DwayneHicks
Structural
- Apr 19, 2005
- 2
I would like to ask for a help with this problem:
I want to make a structural model with material nonlinearity. There are many types of material models in Ansys which can be used for modeling of nonlinear behaviour. For example TB,MELA multilinear elastic model. This model is used very widely an can be found very often in various Ansys tutorials which are considering material nonlinearities.
My problem is that I'm doing a tension test of beam and I want to observe large strains when the ultimate limit state is reached. The ULS corresponds to the highest load under which the highest stresses are induced in model.
But when the ULS is reached the strains or deformations were very small and I expected that the large strains will be visible in the model. Where is the problem?
Maybe I have to use another type of material model like Mooney-Rivlin or Hill or another type of hyperelastic or viscoelastic material. But I'm not sure about it. The parameters of Newton-Rhapson solver was following:
numer of substeps: 100
max. number of iterations 1000
min. number of iterations 10
large deformation analysis: on
I really can understand the fact, that if I'm using MELA option for material that has very high deformation capabilities (500 x epsilon) for sufficiently high stress limit (fu)and vhen the analysis is finished, the ultimate limit state corresponds to deformation like 0.2 mm or less.
For linear analysis, conservative and path dependent process all deformation are equal to imposed loads this is because of Hook law.
For nonlinear analysis when you impose a very big force, you reach the nonlinear area of material behaviour, and in the end of analysis there must be some large strains visible. But they aren't visible. Why?
I want to make a structural model with material nonlinearity. There are many types of material models in Ansys which can be used for modeling of nonlinear behaviour. For example TB,MELA multilinear elastic model. This model is used very widely an can be found very often in various Ansys tutorials which are considering material nonlinearities.
My problem is that I'm doing a tension test of beam and I want to observe large strains when the ultimate limit state is reached. The ULS corresponds to the highest load under which the highest stresses are induced in model.
But when the ULS is reached the strains or deformations were very small and I expected that the large strains will be visible in the model. Where is the problem?
Maybe I have to use another type of material model like Mooney-Rivlin or Hill or another type of hyperelastic or viscoelastic material. But I'm not sure about it. The parameters of Newton-Rhapson solver was following:
numer of substeps: 100
max. number of iterations 1000
min. number of iterations 10
large deformation analysis: on
I really can understand the fact, that if I'm using MELA option for material that has very high deformation capabilities (500 x epsilon) for sufficiently high stress limit (fu)and vhen the analysis is finished, the ultimate limit state corresponds to deformation like 0.2 mm or less.
For linear analysis, conservative and path dependent process all deformation are equal to imposed loads this is because of Hook law.
For nonlinear analysis when you impose a very big force, you reach the nonlinear area of material behaviour, and in the end of analysis there must be some large strains visible. But they aren't visible. Why?