Institute of MechanicsInstitute of Mechanicsand Fluid Dynamicsand Fluid Dynamics

Research GroupResearch GroupSolid MechanicsSolid Mechanics

Prof.Dr.rer.nat.habil. Meinhard Kuna

Main research topics

Offered engineering service

Fracture mechanical stress analysis and safety assess- ment of structural compo- nents

Fracture mechanical stress analysis of compo- nents (static, dynamic, cyclic, stochastic)

Assessment of strength, reliability and life time

Materials testing with small specimens and para- meter identification

Provision of numerical techniques (FEM, BEM) and software for fracture and damage mechanics

Development and implementation of progressive user-specific material models

Damage mechanics simulation of material failure (metal forming, crash, …)

Further education seminars on„Finite element methods in fracture mechanics“

Development of computa- tional methods in fracture and solid mechanics

Smart mechanical systems

Mechanics of materials and damage mechanics

Technical equipment

Experimental technique

Universal materials testing machines AGS: max. force 10 kN and 250 kN

Micro testing machine SHIMADZU-Micro-Servo-Pulser (max. 100 N, 0 – 60 Hz)

Optical three dimensional deformation measurement system with object grating method ARAMIS

Optical stress measurement systems VISHAY (light polarization in transmission and reflexion)

Computational technique

Compute server LINUX-Cluster with 10 nodes (each 16 CPU AMD Barcelona, 64 GByte RAM, Infiniband, 300 GByte disk)

File Server 6 TByte, RAID, Backup system, USV

Computer Pool FEM/CAD for students (10 High per- formance PC 2 CPU AMD Opteron, LINUX)

FEM: ABAQUS, ANSYS, PATRAN

own developed FEM, BEM and DEM codes

MATLAB, Mathematica, CAD-systems a. o.

Software

Fracture mechanical stress analysis and safety assessment of components

Fundamental and applied research in fracture mechanics and classical theory of strength to evaluate the safety, reliability and life time of engineering constructions from nuclear power plants, gas pipelines, wind turbines, comminution machines, automotives and microelec- tronics. Development of failure criteria and assessment procedures.

Development of fracture mechanics assessment system for high-pressure gas pipelines

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Safety evaluation of girth welds in the pipeline system of former east Germany

Development of a fracture mechanics concept based on Failure-Assessment-Diagram FAD

Interactive software tool, supporting the test engineer during non-destructive inspections of welds to evaluate detected defects in dependence on pressure, additional axial loads and eigenstresses.

Fracture mechanical strength analysis of railway wheels from ductile cast iron ADI

Verification of safety against static fracture and fatigue crack growth during design phase

Deduction of tolerable crack size in connection with in-service inspection procedures

Simulation of drop tests of nuclear shipping casks

Safety design requires consideration of dynamic impact loading

Development of computational tools to determine dynamic fracture mechanics loading parameters

FEM-simulation of drop tests assuming hypothetical cracks in the casks

Smart mechanical structures

In high-tech-branches as aeronautics, automotives, mechatronics and micro system technology one aims a smart, self-adapting behaviour of engineering construc- tions by combining structural, sensoric, actoric as well as controlling components. These recent developments need investigations by simulation of coupled mechanical, thermal and electromagnetical behaviour of the smart structures and the new smart composite materials.

Electromechanical modelling of composites with integrated piezo ceramics

Continuum mechanical analysis of internal electro- mechanical loading in smart piezoelectric fibre or layer composites to optimize the materials design

Development of analytical and numerical models to eva- luate the elec-tromechanical strength of in- terface cracks

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Fracture mechanics of ferroelectric ceramics

Calculations to analyse and interpret fracture mechanical experiments with piezoelectrica

Simulation of micromechanical processes at the crack tip, e. g. numerical and semi-analytical models of ferroelectric domain switching and its effect on frac- ture toughness

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Development of numerical methods to compute intensity factors and energy release rates

Theoretical modelling and numerical simulation of micro structural processes during deformation and failure in techniqual materials using methods of constitutive thermodynamics theory, damage mechanics and homogenization. Application to optimization and evaluation of material properties during their production and under complex in-service conditions. Particularly, the brittle, ductile and the nil-ductile transition behaviour of failure in metals, ceramics and semi-conductors is studied.

Materials modelling and damage mechanics

Identification of elastoplastic and damage parameters

To apply plastic and damage mechanics material laws, determination of relevant parameters is needed (e. g. Gurson law)

Measurement of displacement fields on notched tensile specimens by means of object grating method

Identification of material parameters from measured inhomogeneous displacement fields and FEM- simulation using non-linear optimization algorithms

Determination of ductile deformation and failure properties by miniaturized Small-Punch-Test

Surveillance of the local material state in structural components by minimal invasive removal of repre- sentative miniature specimens

Mechanical loading of the specimens in a deep drawing test (SPT) until failure

Determination of true yield curve and damage parame- ters (Gurson, Beremin) from test records by means of numerical simulation and neural networks

Solder joints in micro electronics

Challenge of new lead free solder alloys in surface mounting technology

Prediction of life time and reliability of solder joints under thermomechanical fatigue

Development of viscoplastic ma- terial model for temperature de- pendent creep, cyclic plasticity and damage (by void growth)

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Granular matter

Numerical simulation of brittle granular materials under mechanical loading

Application of finite ele- ment (FEM) and discrete element methods (DEM)

Investigation of force dis- tribution and brittle frac-ture Weibull parameters as function of statistical arrangement and proper-ties of particles

Development of computational methods in solid and fracture mechanics

Enhancements of numerical methods in solid mechanics (finite element method FEM, boundary element method BEM) for the analysis of crack problems, fo r implementation of damage laws and for treatment of coupled field problems.

Finite element simulation of crack growth

Simulation of crack growth requires adaptive remeshing of finite elements

Development of effective numerical algorithms for auto- matic, error-con- trolled mesh adap- tation

Supply of compu- tational tools for crack growth under mixed-mode-loading

Contact

TU Bergakademie FreibergInstitute of Mechanics and Fluid DynamicsLampadiusstr. 409596 Freiberg

Secretary: +49 (0)3731 39 2465

Prof. Dr.rer.nat.habil. M. Kuna: +49 (0)3731 39 2092

Telefax: +49 (0)3731 39 3455

Internet: http://imfd.tu-freiberg.de

Email: Meinhard.Kuna@imfd.tu-freiberg.de

Approach