Dear Mahsa,

In explicit simulation, load or boundary condition needs to be defined in terms of time. For example, we need to define displacement with respect to time. Displacement at time = 0 will be considered as initial condition. There are some exceptions say initial velocity in which case velocity with respect to time need not be defined.

I wonder if the displacement is defined for outlet condition as typically done in cases to represent infinite fluid media.

Regards,

Chandrashekhar

Dear Chandrashekhar

Thanks a lot for your answer. Actually I want to apply initial displacement in the soil medium to study wave propagation in it. But since abaqus/ explicit does not admit jumps in displacement, I face with this problem. I was wondering whether there is a way to apply these kind of displacements in abaqus/explicit?

Sincerely

Mahsa

Dear Mahsa,

Is it possible to elaborate the problem definition and objective of simulation? Wave propagation is generally required for modeling earthquake or explosive effect. In case of earthquake, one can input ground acceleration with respect to time. In case of explosion, one need to input pressure, velocity, density with respect to time.

Typical seismic analysis of a dam using abaqus is given in the example problems manual as follows.

http://abaqusdoc.ucalgary.ca/books/exa/default.htm?startat=ch02s01aex74.html

Regards,

Chandrashekhar

Dear Chandrashekhar

Thanks a lot for your response. in first step of my project I have to model a soil medium with an initial displacement. Then I am going to apply earthquake acceleration to it.

Faithfully

Mahsa

Dear Mahsa,

I am not yet clear on need for initial displacement. However, you can split the problem in two steps. In the first step, apply the displacement to soil over some time (say 100 time units). Let the soil take the shape (displacement) and stabilize. In the second step (from 100 time units) continue earthquake simulation.

Steps in the explicit simulations need to be defined in terms of time. Explicit cannot distinguish steps. However, one can define the loading or boundary conditions with respect to time to differentiate the two steps.

Regards,

Chandrashekhar

Dear Chandrashekhar

I am very grateful for your response. I wish a very happy year for you.

Sincerely

Mahsa

How can I model dashpot A in abaqus explicit in a soil medium? dashpot A is between 2 points. where should i suppose these 2 nodes?

Dear Mahsa,

How the dashpot is connected in actual case? Is it like a damper in a bike or a partially filled fluid tank? A rough sketch may be useful to understand the problem. Accordingly, I can suggest how to model it.

Regards,

Chandrashekhar

Dear Chandrashekhar

I am modelling a soil medium with absorbing boundaries. i want to model these boundaries with dashpots. Abaqus has 3 kinds of dashpots: Dashpot 1, 2 and A. I can use dashpot A in explicit analysis but dashpot A needs 2 points. my problem is here where to define these 2 nodes. In fact one of them is on the boundary but what about the other one?

Mahsa