Ebba118
Marine/Ocean
- Sep 9, 2012
- 1
Hello all,
hope that someone here can help me out with this problem.
Not a very experienced Ansys user, I'm trying to validify a method of modeling a hull bottom made out of sandwich composite. The hull bottom is basically a sandwich panel with stiffeners (also sandwich) attached in a grid pattern. The way I've modeled this is
- panel = shell281 consisting of three layers, 2 faces and 1 core
- web of stiffeners = shell 281, same as above
- flange of stiffeners = beam 189 (the beam is sharing line with the area defining the stiffener web)
Now, in order to verify this method, I've modeled a sandwich beam where the core is a shell element (1 layer) and the faces are beams. The beam is 2 m long, fixed in one end and at the other end I've applied a point force.
However, this results in a much weaker beam compared with the analytical results -
the FE-beam deflects 8 cm while the analytical deflects 4 mm and the stresses are several factors higher in the FE beam than the analytical beam. If increasing the force on the analytical beam the stresses are at least approx. of the same size - is there something wrong in HOW I apply the force in Ansys (now it's on one node)?
Why is this so wrong? Has it something to do with the incompability of shells and beams (but they seem to be fully attached to each other when deforming....??)?
Greatful for all the help I can get!!
//Ebba
hope that someone here can help me out with this problem.
Not a very experienced Ansys user, I'm trying to validify a method of modeling a hull bottom made out of sandwich composite. The hull bottom is basically a sandwich panel with stiffeners (also sandwich) attached in a grid pattern. The way I've modeled this is
- panel = shell281 consisting of three layers, 2 faces and 1 core
- web of stiffeners = shell 281, same as above
- flange of stiffeners = beam 189 (the beam is sharing line with the area defining the stiffener web)
Now, in order to verify this method, I've modeled a sandwich beam where the core is a shell element (1 layer) and the faces are beams. The beam is 2 m long, fixed in one end and at the other end I've applied a point force.
However, this results in a much weaker beam compared with the analytical results -
the FE-beam deflects 8 cm while the analytical deflects 4 mm and the stresses are several factors higher in the FE beam than the analytical beam. If increasing the force on the analytical beam the stresses are at least approx. of the same size - is there something wrong in HOW I apply the force in Ansys (now it's on one node)?
Why is this so wrong? Has it something to do with the incompability of shells and beams (but they seem to be fully attached to each other when deforming....??)?
Greatful for all the help I can get!!
//Ebba