J. Larsson¹, J. Faleskog¹, A.R. Massih^2,3

CMES-Computer Modeling in Engineering & Sciences, Vol.5, No.1, pp. 73-80, 2004, DOI:10.3970/cmes.2004.005.073

Abstract We consider certain constitutive laws for analyzing the elastic-plastic behavior of granular material, which is subjected to compressive hydrostatic stresses and concomitantly undergoing swelling. The plastic yield functions for this kind of materials are pressure and porosity dependent. The constitutive laws are formulated in a finite element (FE) framework for applications to structures involving granular/porous materials. We have employed an implicit and unconditionally stable algorithm for numerical integration of the constitutive relations. The numerical method has been programmed in a FE computer code. The code is then used to study a plane strain problem for a range of model parameters… More >

Christophe Olivier^1,2, Jean Bruno Mougel^1,2, Patricia Bertoncini¹, Celine Moreau², Isabelle Capron², Bernard Cathala², Olivier Chauvet^1*

Journal of Renewable Materials, Vol.6, No.3, pp. 237-241, 2018, DOI:10.7569/JRM.2017.634168

Abstract Cellulose nanocrystals (CNCs) have a high ability to disperse single-walled carbon nanotubes (SWNTs) in aqueous media and to form hybrids. These hybrids are used to grow layer-by-layer thin films of controlled thickness. Thanks to the presence of SWNTs, these films are conducting. In this article, we describe the process by which the CNC/SWNT hybrids are obtained and discuss the electrical properties of the hybrid-based layer-by-layer films. More >

Bernal Sibaja^1,2,3, Camila Pereira Matheus^1,2, Ricardo Ballestero Mendez^1,2,Ramsis Farag^1,2,4, J. R. Vega-Baudrit³, Maria L. Auad^*,1,2

Journal of Renewable Materials, Vol.5, No.3-4, pp. 241-250, 2017, DOI:10.7569/JRM.2017.634114

Abstract The thermo-mechanical properties and linear fracture mechanics of acrylated soybean oil and the triglycidylated ether of α-resorcylic acid interpenetrated networks as a function of their weight composition are the focus of Part 2 of this article. Thermo-mechanical characterization showed that the obtained materials behave as thermoset amorphous polymers, and that both the modulus and glass transition are extremely dependent on the epoxy/acrylate weight ratio. Modulus values ranged from 0.7 to 3.3 GPa at 30 °C, and glass transition temperatures ranged from around 58 °C to approx. 130 °C. No synergistic effect on these two properties was observed. Interpenetrating networks containing… More >

Bernal Sibaja^1,2,3, Camila Pereira Matheus^1,2, Ricardo Ballestero Mendez^1,2, J. R. Vega-Baudrit³, Maria L. Auad^*,1,2

Journal of Renewable Materials, Vol.5, No.3-4, pp. 231-240, 2017, DOI:10.7569/JRM.2017.634113

Abstract Interpenetrating polymer networks (IPNs) using an epoxy phase synthesized from chemically modified α-resorcylic acid, and an acrylate phase employing acrylated soybean oil are the main focus of this study. Part 1 details the epoxidation of α-resorcylic acid with epichlorohydrin in alkaline medium, as well as the study of the polymerization and network formation of the generated epoxy-acrylate interpenetrated systems. The epoxy content of the epoxidized α-resorcylic acid was measured by means of a titration using HBr in acetic acid solution, and the functionalization was studied by FTIR. From the obtained results, mainly calorimetry and gel time determination, it was clear… More >

María Belén Colombo Migliorero, Valeria Palermo^*, Patricia Graciela Vázquez, Gustavo Pablo Romanelli

Journal of Renewable Materials, Vol.5, No.3-4, pp. 167-173, 2017, DOI:10.7569/JRM.2017.634108

Abstract The utilization and valorization of industrial waste is an effective strategy for environmental protection. Since the juice industry generates a huge amount of citrus waste, we studied the application of thermally treated orange peel in catalysis. On the other hand, Keggin heteropolyacids are excellent oxidant catalysts used as a replacement for conventional oxidants; however, their solubility in polar solvents and the low specific area limit their use as heterogeneous catalysts. The utilization of treated orange peel as heteropolyacid support for the selective oxidation of sulfides is presented here. Firstly, orange peel was thermally treated, and then it was incorporated with… More >

S.-C. Hsiao¹, M.S. Ingber²

CMC-Computers, Materials & Continua, Vol.1, No.1, pp. 51-58, 2004, DOI:10.3970/cmc.2004.001.051

Abstract The lateral migration of nonneutrally-buoyant spherical particles in Poiseuille flow is investigated numerically using the boundary element method. In particular, the steady, Navier-Stokes equations are solved using a classical domain integration method treating the nonlinear terms as pseudo-body forces. The numerical results for the lateral migration velocity are compared with experimental data. The numerical results indicate that the lateral migration velocity does not scale linearly with the Reynolds number. The methodology is extended to include non-Newtonian power-law fluids. The migration velocity is significantly affected for particles suspended in this class of fluids and can actually change direction for large values… More >

Chenxi Xiong^1,2, Xianghe Peng^1,2,3, Chunwei Zhao^1,2,4, Ning Hu^1,5,6

CMC-Computers, Materials & Continua, Vol.31, No.1, pp. 65-86, 2012, DOI:10.3970/cmc.2012.031.065

Abstract A method to reduce the sedimentation of the ferromagnetic particles in magnetorheological fluids (MRFs) is studied with numerical simulation and experiment. It shows that, making use of the magnetic field generated by a permanent magnet put simply above an MRF, the sedimentation of the particles in the MRF can be reduced remarkably. The magnetic force on a ferromagnetic particle and that on a particle chain are computed with the finite element (FE) code ANSYS. It reveals that the magnetic force on a particle-chain is much larger than the sum of the magnetic force on each individual particle in the chain… More >

Chunwei Zhao^1,2, Xianghe Peng^1,2,3, Jin Huang⁴, Ning Hu^1,5,6

CMC-Computers, Materials & Continua, Vol.30, No.3, pp. 219-236, 2012, DOI:10.3970/cmc.2012.030.219

Abstract The validity of the two conventional micro-macro descriptions for MRFs, based respectively on the exact dipole model and the simplified dipole model, is examined with the results obtained with the commercially available finite element (FE) code ANSYS. It is found that although the simplified dipole model can match better the result by FE computation, there is still a marked difference. An enhanced dipole model is then suggested, which takes into account the contribution of the magnetized particles to magnetic field. Making use of a statistical approach and neglecting the interaction between particle chains, a micro-macro approach is developed for the… More >

Leiting Dong¹, Satya N. Atluri1¹

CMC-Computers, Materials & Continua, Vol.30, No.1, pp. 39-82, 2012, DOI:10.3970/cmc.2012.030.039

Abstract In this paper, as an extension to the authors's work in [Dong and Atluri (2011a,b, 2012a,b,c)], three-dimensional Trefftz Voronoi Cells (TVCs) with ellipsoidal voids/inclusions are developed for micromechanical modeling of heterogeneous materials. Several types of TVCs are developed, depending on the types of heterogeneity in each Voronoi Cell(VC). Each TVC can include alternatively an ellipsoidal void, an ellipsoidal elastic inclusion, or an ellipsoidal rigid inclusion. In all of these cases, an inter-VC compatible displacement field is assumed at each surface of the polyhedral VC, with Barycentric coordinates as nodal shape functions. The Trefftz trial displacement fields in each VC are… More >

L. Dong¹, S. N. Atluri¹

CMC-Computers, Materials & Continua, Vol.29, No.2, pp. 169-212, 2012, DOI:10.3970/cmc.2012.029.169

Abstract In this paper, three-dimensionalT-Trefftz Voronoi Cell Finite Elements (VCFEM-TTs) are developed for micromechanical modeling of heterogeneous materials. Several types of VCFEMs are developed, depending on the types of heterogeneity in each element. Each VCFEM can include alternatively a spherical void, a spherical elastic inclusion, a spherical rigid inclusion, or no voids/inclusions at all.In all of these cases, an inter-element compatible displacement field is assumed at each surface of the polyhedral element, with Barycentric coordinates as nodal shape functions.The T-Trefftz trial displacement fields in each element are expressed in terms of the Papkovich-Neuber solution. Spherical harmonics are used as the Papkovich-Neuber… More >