ESIS TC8 "Numerical Methods"
| Chair | Prof Dr Huang YUAN | Dept. of Mechanical Engineering |
TC8 UPDATE 2011
April 14-15, 2011
The two-day workshop was focused on formulation and application of cohesive zone models for fracture and fatigue of most different materials under various loading conditions. 18 papers from 6 countries were presented and discussed intensively. The paper should be published in a special issue of an international journal. A list of the presentations is enclosed in this protocol.
After the workshop plenary sessions were organized to setup a round robin which was initiated some time ago. It was decided to start a new round robin, as the first step, on modeling plane stress mode I ductile fracture process in a CT specimen using cohesive zone models. Based on the round-robin the cohesive zone model should find higher popularity and more acceptance in the mechanics community and, furthermore, to promote research in cohesive zone model for material failure modeling.
The stress-strain curve as well fracture energy release rate will be given, the round robin participants should predict the load-load line displacement curve based on cohesive zone models. A group with 8 institutions has been built. Further details will be communicated in the round robin group. Should additional research group or individual be interested in the activity, he/she may send a notice to This e-mail address is being protected from spambots. You need JavaScript enabled to view it , before the end of April. The first task should be finished in 2011. Further activities will be defined based on the first results.
The next TC8 meeting will be organized in June 2012, together with TC1, at BAM Berlin.
Univ.-Prof. Dr. H. Yuan
Department of Mechanical Engineering
Bergische Universität Wuppertal
D-42119 Wuppertal, Germany
Phone: +49-202-439-2124 / 2018
Fax: +49-202-439-2027
Email:
This e-mail address is being protected from spambots. You need JavaScript enabled to view it
List of the presentations on ESIS TC8 workshop:
| J. Besson, J. Chen, Y. Madi, T.F. Morgeneyer | Centre des Mat´eriaux, Mines ParisTech, France | Ductile rupture of two Aluminium—Copper—Lithium alloys |
| M. Bäcker, P. Seiler | TU Braunschweig, Germany | Simulation of crack propagation in thermal barrier coatings |
| H. Krull, H. Yuan | University of Wuppertal, Germany | An atomistic study of constraint effects to the cohesive traction-separation law in single-crystal aluminum |
| R. Ambati, H. Yuan | University of Wuppertal, Germany | Cutting process simulations using Material Point Method |
| J.A.W. van Dommelen, M. Samimi, M. Kolluri, J.P.M. Hoefnagels, M.G.D. Geers | Eindhoven University of Technology, Netherlands | Characterization and modelling of interfacial delamination |
| I. Scheider, J. Mosler | Helmholtz-Zentrum Geesthacht, Germany | A thermodynamically consistent cohesive zone model for low cycle fatigue including interface plasticity and damage |
| G. Hütter, U. Mühlich, M. Kuna | TU Bergakademie Freiberg, Germany | Effect of the Shape of the Cohesive Law and Constraint on the Stable and Instable Crack Propagation |
| G. Debruyne, J. Laverne | EDF, France | An outline of fracture problems facing EDF, open to CZM analysis |
| H. Yuan, H. Li | University of Wuppertal, Germany | On application of cohesive zone models for mixed-mode fatigue crack propagation |
| N. Blal, L. Darion, Y. Monerie, S. Pagano | Université Montpellier II,France | Overall behavior of elastic materials with embedded cohesive zone models:rigorous bounds and mesh size-to-cohesive properties relationships |
| A. Oinonen, G. Marquis, S. Hurme | Aalto University, Finland | Shear decohesion of clamped - Bonded hybrid interfaces |
| J.C. Gálvez, J.Planas, J.M.Sancho, E.Reyes, D.A.Cendón, S.Guzmán, Juan A.Alonso & M.J. Casati | Universidad Politécnica de Madrid, Spain | An embedded cohesive crack model for finite element analysis of quasi-brittle materials |
| S. Schmauder, U. Weber | U Stuttgart, Germany | Validation of the cohesive model by simulation of structures with various geometries and materials |
| J.L. Coureau, S. Morel | Université de Bordeaux, France | Modeling wooden fracture specimen with cohesive crack model |
| X. Cao, M. Vormwald | Technical University of Darmstadt, Germany | Using cohesive zone model in low cycle fatigue |
| P. Naghipour, M. Bartsch | German Aerospace Center (DLR), Cologne, Germany | Mixed Mode Delamination in Multidirectional CF/PEEK Laminates under Fatigue Loading |
| G. Zhang, H. Yuan | Beijing Institute of Technology, China | Creep fatigue crack simulation using cohesive zone models |
TC8 UPDATE 2010
A Special Issue about the fist meeting of the re-launched TC8 has just been published onto Eng. Fract. Mechanics. In the past year TC8 did not achieved much progress in round-robin on cohesive model. A major problem is funding which should be discussed in the next meeting. During ECF in Dresden Prof. Yuan has organized a meeting for TC8 as well as a workshop for micro- and macro-material modelling.
TC8 UPDATE 2009
The decision of the ESIS Council, held in Brno, was to revitalize the activity of TC8. To this aim, under the proposal of Prof. Kuna, Prof. H. Yuan (University of Wuppertal) was appointed as the new Chairman of TC8.
Contacts:
Professor Dr.-Ing. Huang YUAN
Dept. of Mechanical Engineering
University of Wuppertal, Germany
Phone: +49-202-439-2124
Fax: +49-202-439-2027
Email:
This e-mail address is being protected from spambots. You need JavaScript enabled to view it
Website: www.tech-mech.uni-wuppertal.de
First actions
The first action of Prof. Yuan has been to launch (end of 2008) an enquiry about the interests for the prospective future activities of TC8:
Questionnaire.doc
Based on the questionnaire results Prof. Yuan has come to the conclusion that we a meeting in April 2009 should have been organized to exchange results and to discuss activities in TC8. On this basis, al the researchers who replied to the questionnaire were invited to join the meeting at the University of Wuppertal. Major aims of the workshop have been:
• to strengthen the dialogue and improve mutual comprehension among different
research groups
• to find out new research focuses in computational mechanics and
• to define future activities within the TC8.
Specific Topics to be dealt with primarily within TC8, as emerged from the enquiry, are:
- New numerical methods for material failure modeling
- Micro-mechanical models for fracture and fatigue
- Cohesive zone models for mixed-mode crack and fatigue
- New modeling strategies for fracture and fatigue
First technical Meeting of the renewed TC8
The ESIS-TC8 Workshop on Numerical Modelling of Material’s Failure, was held at University of Wuppertal, Germany onApril 23-24, 2009.
The 17 presentations from China, France, Germany, Italy, Poland and UK were focused on computational modelling and experimental characterisation of material failure from different aspects. Each presentation was carried out for 40 minutes so that a depth discussion was realized. Total 39 participants from eight countries attended the two-day workshop. All speakers have been invited to submit their papers for publication in a special issue of Engineering Fracture Mechanics. The manuscripts should be submitted by the middle of June to the journal online. We have schedule to publish the papers by the end of 2009.
During the workshop a booklet containing all abstracts as well as contact information was distributed. The workshop should give a forum for intensive discussion and exchange between different groups.
The workshop contains following topics:
* M. Kübbeler, I. Roth, U. Krupp, C.-P. Fritzen and H.-J. Christ (Uni. of Siegen, Germany): Simulation of stage I-crack growth using a hybrid boundary element technique
* X. Pan, H. Yuan (Uni. of Wuppertal, Germany): Hyper-singular crack field analysis under gradient-dependent plasticity using meshless methods
* J. Jackiewicz (University of Technology & Life Sciences, Bydgoszcz, Poland): Calibration of parameters for a micromechanical model of growth of microvoids that may compete with shear in a polycrystalline metal by means of a genetic algorithm
* T Seifert, Ch Schweizer, M Schlesinger, M Möser (Fh-IWM, Freiburg, Germany); M Eibl (BMW Germany): Thermomechanical fatigue life prediction of 1.4849 cast steel using a fracture mechanics approach
* Z. M. Shi, H. L. Ma, J. B. Li (Inner Mongolia University of Technology, Hohhot, China): A new mesoparameter for describing plastic damage variation of microstructure of ductile metal materials
* U. Prahl, V. Uthaisangsuk, W. Bleck (RWTH Aachen, Germany): Damage and failure in multiphase high strength DP and TRIP steels
* M. Madia, S. Beretta (Politecnico di Milano, Italy): Cyclic state of stress ahead of cracks and its implications under fatigue crack growth
* I. Scheider, W. Brocks, K.H. Schwalbe (GKSS, Germany): Recommendations for the application of the cohesive model based on various studies
* M. Maziere, B. Fedelich (BAM Berlin, Germany): Opening displacement based cohesive zone models for fatigue crack growth
* Y. Xu, J. Liu, H. Yuan (Uni. of Wuppertal, Germany): Damage evolution in cohesive models for characterizing low cycle fatigue cracks
* M. Vormwald (TU Darmstadt, Germany): Numerical simulation of plasticity induced fatigue crack opening and closure
* S. Münstermann, F. Thönnessen (RWTH Aachen, Germany): Modelling the failure behaviour of ferritic steels in impact loading
* D.W. Zhou (TWI Ltd, Cambridge, UK): R-curve and modelling and testing with constraint effect
* J. Besson, Y. Shinohara, T. Morgeneyer, Y. Madi (Mines ParisTech CNRS, France): Ductile rupture of prestained anisotropic metal sheets
* M. Brünig, S. Gerke, D. Albrecht (TU Dortmund, Germany): Numerical analysis of inelastic behavior of ductile metals based on generalized failure criteria
* H. Krull, H. Yuan (Uni. of Wuppertal, Germany): Suggestions to cohesive traction-separation laws based on atomistic simulations
* Ch. Zhang, X.W. Gao (Uni. of Siegen, Germany): 3-D crack analysis in functionally graded materials
The complete book of abstracts can be here downloaded:
Abstracts_Program_TC8.pdf
On afternoon of April 23 prof. Yuan organized a plenary discussion session to define further activities within the TC8. All participants gave a short report about their research activities and topics interested. The final consensuses are:
* Nine institutes among participants are interested to attend joint-research on cohesive zone model for low cycle fatigue (TU Darmstadt, GKSS, BAM Berlin, Mines Paris, U Wuppertal, DLR Köln, Corus, U Siegen, RWTH Aachen).
Decision: TC8 should organize a round-robin (joint-research) on cohesive zone models for mode I low cycle fatigue. The details of the action will be distributed and discussed in the next weeks via email and telephone. We are contacting more experienced colleagues in this field. Further potential participants should be informed and invited by workshop participants or by the TC8. Please send us your suggestion as soon as possible and give your feedback if any.
* Three institutes are interested in parameter identification for complex micro-mechanical models (RWTH Aachen, TU Dortmund, U Bydgoszcz).
Decision: The topic is of great importance in application of modern material models generally. The action is protocol led and will be organized by next chance.
Furthermore, it is agreed that the workshop should be organized in the present form annually. The next regular TC meeting in September 2010 will be scheduled according to ECF18 Dresden. In 2011 Jacques Besson would be ready to host the workshop in Paris.
Should the round-robin or other joint-research activities make interesting progresses or have special needs, a special meeting for special topics will be organized accordingly.
In the ECF18, sessions on computational methods for fracture will be set up. Please submit your contributions directly to the conference site (www.ecf18.de,
This e-mail address is being protected from spambots. You need JavaScript enabled to view it
). The final date for the workshop will be announced in time.
For the meeting 2009 we received strong support from German delegates and are searching more attention from other European countries. After long breaks the TC8 should be more active in the fracture mechanics community and innovative for further development of structural integrity research. In computer era computations became more important than ever. Numerical Methods should cover developing/validating both computational algorithms and new computational models. Both are connected together such a way that you cannot separate them in both research and industry. In this sense we should contribute in both sides.
TC8 UPDATE 2005
Chairman : Dr. C. SAINTE CATHERINE
Within the TC8, a round robin on finite element simulation of fracture mechanics specimens has been initiated by Prof. W. Brocks (Germany). The objective was to evaluate the ability of the micro mechanical models to describe the fracture process. The overall project was organised in 3 distinct phases:
* Phase I : Determination of local approach parameters for ductile tearing (Task A) and for cleavage (Task B) for a German pressure vessel steel.
* Phase II : Finite element simulations of ductile crack growth (Task A) and cleavage fracture (Task B) on CT specimens.
* Phase III : Finite element simulations of CT specimens in the brittle to ductile transition curve.
Year 2004 was devoted to the completion of the Phase III of the numerical Round-Robin on micromechanical models for fracture. The corresponding report (CEA DMN/SEMI/LCMI/NT/2003-035/A) was written by C. Poussard and has been issued at the beginning of 2005. It was distributed to the round robin participants as well as TC members.
The first part (Phase I) was organised between 1993 and 1995 and the results were published by Brocks in 1995. The material investigated in this work was the German 20MnNiM055 RPV (Reactor Pressure Vessel) steel. This first round robin demonstrated the interest in applying the local approach models but the number of scientists being able to perform such computations was found small, these models being generally not available in commercial codes at the time. However, the results suggested the application of improved experimental techniques so that much more information could be extracted from tensile or fracture mechanics testing.
Then Phase II was organised. Because of the manifold experimental results obtained for the German 22NiMoCr37 RPV Steel within the European project Fracture Toughness of Steel in the Ductile to Brittle Transition Regime (Heerens 1999), it was decided that the numerical analyses for that second phase would be based on that material. Phase II A1 consisted in a numerical analysis of a standard smooth tensile specimen to characterise and identify critical damage parameters for ductile tearing at 0°C. The results of this was then used in phase II A2 to predict the ductile crack growth behaviour of a 1TCT specimen and the material JR curve by applying porous constitutive models. The results of this round robin have been published by Bernauer et al. In 2002. Phase II B1 on the identification of cleavage parameters at low temperature from notched tensile specimens was then organised and the results were summarised Bernauer in 2000. At the end of this round robin, it was decided that CEA Saclay would continue the organisation and Phase II B2 was initiated in 2000. This was round robin was accomplished in 2001 and the results have been published by Poussard in 2002.
Phase III was launched in 2003. As this was initially intended, this third phase is devoted to the prediction of the brittle to ductile transition curve for the 22NiMoCr37 Geman RPV steel using local approach micro-mechanical models. In the final report for this Phase III, an outline of the specification is recalled in chapter 2. A total of ten laboratories including nine disseminated in Europe as well as one in Asia have contributed. Seven finite element codes have been used. The results are given in chapter 4, 5 and 6 for the three steps that were proposed to the participants. The transition curve computed with the models agrees very well with that determined experimentally although significant differences between the sets of damage parameters have been obtained. The comparison between the computed and experimental data is further improved when a temperature dependant critical cleavage stress is accounted for. The results will now be used in order to support an ESIS guideline document entitled Guidance on local approach of rupture of metallic materials, document that describes the state of the art to apply the local approach to crack components. Finally, in order to keep track of the work that was done, Appendices 1 to 7 give an outline of the reports, notes or remarks that were made by a number of participants. Also, the interpreted results are supplied to the participants on a CD so that further work may be done by those interested.
A future combined meeting with TC1 is planned on April 20-21, 2005 at Risley, UK.