A5079667143- Metal Forming Simulation Techniques
- Metallurgy and Material Forming
- Microstructure and mechanical properties
- High-Velocity Impact and Material Behavior
- Numerical methods in engineering
- Composite Material Mechanics
- Nanoporous metals and alloys
- Advanced Mathematical Modeling in Engineering
- Anodic Oxide Films and Nanostructures
- Cellular and Composite Structures
- Laser and Thermal Forming Techniques
- Advanced Materials and Mechanics
- Magnetic Properties and Applications
- Model Reduction and Neural Networks
- Elasticity and Material Modeling
- Additive Manufacturing Materials and Processes
- Advanced Numerical Methods in Computational Mathematics
- Microstructure and Mechanical Properties of Steels
- Aluminum Alloys Composites Properties
- Innovations in Concrete and Construction Materials
- Nonlocal and gradient elasticity in micro/nano structures
- Structural Analysis of Composite Materials
- Material Properties and Failure Mechanisms
- Powder Metallurgy Techniques and Materials
- Mechanical Behavior of Composites
University of Twente
2021-2024
University of Wuppertal
2017-2022
Universität Hamburg
2014-2016
Hamburg University of Technology
2014-2016
TU Dortmund University
2009-2015
Institut für Umformtechnik (Germany)
2014
Atilim University
2009-2011
Middle East Technical University
2008-2009
Motivated by recent experimental investigations of the mechanical behavior nanoporous metal we explore an efficient and robust method for generating 3D representative volume elements (RVEs) with strikingly similar behavior. Our approach adopts Cahn's a Gaussian random field taking superposition standing sinusoidal waves fixed wavelength but in direction phase. In its theory part, our study describes closed-form expressions how solid fraction affects binarization level, mean structure size,...
We investigate the influence of various critical structural aspects such as pore density, distribution, size and number on deformation behavior nanoporous Cu64 Zr36 glass. By using molecular dynamics finite element simulations an effective strategy to control strain localization in heterostructures is provided. Depending distribution heterostructure, upon tensile loading glass showed a clear transition from catastrophic fracture localized one dominant shear band, ultimately homogeneous...
We explore the elastic and plastic Poisson's ratios, νE νP, of nanoporous gold, using digital image correlation during compression experiments including load/unload segments. The two coefficients differ significantly, with independent ligament size, L, a trend for νP∝L at not too large L. Disorder in network ligaments may explain why is smaller than predicted by lattice-based models. Finite element simulations, based on Deshpande–Fleck constitutive law, validate data analysis. law captures...
Thin-walled metamaterials based on triply periodic surfaces are relatively simple, light-weight structures that, as shown in the following, possess extraordinary material properties. As opposed to their filled counterparts, these can be tuned elastically isotropic and isotropically auxetic - latter is property of extending all directions under tensile loading one direction. Considering level topologically equivalent minimal types Primitive, Diamond, Gyroid I-WP, we focus stiffness, symmetry,...
Metamaterials are man-made, usually periodically microstructured materials with at least one uncommon property, e.g., auxeticity. Often, their properties due to specific microstructural layouts in addition constituent materials. In this work, we explore the influence of on effective elasticity a two-phase composite consisting infilled re-entrant honeycomb microstructure. We show that non-auxetic becomes auxetic if Young's modulus contrast between two phases exceeds certain critical value....
The Small Punch (SP) test serves the screening of mechanical material properties and their degradation in a virtually non-invasive way. It requires robust frameworks for derivation microstructure–mechanical property correlation. tensile yield stress σy is commonly associated with an elastic-plastic transition force Fe via = αFe/h2 h denoting SP disc thickness dimensionless coefficient α considered constant. Here it shown that cannot be taken as Instead new self-consistent data reduction...
We study effective elastic properties of 3D bicontinuous random composites (such as, e.g., nanoporous gold filled with polymer) considering linear and infinitesimal elasticity using asymptotic homogenization along the finite element method. For generation microstructures, a leveled-wave model based on works Cahn (1965) Soyarslan et al. (2018) is used. The influences volume size, phase contrast, relative fraction phases applied boundary conditions computed apparent moduli are investigated....
We apply physics-informed neural networks (PINNs) to first-order, two-scale, periodic asymptotic homogenization of the property tensor in a generic elliptic equation. The problem lack differentiability tensors at sharp phase interfaces is circumvented by making use diffuse interface approach. Periodic boundary conditions are incorporated strictly through introduction an input-transfer layer (Fourier feature mapping), which takes sine and cosine inner product position reciprocal lattice...
A hybrid experimental–numerical methodology is presented for the parameter identification of a mixed nonlinear hardening anisotropic plasticity model fully coupled with isotropic ductile damage accounting microcracks closure effects. In this study, three test materials are chosen: DP1000, CP1200, and AL7020. The experiments involve tensile tests smooth notched specimens two types shear tests. conducted in different directions respect to rolling direction. This helps determine plastic...
We present a systematic numerical study on temperature dependent fracture mode change in small punch tests. Following Needleman and Tvergaard (2000), we model the material as thermo-inelastic, where ductile mode, by void nucleation, growth coalescence is accounted for Gurson׳s porous metal plasticity (Gurson, 1977). The brittle cleavage Ritchie–Knott–Rice׳s deterministic maximum principal stress criterion (Ritchie et al., 1973). well-known problem of mesh dependence associated with softening...
Additive manufacturing has revolutionized the creation of complex and intrinsic structures, offering tailored designs for enhanced product performance across various applications. Architected cellular or lattice structures exemplify this innovation, customizable specific mechanical functional requirements, boasting advantages such as reduced mass, heightened load-bearing capabilities, superior energy absorption. Nonetheless, their single-use limitation arises from plastic deformation...
Abstract Materializing Continuum Damage Mechanics (CDM), numerical modeling of discrete internal cracks, namely central bursts, in direct forward extrusion process is presented. Accordingly, a thermodynamically consistent setting, local Lemaitre variant damage model with quasi‐unilateral evolution coupled hyperelastic‐plasticity. The formulations are constructed the principal axes where simultaneous integration schemes efficiently developed. To this end, framework implemented as ABAQUS/VUMAT...
Materials displaying negative Poisson’s ratio, referred to as auxeticity, have been found in nature and created engineering through various structural mechanisms. However, uniting auxeticity with high strength stiffness has challenging. Here, combining situ nanomechanical testing microstructure-based modeling, we show that the leading part of limpet teeth successfully achieves this combination properties a unique microstructure consisting an amorphous hydrated silica matrix embedded bundles...
Extended crystal plasticity theories are well established to study size-dependent hardening of metals. Surface and inner grain boundary conditions play a significant role for crystals at small scales as they affect the dislocation activity and, hence, alter strength strain behavior. Conventional micro conditions, i.e., microhard microfree, unable capture underlying physics describe ideal over-simplified surface/interface conditions. In this work, advanced gradient extended introduced map...
Gradient structured materials have been proven to excellent mechanical properties, such as strength–ductility synergy and strain hardening. In this study, the deformation mechanism of heterostructured bulk aluminum with submicron mechanisms was investigated using a mechanism-based strain-gradient plasticity model, whose gradient information obtained discrete computation method. The model then used simulate bending material investigate extra microstructure characterized electron backscattered...