Introduction

LS-DYNA Implicit Workshop

Problem #10: Adaptive Ellipsoidal Dome

Objectives
* Learn to activate mesh adaptivity in an implicit simulation.
* Learn how to minimize hourglass problems.

Problem Description
A static load is applied to the center of an ellipsoidal dome.
Shell elements are used. Nodes at the base of the dome are
constrained, and included in a NODFOR output database. Adaptivity
is used to automatically refine the mesh in areas of high curvature.

Input Filename: aellipse.k

Procedure
Copy the input file to your local directory. Using an editor, view the input file and
answer the following questions:

1. How frequently will the mesh be evaluated for refinement?

2. How many times can each element be subdivided?

3. How do you indicate which parts will be adapted?

4. Which element formulation is used?

5. How is load applied?

Execute the simulation, and view the results with the postprocessor.

6. How many time steps and cycles were used? steps cycles

7. Applied load: Center displacement:

8. Does the adaptive mesh improve the hourglassing problem

Switch to pressure driven load application, and repeat the simulation. Postprocess the
results. Using the NODFOR database, verify that the load is applied correctly as the
mesh is refined.

9. How many time steps and cycles were used? steps cycles

10. Does the pressure load improve nonlinear convergence?

11. Applied loadr: Center displacement:

Experiment with shell element formulation #16.

12. Does shell type #16 improve hourglassing?

13. Does shell type #16 improve convergence behavior (number of steps/cycles)?