The Zebulon Gazette

The Zebulon Gazette is the periodical newsletter of user feedback and technical use associated with the Z-set/Z-mat software and research. From these newsletters it should be apparent about the very large breadth of application and highly important industrial use we are used to seeing. These newsletters are prepared at the Centre des Materiaux anc can also be found on their Website.

Num 20
 February 2004 Effect of specimen geometries on the C* versus da/dt master curve
of type 316L steel.
Num 19
 February 2003
 Nouvelles fonctionnalités de ZéBuLoN pour les problèmes
couplés hors thermo-mécaniques.
Modélisation tridimentionnelle du serrage d'une vis dans un écrou.
Num 18
 October 2002
 Contact in 8.2
Contact, an industrial example.
Num 17
Zebulon celebrates its 20 years
Num 16
 August 2001
 Linear solvers in Zebulon
Zlanguage: an integrated interpreted language for multiple uses
Num 15
 March 2000
 Zmaster and Z-mesh, deux atouts maîtres du maillage 3D.
Use of mixed dimension 2D-3D meshes
Meshing an assembly of subterranian cavities in 3D.
Num 14
 August 1999
 The Zebulon Toolbox
The interface Zmaster for Zebulon
Num 13
 December 1998
 Calculation of crack closure by a node release method
Proceedures of 3D meshing in Zebulon by example
Num 12
 February 1998
 Elasto-plasticity in a Cosserat continuum
Presentation of the simulation mode of Zebulon
Parallel computations of multi-crystaline agregates
Num 11 October 1997
 The post processing in Zebulon 7
Fatigue limit critera
The optimization module of ZeBuLoN 7

NWNM / Zebulon Related Publications

Please find here some publications which are related to the company, and Zebulon.

Large scale object oriented finite element code design

g-zipped postscript (84K)
pdf file (225K)

R. Foerch and J. Besson Accepted in Computer Methods in Applied Mechanics and Engineering .

Abstract

This paper discusses the aspects of object oriented finite element design which become relevant as the project size increases. A simple core library is described which aids program development by isolating repetitive tasks into optimized classes. This library addresses particularly the mathematical entities which appear in mechanics. Several object oriented class idioms are given as well, with implementation syntax in C++. The classes address the reduction of interdependence in the code project, and facility expandability in the long-term. Application of these abstract programming techniques are given within the context of a complete, working FEM code design which employs the object techniques thoroughly on every level of the computation. Furthermore, suggestions are given on how to reformulate problems in an object oriented fashion in order to plan on expandability. Results for CPU performance are given with respect to a Fortran code, but are seen to have very limited real relevance.

Polymorphic Constitutive Equations in Finite Element Codes

g-zipped postscript (91K)
pdf file (364K)

R. Foerch, J. Besson, G. Cailletaud, and P. Pilvin. Accepted in Computer Methods in Applied Mechanics and Engineering .

Abstract

This work presents an object-oriented design approach to the programming of finite element constitutive equations. A universal interface for arbitrary material laws is introduced from which easy addition and expansion of the material library can take place. Although such expansion using a generic interface is by definition polymorphic, the idiom is carried much further in several aspects of program design. Deriving from abstract examples of equation and algorithmic encapsulation, simple elastic damage and complex inelastic constitutive laws are developed. Examples of calculations show that adequate performance is given by C++ with respect to Fortran77 for simple to very complex material laws. The performance is seen to be a much stronger function of the compiler used than the actual numerical complexity.

Some Aspects of the Numerical Implementation of SUVIC-D

g-zipped postscript (84K)
pdf file (212K)

M.R. Julien, R. Foerch, M. Aubertin and G. Cailletaud. Presented at the 4th Conference on the Mechanical Behavior of Salt, Montreal, Canada, June 17, 18 (1996).

Abstract

A unified constitutive model using internal state variables (ISV) to describe the inelastic behavior of salt in the ductile and semi-brittle regimes has been implemented into a 2D/3D object oriented finite element code (Zebulon). This program was specifically designed for the analysis of complex material behavior under a variety of loading conditions, including cyclic and non-isothermal loading. The constitutive model (SUVIC-D) is composed of a viscoplastic and a damage component. The viscoplastic component implementation has been done for both explicit and implicit integration methods. Damage has so far been done only with the explicit scheme. This paper presents some details of the implementation, a discussion about the integration techniques, and numerical simulations of experimental results for artificial salt using both the viscoplastic and the damage components. The results show that the extra effort in implementing the implicit integration scheme is worth the effort since it allows an improved convergence for load control conditions.

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Other References

Material modeling and rupture
  • J. Besson, G. Cailletaud, J.L. Chaboche, S. Forest, Mecanique non lineaire des materiaux, 445 pages, Hermes-Science (www.hermes-science.com), 2001.
  • CHABOCHE, J.L., JUNG, O., ``Application of a kinematic hardening viscoplasticity model with thresholds to the residual stress relaxation'', Int. J. Plasticity,Vol. 13, No. 10, pp. 785-807, 1998.
  • L. DEVILLERS-GUERVILLE, J. BESSON, A. PINEAU, ``Notch fracture toughness of a cast duplex stainless steel: Modelling of experimental scatter and size effect'', to be published in Nuclear Engineering and Design, 1997.
  • K. DECAMP, L. BAUVINEAU, J. BESSON, A. PINEAU, ``Size and Geometry Effects on Ductile Rupture of Notched Bars in a C-Mn St eel: Experiments and Modelling'', to be published in Int. J. Frac., 1997.
  • CHABOCHE, J.L., ``Thermodynamic formulation of constitutive equations and application to the viscoplasticity and viscoelasticity of metals and polymers'', Int. J. Solids Structures, Vol.34, No. 18, pp.2239-2254, 1997.
  • CHABOCHE, J.L., GIRARD, R., SCHAFF, A., ``Numerical analysis of composite systems by using interphase/interface models'', to be published in Computational Mechanics, 1997.
  • CHABOCHE, J.L., GIRARD, R., LEVASSEUR, P., ``On the interface debonding models'', to be published in Int. J. Damage Mechanics, 1997.
  • JULIEN M.R., FOERCH R., AUBERTIN M., CAILLETAUD G., ``Aspects of the numerical implementation of an ISV model for viscoplasticity and damage of salt'', 8th Int. Conf. on Salt, Montreal (Canada), juin 1996.
  • BURLET H., LOVATO G., CHAUMAT G., MORET F., CAILLETAUD G., PILVIN P., ``Determination of a dissimilar brazed joint constitutive law'', 2nd Int. Symp. on Mismatching of Welds, Lüneburg, 24-26 avril 1996.
  • CHABOCHE, J.L., ``Unified cyclic viscoplastic constitutive equations : development, capabilities and thermodynamic framework'', in Unified Constitutive Laws of Plastic Deformation, Krauss & Krauss eds., Academic Press, 1-68, 1996.
  • JUNG., O., OUSSET, Y., ``Influence of residual stresses of shot-peening on cracks propagation'', ECF 11, Poitiers, sept.1996.
    K. SAI, G. CAILLETAUD, ``Study of Plastic/Viscoplastic Models with Various Inelastic Mechanisms'', Int. Journal of Plasticity, 11, 991-1005, 1995.
  • D. NOUAILHAS, G.CAILLETAUD, ``Finite element analysis of the mechanical behavior of two-phase single crystal superalloys'', Scripta Materiala, 34, 565-571, 1996.
  • S. Kruch, Numerical analysis of an engine turbine disk loaded with a large number of thermomechanical cycles, 3rd Int. Conf on Computational Plasticity, Barcelona, 1992.
  • MÉRIC, L., POUBANNE, P., et CAILLETAUD, G., ``Single Crystal Modeling for Structural Calculations. Part 1: Model Presentation'', J. of Eng. Materials and Technology, 113, 162-170, 1991.
Shaping/Manufacturing
  • J. BESSON and M. ABOUAF, ``Rheology of porous alumina and simulation of the HIP process'', J. Amer. Ceram. Soc., 75 [5] 2165-2172, 1992.
  • J. BESSON, F. VALIN, P. LOINTIER and M. BONCUR, ``Densification of Titanium Diboride by Hot Isostatic Pressing and Production of Near Net Shape Components'' J. Mater. Eng. Perform., 1 [5] 637-656, 1992.

Object oriented FEA

  • R. FOERCH, J. BESSON, G. CAILLETAUD, P. PILVIN, ``Polymorphic Constitutive Equations in Finite Element Codes'', to be published in Computer Methods in Applied Mechanics and Engineering,1996.
  • J. BESSON, R. FOERCH, ``Large Scale Object Oriented Finite Element Code Design'', to be published in Computer Methods in Applied Mechanics and Engineering, 1996.
Algorithms
  • G. CAILLETAUD, J. L. CHABOCHE, ``Integration Methods for Complex Constitutive Equations'', Computer Methods in Applied Mechanics and Engineering, 133, 125-155, 1996.
  • L. MÉRIC, G. CAILLETAUD, G., ``Single Crystal Modeling for Structural Calculations. Part 2 : Finite Element Implementation'', J. of Eng. Materials and Technology, 113, 171-182, 1991.
  • P. M. Lesne and S. Savalle, An efficient "cycles jump technique" for viscoplastic structure calculations involving large number of cycles, in Computational Plasticity, Owen et al. eds., 2nd Int. Conf. on "Computational Plasticity", Barcelona, 1989.
Structures
  • NOUAILHAS D., CULIÉ J.P., CAILLETAUD G., MÉRIC L., ``Finite Element Analysis of the Stress-Strain Behaviour of Single Crystal Tubes'', European Journal of Mechanics, A, 14, 137-154, 1994.
  • MÉRIC L., CAILLETAUD G., GASPÉRINI M., ``Finite Element Calculations of Copper Bicrystal Specimens Submitted to Tension-Compression Tests'', Acta Metallurgica Materiala, 42, 921-935, 1994.
  • AAZIZOU K., CAILLETAUD G., DIBOINE A., ``Modelling of Viscoplasticity and Structural Analysis of Diesel Cylinder Heads '', EGF Conf., Venise, ed. L.H. Larsson, 221-242, 1992.
  • POUBANNE, P., CAILLETAUD, G., ``Calculs de structures monocristallines : un modèle micro-macro'', Revue scientifique SNECMA, 412, 37-50, 1992.
Optimisation
  • CAILLETAUD G., PILVIN P., ``Identification and Inverse problems related to Material Behaviour'', in Inverse Problems in Engineering Mechanics, ed. H.D. Bui, M. Tanaka et al., Balkema, 79-86, 1994.
  • CAILLETAUD G. : ``Computer aided identification : material element, specimen, component'', Int. Seminar on Local Measurements at High Temperature, Berlin, 13-15 mars 1996.