Commit Graph

99 Commits

Author SHA1 Message Date
Christoph Kords faba13f7fd * now able to introduce some scatter in the initial single dislocation density (only for nonlocal model!) ; setting the parameter "rhoSglScatter" to a positive value generates a gauss distribution for the dislocation density with standard deviation equal to "rhoSglScatter"
* dislocation stress calculation is only done for nonlocal constitution ("/nonlocal/" keyword is present in material.config)
2011-02-04 15:41:32 +00:00
Christoph Kords b72d75ed05 corrected indices in flux density output 2011-01-28 12:49:58 +00:00
Christoph Kords 05d4d5fef2 * kinetics now according to Mohles; enables solid solution hardening
* changed example in material.config accordingly
2011-01-26 10:17:42 +00:00
Christoph Kords 062c6b3d54 * allow zero cutoff radius
* added missing error codes
2011-01-12 12:36:48 +00:00
Christoph Kords d92f992eb7 if nonlocal ip has local neighbor assume perfect transparency of the (perhaps virtual) phase boundary. this is only a quick fix! need to rethink the way constitutive and real boundaries are treated! 2011-01-11 18:00:29 +00:00
Christoph Kords 6a3dd78259 fluxes are disabled when keyword "/nonlocal/" is omitted in the material.config (this is a way to use the constitutive_nonlocal model as a local dislocation based model) 2011-01-11 14:55:36 +00:00
Christoph Kords 405d5529e7 * checked and corrected parallelization of code. compiles now successfully, but simply aborts computation with first parallel directive without any comment :-(((
* also put a call to constitutive_microstructure at the start of each crystallite_integration subroutine like it was before. need that for nonlocal model in case of crystallite cutback
2010-11-03 17:22:48 +00:00
Christoph Kords 4439282239 no change to previous version, just forget to mention one important change of the last revision:
* fluxes are now again calculated and distributed only! by the originating material point. this means that the central MP might change the dotState of its neighbor. have to see whether locks slow down parallel computation
2010-10-26 13:49:58 +00:00
Christoph Kords 62d06001ea * corrected compatibility for screws (always positive)
* detection of grain boundary in constitutive_nonlocal_microstructure with the help of transmissivity
* enforce positive densities in constitutive_nonlocal_microstructure (needed because dotState does not create cutbacks for negative densities anymore)
* reset single mobile densities below certain threshold to zero (also done in constitutive_nonlocal_microstructure)
* constitutive_nonlocal_kinetics only gets local state variable as input, no need for the entire array here
* dv_dtau is always positive
* multiplication is only active when there is already some initial density of the respective type
2010-10-26 13:42:18 +00:00
Christoph Kords 366d52bd71 * former "relevantRho" and "relevantResistance" is renamed to "atol_rho" and "atol_resistance" and now used as an absolute tolerance for the state residuum. before it was used rather as significant state, so whenever the state dropped below that value it was considered converged. (In dislotwin and titanmod constitutive law there is only one value atol_rho which is used for all the states, though the state array consists not only of densities. We need further parameters here!)
* somewhat simplified convergence check for adaptive euler and runge-kutta
2010-10-26 13:16:37 +00:00
Christoph Kords fffe731447 * had to correct nonlocal slip system compatibility and flux calculation. last update gave wrong results. 2010-10-15 13:19:26 +00:00
Christoph Kords 724960686f * in nonlocal model: dislocation flux now with valid description also for large angle grain boundaries; transfer of dislocations from one slip system to the other according to new variable "constitutive_nonlocal_compatibility" which depends on the angle between slip plane normals and slip directions and is updated once per cycle in function "crystallite_orientations"
* reactivated debugging functionality for "non-standard" integration methods
2010-10-12 13:08:54 +00:00
Christoph Kords fce7590c17 * now able to choose method for state integration (integrator and integratorStiffness in numerics.config); standard is "Fixed Point Iteration", which is basically the same as before; others available are "Explicit Euler", "AdaptiveEuler", "Classical Runge-Kutta" and "Runge-Kutta Cash-Karp"
* now remembering stiffness similar to how we do it for Lp etc.; avoids undefined stiffness values for nonconverged stiffness calculation

* non-local stuff:
   * changed non-local kinetics (Gilman2002)
   * enforce zero shearrate for overall carrrier density below relevant density
   * enforce zero density for those states that become negative and were below relevant density before
   * dislocation velocity is not limited by V^(1/3) / dt anymore
2010-10-01 12:18:49 +00:00
Philip Eisenlohr da53656c9a added C3D20R (type 9) to list of possible non-local elements (Christoph, should we invent a reasonable error number for this? "-1" may not be optimal...) 2010-08-19 23:00:26 +00:00
Philip Eisenlohr 298cecbfec corrected syntax errors (long lines, line continuation by \) and logical mistake in mpie_cpfem_marc / abq_std which went unnoticed in ifort. Using SunStudio f90 surfaced those... 2010-08-03 23:47:00 +00:00
Christoph Kords eb0cc24a8e no need for material parameter "a" anymore, dislocation stress calculation now works without "core spreading" 2010-06-21 16:01:05 +00:00
Christoph Kords 7d6e52067b dislocation stress based on dislocation density gradients 2010-06-21 15:58:56 +00:00
Christoph Kords 740db98090 - use upwind differences scheme for fluxes instead of central differences
- introduced possibility to "reflect" fluxes at free surfaces in order to have quasi-periodic fluxes
2010-06-09 08:56:00 +00:00
Christoph Kords 71c6179ee5 dislocation stress had wrong sign in some components 2010-06-08 09:34:23 +00:00
Christoph Kords 3ce1882d29 when calculating dislocation stress at grain boundaries, densities are now extrapolated similarly to like it was already done at free surfaces 2010-06-07 16:01:37 +00:00
Christoph Kords 3989cc2688 dislocation stress now considers dislocation segments of length V^(1/3) and ensures non-singular solution for points that are collinear to the dislocation line by means of a core spreading parameter "a". stress is scaled by a reference cutoff radius "r" to avoid mesh-dependent stress values.
corrected formula for conversion of anisotropic elastic constants to isotropic Youngs modulus and poissons ratio
2010-06-07 14:32:23 +00:00
Christoph Kords 76b392e12f dislocation stress calculation in constitutive_nonlocal_microstructure: corrected mapping from lattice to slip system frame and the neighboring dislocation density formulation 2010-05-28 13:12:36 +00:00
Franz Roters bb73a74325 there was a line break missing so that it did not compile 2010-05-26 17:10:26 +00:00
Christoph Kords e5f0af638e fixed calculation of dislocation stress for elements with a single ip and no neighbors; used to get segmentation fault 2010-05-26 09:17:10 +00:00
Christoph Kords 0c5bc83469 in nonlocal_microstructure: at the model surface the excess density is now extrapolated from opposite neighbor instead of assuming zero density; this results in better modeling of the dislocation stress at the surface
restructured nonlocal_dotstate, to be able to easily switch on and off particular effects in the microstructure evolution
nonlocal_dotstate now enforces a cutback when single density runs the risk of becoming negative; in the case of a state already below the relevantState dotState is set to zero
introduced two new output variables: rho_dot_edge and rho_dot_screw
2010-05-21 08:51:15 +00:00
Christoph Kords 472684c30e make element type 8 (= hex8 reduced integration) available for nonlocal constitutive law 2010-05-18 08:13:23 +00:00
Denny Tjahjanto 9026cc4016 again corrections. but this version must work. 2010-03-24 16:23:21 +00:00
Denny Tjahjanto 40b1478dac the latest RGC model + corrections for "element homogeneous" feature 2010-03-24 13:20:12 +00:00
Christoph Kords f4e5d32cde added flag verboseDebugger to debug in order to have more control about debugging statements
set this to true if you want extended debugging info in the output file
2010-03-19 14:14:08 +00:00
Christoph Kords 948c119ee9 changed internal representation of orientation and misorientation from euler angles to quaternions (this should also fix some bugs in the math_misorientation subroutine). includes a couple of new functions in math.f90 and some changes in crystallite.f90.
beware that crystallite output "orientation" now by default returns the orientation as quaternion. if you want euler angles instead, you have to add "eulerangles"  as a crystallite output in your material.config file (see material.config template).

for input of orientations in the texture block of the material.config you still have to specify the rotation in terms of euler angles, quaternions are not yet supported for input.
2010-03-18 12:23:17 +00:00
Christoph Kords e3dd7551dc added output for dislocation evolution rate associated with flux: "rho_dot_flux" 2010-03-10 09:49:40 +00:00
Christoph Kords a0d28ebc18 - flux calculation is now also compatible to neighborhood of local constitution
- flux density interpolation now depends on the position of the interface between ttwo neighboring material points
- simplified flux calculation scheme
- introduced sanity check for dislocation velocity to ensure v*dt< cellsize
2010-03-04 17:14:47 +00:00
Christoph Kords 538faecf45 new output "dislocationvelocity" 2010-02-23 17:23:07 +00:00
Christoph Kords 97db70cf23 constitutive_nonlocal:
- reworked contribution of immobile dislocation density for rate equations
- flux is now calculated on the basis of interpolated velocities and densities at the interface; both incoming and outgoing fluxes are considered, so every material point only changes his own dotState
- dislocation velocity is now globally defined and calculated by subroutine constitutive_nonlocal_kinetics; the subroutine is called inside _LpAndItsTangent as well as _microstructure; therefore, microstructure now needs Tstar_v as additional input; in the future one should perhaps create a subroutine constitutive_kinetics that calls constitutive_nonlocal_kinetics separately, to clearly distinguish between microstructural and kinetic variables 
- better use flux density vector as output variable instead of scalar flux values for each interface
- added output variables internal and external resolved stress

crystallite:
- added flag to force local stiffness calculation in case of nonlocal model
- misorientation angle is explicitly set to zero when no neighbor can be found

debug:
- added flag "selectiveDebugger" that is used when debugging statements should only affect a specific element, ip and grain; these are specified with the new variables debug_e, debug_i and debug_g
- debugger can now be used in its original sense
2010-02-17 13:21:36 +00:00
Christoph Kords a2037db9c6 corrected sign of screw part of dislocation stress 2010-02-12 12:54:00 +00:00
Christoph Kords ed8446e0f3 - corrected contribution of immobile singles to dipole formation and annihilation rates
- remobilization of immobile singles immediately increases the mobile single dislocation density and therefore directly affects all other mechanisms in dotState
2010-01-06 09:54:00 +00:00
Christoph Kords dce840c0a5 - introduction of immobile (used) single dislocation densities as new state variables
- changed nomenclature (rho -> rhoSgl) to distinguish precisely between single dislocation density and total dislocation density
- changed material.config accordingly
2010-01-05 16:07:24 +00:00
Christoph Kords 1f7aebfa4d new subroutine crystallite_orientations: calculates the orientation matrix and the euler angles and - in case of single grain ips - the misorientation for each neighboring ip.
The calculation of the misorientation is now done once in crystallite init and at the end of every FE increment. This saves a lot of time compared to doing it in dotState for every crystallite subinc.
2009-12-18 15:46:33 +00:00
Christoph Kords d784153e0c constitutive_nonlocal:
- corrected flux term
- multiplication is now aware of dislocation type
- corrected change rate for "dipole size" dupper
- corrected term for dipole dissociation by stress change
- added transmissivity term in fluxes which accounts for misorientation between two neighboring grains (yet hardcoded transmissivity according to misorientation angle)
- added more output variables

constitutive:
-  2 additional variables "previousDotState" and "previousDotState2", which are used to store the previous and second previous dotState (used in crystallite for acceleration/stabilization of state integration)
- timer for dotState now measures the time for calls to constitutive_ collectState (used to reside in crystallite_updateState, which is not critical in terms of calculation time anymore) 

crystallite:
- convergence check for nonlocal elments is now done at end of crystallite loop, not at the beginning; we simple set all elements to not converged if there is at least one nonlocal element that did not converge
- need call to microstructure before first call to collect dotState for dependent states
- stiffness calculation (jacobian): if there are nonlocal elements, we also have to consider changes in our neighborhood's states; so for every perturbed component in a single ip, we have to loop over all elements; since this is extremely time-consuming, we just perturb one component per cycle, starting with the one that changes the most during regular time step.
- updateState gets a damping prefactor for our dotState that helps to improve convergence; prefactor is calculated according to change of dotState

IO:
- additional warning message for unknown crystal symmetry
2009-12-15 08:20:31 +00:00
Luc Hantcherli 67f87486b1 in constitutive_dislotwin.f90:
in constitutive_nonlocal.f90:

Derivatives of shear rates w.r.t. resolved shear stress HAVE to be positive.
Computation of dgdot_dtauslip is now correct.
2009-11-06 17:46:12 +00:00
Christoph Kords 9892fd9a10 sorry: initialization of periodicBC was erroneous 2009-10-20 16:38:05 +00:00
Christoph Kords c1ee34d235 constitutive_nonlocal:
- read in activation energy for dislocation glide from material.config
- changed naming of dDipMin/Max to dLower/dUpper
- added new outputs: rho_dot, rho_dot_dip, rho_dot_gen, rho_dot_sgl2dip, rho_dot_dip2sgl, rho_dot_ann_ath, rho_dot_ann_the, rho_dot_flux, d_upper_edge, d_upper_screw, d_upper_dot_edge, d_upper_dot_screw
- poisson's ratio is now calculated from elastic constants
- microstrucutre has state as first argument, since this is our output variable
- periodic boundary conditions are taken into account for fluxes and internal stresses. for the moment, flag has to be set in constitutive_nonlocal. 
- corrected calculation for dipole formation by glide
- added terms for dipole formation/annihilation by stress decrease/increase 

constitutive:
- passing of arguments is adapted for constitutive_nonlocal model

crystallite:
- in stiffness calculation: call to collect_dotState used wrong arguments
- crystallite_postResults uses own Tstar_v and temperature, no need for passing them from materialpoint_postResults

homogenization:
- crystallite_postResults uses own Tstar_v and temperature, no need for passing them from materialpoint_postResults

IO:
- changed error message 229

material.config:
- changed example for nonlocal constitution according to constitutive_nonlocal

all:
- added some flush statements
2009-10-20 14:36:03 +00:00
Christoph Kords 9b3a59646a constitutive_nonlocal
- take orientation gradients into account when calculating dislocation stress and dislocation fluxes
- hard coded value for nu
- changed kinetics (parameter G0 is currently defined as a parameter, needs to be read from material.config)
- added some output statements

constitutive: 
- some functions and subroutines needed additional input variables for passing to constitutive_nonlocal 

crystallite:
- some functions and subroutines needed additional input variables for passing to constitutive
- call microstructure with current temperature, Fp, Fe, not "sub0" values
- show number of IPs, that are "onTrack" instead of those not "onTrack"
- calculate Fe at beginning of substep, since we need it for state preguess
2009-10-07 15:31:52 +00:00
Christoph Kords b09b2b17f3 convergence of state in crystallite is now tested as follows:
(state < relevant state) or (residuum < relative tolerance * state)
since the relevant value for the state variables depend on their nature and can vary by large scales (e.g. volume fraction: 1e-10, dislocation density: 1e5) it is not possible to set a unique value. instead the constitutive law has to decide what is relevant. therefore, all constitutive laws now read in parameters from the material.config that determine the values for relevantState [@luc: in dislobased law relevant State is for the moment generally set to 1e-200, so no additional parameters necessary in material.config. if you also want this feature, we can still implement it, no big deal]

- added sanity checks in constitutive_nonlocal.f90

- corrected coordinate transformation for backstress calculation in constitutive_nonlocal.f90

- corrected equations for evolution of dipole dislocation densities (athermal annihilation and formation by glide)
2009-09-18 15:37:14 +00:00
Franz Roters 2029b23f98 added version information to all files
do NOT edit text like this:
$Id: constitutive_phenopowerlaw.f90 406 2009-08-31 14:13:10Z MPIE\f.roters $
2009-08-31 15:09:15 +00:00
Christoph Kords f27d66a9ae constitutive_nonlocal:
- dipole dislocations with evolution

crystallite.f90:
- collect state uses subdt and subTstar0_v
- in nonlocal modus: set all crystallites to broken if one is not on track anymore after either stress integration or state update
- constitutive_microstructure is now called inside state update and not in integrate_stress anymore

material.config:
- new parameter for nonlocal constitution

CPFEM.f90:
- age Tstar after increment was finished
2009-08-28 13:50:47 +00:00
Christoph Kords 1dbd0865db constitutive_nonlocal.f90
- completed postResults output function
- connecting vector of neighboring material points is mapped to intermediate configuration of my neighbor

crystallite.f90
- zero out dotState only when crystallite is non-finished
- set nonfinished flag to false if crystallite is not on Track after state update
- in updateState: set onTrack flag to false if encounter NaN
- removed some old debugging outputs and added others

homogenization.f90
- in debugging mode now telling when a cutback happens
2009-08-24 08:16:01 +00:00
Christoph Kords 2aae7b7574 added dislocation multiplication to dotState in constitutive_nonlocal.f90
cleaned up debugging output statements to *.out file
2009-08-12 11:22:02 +00:00
Christoph Kords 8ed3ddc03b now with first draft of nonlocal constitutive law
debugging memory leak closed
debugging counters corrected

center of gravity stored in mesh

state updated is now split into a collecting loop and an execution

updateState and updateTemperature fill sequentially separate logicals and evaluate afterwards to converged

added 3x3 transposition function, norm for 3x1 matrix and 33x3 matrix multiplication in math

non-converged crystallite triggers materialpoint cutback (used to respond elastically)

non-converged materialpoint raises terminal illness which in turn renders whole FE increment useless by means of odd stress/stiffness and thus waits for FE cutback
2009-08-11 16:31:57 +00:00