properties of nano-particles, nano-wires and nano-films quantitatively. The solution shows that the electromechanical properties of piezoelectric nano-material are size-dependent but the size effects on the elastic property and dielectric property are different. More >

R. Khanna^1,2, D. R. Katti¹, K. S. Katti¹

CMES-Computer Modeling in Engineering & Sciences, Vol.87, No.6, pp. 530-556, 2012, DOI:10.3970/cmes.2012.087.530

Abstract Here we report a new in situ nanoindentation technique developed to evaluate the composite mechanical behavior of cell-biomaterial construct under physiological conditions over the time scale of bone nodule generation. Using this technique, mechanical behavior of osteoblast cell-substrate interfaces on tissue engineered materials (chitosan-polygalacturonic acid-nanohydroxyapatite (CPH) films) is investigated. Mechanical behavior of cells in the elastic regime over the time scale of cell adhesion (1 day), proliferation (4 days), development (8 days) and maturation (22 days) of bone nodules is evaluated. Our results indicate that the elastic properties of flat cells are higher (indicating stiffer response, after 4 days, as… More >

M.A. Argenta¹, A.P. Gebert², E.S. Filho³, B.A. Felizari⁴, M.B. Hecke⁵

CMES-Computer Modeling in Engineering & Sciences, Vol.79, No.3&4, pp. 159-182, 2011, DOI:10.3970/cmes.2011.079.159

Abstract Various methods in the literature proposesequations to calculate the stiffness as a function of density of bone tissue such as apparent density and ash density among others[Helgason, Perilli, Schileo, Taddei, Brynjolfsson and Viceconti, 2008]. Other ones present a value of an equivalent elasticity modulus, obtained by statistical adjustments of curves generated through mechanical compression tests over various specimens[Chevalier, Pahr, Allmer, Charlebois and Zysset, 2007; Cuppone, Seedhom, Berry and Ostell, 2004]. Bone tissue is a material withdifferent behaviors according to the scale of observation. It has a complex composite hierarchical structure, which is responsible for assign optimal mechanical properties. Its characteristics,… More >

D. H. Pahr¹, H.J. Böhm¹

CMES-Computer Modeling in Engineering & Sciences, Vol.34, No.2, pp. 117-136, 2008, DOI:10.3970/cmes.2008.034.117

Abstract The combination of heterogeneous volume elements and numerical analysis schemes such as the Finite Element method provides a powerful and well proven tool for studying the mechanical behavior of composite materials. Periodicity boundary conditions (PBC), homogeneous displacement boundary conditions (KUBC) and homogeneous traction boundary conditions (SUBC) have been widely used in such studies. Recently Pahr and Zysset (2008) proposed a special set of mixed uniform boundary conditions (MUBC) for evaluating the macroscopic elasticity tensor of human trabecular bone. These boundary conditions are not restricted to periodic phase geometries, but were found to give the same predictions as PBC for the… More >

S. Namilae¹, U. Ch,ra², A Srinivasan³, N. Ch,ra⁴

CMES-Computer Modeling in Engineering & Sciences, Vol.22, No.3, pp. 189-202, 2007, DOI:10.3970/cmes.2007.022.189

Abstract Molecular dynamics (MD) simulations play an important predictive role in understanding the behavior of nanoscale systems. In this paper, parallel MD simulations are used to understand the mechanical behavior of interfaces in CNT based composites. We present an algorithm for parallel implementation of MD simulations of carbon nanotube (CNT) based systems using reactive bond order potentials. We then use that algorithm to model the CNT-polymer interfaces with various levels of interaction as (a) described only by long range Van Der Waals interactions (b) chemically bonded with fixed matrix and (c) chemically bonded with matrix explicitly modeled. It is shown that… More >