I really appreciate your help in this regard. Why i cant do frequency analysis for a contact problem. After an actual rupture, deformation of the region surrounding the fault can continue for months, years, or even decades. I've added earthquake motion to Abaqus in this paper. I even bet you'll get better results as Abaqus is really poor in analyzing concrete damage, because of the damage models it provides no good for concrete. If you could help me about History Output Data, it would be very helpful to me.
More input comes from geologic field observations as well as an array of geophysical data, such as seismicity, seismic reflection and tomography, gravity measurements, and pressure measurements in water wells. The promise of forward models, driven by the estimated fault-slip, is that they will predict the location and time of future events-a rupture beneath the ocean floor, for example, that might catastrophically deform the ocean bedrock and produce a tsunami. For computational ease, and due to its symmetry, only half of the soil-pile model has been built and the adequate boundary conditions have been applied as shown in Figure 1. The hollow pile walls were meshed with of 18 continuum elements per annulus. The input file extension was changed to txt so the server can accept it. Best of luck and do ask if u need to know some other thing.
My problem is a contact problem. At a non-dimensional liquefaction depth value of approximately 1. On explicit, you can scale the mass to improve the speed of analyses but its tricky. Performance improvements approaching 50% have been observed. So, in answer to your questions above: 1 No 2 Yes. The main factor governing the behaviour of piles in liquefied soil is the depth of liquefaction. Consequently any numerical, analytical and experimental studies on the stability of pile foundations in liquefied soil are a relatively new initiative.
Knowing this information, you will need to then try and resolve the frequencies you are interested in by setting the time step. In reality the interaction between the soil and pile is much more complex, especially under liquefied conditions. My computers are running 24 hours a day. Proceedings of the American Society of civil engineers, Vol. As for as i know, for the explicit analysis u need to select the Step after initial step named as Dynamic, Explicit. Bashar, did you change the density of materials? The above is only a short summary of what needs to be considered, but hope this helps.
And the results would also be quite good, compared with experimental ones. The change in depth of fixity with depth of liquefaction for constant values of embedment ratio, and soil stiffness degradation. However we can specify the max dt. I also removed in this step the boundary conditions in the acceleration direction. After this I defined as a boundary condition the acceleration of interest and I put there a number which is sth like a scaling factor. It's fine to use automatic incrementation as long as you put the correct controls in place for this ie you limit the dt to ensure you capture your main response frequency as I've described.
Most research in the topic of pile stability is based on the use of Winkler foundation, or p-y method, which offers a straightforward analytical tool, which models the lateral restraining effect of the soil on the pile as a set of discrete one-dimensional springs distributed along the length of the pile. At the same time the other boundary conditions where the sample is fixed have displacements of 0. It's all about simulation A realistic simulation model, also constructed with Abaqus, shows the coseismic warping of the ocean floor that set off the tsunami following the Sumatra-Andaman earthquake. Select the plane of the sample which you want to move and associate it with some non-zero displacement. Therefore the pile-model becomes less sensitive to the size of the soil-model for larger soil-model diameters, Ds. Both, eignvalues and frequencies and also responses are not correct. I'm fairly sure a dynamic implicit would almost always fail to converge after wasting your time for 1 to 2 hours.
It seems you have a very good conceptual clarity. These th The 14 World Conference on Earthquake Engineering October 12-17, 2008, Beijing, China are directly compatible with the friction conditions of the soil-pile model in this paper. That is, pinching cannot be modeled in Abaqus. The study of the buckling behaviour of pile foundations in liquefied soils is a new but critical subject which requires careful attention by researchers and designers. Figure 2: Mesh density used for the soil model. Plz kindly tell me or refer me any links that can explain the procedure to apply this excitation as i am just a beginner in Abaqus.
Then maybe we can say, 'look out on that section of fault down there, we think there's another quake coming. It is unconditionally stable, and the solution accuracy is also governed by increment size and half step residual tolerance in addition to mesh. You need to change your step from Riks to Dynamic implicit or explicit. If you are not used to do these types of analysis, do it first in Seismostruct where fiber model elements are used and concrete and steel damage models are built-in. This can be explained by the fact that a stiffer soil will lead to smaller pile and soil displacements, and therefore, the subsequent effect of the continuum stress-strain behaviour of the soil is less emphasised, and the one-dimensional Winkler foundation model represents more accurately the real behaviour of the soil. Hexahedral, continuum, second order finite elements were used to model the soil and a 25mm-thick hollow section.