scholarly journals Self-consistent, polycrystal rate-independent crystal plasticity modeling for yield surface determination

2021 ◽  
Author(s):  
Semih Perdahcioglu ◽  
Shahrzad Mirhosseini ◽  
Ton van den Boogaard
Keyword(s):  
Crystal Plasticity ◽  
Yield Surface ◽  
Full Field ◽  
Macroscopic Models ◽  
Aggregate Behavior ◽  
Backward Euler ◽  
Self Consistent ◽  
Homogenization Scheme ◽  
The Difference ◽  
Homogenization Methods

The evolution of the macroscopically observed yield surface has been the subject of many studies due to its significant effect on the numerical simulation of metal forming processes. Although macroscopic models exist that aim to define this evolution accurate data for calibration as well as validation of these models are difficult to obtain. One common approach is to use crystal plasticity simulations for analyzing the mesoscopic behavior followed by a homogenization scheme for gathering the aggregate behavior. In this study a similar approach is followed the difference being the choice of the crystal plasticity and homogenization methods. A rate-independent crystal plasticity framework where all slip system activities are solved implicitly using a backward Euler approach in combination with an interior point method for constrained optimization is used for single crystal behavior. The aggregate behavior is obtained using a self-consistent analytical homogenization scheme. The results of the homogenization scheme are compared against full-field crystal plasticity finite element simulations. The determination of the yield surface is done by considering the macroscopic behavior where the strain rate direction and magnitude changes over a threshold during stress-based loading.

SCONES: Self-Consistent Neural Network for Protein Stability Prediction Upon Mutation

2021 ◽  
Author(s):  
Yashas Samaga B L ◽  
Shampa Raghunathan ◽  
U. Deva Priyakumar
Keyword(s):  
Neural Network ◽  
Machine Learning ◽  
Protein Stability ◽  
Data Augmentation ◽  
Stability Prediction ◽  
Structural Environment ◽  
Self Consistent ◽  
The Difference ◽  
Protein Sequence Space ◽  
New Machine

<div>Engineering proteins to have desired properties by mutating amino acids at specific sites is commonplace. Such engineered proteins must be stable to function. Experimental methods used to determine stability at throughputs required to scan the protein sequence space thoroughly are laborious. To this end, many machine learning based methods have been developed to predict thermodynamic stability changes upon mutation. These methods have been evaluated for symmetric consistency by testing with hypothetical reverse mutations. In this work, we propose transitive data augmentation, evaluating transitive consistency, and a new machine learning based method, first of its kind, that incorporates both symmetric and transitive properties into the architecture. Our method, called SCONES, is an interpretable neural network that estimates a residue's contributions towards protein stability dG in its local structural environment. The difference between independently predicted contributions of the reference and mutant residues in a missense mutation is reported as dG. We show that this self-consistent machine learning architecture is immune to many common biases in datasets, relies less on data than existing methods, and is robust to overfitting.</div><div><br></div>

Study on the Relationship between Supervisors' Remuneration in Listed Companies and Tobacco Control Measures

2021 ◽  
Vol 7 (6) ◽  
pp. 5074-5086
Author(s):  
Miao Wang ◽  
Pengfei Li
Keyword(s):  
Theoretical Study ◽  
Company Law ◽  
Theory And Practice ◽  
Control Measures ◽  
Clear Understanding ◽  
Corporation Governance ◽  
Legal Principle ◽  
Self Consistent ◽  
The Difference ◽  
The Relationship

Objectives: At present, the theoretical study on supervisors' remuneration under the Company Law is still too principled, and many "chaos" occur in the remuneration practices for supervisors. First, the lack of clear understanding of the incentive function and institutional specificities of supervisors' remuneration results in many problems in the application of supervisors' remuneration in practice, as well as the ignoration of the Board of Supervisors in corporation governance. Second, rather than reaching the intended effect, the legislative approach of authorized "blank" intentionally adopted under the Company Law leaves an inducement for the ineffective supervision of supervisors in practice. Third, there is not only a lack of theoretically self-consistent discussion on the special problems of concurrent supervisors and employee supervisors' remuneration, but also a divorce of the institutional structure and application from good expectations. If the research background of the problem is placed in "tobacco regulatory science", it will be found that there is no inevitable connection between supervisors' compliance expectations and remuneration, but mainly depends on the provisions of legislation. Going back and forth between theory and practice of supervisors' remuneration, this paper combs and interprets the issue of supervisors' remuneration from the perspective of the legislative provisions and theoretical study under the Company Law, and analyzes the difference between the reality and the necessity of the Company Law with respect to the issue of supervisors' remuneration in the light of the legal principle of the Company Law, with the view to improvement of the rules of the Company Law.

scholarly journals Collagen Structure and Mechanical Properties of the Human Sclera: Analysis for the Effects of Age

2015 ◽  
Vol 137 (4) ◽  
Author(s):  
Baptiste Coudrillier ◽  
Jacek Pijanka ◽  
Joan Jefferys ◽  
Thomas Sorensen ◽  
Harry A. Quigley ◽  
...  
Keyword(s):  
Material Properties ◽  
Collagen Fiber ◽  
Image Correlation ◽  
Mechanical Anisotropy ◽  
Matrix Stiffness ◽  
Fiber Structure ◽  
Human Donor ◽  
Full Field ◽  
X Ray Scattering ◽  
The Difference

The objective of this study was to measure the collagen fiber structure and estimate the material properties of 7 human donor scleras, from age 53 to 91. The specimens were subjected to inflation testing, and the full-field displacement maps were measured by digital image correlation. After testing, the collagen fiber structure was mapped using wide-angle X-ray scattering. A specimen-specific inverse finite element method was applied to calculate the material properties of the collagen fibers and interfiber matrix by minimizing the difference between the experimental displacements and model predictions. Age effects on the fiber structure and material properties were estimated using multivariate models accounting for spatial autocorrelation. Older age was associated with a larger matrix stiffness (p = 0.001), a lower degree of fiber alignment in the peripapillary sclera (p = 0.01), and a lower mechanical anisotropy in the peripapillary sclera (p = 0.03).

Forming Limit Analysis of Hexagonal Metal Considering Volume Fraction of Deformation Twinning

2019 ◽  
Vol 794 ◽  
pp. 226-231
Author(s):  
Tomoaki Koga ◽  
Yuichi Tadano
Keyword(s):  
Plastic Deformation ◽  
Finite Element ◽  
Crystal Plasticity ◽  
Limit Analysis ◽  
Volume Fraction ◽  
Deformation Twinning ◽  
Forming Limit ◽  
Strain Paths ◽  
Homogenization Scheme ◽  
Slip Deformation

In the plastic deformation of hexagonal metals, deformation twinning plays an important role as well as slip deformation. Therefore, a modelling of deformation twinning is essential in the crystal plasticity modeling. In this study, a model considering the volume fraction of deformation twinning is presented in the framework of crystal plasticity, and it is combined with a finite element-based homogenization scheme to represent the polycrystalline behavior. The presented model is adopted to a sheet necking formulation. Plastic flow behaviors under several strain paths are evaluated using the present framework, and the effect of volume fraction of deformation twinning on the formability of hexagonal metal is discussed.

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