hummad
Bioengineer
- Aug 10, 2013
- 5
Hi,
I have finally gotten stuck on this model I am working on and was hoping someone here could give me some input on how to proceed.
The model represents a tear test occurring on a unaxial extension device (instron machine). The two materials are surgical mesh and the abdominal wall where the mesh prosthetic has healed over a course of a few weeks and has become embedded into the tissue. I have quite a bit of experimental data and wish to create a model that can, to an extent, replicate these results.
The individual models for each material uses the direct unaxial data from my experiments (marlow hyperelastic models) and works great. However when the two materials are put together with the corresponding constraints and boundary conditions the model seems to abort due to excessive distortion.
My model is summerized below:
Material 1: Mesh (soft knit polypropylene)
width=3 cm; height= 5 cm (3D Shell)
thickness= 0.1 cm
Hyperelastic material, Marlow (test data)
Density= 0.000946
Material 2: Abdominal wall Tissue
Width= 3 Gauge height= 4 cm (3D SOLID)
thickness= 0.75 cm
Hyperelastic material, Marlow (test data)
Density= 0.001034
Contraint:
Embedded
(mesh is embedded into 0.1 cm into the abdominal wall)
Boundary Conditions:
1) Displacement (Mesh top): U2= 3.0 cm (extension at max peak of force vs extension graph)
2) Encastre (abdominal wall bottom)
Step
time period= 0.75 (strain at max peak)
increment= 0.1
neogem on
Results are compared
by taking the sum of the reaction force from the fea model and comparingi to the total load of the experimental data
ive attached the fea model
if you have any input on what i may be doing wrong or what I could try so that this model would run
I would very much appreciate it
I have finally gotten stuck on this model I am working on and was hoping someone here could give me some input on how to proceed.
The model represents a tear test occurring on a unaxial extension device (instron machine). The two materials are surgical mesh and the abdominal wall where the mesh prosthetic has healed over a course of a few weeks and has become embedded into the tissue. I have quite a bit of experimental data and wish to create a model that can, to an extent, replicate these results.
The individual models for each material uses the direct unaxial data from my experiments (marlow hyperelastic models) and works great. However when the two materials are put together with the corresponding constraints and boundary conditions the model seems to abort due to excessive distortion.
My model is summerized below:
Material 1: Mesh (soft knit polypropylene)
width=3 cm; height= 5 cm (3D Shell)
thickness= 0.1 cm
Hyperelastic material, Marlow (test data)
Density= 0.000946
Material 2: Abdominal wall Tissue
Width= 3 Gauge height= 4 cm (3D SOLID)
thickness= 0.75 cm
Hyperelastic material, Marlow (test data)
Density= 0.001034
Contraint:
Embedded
(mesh is embedded into 0.1 cm into the abdominal wall)
Boundary Conditions:
1) Displacement (Mesh top): U2= 3.0 cm (extension at max peak of force vs extension graph)
2) Encastre (abdominal wall bottom)
Step
time period= 0.75 (strain at max peak)
increment= 0.1
neogem on
Results are compared
by taking the sum of the reaction force from the fea model and comparingi to the total load of the experimental data
ive attached the fea model
if you have any input on what i may be doing wrong or what I could try so that this model would run
I would very much appreciate it