v6.03.305 SSNP305 - Compressed bar element - Appearance of a negative pivot

Summary:

This 2D linear quasistatic mechanics test consists in loading a member element into compression. On the one hand, the element is fixed according to the degrees of translation on a node. On the other side, the element is fixed according to the second degree of translation on a node in order to model the sliding along a line. At a certain moment the stiffness becomes negative (= negative slope). This test is taken from guide NAFEMS (analytical solution). The structure will be loaded using displacement control.

The plate is modelled by 12 plane elements (MECPQU4). The material has a linear behavior and geometric nonlinearities are taken into account. We use the keyword factor COMPORTEMENT option GREEN.

• 1. Reference problem
  • 1.1. Geometry
  • 1.2. Material properties
  • 1.3. Boundary conditions and loads
• 2. Benchmark solution
  • 2.1. Calculation method used for the reference solution
  • 2.2. Benchmark results
  • 2.3. Bibliographical references
• 3. Modeling A
  • 3.1. Characteristics of modeling A
  • 3.2. Characteristics of the mesh
  • 3.3. Tested values
  • 3.4. notes
• 4. Summary of results