During early development, the tubular embryonic chick brain undergoes a combination of progressive ventral bending and rightward torsion, one of the earliest organ-level left–right asymmetry events in development. Existing evidence suggests that bending is caused by differential growth, but the mechanism for the predominantly rightward torsion of the embryonic brain tube remains poorly understood.
In this work, the evolution of the dislocations microstructure in single crystal two-phase superalloy microcrystals under monotonic loading has been studied using the three-dimensional discrete dislocation dynamics (DDD) method. The DDD framework has been extended to properly handle the collective behavior of dislocations and their interactions with large collections of arbitrary shaped precipitates. Few constraints are imposed on the initial distribution of the dislocations or the precipitates, and the extended DDD framework can support experimentally-obtained precipitate geometries.
My doubt is related with the obtenion of the true stress when using incrementally linear constitutive models (hypoelastic models). These models, alternatively to total stress strain models, related increment of strain and increment of stress. The predicted stress is obtained by adding to the previous stress the stress increment obtained by using the tangent matrix. By using total stress-strain models it is clear that the true stress is obtained by substituting the current strain into the constitutive equation. How do we do this for hypoelastic models?
In 1979 Qian Weichang studied the slender toroidal shell systematically and derived a called Qian’s equation, then obtained a series solution with the expression of continued fractions. But Qian did not mention if the series solution can be converted to a well-known special functions. In this paper, a linear transformation has been introduced, which will transfer the equation into a Mathieu equation, whose solution can be expressed in terms of Mathieu functions. This study has revealed a intrinsic relationship between the Qian’s solution and the Mathieu solutions.
The paper gives a systematical introduction on dimensional analysis (DA), and proposes a six-steps on how to use the dimensional analysis, the universality of the DA will be shown by some typical examples, such as, point blast, pipe flow and a small sphere moving through a viscous fluid.
published: Physics and Engineering, Vol 26, No.6, pp.11-20, 2016. Invited article, in Chinese)
Since the beginning of the industrial age, material performance and design have been in the midst of innovation of many disruptive technologies. Today’s electronics, space, medical, transportation, and other industries are enriched by development, design and deployment of composite, heterogeneous and multifunctional materials. As a result, materials innovation is now considerably outpaced by other aspects from component design to product cycle. In this article, we review predictive nonlinear theories for multiscale modeling of heterogeneous materials.
I am developing a solver implemeting Polygonal Finite Element Method (PolyFEM). Currently my code can handle n-gons with nmax=6 (hexgon).
I am trying to test the code with comlex geometries for which I need to obtain polygonal meshes. PolyMesher developed by Dr Paulino's group can obtain polygonal mesh using voronoi doagrams but the code doesn't provide control over the maximum number of edges of a polygon in mesh and ends up creating octagons etc. Hence I am thinking of using a code which can convert a structured T3 mesh into hexagonal mesh.
This work deals with the quantification and application of the modified two-mode phase-field crystal model (M2PFC; Asadi and Asle Zaeem, 2015) for face-centered cubic (FCC) metals at their melting point. The connection of M2PFC model to the classical density functional theory is explained in this article. M2PFC model in its dimensionless form contains three parameters (two independent and one dependent) which are determined using an iterative procedure based on the molecular dynamics and experimental data.
I am wondering how to insert the cohesive element between every two solid elements in Abaqus, such that each element can separate with others? Is there a tool can do this and generate Abaqus input file?
In this contribution, an elasto-viscoplastic constitutive model based on the single mode EGP (Eindhoven Glassy Polymer) model is proposed to describe the deformation behaviour of solid polymers subjected to finite deformations under different stress states. The material properties of the original model are determined and calibrated from a uniaxial compression-loading test. Then, several numerical examples under different stress states are presented to illustrate the limitations.
The elastic Ericksen's problem consists of finding deformations in isotropic hyperelastic solids that can be maintained for arbitrary strain-energy density functions. In the compressible case, Ericksen showed that only homogeneous deformations are possible. Here, we solve the anelastic version of the same problem, that is we determine both the deformations and the eigenstrains such that a solution to the anelastic problem exists for arbitrary strain-energy density functions. Anelasticity is described by finite eigenstrains.
Imitating origami principles in active or programmable materials opens the door for development of origami-inspired self-folding structures for not only aesthetic but also functional purposes. A variety of programmable materials enabled self-folding structures have been demonstrated across various fields and scales. These folding structures have finite thickness and the mechanical properties of the active materials dictate the folding process. Yet formalizing the use of origami