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Subject: Re: STRUC- Brick model_Convergence
Author: Linh Truong Hong
Date: 2008-04-12 22:18:32

Dear Michele and Balasubramanian,

Thank you very much for your help.

To Michele, your proposed reference is very useful for me. I use micro model
including bricks and mortar joints which modeled separate, in which
mechanical properties of both bricks and mortars following:

!******************************************************

!Mortar properties

Em = 2760e6 ! N/m2

vm = 0.45

Dens_m = 1740 ! kg/m3

fmc = 1.31e6 ! N/m2

fmt = 0.152e6 ! N/m2

!Brick properties

Eb = 88.8e6 ! N/m2

vb = 0.25

Dens_b = 1919.012 ! kg/m3

fbc = 4.43e6 ! N/m2

fbt = 1.26e6 ! N/m2

!******************************************************

and I define the material characteristic below:

!******************************************************

!Defines material properties for each types of element

!For bricks: MAT: 1

MP, EX, 1, Eb

MP, PRXY, 1, vb

MP, DENS, 1, Dens_b

R, 1

TB, CONCR, 1

TBDATA, 1, 0.2, 0.8, fbt, -1

!For mortar joints: MAT: 2

MP, EX, 2, Em

MP, PRXY, 2, vm

MP, DENS, 2, Dens_m

R, 2

TB, CONCR, 2

TBDATA, 1, 0.2, 0.8, fmt, -1

!******************************************************

And the parameter for nonlinear solution option:

!******************************************************

ANTYPE, STATIC

OUTRES, ALL, 1

OUTPR, ALL,ALL

SOLCONTROL, ON

CNVTOL, U, , 0.05, 2

AUTOTS, ON

NEQIT, 30

NSUBST, 30, 1000000, 20

NROPT, FULL

CUTCONTROL, NOITERPRED, 1

!******************************************************

In this model, I do not implement Drucker-Prager Plasticity criterion into
model.

Could you give me your idea to solve this problem? Can you give me
parameters (cohesion, friction angle and dilatancy angle) of bricks and
mortar joints for Drucker-Prager yield criterion or reference documents?

To Balasubramanian, I use Willam-Warnke criteria for predicting the
failure. In this case of the dis-convergence due to numerical solution, can
you give me advice to refine it? In some case I try increase NUSUBT but the
solver is not convergence.

Thank you very much,

TRUONG Hong Linh - PhD student
-----------------------------------------------------------------------
School of Architecture, Landscape and Civil Engineering
University College Dublin,
Newstead Building, G67,
Belfield, Dublin4, Ireland.
Email: linh.truong-hong_at_ucdconnect.ie

Phone office: +353 1 716 3232
Mobile phone: +353 86 351 3569
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On 2008-04-10 22:50, Linh Truong Hong wrote:
> Hi all,
>
> I am using Solid65 for modeling scale model of the brick wall under
> self-weight (load case 1), live load (load case 2) and foundation
> settlements (load case 3).
>
> The dimensional model is length of 1.83m, height of 0.609m and width of
> 0.0285m, which is containing 12 windows. The micro model is used which
have
> 18812 nodes and 9316 elements. The tensile strength of mortar joint is
> 0.152E6 N/m2.
>
> In the first second load case I have convergence solution, but for load
step
> 3 I only get convergence at load total time 2.316 (the maximum
displacement
> of foundation for load case 3 is 0.6mm). At the results corresponding to
> time 2.316 I see several points having values of the principal stress are
> higher than tensile strength of the mortar.
>
> I wonder that my model can not get convergence because the structure
fails.
> Am I correct??
>
> I am long for hearing from you,
>
> Thank you,
>
> Linh Truong Hong
>
> University College Dublin
>
> School of Architecture, Landscape and Civil Engineering
>
> Urban Group Modelling Laboratory
Posts possibly associated with message #92829AuthorDateScore
92801STRUC- Brick model_ConvergenceLinh Truong Hong 2008/04/10 
92813Re: STRUC- Brick model_ConvergenceRam Balasubramanian2008/04/11 
92822R: STRUC- Brick model_ConvergenceMichele Betti2008/04/11 
92823R: STRUC- Brick model_ConvergenceMichele Betti2008/04/11 
92829Re: STRUC- Brick model_ConvergenceLinh Truong Hong 2008/04/12