Studies on the mechanics of plant cells usually focus on understanding the effects of turgor pressure and properties of the cell wall (CW). While the functional roles of the underlying cytoskeleton have been studied, the extent to which it contributes to the mechanical properties of cells is not elucidated. Here, we study the contributions of the CW, microtubules (MTs) and actin filaments (AFs), in the mechanical properties of Nicotiana tabacum cells. We use a multiscale biomechanical assay comprised of atomic force microscopy and micro-indentation in solutions that (i) remove MTs and AFs and (ii) alter osmotic pressures in the cells. To compare measurements obtained by the two mechanical tests, we develop two generative statistical models to describe the cell’s behaviour using one or both datasets. Our results illustrate that MTs and AFs contribute significantly to cell stiffness and dissipated energy, while confirming the dominant role of turgor pressure.

High-entropy composites (HECs) were subjected to severe straining by high-pressure torsion (HPT) to evaluate their influence on the evolution of microstructure and deformation behavior. Severe straining leads to a homogeneously strained microstructure and inhomogeneous micro-shear bands in these HECs. Nb addition in HECs varies the microstructure from single phase to eutectic, and the Vickers microhardness in HPT HECs increases to 7.45 GPa. Nb addition up to x = 0.80 in as-cast HECs improves the strength of these materials at the expense of its plasticity. Nevertheless, severe straining provides a better combination of strength and ductility without sacrificing its plasticity. Such improvement in properties is attributed to the evolved microstructural features, formation of “transformation-shear bands (T-SBs)” and “deformation-shear bands (D-SBs)” at severe straining. This assures the homogeneous deformation by shear banding and suggests that shear banding is the dominant deformation mechanism when the lamellar spacing becomes saturated upon severe straining.

In this paper, a modeling method was introduced for SiC particle reinforced aluminum matrix composite. Micro-indentation technique was used to study the micro properties of both SiC particles and aluminum matrix with Micro-Compression-Tester. Mechanical properties like Young's modulus and hardness were calculated using Oliver and Pharr method. After repeated experiments, the average Young's modulus and the hardness of matrix and particle were calculated as 76.8 and 334.7 GPa, 1.58 and 32.56 GPa, respectively. During the indentation experiments on particle, the phenomenon of particle acting as “second indenter” was detected from the recorded P–h curves. Besides, the material elastic–plastic properties of matrix were analyzed using inverse method. Based on the micro material properties from indentation, the indentation processing of particle as second indenter has been simulated. Also, the simulation model at micro scale has been established by using such material properties for further investigation.

Lors de leur cycle de fabrication, des contraintesrésiduelles sont générées notamment dans la partie fragiled'assemblages céramique/métal. Ces dernières sont responsables del'amorçage et de l'arrêt des fissures générées par ce cycle,mettant en défaut les traitements probabilistes de la rupturebasés sur l'hypothèse du maillon le plus faible. Un modèleprobabiliste de fissuration est proposé et permet d'appréhender detels arrêts. Une extension de ce modèle considère la fiabilité desassemblages soumis à de la fatigue statique. Une méthodologied'identification des paramètres aléatoires microstructuraux estproposée. La démarche est ensuite appliquée à la prévision de ladurée de vie d'un composant industriel.