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Stiffening behaviour of the heterogeneous H-T, Mancarella and ROM models with increasing surface tension. For í µí»¾ = 0.001 N/m and E = 3 kPa, we have í µí°¿ = 0.33 í µí¼í µí± which is smaller than í µí± =
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Liquid droplets in solid soft composites have been attracting increasing attention in biological
applications. In contrary with conventional composites, which are made of solid elastic inclusions, available material
models for composites including liquid droplets are for highly idealized configurations and do not include all material
real parameter...
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... surface tension í µí»¾ can also vary the value of í µí°¿. As shown in Figure 8, by increasing í µí»¾, the capillary length also increases and for í µí»¾ = 0.001 and E = 3 kPa, we have í µí°¿ = 0.33 í µí¼í µí± which is smaller than í µí± = 1 í µí¼í µí±; thus, the softening effect happens. The more increase in í µí»¾, the more increase in í µí°¿ happens and since í µí± = 1 í µí¼í µí± is constant, the stiffening effect becomes intense. ...
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Citations
... Multiscale models contain multiple connected models at different length scales which are capable to address different features of the problem. Ghasemi (2021) has presented a computational framework bridging models from micro-to macroscale and developed a multiscale material model for heterogeneous liquid droplets in solid soft composites. The model predicts, via a random approach, the effective elastic modulus of a typical polydisperse liquid in solid soft composite. ...
... Subsequently we summarize the equations of the multiscale setup. To find more about the formulations, the readers are referred to Ghasemi (2021) and references therein. In the analysis, homogenization models are build at multiple length scales. ...
The goal of this paper is to evaluate the uncertainties in soft composites composed of a soft solid as the matrix filled by incompressible liquid inclusions. The surface stresses at the liquid–solid interfaces can significantly impact the elastic deformation of the bulk composite at the macroscale. Depending on the characteristic dimension, a stiffening or softening can happen. We model the elastic behavior employing a stochastic multiscale approach and counting on well established rules for composites. Insights on the mechanics of elasto-capillary coupling are provided considering the heterogeneity at different length scales. Global sensitivity analysis is performed to quantify the effect of variation in the material properties, surface tension, the size, and the random dispersion and agglomerations of the inclusions. The influence of the model choice at the mesoscale on the uncertainty of the response is also taken into account as an additional source of uncertainty. The results show that the relative stiffness is mainly influenced by the uncertainties in the size of liquid inclusions and the surface tension, while the remaining parameters show a significant interaction effects.
... Therefore, isogeometric analysis (IGA) with higher order derivatives and continuity of NURBS basic function can be considered a suitable numerical method, because it easily fulfills the weak formulation of nano/microplates. Recently, IGA has been successfully applied to several engineering fields such as flexoelectric materials [29], optimization [30,31], composites [32,33], and nanoplates [34,35]. This paper aims to sign in this research opening using an NURBS formulation for the size-dependent nonlocal strain gradient analysis of the FG GPLRC nanoplates. ...
In this paper, a nonlocal strain gradient isogeometric model based on the higher order shear deformation theory for free vibration analysis of functionally graded graphene platelet-reinforced composites (FG GPLRC) plates is performed. Various distributed patterns of graphene platelets (GPLs) in the polymer matrix including uniform and non-uniform are considered. To capture size dependence of nanostructures, the nonlocal strain gradient theory including both nonlocal and strain gradient effects is used. Based on the modified Halpin–Tsai model, the effective Young’s modulus of the nanocomposites is expressed, while the Poisson’s ratio and density are established using the rule of mixtures. Natural frequencies of FG GPLRC nanoplates is determined using isogeometric analysis. The effects played by strain gradient parameter, distributions of GPLs, thickness-to-length ratio, and nonlocal parameter are examined, and results illustrate the interesting dynamic phenomenon. Several results are investigated and considered as benchmark results for further studies on the FG GPLRC nanoplates.
The compression-induced deformation mechanisms of boron carbide (B4C) have not been well understood due to its complex crystal structure. Here, we investigate the mechanical behaviors and deformation mechanisms of B4C under various compression conditions, using molecular dynamics simulations with a machine-learning force field. Two structural transitions in B4C under bulk compression are identified: the formation of new chains–icosahedra bonds, and icosahedral deconstruction. The former triggers the “pop-in” event observed in the nanoindentation experiments due to chain bending, while the latter facilitates icosahedral sliding and amorphization. Furthermore, the results reveal a mechanism involving an intermediate structure characterized by the development of new chains–icosahedra bonds across the entire model, followed by the amorphization process. This mechanism induced by increased stress in icosahedra due to the new chains–icosahedra bond formation plays an important role in significantly improving the strength and ductility of B4C. In contrast, B4C with free surfaces or nanopores exhibits a direct transformation from chain bending to icosahedral deconstruction without the intermediate structure formation, consequently reducing strength and ductility. However, this intermediate configuration is not stable and maintained only under stress, because structural recovery within non-amorphized regions occurs after amorphization under quasi-static compression with a relaxed stress state. This study provides a thorough understanding of the deformation behaviors and mechanisms of B4C.