A5000502007- Microstructure and mechanical properties
- High Temperature Alloys and Creep
- Metal and Thin Film Mechanics
- Nonlocal and gradient elasticity in micro/nano structures
- Metallurgy and Material Forming
- Aluminum Alloy Microstructure Properties
- Force Microscopy Techniques and Applications
- Advanced machining processes and optimization
- Microstructure and Mechanical Properties of Steels
- Metal Forming Simulation Techniques
- Aortic Disease and Treatment Approaches
- Cardiac Valve Diseases and Treatments
- Advanced Surface Polishing Techniques
- Aortic aneurysm repair treatments
- Solidification and crystal growth phenomena
- Composite Material Mechanics
- Fatigue and fracture mechanics
- Metallurgical Processes and Thermodynamics
- Engineering Technology and Methodologies
- Blood properties and coagulation
- Hydrogen embrittlement and corrosion behaviors in metals
- Manufacturing Process and Optimization
- Fusion materials and technologies
- Advanced materials and composites
- Numerical methods in engineering
Graz University of Technology
2017-2024
University of Bremen
2012-2016
Florida State University
2011-2014
Karlsruhe Institute of Technology
2005-2013
Fraunhofer Institute for Mechanics of Materials
2008-2011
Institute of Strength Physics and Materials Science
2003-2009
University of Edinburgh
2009
Quality and Reliability (Greece)
2006
Crystal Plasticity (CP) modeling is a powerful and well established computational materials science tool to investigate mechanical structure–property relations in crystalline materials. It has been successfully applied study diverse micromechanical phenomena ranging from strain hardening single crystals texture evolution polycrystalline aggregates. However, when considering the increasingly complex microstructural composition of modern alloys their exposure to—often harsh—environmental...
Abstract We propose a dislocation density measure which is able to account for the evolution of systems three-dimensional curved dislocations. The definition and equation this arise as direct generalizations kinematic classical tensor. allows us determine plastic distortion rate in natural fashion therefore yields kinematically closed dislocation-based theory plasticity. A self-consistent built upon accounts both long-range interactions dislocations their short-range self-interaction...
Crystal plasticity is governed by the motion of lattice dislocations. Although continuum theories static dislocation assemblies date back to 1950s, line-like character these defects posed serious problems for development a theory which based on averaged dynamics systems. Only recently geometrical problem performing meaningful averages over systems moving, oriented lines has been solved. Such averaging leads definition density tensor second order along with its evolution equation. This can be...
The development of a dislocation-based continuum theory plasticity remains one the central challenges applied physics and materials science. Developing dislocations requires solution two long-standing problems: (i) to find faithful representation dislocation kinematics with reasonable number variables (ii) derive averaged descriptions dynamics (i.e. material laws) in terms these variables. In current paper, we solve first problem, i.e. develop tensorial conservation laws for distributions...
Abstract FE simulation was applied to study the material flow during infeed rotary swaging. The neutral plane according process parameters investigated and compared with experimental results. A single forming stroke analyzed precisely by using small time points of 10 -4 s. For analysis essential steps between first contact wire forging die last before opens again are represented. In that range feed velocity is eliminated can be observed as spatial at nodes in axial direction equal 0 mm/s....
We study a continuum model of dislocation transport in order to investigate the formation heterogeneous patterns. propose physical mechanism that relates patterns with well-defined wavelength stress-driven dynamics densities tries minimize internal energy while subject dynamic constraints and density-dependent, friction-like flow stress. This leads us an interpretation resolves old ``energetic vs dynamic'' controversy regarding origin emphasizes hydrodynamic nature instability patterning,...
Background: Type B aortic dissection (TBAD) is a dangerous pathological condition with high mortality rate. TBAD initiated by an intimal tear that allows blood to flow between the wall layers, causing them separate. As result, alongside original aorta (true lumen), false lumen (FL) develops. compromises whole cardiovascular system, in worst case resulting complete rupture. Clinical studies have shown dilation and rupture of FL are related failure thrombose. Complete thrombosis has been found...
Abstract Vacancy condensation, that is, nucleation of voids from high vacancy supersaturation, plays a significant role in ductile fracture and radiation materials science. Void is commonly treated through classical theory (CNT). Various shortcomings CNT have led to the development alternative models for nucleation, collectively known as non-classical theory, other fields concerned with nucleation. In current work, we employ phase-field model (PFM) approach void where recent modification...
Abstract The miniaturization of cutting processes shows process specific size-effects like the exponential increase force k c with decreasing depth cut h. Experiments were carried out in an orthogonal turning process. influence different parameters on results was investigated separately to identify size-effects. Two materials studied: a normalized steel AISI 1045 and annealed O2. To complement experiments, parameter variations performed two-dimensional, thermo-mechanically coupled finite...
The high work hardening rate and ductility of manganese austenitic steels is mainly attributed to the strong twinning induced plasticity (TWIP) effect found in material. With a low stacking fault energy, mechanical acts as competitive mechanism more common dislocation glide. In order understand micromechanical behaviour such steels, especially with respect texture anisotropy, constitutive models for which account TWIP both orientation changes plastic are required. Using self-consistent...
Abstract We use density-based continuity equations to model strain patterns and size effects in confined plastic flow, namely, shearing of thin films microbending. To this end, we a representation terms coupled for the densities screw edge components. show how these derive from more general formulation higher-dimensional configuration space, discuss relations with other approaches proposed past. The new element here is incorporation into previous continuum formulations geometrical features...
Significant progress in our understanding of plasticity body-centered cubic (bcc) metals during the last decade has enabled rigorous multiscale modeling based on quantitative physical principles. advances have been made at atomistic level dislocation core structures and energetics associated with glide by using high-fidelity models originating from quantum mechanical These simulations revealed important details about influence non-Schmid (nonglide) stresses mobility screw dislocations bcc...
Abstract We introduce a new material point homogenization scheme – the ‘Relaxed Grain Cluster’ (RGC) based on cluster of grains and formulated in framework finite deformations. Two variants this scheme, which allow for different degrees relaxation, are compared to two derived from infinitesimal-strain grain interaction model regarding evolution texture predicted plane-strain compression commercial aluminum alloy. The RGC schemes give closest match experimental reference both -fiber -skeleton...
Cardiovascular diseases are a leading global cause of mortality. The current standard diagnostic methods, such as imaging and invasive procedures, relatively expensive partly connected with risks to the patient. Bioimpedance measurements hold promise offer rapid, safe, low-cost alternative methods. In realm cardiovascular diseases, bioimpedance methods rely on changing electrical conductivity blood, which depends local hemodynamics. However, exact dependence blood hemodynamic parameters is...
Type B aortic dissection (TBAD) carries a high risk of complications, particularly with partially thrombosed or patent false lumen (FL). Therefore, uncovering the factors leading to FL thrombosis is crucial identify high-risk patients. Although studies have shown that morphological parameters dissected aorta are related thrombosis, often conflicting results been reported. We show recent models thrombus evolution in combination sensitivity analysis methods can provide valuable insights into...
A thermodynamic formalism for the interaction of point defects with free surfaces in single-component solids has been developed and applied to problem void growth by absorption irradiated metals. This consists two parts, a detailed description dynamics within non-equilibrium frame, application second law thermodynamics provide closure relations all kinetic equations. Enforcing principle non-negative entropy production showed that evolution under irradiation must include relationship between...