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Abstract: Ductile fracture of a C–Mn steel was characterized by tensile tests performed in a large temperature range (from 20 to 350°C) on round notched and CT specimens. The experimental results revealed a sharp decrease in fracture strain and fracture toughness around 200°C. These temperatures correspond to the domain of dynamic strain ageing (DSA). The Portevin-Le Chatelier (PLC) effect, which is the most classical manifestation of DSA, was simulated for round notched and CT specimens with a mechanical constitutive model which includes the strain ageing effect and the stiffness of the testing machine. It is shown that changes in stiffness can amplify the DSA effect. 3D-Modeling was used to correctly capture the complex space-time correlation of strain localization, particularly in side-grooved CT specimens. The results were compared to classical elastic–plastic simulations. The local approach to fracture was then applied to predict the ductile fracture of round notched specimens using the Rice and Tracey criterion. In the DSA domain, the approach used in this study predicts a decrease of the fracture strain which is less than observed experimentally. [Copyright &y& Elsevier]

Abstract: Finite element simulations of PLC effects in notched and CT (compact tensile) specimens of aluminium alloys are presented, based on a macroscopic PLC constitutive model. They predict the formation and propagation of intense strain rate localization bands. In particular, the predicted size of the plastic zone around the crack tip in a pre-cracked CT specimen is compared to the value found when using a standard elastoplastic model neglecting PLC effects. [Copyright &y& Elsevier]

• Complex foods with identical composition but different microstructures were designed. • Food structure strongly influences both the kinetics and final extent of lipid digestion. • The key moments of digestion are highlighted by multidimensional statistical analysis. • The food structure impacts on the micronutrient bioaccessibility. • This impact depends on the hydrophilicity vs hydrophobicity of the micronutrient. Digestion is a mechanical and chemical process that is only partly understood, and even less so for complex foods. In particular, the issue of the impact of food structure on the digestion process is still unresolved. In this study, the fate of four micronutrient-enriched foods with identical compositions but different microstructures (Custard, Pudding, Sponge cake, Biscuit) was investigated using the 3-phase in vitro model of human digestion developed by the INFOGEST network. Matrix disintegration and hydrolysis of macronutrients (proteins, lipids and carbohydrates) were monitored during the three phases of digestion using biochemical techniques, size-exclusion chromatography, thin-layer chromatography and gas chromatography. Micronutrient release (vitamin B9 and lutein) was monitored using reverse-phase chromatography. Food structure did not greatly influence macronutrient hydrolysis, except for lipolysis that was four-times higher for Biscuit compared to Custard. However, the bioaccessibility of both micronutrients depended on the food structure and on the micronutrient. Vitamin B9 release was faster for Biscuit and Sponge cake during the gastric phase, whereas lutein release was higher for Custard during the intestinal step. Extensive statistical analysis highlighted the impact of food structure on the digestion process, with different digestion pathways depending on the food matrix. It also made it possible to characterise the gastric step as a predominantly macronutrient solubilisation phase, and the intestinal step as a predominantly hydrolysis phase. [ABSTRACT FROM AUTHOR]