Skip to main content
Article thumbnail
Location of Repository

Modelling of behaviour of metals at high strain rates

By Vili Panov

Abstract

The aim of the work presented in this thesis was to produce the improvement of the existing simulation tools used for the analysis of materials and structures, which are dynamically loaded and subjected to the different levels of temperatures and strain rates. The main objective of this work was development of tools for modelling of strain rate and temperature dependant behaviour of aluminium alloys, typical for aerospace structures with pronounced orthotropic properties, and their implementation in computer codes. Explicit finite element code DYNA3D has been chosen as numerical test-bed for implementation of new material models. Constitutive model with an orthotropic yield criterion, damage growth and failure mechanism has been developed and implemented into DYNA3D. Second important aspect of this work was development of relatively simple experimental methods for characterization of engineering materials, and extensive experimental work has been undertaken. Tensile test has been used for the characterisation of two aluminium alloys, at different levels of the strain rates and temperatures, and for three different orientations of materials. The results from these tests allowed derivation of material constants for constitutive models and lead to a better understanding of aluminium alloy behaviour. Procedures for derivation of parameters for temperature and strain rate dependant strength models were developed and parameters for constitutive relations were derived on the basis of uniaxial tensile tests. Taylor cylinder impact test was used as a validation experiment. This test was used to validate the implementation, and accuracy of material model in computer code. At the end of each incremental development, validation of the constitutive material model has been performed through numerical simulations of Taylor cylinder impact test, where simulation results have been compared with the experimental post-test geometries in terms of major and minor side profiles and impact-interface footprints. Plate impact test has been used to determine the material properties at high strain rate, and to investigate damage evolution in impact-loaded material. Initially the material model has been designed as a temperature and strain rate dependant strength model in a simple isotopic form, which then has been tested and verified against the experimental results. Coupling of the Hill’s orthotropic yield criterion with isotropic, temperature and strain rate dependant, hardening material model, has been chosen to suit the orthotropic behaviour. Method for calibration of orthotropic yield criterion has been developed and parameters have been identified for the orthotropic model under the associated flow rule assumption and in case of plane stress on the basis of tensile and cylinder impact tests. The complexity of the model has been further increased through coupling of hardening model with orthotropic yield criterion including damage evolution and failure criteria. The constitutive model was developed within the general framework of continuum thermodynamics for irreversible processes, and plate impact test and tensile tests have been used for determination of parameters for damage part of the new material model.Airbus U

Publisher: Cranfield University
Year: 2006
OAI identifier: oai:dspace.lib.cranfield.ac.uk:1826/1481
Provided by: Cranfield CERES

Suggested articles

Citations

  1. (1987). [39] T k: Elsevier A plied Science,
  2. (2002). [82] Han for sheet m the concept of combined isotropic-kinematic hardening”, doi
  3. (2005). 2 ogress Report on pic Mater el Develo , Univer
  4. (1988). A constitutive description of the deformation of copper based on the use of the mechanical threshold stress as internal state variable”, doi
  5. (1983). A constitutive model and data for metals subjected to large strains, high strain rates and high temperatures”,
  6. (1988). A constitutive model for metals applicable at high-strain rate”, doi
  7. (1988). A constitutive model for strain rates from 10 -4 to 6 s -1”, doi
  8. (1985). A continuous damage mechanics model for ductile fracture”, doi
  9. (1997). A continuum mechanics code analysis of steady plastic wave propagation in the Taylor test”, doi
  10. (1968). A criterion the time dependence of dynamic fracture”, doi
  11. (1999). A critical review of experimental results and constitutive models for BCC and FCC metals over a wide range of strain rates and temperatures”, doi
  12. (1991). a eta nal r a ates posium o stic, The therland [44 re au
  13. (1995). A fully coupled elasto-visco-plastic damage theory for anisotropic materials”, doi
  14. (1997). A numerical scheme f r extracting strength model coefficients from doi
  15. (1994). A thermodynamically consistent framework for theories of elastoplasticity coupled with damage”, doi
  16. (1989). A unified approach for ssure and temperature effects in 187[114] C
  17. (1946). A velocity-modified temperature for the plastic flow of metals”,
  18. (1987). An anisotropic theory of continuum damage mechanics for ductile fracture”, doi
  19. (1987). An anisotropic theory of elasticity for continuum damage mechanics”, doi
  20. (2003). An E ental study of the effect of the prestraining history on the yield surfaces of an aluminium So ds,
  21. (1999). An evaluation of yield criteria and flow rules for aluminium alloys”, doi
  22. (2004). An irreversible thermodynamics theory [120]
  23. (2002). Anisotropic parameter identification using inhomogeneous tensile test”, doi
  24. (1992). Anisotropic plasticity etals using 186[95] G. Maugin, “The Thermomechanics of Plasticity and Fracture”, doi
  25. (2003). Application of the theory of representation to describe yielding of anisptropic aluminium alloys”, doi
  26. (1999). Behaviors of three BCC metal over a wide range of strain rates and temperatures: experiments and modelling”, doi
  27. (1998). C ti f Model FCC, BC , and ng and V onstutive and Damage Mo Phase T tion,
  28. (1998). Calibration and validation of an anisotropic elasto-plastic damage model for sheet metal forming”, doi
  29. (1998). Calibration of anisotropic yield criteria using uniaxial tension tests and bending tests”, doi
  30. (1948). Character Aluminium-Alloy Plate”,
  31. (2003). Constitutive analysis of the hightemperature d tion of Ti-6Al-4V with a tra doi
  32. (1999). Constitutive equations for annealed and explosively shocked nd large strains”, doi
  33. (1977). Continum theory of ductile rupture by void nucleation and , doi
  34. (1979). Continuous damage mechanics – a tool to describe phenom [131] Cordebois
  35. (1990). Cumulative damage model for mean fatigue crack growth based on the kinetic theory of thermally activated fracture”, doi
  36. (1996). Damage mechanics”, doi
  37. (1975). Deformation kinetics”, doi
  38. (1987). Dislocation-mechanics-based constitutive relations for material dynamics calculations”, doi
  39. (1994). Dynamic Behavior of Materials”, doi
  40. (1990). Dynamic crack initiation, some experimental methods and modelling”, doi
  41. (1987). Dynamic failure of solids”, doi
  42. (2003). e in Press. en hock and impact loading conditions”,
  43. (2001). eforma nsformed microstructure”,
  44. (1983). Engineering Plasticity”, Ellis Horwood Limited, doi
  45. (1982). Experimental and Theoretical Investi [126]
  46. (2004). Experimental investigation of the biaxial behaviour of an aluminium sheet”, doi
  47. (2001). f the mater models on the adiabatic shear band spacing: MTS, power law and Johnson-Cook o m ernational Jour doi
  48. F uck, “Th g of eng materi s”, New cGraw-Hill, 198 hn, “Te of materials”,
  49. (1966). f Yield and Fracture (London: Inst. Of Phys. And Physical Soc.),
  50. (1991). Flow stress of OFE copper at strain rates from to : Grain-size effects and comparison to the mechanical threshold stress model”, doi
  51. (1985). Fracture characteristics of three metals subjected to various strains, strain rates, temperatures and pressures”, doi
  52. (2001). Fracture criterion for glass under impact loading”, doi
  53. (1996). Ham events of mi, “Modelling the im rials: C tics of material ,
  54. (1975). haviour of -Tungsten Alloys”, Metallurgical a Transaction p [67 Metals,
  55. (2001). HCP Metals: Experiments, Modeli ve Behavior o alidation”, C delling of Inelastic Deformation and ransforma by n,
  56. (2000). igh-Strain-Ra terials: T t-Hopkinson ressure ar”,
  57. (1982). Impact Dynamics”,
  58. (1969). Introduction to the Mechanics of a Continuous Medium”, Prentice-Hall Inc.,
  59. (1965). K f solids”,
  60. (2002). M fects of orientation on the strength of the aluminium alloy 7010-T6 during shock loading: Experiment and simulation”, doi
  61. (2000). M tutive strength modelling cript
  62. (2005). Material characterization and constitutive modelling of ductile high strength steel for a wide range of strain rates”, doi
  63. (1984). Material failure by void coalescence in localized shear bands”, [129] Tvergaard V., Needleman A., “Analysis of cup-cone fracture in a round tensile bar”, Acta Mettallurgica, doi
  64. (1995). Material Metals at train R ference ngs SCC V p [9 al
  65. (1999). Mechanics and Materials”,
  66. (1986). Molodets, all strength of metals”,
  67. (2003). Non-quadratic yield criterion for orthotropic sheet metals under plane-stress conditions”, doi
  68. (2001). Numerical study of spalling in an aluminium alloy [105 pre dynamic failure criteria”,
  69. (1990). On constitutive equations of inelastic solids with anisotropic damage”, doi
  70. (1999). On the modelling of the Taylo ls, experiments and simulations”, doi
  71. (1994). P igh-rate aterial behaviour using the tensile Hopkinson-bar”,
  72. (2004). Pa .0.2 on Orth aterial M lop Cranfield sity,
  73. (2003). Pan .0.1. on doi
  74. (1987). pp egazzoni and U.
  75. (2006). Pr Orthotro ial Mod pment” Cranfield [6] V. P sity, .2.0. on
  76. (2000). R esuer, “Experi tal investig ns of material models for Ti-6Al-4V titanium and
  77. (1995). rapidly solidified 7475 aluminium alloy”, doi
  78. (1996). Reg lansbee, “D on kinetics at high str n rates” .
  79. (1976). Regazzoni, “The mechanical threshold of y opper and nitronic 40”,
  80. (1983). Response of various m ls to large torsio strains ove large range of strain r – Part2: Less ductile metals”,
  81. (1999). Spall fracture: Mechanical and microstructural aspects”, doi
  82. (1977). Spall studies in uranium”, doi
  83. (1996). Spalling of aluminium alloy doi
  84. (1984). Structures -5H, terials a ents fo V artmen andbook 998. [17 and IMI550 alloys form”,
  85. (1970). Temperature Dependence of the Elastic Constants”, doi
  86. (1989). The development of constitutive relationships for material behaviour at high rates of strain”,
  87. (1998). The effect of strain rate on the anomalous peak of yield ress in β-CuZn alloy”, doi
  88. (2004). The influence of plastic strain ratios on the numerical modelling of stretch forming”, doi
  89. (1991). The mathemati ord Univer 7
  90. (2000). The Mechanical Threshold Stress Constitutiv Steel”, Metallurgical and Materials Transactions
  91. TS consti in HY-100 steel”, S 25-1131. “Influence o ial constitutive dels”, Int nal ofSolids and Structures,
  92. (1994). Ultra hig ature mechanical testing”, Cambridge: E . F i e l d , . W a l l e y ,
  93. (1980). Upper-Bound Anisotropic Yield Locus Calculations Assuming <111>-Pencil Glide”, doi
  94. (2003). Use of different damage models for simulating impact-driven spallation in metals”, Inter ational doi

To submit an update or takedown request for this paper, please submit an Update/Correction/Removal Request.