I know that in Abaqus there is a way to apply foundation which is through interaction modulus. However, using this method only Winkler type foundation can be defined. While, I need to define Pasternak foundation? Is there any way to do that? Maybe I need to define subroutine, in such a case can you help me to do that?
Dear Mr. Dabbagh,
before your question could be answered, a brief note on the developments in the foundation modeling may help you assess the need arising thereof.
After the well-known Winkler's one-parameter spring-bed model, which was only based on the soil's coefficient of sub-grade modulus (k), several two-parameter models were developed to incorporate the shear interaction between the adjacent springs. For that purpose, beam or plate with some defined mechanical properties, connecting the springs together while undergoing transverse shear deformation were developed "phenomenologically". Subsequently, once the present-day finite element (FE) solutions, based on relatively rigorous and more accurate half-space approaches, became easily achievable, the need to rely on the previous rather approximate modeling approaches became unnecessary. In the FE software, why shouldn't we model the foundation in a more detailed manner than the two-parameter phenomenological model?
Well, having said that, assuming that for some reason(s) you might be required to model it, say for comparison purpose, it is possible to develop a discrete FE model for the Pasternak foundation using appropriate combinations of the spring, beam or plate elements assigned with corresponding material properties (material subroutine could be used for assigning specific requirements) and with due interactions between the elements. Note that, several theories are available to define the parameters required for the Pasternak foundation model; you need to choose appropriate one based on the problem in hand (e.g., soil type).
Hope you would be able to obtain desired results in the foundation modelling.
Good luck,
Vasant Matsagar.
Dear Mr. Dabbagh,
A method to simulate the 2 parameter Pasternak model is the programming of the corresponding stiffness matrix (as well as the corresponding load matrices) of a beam which is resting on foundation of this type. I hope that the attached file will be useful for you.
Konstantinos Morfidis
you can refer to following paper in which they have proposed analytical model by incorporating Pasternak’s shear layer model (1954) for the soil spring-coupling effects and they compared results of proposed model with ABAQUS 3D as well as experimental data.
http://www.git4cc.com/korean/files/5_1437631509.pdf
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