04-23-2010, 08:49 PM
Regards
The membrane element has three degrees of freedom (X and Y movements more twist in Z) while the shell element has 6 degrees of freedom (3 rotations + 3 shifts). Now which to use depends on the situation.
For example if you want to model a building multistory reinforced concrete it is best to model the slab as a membrane with the rigid diaphragm condition, thus the function of the slab is only to distribute both vertical and horizontal loads. Slabs then modeled independently, using shell elements but considering only the degrees of freedom of movement in Z plus spins X and Y. The reasons for considering the building model as a membrane for unwanted tiles are basically two: 1) The model has many fewer degrees of freedom, thereby reducing analysis time and 2) If you do not make a suitable mesh to model the slabs with elements shell loads applied to these not be transferred correctly to the resistance elements (walls and frames).
As for the common wall is modeled with shell elements, but watch the results as it recalls that these have practically no stiffness out of his plane.
Eye in the case of the balconies, you can not use membrane have vertical displacements.
For walls clearly must take the shell element. Now generally applies the same element (shell), both for walls and slabs.
Jaime
P.D. Please excuse if my English is a bit entangled
The membrane element has three degrees of freedom (X and Y movements more twist in Z) while the shell element has 6 degrees of freedom (3 rotations + 3 shifts). Now which to use depends on the situation.
For example if you want to model a building multistory reinforced concrete it is best to model the slab as a membrane with the rigid diaphragm condition, thus the function of the slab is only to distribute both vertical and horizontal loads. Slabs then modeled independently, using shell elements but considering only the degrees of freedom of movement in Z plus spins X and Y. The reasons for considering the building model as a membrane for unwanted tiles are basically two: 1) The model has many fewer degrees of freedom, thereby reducing analysis time and 2) If you do not make a suitable mesh to model the slabs with elements shell loads applied to these not be transferred correctly to the resistance elements (walls and frames).
As for the common wall is modeled with shell elements, but watch the results as it recalls that these have practically no stiffness out of his plane.
Eye in the case of the balconies, you can not use membrane have vertical displacements.
For walls clearly must take the shell element. Now generally applies the same element (shell), both for walls and slabs.
Jaime
P.D. Please excuse if my English is a bit entangled
jcoronellr, proud to be a member of Engineering Forum since Jan 2009.