A generic architecture to synchronise design models issued from heterogeneous business tools: towards more interoperability between design expertises

Product development involves many experts collaborating to the same design goal. Every expert has his own formalisms and tools leading to a high heterogeneity of information systems supporting design activities. Interoperability became a major challenge to avoid information incompatibility along the product life cycle. To synchronise heterogeneous representations of product will be a major step to integrate expert activities. In this paper, the authors propose a meta-model framework to connect together heterogeneous design models. This meta-model framework is used to formalise possible interactions between heterogeneous representations. Interaction formalisation is considered as a key point to synchronise heterogeneous models and to provide more interoperability between various computer assisted systems. The synchronisation loop is also presented as a major sequence of activities to manage collaborative design. Tools to support synchronisation are proposed. However, through a basic case study, authors highlight what can be automated and where human intervention is still expected.     

Size Effects in Thin Face-Centered Cubic Metals for Different Complex Forming Loadings

Influence of the size effects on the mechanical behavior of face-centered cubic metals was studied for complex loadings close to microforming ones. The effect of a reduction in thickness (t) over grain size (d) ratio on the mechanical behavior for high-purity nickel and copper is investigated for three different loadings by tensile and Nakazima tests (plane strain conditions and balanced biaxial expansion). Experimental results highlight a strong degradation of the mechanical properties of Cu and Ni when the t/d ratio is reduced below a critical value, independently of the strain path. However, this effect occurs if the equivalent plastic strain is larger than a critical level which is strain path dependent and related to the stress triaxiality. The current study reveals that plastic anisotropy is also affected by size effects. An excellent correlation is obtained between the t/d ratio and the thickness reduction, through the mean normal plastic anisotropy parameter which is widely used to estimate sheet formability. A size effect map based on forming limit diagrams is proposed to depict the optimal conditions of microforming.     

Effects of Extraction Solvents and Provenances on Phenolic Contents and Antioxidant Activities of Cumin (Cuminum cyminum L.) Seeds

Polyphenol contents and 1,1-diphenyl-2-picrylhydrazyl radical (DPPH) scavenging activity of cumin (Cuminum cyminum L.) seed extracts were compared depending on their geographical origin (Tunisia and India: TCS and ICS, respectively) and the extraction solvent polarity. The ??-carotene bleaching assay, the chelating ability and the reducing power of the most promising solvent extracts were also assessed. In addition, TCS and ICS extracts were acid-hydrolyzed and the phenolics identified by reversed-phase high-performance liquid chromatography (HPLC). Seed phenolic contents and antioxidant activity appeared to be accession and solvent dependent. Extraction with 80% acetone led to the highest polyphenol (18.60 and 16.50?mg gallic acid equivalents (GAE)/g dry weight (DW)), flavonoid (5.91 and 4.99?mg catechin equivalents (CE)/g DW) and tannin (83.23 and 80.23?mg CE/g DW) contents, respectively for TCS and ICS. DPPH scavenging activity, ??-carotene bleaching assay, chelating ability and reducing power were maximal in 80% acetone for both TCS and ICS. HPLC analysis revealed several phenolic compounds in C. cyminum seeds, with p-coumaric (4.83 and 2.33?mg/g DW), trans-2-dihydrocinnamic (1.09 and 1.20?mg/g DW) and rosmarinic (0.70 and 1.04?mg/g DW) acids as major phenolics in TCS and ICS, respectively. Thus, phenolic composition of cumin seeds is also origin dependent. Taken together, our findings indicate that cumin might constitute a rich and novel source of natural antioxidants as food additives in food industry and that acetone 80% would be the most appropriate solvent for seed extraction.     

Numerical modeling of damage evolution of DP steels on the basis of X-ray tomography measurements

In order to couple the damage evolution and the stress state of DP steel grades, a new advanced GTN (Gurson-Tvergaard-Needleman) model was developed and implemented into a finite element code. This model is an extension of the original one. It takes into account the plastic anisotropy and the mixed (isotropic + kinematic) hardening of the matrix. Two different methods to compute the void volume fraction were developed and used within the constitutive equations. The first method is new and allows the accurate modeling of the observations of damage initiation and growth in DP steels measured using high-resolution X-ray absorption tomography ( [Bouaziz et al., 2008] and [Maire et al., 2008]). The second method is classic and assumes the additive decomposition of the total void volume fraction into a nucleation and a growth part. A parametric study is carried out to assess the effect of the kinematic hardening on some mechanical parameters such as the equivalent plastic strain, the triaxiality and the porosity. The numerical predictions are favorably compared to the experimental results.     

Polyphenol composition and antioxidant activity of cumin (Cuminum cyminum L.) seed extract under drought

This research evaluated the effect of drought on total and individual polyphenol contents as well as the antioxidant activities of cumin (Cuminum cyminum L.) seeds of 2 geographic origins, Tunisia (TCS) and India (ICS). Plants were treated with different levels of water deficit: control. Our results indicated that, in both varieties, moderate water deficit (MWD) improved the number of umbels per plant as well as the number of umbellets per umbel and the seed yield, in comparison to the control, but it decreased under severe water deficit (SWD). Besides, total phenolic contents were higher in the treated seeds and drought increased the level of total and individual polyphenols. This increase was appreciably more important in TCS than in ICS. Moreover, antioxidant activities of the extracts were determined by 4 different test systems, namely 2,2-diphenyl-1-picrylhydrazyl, β-carotene/linoleic acid chelating, and reducing power assays, and showed that treated seeds exhibited the highest activity, for both TCS and ICS.     

On the numerical integration of an advanced Gurson model

This article is focused on a new extended version of Gurson's model (J. Eng. Mater. Technol. 1977; 99 :2–15), its numerical integration scheme and its consistent tangent matrix being within an FE code. First, this new advanced Gurson model is proposed, which is an extension of the original to take into account plastic anisotropy and mixed (isotropic+kinematic) hardening. In this paper, only the growth phase of cavities is considered (the nucleation of new voids is ignored). Second, a new numerical algorithm for the integration of this new Gurson model is presented. The algorithm is implicit in all variables and is unconditionally stable. This algorithm is generic and could be used for other anisotropic yield functions and other hardening laws. Third, the consistent tangent matrix is computed in an explicit way by exact linearization of the constitutive equations. To check its efficiency and robustness, the proposed integration algorithm is compared, under some simplified assumptions and choices, with the algorithms of Aravas (Int. J. Numer. Meth. Engng 1987; 24 :1395–1416) and Kojic (Int. J. Numer. Meth. Engng 2002; 53 (12):2701–2720). The performance of the developed consistent modulus, compared to other techniques for the computation of the tangent matrix is assessed. The paper ends with numerical simulations of tensile tests on homogeneous and notched specimens. Copyright © 2010 John Wiley & Sons, Ltd.     

Characterization of composite materials based on LDPE loaded with agricultural tunisian waste

This study investigated the use of an available agricultural Tunisian vine stem waste as a filler material. Composites of green materials were prepared using vine stems as filler and low density polyethylene (LDPE) as a matrix. A series of composite films was prepared by different loadings of the vine stem waste with 10–50% of the filler in 10% intervals. The ensuing materials were characterized by several techniques. The morphology of the composites was investigated using scanning electron microscopy (SEM). The thermal and mechanical properties were studied using differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA), respectively. The results indicated that vine‐stem based particles enhanced the thermo‐mechanical properties of the thermoplastic matrix and demonstrated that this available lignocellulosic biomass of vine stems can be considered to be a promising filler material. However, the obtained result of water absorption indicated that the maximum limit of the filler content should not exceed 30% of vine stems. POLYM. COMPOS., 36:817–824, 2015. © 2014 Society of Plastics Engineers     

Interests and limitations of nanoindentation for bulk multiphase material identification: Application to the β phase of Ti-5553

This paper focuses on the numerical modeling of nanoindentation tests. The first goal of this study is to collect essential material parameters and boundary conditions from the literature and to complete the data required to accurately model nanoindentation tests. The second goal of this study consists in validating the material parameters identified from macroscopic tensile tests of the body-centered cubic β phase of Ti-5553, a new generation of titanium alloy. This validation is performed looking at experimental and numerical nanoindentation curves obtained for different grain orientations.