
[Sponsors] 
[solidMechanics] Support thread for "Solid Mechanics Solvers added to OpenFOAM Extend" 

LinkBack  Thread Tools  Search this Thread  Display Modes 
May 7, 2019, 09:42 

#441 
New Member
Maxime
Join Date: Mar 2019
Location: Paris
Posts: 5
Rep Power: 7 
Hello everyone,
I have a question, probably a stupid one because I'm just starting with foamextend. It it possible to extract the velocity of the solid in precise points when we run a fsi simulation? I'll try to be more precise, when I run a simulation I have new files in the fluid folder with new pressure, velocity fields... but not in the solid one so how can I get these informations Thanks, Maxime 

May 7, 2019, 09:47 

#442  
Super Moderator
Philip Cardiff
Join Date: Mar 2009
Location: Dublin, Ireland
Posts: 1,089
Rep Power: 34 
Quote:
Which solver are you using? The solid fields are typically written to the timesteps in a subdirectory called "solid". Philip 

May 7, 2019, 09:52 

#443 
New Member
Maxime
Join Date: Mar 2019
Location: Paris
Posts: 5
Rep Power: 7 
Hi,
I have found it thank you for the quick reply! Maxime 

May 27, 2019, 14:01 

#444  
New Member
Iago Lessa de Oliveira
Join Date: May 2015
Posts: 23
Rep Power: 11 
Quote:
I am currently trying to implement the MooneyRivlin model and an exponential model based on the first invariant of the right CauchyGreen deformation tensor in solids4foam. However, both of these models use material constants that do not relate to the Lamé constants of the neoHookean constitutive model, for example. So, in this case, how should I calculate the implicit stiffness for a specific model? Based on a paper by Prof. Jasak regarding solvers for elasticity problems, I tried to extract the linear part of the complete equation when I replace the Cauchy stress expression in the governing equation and. hence, the coefficient of this Laplacian term would be the implicit stiffness. However, I am not sure if this is a theoretically correct procedure. Could you help me with this issue? Thanks in advance Best regards Iago Lessa 

May 27, 2019, 15:43 

#445  
Super Moderator
Philip Cardiff
Join Date: Mar 2009
Location: Dublin, Ireland
Posts: 1,089
Rep Power: 34 
Quote:
The 'implicit stiffness' coefficient only affects convergence and does not affect the result (assuming the procedure converges), so I suggest you try set it to "2*mu" (twice the linearised shear modulus, or something similar) and see if it converges. You may need some field relaxation for the D field (or DD depending on the solid model). Philip 

May 29, 2019, 15:29 

#446  
New Member
Iago Lessa de Oliveira
Join Date: May 2015
Posts: 23
Rep Power: 11 
Quote:
I tried with the "2*mu" and with "2*c01" (c01 is one of the material constants of the Mooney model I am using), however both procedures lead to divergence I printed the determinant of the deformation gradient and it increases until divergence (since the initial iterations the Jacobian is negative and very high), even changing the relaxation. I am currently reviewing the code and the equations of the model, but do you think that it could be caused by the highly nonlinear behavior of this model? Any help would be great Thanks again and kind regards, Iago 

May 30, 2019, 18:27 

#447 
Super Moderator
Philip Cardiff
Join Date: Mar 2009
Location: Dublin, Ireland
Posts: 1,089
Rep Power: 34 
sigh... I wrote a reply and then the internet dropped when I clicked "post". OK, here I go again (when my clipboard now has my back covered):
All hyperelastic laws should reduce to linear elasticity when the strains are small, so I suggest you try a case with small strains. Keep the case simple with a simple orthogonal mesh. Related to this is the traction boundaries, their implementation (in the tractionBoundarySnGrad function within a solid model) can also greatly affect convergence: you may need to use 2*mu there too. For trying underrelaxation for the D field, make sure to try values as low as 0.1. If your law is incompressible then how do you calculate the hydrostatic pressure? This could be causing the problem. I guess you need to solve a pressure equation, and then be careful of the boundary conditions. You may try a compressible form first to see if this is the issue. Philip 

June 6, 2019, 07:17 
solids4foam installation

#448 
Member
Lilian Chabannes
Join Date: Apr 2017
Posts: 58
Rep Power: 9 
Hello, I installed solids4foam but every tutorial crashes after few iterations. I joined the cavity tutorial log below.
I thought I just broke foamextend4.0 after replacing fvMesh.C, solution.C etc.. but the fe40 tuto works properly. Any idea of what I missed here? Thanks Code:
/**\  =========    \\ / F ield  foamextend: Open Source CFD   \\ / O peration  Version: 4.0   \\ / A nd  Web: http://www.foamextend.org   \\/ M anipulation  For copyright notice see file Copyright  \**/ Build : 4.0f500917045c0 Exec : solids4Foam Date : Jun 06 2019 Time : 13:09:19 Host : lilianVB PID : 9776 CtrlDict : "/home/lilian/foam/lilian4.0/tutorials_solids4foam/fluids/cavity/system/controlDict" Case : /home/lilian/foam/lilian4.0/tutorials_solids4foam/fluids/cavity nProcs : 1 SigFpe : Enabling floating point exception trapping (FOAM_SIGFPE). // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * // Create time /**\  For further information on the solids4Foam toolbox implementations,   please see the following publications:     P. Cardiff, A Karac, P. De Jaeger, H. Jasak, J. Nagy, A. Ivankovic,   Z. Tukovic: An opensource finite volume toolbox for solid mechanics and   fluidsolid interaction simulations. arXiv:1808.10736v2, 2018, available   at https://arxiv.org/abs/1808.10736.     Z. Tukovic, A. Karac, P. Cardiff, H. Jasak, A. Ivankovic: OpenFOAM   finite volume solver for fluidsolid interaction. Transactions of   Famena, 42 (3), pp. 131, 2018, 10.21278/TOF.42301.  \**/ Selecting physicsModel fluid Selecting fluidModel icoFluid Selecting dynamicFvMesh staticFvMesh g field not found in constant directory: initialising to zero PISO: Operating solver in PISO mode Time = 0.005 Evolving fluid model: icoFluid Courant Number mean: 0 max: 0 velocity magnitude: 0 DILUPBiCG: Solving for Ux, Initial residual = 1, Final residual = 2.96338e06, No Iterations 8 PBiCG: Solving for Uy, Initial residual = 0, Final residual = 0, No Iterations 0 DICPCG: Solving for p, Initial residual = 1, Final residual = 7.56362e07, No Iterations 35 PCG: Solving for p, Initial residual = 3.4915e07, Final residual = 3.4915e07, No Iterations 0 time step continuity errors : sum local = 5.61198e09, global = 1.60142e19, cumulative = 1.60142e19 DICPCG: Solving for p, Initial residual = 0.0373132, Final residual = 6.84278e07, No Iterations 32 PCG: Solving for p, Initial residual = 6.55699e07, Final residual = 6.55699e07, No Iterations 0 time step continuity errors : sum local = 1.14621e08, global = 1.25731e19, cumulative = 3.44107e20 DICPCG: Solving for p, Initial residual = 0.0306494, Final residual = 8.90318e07, No Iterations 31 PCG: Solving for p, Initial residual = 8.59511e07, Final residual = 8.59511e07, No Iterations 0 time step continuity errors : sum local = 1.60703e08, global = 4.35428e19, cumulative = 4.01017e19 ExecutionTime = 0.01 s ClockTime = 0 s Time = 0.01 Evolving fluid model: icoFluid Courant Number mean: 0.0633348 max: 0.652495 velocity magnitude: 0.652495 DILUPBiCG: Solving for Ux, Initial residual = 0.564705, Final residual = 5.02236e06, No Iterations 7 DILUPBiCG: Solving for Uy, Initial residual = 1, Final residual = 6.02072e06, No Iterations 7 DICPCG: Solving for p, Initial residual = 0.955695, Final residual = 7.23834e07, No Iterations 34 PCG: Solving for p, Initial residual = 3.97939e07, Final residual = 3.97939e07, No Iterations 0 time step continuity errors : sum local = 4.26527e08, global = 7.51742e19, cumulative = 1.15276e18 DICPCG: Solving for p, Initial residual = 0.0469785, Final residual = 7.02703e07, No Iterations 32 PCG: Solving for p, Initial residual = 7.01974e07, Final residual = 7.01974e07, No Iterations 0 time step continuity errors : sum local = 7.57423e08, global = 5.20131e19, cumulative = 1.67289e18 DICPCG: Solving for p, Initial residual = 0.0396281, Final residual = 9.64776e07, No Iterations 31 PCG: Solving for p, Initial residual = 9.68577e07, Final residual = 9.68577e07, No Iterations 0 time step continuity errors : sum local = 1.03807e07, global = 6.5248e19, cumulative = 2.32537e18 ExecutionTime = 0.01 s ClockTime = 0 s Time = 0.015 Evolving fluid model: icoFluid Courant Number mean: 0.133341 max: 1.24061 velocity magnitude: 1.24061 DILUPBiCG: Solving for Ux, Initial residual = 0.712947, Final residual = 5.34155e06, No Iterations 7 DILUPBiCG: Solving for Uy, Initial residual = 0.988583, Final residual = 9.34277e06, No Iterations 7 DICPCG: Solving for p, Initial residual = 0.961172, Final residual = 6.79535e07, No Iterations 33 PCG: Solving for p, Initial residual = 3.70372e07, Final residual = 3.70372e07, No Iterations 0 time step continuity errors : sum local = 2.22259e07, global = 8.78797e19, cumulative = 1.44657e18 DICPCG: Solving for p, Initial residual = 0.0176281, Final residual = 6.8951e07, No Iterations 29 PCG: Solving for p, Initial residual = 6.95257e07, Final residual = 6.95257e07, No Iterations 0 time step continuity errors : sum local = 4.11115e07, global = 6.14099e19, cumulative = 2.06067e18 DICPCG: Solving for p, Initial residual = 0.0154448, Final residual = 6.57921e07, No Iterations 29 PCG: Solving for p, Initial residual = 6.63021e07, Final residual = 6.63021e07, No Iterations 0 time step continuity errors : sum local = 3.86489e07, global = 5.50571e19, cumulative = 2.61124e18 ExecutionTime = 0.02 s ClockTime = 0 s Time = 0.02 Evolving fluid model: icoFluid Courant Number mean: 0.193945 max: 1.27361 velocity magnitude: 1.27361 DILUPBiCG: Solving for Ux, Initial residual = 0.820961, Final residual = 7.95315e07, No Iterations 8 DILUPBiCG: Solving for Uy, Initial residual = 0.998289, Final residual = 5.30591e06, No Iterations 7 DICPCG: Solving for p, Initial residual = 0.966537, Final residual = 5.67282e07, No Iterations 32 PCG: Solving for p, Initial residual = 3.04536e07, Final residual = 3.04536e07, No Iterations 0 time step continuity errors : sum local = 1.05194e06, global = 4.80691e18, cumulative = 2.19567e18 DICPCG: Solving for p, Initial residual = 0.0134272, Final residual = 5.81579e07, No Iterations 28 PCG: Solving for p, Initial residual = 5.87513e07, Final residual = 5.87513e07, No Iterations 0 time step continuity errors : sum local = 1.97667e06, global = 6.56451e19, cumulative = 1.53922e18 DICPCG: Solving for p, Initial residual = 0.0125092, Final residual = 5.38448e07, No Iterations 28 PCG: Solving for p, Initial residual = 5.4365e07, Final residual = 5.4365e07, No Iterations 0 time step continuity errors : sum local = 1.80577e06, global = 2.29758e18, cumulative = 3.83679e18 ExecutionTime = 0.02 s ClockTime = 0 s Time = 0.025 Evolving fluid model: icoFluid Courant Number mean: 1.37537 max: 11.0114 velocity magnitude: 11.0114 DILUPBiCG: Solving for Ux, Initial residual = 0.798569, Final residual = 5.6189e06, No Iterations 8 DILUPBiCG: Solving for Uy, Initial residual = 0.983555, Final residual = 4.88237e06, No Iterations 9 DICPCG: Solving for p, Initial residual = 0.95958, Final residual = 4.82828e07, No Iterations 33 PCG: Solving for p, Initial residual = 2.57333e07, Final residual = 2.57333e07, No Iterations 0 time step continuity errors : sum local = 4.99873e06, global = 9.82558e18, cumulative = 5.98879e18 DICPCG: Solving for p, Initial residual = 0.0178135, Final residual = 8.20424e07, No Iterations 29 PCG: Solving for p, Initial residual = 8.27314e07, Final residual = 8.27314e07, No Iterations 0 time step continuity errors : sum local = 1.58687e05, global = 1.47384e17, cumulative = 8.74959e18 DICPCG: Solving for p, Initial residual = 0.0176538, Final residual = 8.08312e07, No Iterations 29 PCG: Solving for p, Initial residual = 8.14435e07, Final residual = 8.14435e07, No Iterations 0 time step continuity errors : sum local = 1.54528e05, global = 2.24464e18, cumulative = 1.09942e17 ExecutionTime = 0.02 s ClockTime = 0 s Time = 0.03 Evolving fluid model: icoFluid Courant Number mean: 5.76872 max: 48.0483 velocity magnitude: 48.0483 DILUPBiCG: Solving for Ux, Initial residual = 0.783183, Final residual = 1.07369e06, No Iterations 13 DILUPBiCG: Solving for Uy, Initial residual = 0.92337, Final residual = 2.04154e06, No Iterations 12 DICPCG: Solving for p, Initial residual = 0.925342, Final residual = 8.81149e07, No Iterations 33 PCG: Solving for p, Initial residual = 4.71599e07, Final residual = 4.71599e07, No Iterations 0 time step continuity errors : sum local = 4.77081e05, global = 3.72694e17, cumulative = 4.82637e17 DICPCG: Solving for p, Initial residual = 0.0464455, Final residual = 5.58182e07, No Iterations 30 PCG: Solving for p, Initial residual = 5.61316e07, Final residual = 5.61316e07, No Iterations 0 time step continuity errors : sum local = 5.63008e05, global = 1.00289e16, cumulative = 1.48552e16 DICPCG: Solving for p, Initial residual = 0.0518286, Final residual = 5.84817e07, No Iterations 30 PCG: Solving for p, Initial residual = 5.8853e07, Final residual = 5.8853e07, No Iterations 0 time step continuity errors : sum local = 5.8646e05, global = 4.60786e17, cumulative = 1.94631e16 ExecutionTime = 0.03 s ClockTime = 0 s Time = 0.035 Evolving fluid model: icoFluid Courant Number mean: 25.4612 max: 145.647 velocity magnitude: 145.647 DILUPBiCG: Solving for Ux, Initial residual = 0.721755, Final residual = 4.05054e06, No Iterations 21 DILUPBiCG: Solving for Uy, Initial residual = 0.772057, Final residual = 5.8086e06, No Iterations 21 DICPCG: Solving for p, Initial residual = 0.874298, Final residual = 3.50262e07, No Iterations 33 PCG: Solving for p, Initial residual = 1.90244e07, Final residual = 1.90244e07, No Iterations 0 time step continuity errors : sum local = 8.25885e05, global = 4.45878e16, cumulative = 6.40509e16 DICPCG: Solving for p, Initial residual = 0.121134, Final residual = 4.58234e07, No Iterations 31 PCG: Solving for p, Initial residual = 4.34285e07, Final residual = 4.34285e07, No Iterations 0 time step continuity errors : sum local = 0.000210197, global = 3.46945e16, cumulative = 2.93564e16 DICPCG: Solving for p, Initial residual = 0.352347, Final residual = 4.87244e07, No Iterations 32 PCG: Solving for p, Initial residual = 4.12811e07, Final residual = 4.12811e07, No Iterations 0 time step continuity errors : sum local = 0.000287, global = 2.70508e15, cumulative = 2.99865e15 ExecutionTime = 0.03 s ClockTime = 0 s Time = 0.04 Evolving fluid model: icoFluid Courant Number mean: 208.417 max: 1327.69 velocity magnitude: 1327.69 DILUPBiCG: Solving for Ux, Initial residual = 0.938117, Final residual = 5.97465e06, No Iterations 126 DILUPBiCG: Solving for Uy, Initial residual = 0.970662, Final residual = 6.63502e06, No Iterations 143 DICPCG: Solving for p, Initial residual = 0.6835, Final residual = 5.56485e07, No Iterations 33 PCG: Solving for p, Initial residual = 3.62332e07, Final residual = 3.62332e07, No Iterations 0 time step continuity errors : sum local = 0.000557523, global = 1.07336e15, cumulative = 4.07201e15 DICPCG: Solving for p, Initial residual = 0.820069, Final residual = 7.85147e07, No Iterations 32 PCG: Solving for p, Initial residual = 4.52001e07, Final residual = 4.52001e07, No Iterations 0 time step continuity errors : sum local = 0.00474066, global = 2.4503e15, cumulative = 6.52231e15 DICPCG: Solving for p, Initial residual = 0.986497, Final residual = 7.76072e07, No Iterations 32 PCG: Solving for p, Initial residual = 3.92988e07, Final residual = 3.92988e07, No Iterations 0 time step continuity errors : sum local = 0.286096, global = 1.78607e12, cumulative = 1.77955e12 ExecutionTime = 0.03 s ClockTime = 0 s Time = 0.045 Evolving fluid model: icoFluid Courant Number mean: 154828 max: 4.23053e+06 velocity magnitude: 4.23053e+06 DILUPBiCG: Solving for Ux, Initial residual = 0.999996, Final residual = 4.28954e06, No Iterations 507 DILUPBiCG: Solving for Uy, Initial residual = 0.999997, Final residual = 9.50619e06, No Iterations 369 DICPCG: Solving for p, Initial residual = 0.618983, Final residual = 3.07179e07, No Iterations 32 PCG: Solving for p, Initial residual = 2.43946e07, Final residual = 2.43946e07, No Iterations 0 time step continuity errors : sum local = 0.286393, global = 2.33147e12, cumulative = 4.11102e12 DICPCG: Solving for p, Initial residual = 0.999994, Final residual = 8.15227e07, No Iterations 33 PCG: Solving for p, Initial residual = 4.07379e07, Final residual = 4.07379e07, No Iterations 0 time step continuity errors : sum local = 77527.3, global = 9.20301e07, cumulative = 9.20297e07 DICPCG: Solving for p, Initial residual = 0.999995, Final residual = 9.44633e07, No Iterations 32 PCG: Solving for p, Initial residual = 4.72084e07, Final residual = 4.72084e07, No Iterations 0 time step continuity errors : sum local = 2.49645e+10, global = 0.292119, cumulative = 0.292118 ExecutionTime = 0.04 s ClockTime = 0 s Time = 0.05 Evolving fluid model: icoFluid Courant Number mean: 1.61649e+16 max: 9.0784e+17 velocity magnitude: 9.0784e+17 DILUPBiCG: Solving for Ux, Initial residual = 1, Final residual = 9.13487e06, No Iterations 533 DILUPBiCG: Solving for Uy, Initial residual = 1, Final residual = 5.68473e06, No Iterations 396 DICPCG: Solving for p, Initial residual = 1, Final residual = 9.07758e07, No Iterations 416 PCG: Solving for p, Initial residual = 4.47002e07, Final residual = 4.47002e07, No Iterations 0 time step continuity errors : sum local = 1.6131e+13, global = 265.796, cumulative = 265.504 DICPCG: Solving for p, Initial residual = 1, Final residual = 9.12404e07, No Iterations 386 PCG: Solving for p, Initial residual = 4.49842e07, Final residual = 4.49842e07, No Iterations 0 time step continuity errors : sum local = 4.07351e+19, global = 8.56115e+08, cumulative = 8.56116e+08 DICPCG: Solving for p, Initial residual = 1, Final residual = 5.90091e07, No Iterations 366 PCG: Solving for p, Initial residual = 2.85712e07, Final residual = 2.85712e07, No Iterations 0 time step continuity errors : sum local = 1.93922e+26, global = 6.02541e+15, cumulative = 6.02541e+15 ExecutionTime = 0.06 s ClockTime = 0 s Time = 0.055 Evolving fluid model: icoFluid Courant Number mean: 1.71569e+33 max: 1.95088e+34 velocity magnitude: 1.95088e+34 DILUPBiCG: Solving for Ux, Initial residual = 1, Final residual = 6269.35, No Iterations 1000 DILUPBiCG: Solving for Uy, Initial residual = 1, Final residual = 1002.2, No Iterations 1000 DICPCG: Solving for p, Initial residual = 1, Final residual = 5.75833e07, No Iterations 865 PCG: Solving for p, Initial residual = 2.84033e07, Final residual = 2.84033e07, No Iterations 0 time step continuity errors : sum local = 5.65699e+38, global = 2.94018e+27, cumulative = 2.94018e+27 DICPCG: Solving for p, Initial residual = 1, Final residual = 6.2911e07, No Iterations 885 PCG: Solving for p, Initial residual = 2.43513e07, Final residual = 2.43513e07, No Iterations 0 time step continuity errors : sum local = 3.4619e+47, global = 7.89303e+37, cumulative = 7.89303e+37 DICPCG: Solving for p, Initial residual = 1, Final residual = 3.4134e07, No Iterations 959 PCG: Solving for p, Initial residual = 1.61789e07, Final residual = 1.61789e07, No Iterations 0 time step continuity errors : sum local = 1.58512e+57, global = 9.87592e+46, cumulative = 9.87592e+46 ExecutionTime = 0.1 s ClockTime = 0 s Time = 0.06 Evolving fluid model: icoFluid Courant Number mean: 5.84558e+63 max: 1.6118e+65 velocity magnitude: 1.6118e+65 DILUPBiCG: Solving for Ux, Initial residual = 1, Final residual = 858486, No Iterations 1000 DILUPBiCG: Solving for Uy, Initial residual = 1, Final residual = 79426.9, No Iterations 1000 DICPCG: Solving for p, Initial residual = 1, Final residual = 0.00450428, No Iterations 1000 DICPCG: Solving for p, Initial residual = 0.00224882, Final residual = 0.00213946, No Iterations 1000 time step continuity errors : sum local = 1.57344e+77, global = 3.08363e+61, cumulative = 3.08363e+61 DICPCG: Solving for p, Initial residual = 1, Final residual = 0.000290142, No Iterations 1000 DICPCG: Solving for p, Initial residual = 0.000145062, Final residual = 6.33882e07, No Iterations 252 time step continuity errors : sum local = 5.0545e+81, global = 6.32137e+69, cumulative = 6.32137e+69 DICPCG: Solving for p, Initial residual = 1, Final residual = 7.29587e05, No Iterations 1000 DICPCG: Solving for p, Initial residual = 3.64753e05, Final residual = 6.83794e07, No Iterations 190 time step continuity errors : sum local = 1.10318e+92, global = 1.18135e+80, cumulative = 1.18135e+80 ExecutionTime = 0.15 s ClockTime = 0 s Time = 0.065 Evolving fluid model: icoFluid Courant Number mean: 1.89699e+97 max: 5.96825e+98 velocity magnitude: 5.96825e+98 Floating point exception (core dumped)
__________________
Feel free to join the OpenFOAM Discord https://discord.gg/P9p9eHn, a live chat about OpenFOAM 

June 6, 2019, 08:39 

#449  
New Member
Iago Lessa de Oliveira
Join Date: May 2015
Posts: 23
Rep Power: 11 
Quote:
I will do that, they are pretty new to me, especially the one about the traction boundaries, i didn't know that the change must done for the tractionBoundarySnGrad function too. Regarding the compressibility, I am modeling my problem as incompressible and the law I use is indicated to this case, but in the class implementation, I just changed the Cauchy stress tensor function without actually accounting for the hydrostatic pressure. So to include it i must also change the equation being solved, right? Because it will appear as a term in the Cauchy stress. And just to be sure: an incompressible form of the law is one that do not depend on the third invariant of the deformation tensor? iago 

June 6, 2019, 08:56 

#450  
Super Moderator
Philip Cardiff
Join Date: Mar 2009
Location: Dublin, Ireland
Posts: 1,089
Rep Power: 34 
Quote:
Apoligies, this is a temporary issue with the "master" branch: I will merge the fix from the development branch soon. For now, please change to the "development" branch: Code:
$> cd solids4foamrelease $> git checkout development $> ./Allwclean $> ./Allwmake 

June 6, 2019, 09:00 

#451  
Super Moderator
Philip Cardiff
Join Date: Mar 2009
Location: Dublin, Ireland
Posts: 1,089
Rep Power: 34 
Quote:
The mechanical law should return the total Cauchy stress i.e. deviatoric term plus volumetric/dilatation/pressure term. Can you give a link to the form of law you are using? Be careful in case you are just using the definition of deviatoric stress (shape change) without the pressure contribution. You may or may not need to solve an equation to get the pressure; there is probably no need to modify the solidModel as you could solve the equation within the mechanical law to get the pressure. Philip 

June 6, 2019, 10:21 

#452  
Member
Lilian Chabannes
Join Date: Apr 2017
Posts: 58
Rep Power: 9 
Quote:
restarted everything from 0, did that, but the problem is still the same unfortunately
__________________
Feel free to join the OpenFOAM Discord https://discord.gg/P9p9eHn, a live chat about OpenFOAM 

June 6, 2019, 10:50 

#453  
Super Moderator
Philip Cardiff
Join Date: Mar 2009
Location: Dublin, Ireland
Posts: 1,089
Rep Power: 34 
Quote:
I have pushed the fixes to the master now so try a fresh copy and see if it works: Code:
$> git clone git@bitbucket.org:philip_cardiff/solids4foamrelease.git $> cd solids4foamrelease $> ./Allwmake Philip 

June 12, 2019, 05:17 

#454  
Super Moderator
Philip Cardiff
Join Date: Mar 2009
Location: Dublin, Ireland
Posts: 1,089
Rep Power: 34 
Quote:
Quote:
Using a penalty parameter approach for an incompressible pressure term basically means assume the material is compressible and then use a large value for the bulk modulus (the bulk modulus is termed the penalty factor/stiffness in this case); as the bulk modulus is increased, the answer approaches the incompressible solution. So, I suggest you use the pressure term from the implemented compressible neoHookean law: Code:
// Calculate Jacobian const volScalarField J = det(F()); // Calculate hydrostatic pressure const volScalarField p = (1.0/J)*(0.5*K_*(pow(J, 2)  1)*I; // Calculate total Cauchy stress (where 's' is the deviatoric stress that you already calculated): sigma = s  p*I; Best, Philip 

June 21, 2019, 04:10 
How to choose a proper constitutive law?

#455 
New Member
wulonglong
Join Date: Jan 2018
Posts: 7
Rep Power: 8 
Hi everyone!
I have a question(or stupid question). How do i know which constitutive law should be choosed? If my problem is small strain, small deformation then I should use the linear constitutive law. And if the problem is finite strain then need to use nonlinear constitutive law. But is there a simple idea to choose the proper constitutive law? Such like if the ratio of water depth to water length smaller than 1/20 (i.e h/L < 1/20) then I can say this is a shallow water problem. Wu 

June 21, 2019, 07:02 

#456  
Super Moderator
Philip Cardiff
Join Date: Mar 2009
Location: Dublin, Ireland
Posts: 1,089
Rep Power: 34 
Quote:
I would say that this is not a stupid question at all! Generally, if the strains are less than or equal to 1% and the rotations (or each cell/element) are small (less than a few degrees), then the linear geometry (small strain) approach is probably fine, though in some cases it is fine to larger strains e.g. ~5%. So if the linear geometry approach is OK, then you have to decide what material behaviour is most important i.e. what material are you modelling and what are you interested in? For example:
The same points also apply for finite/large strains, in that case, the constitutive laws can become more complex. Feel free to describe your material and problem for me and others to give our thoughts. Philip Last edited by bigphil; June 21, 2019 at 07:04. Reason: added " are small (less than a few degrees)" after "the rotations (or each cell/element)" 

June 24, 2019, 07:40 

#457  
New Member
Iago Lessa de Oliveira
Join Date: May 2015
Posts: 23
Rep Power: 11 
Hello!
I have successfully compiled solids4foam before with foamextend4.1. However, I tried again in a new machine yesterday and it did not completely compile due to the following error: Quote:
I tried in Ubuntu 16.04 and Ubuntu 18.04, with foamextend4.1. Thanks a lot, Iago 

June 25, 2019, 05:47 

#458 
Member
Emad Tandis
Join Date: Sep 2010
Posts: 77
Rep Power: 15 
Hello Philip,
I have implemented a solver for neohookean material deformation. Now, I want to extend it for mooneyrivlin model. I was thinking of finding a relation between Elasticity (E) and mooneyrivlin constants. Is there any relation like this? I have used B (left CauchyGreen deformation) in my code. Do you think I can find Elasticity as a function of B which makes the material behave like mooenyrivlin? 

June 27, 2019, 09:14 

#459  
Super Moderator
Philip Cardiff
Join Date: Mar 2009
Location: Dublin, Ireland
Posts: 1,089
Rep Power: 34 
Quote:
Many forms of MooneyRivlin laws can be found in the literature; for example of a compressible form, see equation 27 in the following paper: https://www.sciencedirect.com/scienc...478?via%3Dihub. Best, Philip 

June 27, 2019, 09:18 

#460  
Super Moderator
Philip Cardiff
Join Date: Mar 2009
Location: Dublin, Ireland
Posts: 1,089
Rep Power: 34 
Quote:
Which compiler are you using? My guess is that these errors are related to you using "too new" a compiler. It should work with gcc 4, 5 and 6 (as well as relatively recent Intel compilers); I have not (yet) checked with later gcc versions. Best, Philip 

Thread Tools  Search this Thread 
Display Modes  


Similar Threads  
Thread  Thread Starter  Forum  Replies  Last Post 
GPU Linear Solvers for OpenFOAM  gocarts  OpenFOAM Announcements from Other Sources  37  August 17, 2022 14:22 
[Virtualization] OpenFOAM oriented tutorial on using VMware Player  support thread  wyldckat  OpenFOAM Installation  2  July 11, 2012 16:01 
New OpenFOAM Forum Structure  jola  OpenFOAM  2  October 19, 2011 06:55 
Crosscompiling OpenFOAM 1.7.0 on Linux for Windows 32 and 64bits with Mingww64  wyldckat  OpenFOAM Announcements from Other Sources  3  September 8, 2010 06:25 
OpenFOAM Debian packaging current status problems and TODOs  oseen  OpenFOAM Installation  9  August 26, 2007 13:50 