A Mean-Field Homogenization Approach to Predict Fracture in As-Quenched Microstructures of Ductibor® 500-AS Steel: Characterization and Modelling

2021 ◽  
pp. 111137
Author(s):  
Pedram Samadian ◽  
Clifford Butcher ◽  
Michael J. Worswick
Keyword(s):  
Mean Field ◽  
Homogenization Approach

Design of Discontinuous Fiber Reinforced Injection Molded Polymer Matrix Composite Parts

2014 ◽  
Vol 633-634 ◽  
pp. 266-269 ◽  
Author(s):  
Zoltan Major ◽  
Martin Reiter
Keyword(s):  
Mean Field ◽  
Orientation Distribution ◽  
Fiber Reinforced ◽  
Glass Fiber Reinforced ◽  
Fiber Orientation Distribution ◽  
Discontinuous Fiber ◽  
Homogenization Approach ◽  
Component Strength ◽  
Injection Molded ◽  
Phd Thesis

Injection molded discontinuous fiber reinforced components are widely used in many demanding engineering applications and are exposed to a complex combination of thermo-mechanical loads. Mean field homogenization approach was successfully applied for predicting the global stiffness behavior over wide part geometry complexity, fiber orientation distribution (FOD) and loading situations including loading rate and temperature dependence. The prediction of the component strength, however, is significantly more complicated and requires additional and theoretical considerations as well as the application of various numerical tools and sophisticated experiments. To overcome above difficulties the MFH technique was extended with the first pseudo grain failure or damage (FPGF or FPGD) approach proposed by the research group of Doghri [1] elaborated in detail using short glass fiber reinforced PP-GF in the PhD Thesis of Reiter [2] and shortly described in this study.

A two-stage homogenization for modelling of elastic-plastic functionally graded composites

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Witold Ogierman
Keyword(s):  
Volume Fraction ◽  
Mean Field ◽  
Functionally Graded ◽  
Two Stage ◽  
Graded Materials ◽  
Content Type ◽  
Elastic Plastic ◽  
Functionally Graded Composites ◽  
Homogenization Approach ◽  
Arbitrary Volume

Purpose The purpose of this study is to develop a homogenization approach that ensures both high accuracy and time-efficient solution for elastic-plastic functionally graded composites. Design/methodology/approach The paper presents a novel two-stage hybrid homogenization approach that combines advantages of the mean field homogenization and homogenization based on the finite element method (FEM). The groundbreaking nature of the developed approach is associated with division of the hybrid homogenization procedure into two stages, which allows to very efficiently determine the solution for arbitrary volume fraction of the reinforcement. This paper concerns also on modelling of composites with randomly distributed prolate and oblate particles. For this purpose, the hybrid homogenization was implemented in the framework of the discrete orientation averaging procedure involving pseudo-grain discretization method. Findings Agreement between the results obtained using the proposed approach and the standard FEM-based homogenization is very good (up to the volume fraction of 0.3). Originality/value The proposed two-stage homogenization approach allows to obtain the solution for materials with arbitrary volume fraction of the reinforcement very efficiently; therefore, it is highly beneficial for the two-scale modeling of nonlinear functionally graded materials and structures.

scholarly journals Design and Development of Hybrid Al2O3 Based Composites with Toughening and Self-Lubricating Second-Phase Inclusions

Materials ◽  
2019 ◽  
Vol 12 (15) ◽  
pp. 2378 ◽  
Author(s):  
Akhtar ◽  
Waqar ◽  
Hakeem ◽  
Arif ◽  
Al-Athel
Keyword(s):  
Fracture Toughness ◽  
Hybrid Composites ◽  
Mean Field ◽  
Material Design ◽  
Computational Design ◽  
Ceramic Composites ◽  
Second Phase ◽  
Homogenization Approach ◽  
Single Inclusion ◽  
Al2o3 Matrix

Polycrystalline ceramics, such as alumina (Al2O3), are brittle and they generally wear by fracture mechanism, which limits their potential in tribological applications. In the present work, computational design tools are used to develop hybrid Al2O3 composites reinforced with best combinations of toughening and self-lubricating second-phase particles for cutting tool inserts in dry machining applications. A mean-field homogenization approach and J-integral based fracture toughness models are employed to predict the effective structural properties (such as elastic modulus and fracture toughness) and related to the intrinsic attributes of second- phase inclusions in Al2O3 matrix. Silicon carbide (SiC), boron nitride (cBN and hBN), zirconia (ZrO2), graphite, titanium dioxide (TiO2), and titanium carbide (TiC) were found the most suitable candidates to be added in Al2O3 matrix as individual or hybrid combinations. A series of samples including standalone Al2O3, single inclusion composites (Al2O3/SiC, Al2O3/cBN) and hybrid composites (Al2O3/SiC/cBN, Al2O3/SiC/TiO2 and Al2O3/SiC/graphite) are sintered by Spark Plasma Sintering (SPS) for validation purpose. Properties of the sintered composites are measured and compared with the proposed computational material design. Composition and phase transformation of the sintered samples are studied using X-Ray diffraction (XRD) and Raman spectroscopy, while their morphology is studied using Field Emission Scanning Electron Microscope (FESEM). The presented nontraditional material design approach is found to significantly reduce experimental time and cost of materials in developing toughened and anti-friction ceramic composites.

On closed-loop equilibrium strategies for mean-field stochastic linear quadratic problems

2020 ◽  
Vol 26 ◽  
pp. 41
Author(s):  
Tianxiao Wang
Keyword(s):  
Optimal Control ◽  
Closed Loop ◽  
Optimal Control Problems ◽  
Mean Field ◽  
Open Loop ◽  
Time Inconsistency ◽  
Control Problems ◽  
Linear Quadratic ◽  
Linear Quadratic Optimal Control ◽  
Equilibrium Strategies

This article is concerned with linear quadratic optimal control problems of mean-field stochastic differential equations (MF-SDE) with deterministic coefficients. To treat the time inconsistency of the optimal control problems, linear closed-loop equilibrium strategies are introduced and characterized by variational approach. Our developed methodology drops the delicate convergence procedures in Yong [Trans. Amer. Math. Soc. 369 (2017) 5467–5523]. When the MF-SDE reduces to SDE, our Riccati system coincides with the analogue in Yong [Trans. Amer. Math. Soc. 369 (2017) 5467–5523]. However, these two systems are in general different from each other due to the conditional mean-field terms in the MF-SDE. Eventually, the comparisons with pre-committed optimal strategies, open-loop equilibrium strategies are given in details.

Mean field theory of n-layer unbinding

1993 ◽  
Vol 3 (3) ◽  
pp. 385-393 ◽  
Author(s):  
W. Helfrich
Keyword(s):  
Field Theory ◽  
Mean Field Theory ◽  
Mean Field
Sign in / Sign up

Export Citation Format

Share Document