Once the analyst has defined the model, the next step is to define the analysis that is to be performed on the model. This may vary from a simple static linear analysis to a transient non-linear analysis.

This folder contains the code that deals with the solution of the finite element problem.

References

• What is a FEA Solver?
• Like spinning nodes
• Not All at Once
• Finite Differences
• See the Convergence
• OpenSees Spy
• Non-Convergence Is Not Structural Collapse
• Negative Feedback Loop
• Don’t Invert the Matrix
• A Load at a Fixed DOF

Failure to solve

• https://github.com/xcfem/xc/blob/master/verif/tests/solution/ill_conditioning/readme.md "Ill-conditioning in structural finite element models"
• Failure to Solve
• Invertible Does Not Mean Stable

Continuation methods

• Arc Length Parameters

Modal analysis

• Modal analysis of rigid multy-storey frames

Time-domain transient analysis

• OpenSeesaw
• Structural dynamics
• Initial conditions
• OpenSees: Static, Cyclic, and Dynamic Analysis Examples
• Transient Analysis of a Cantilever Beam
• The time-domain transient method in structural finite element analysis
• Newmark method
• Newmark method
• Newmark-beta method

Eigenvalue analysis

• Ordinary Eigenvalues
• Eigenvalues During an Analysis
• More Than You or Eigen Chew
• Eigenvalues and eigenvectors
• Eigenvalue algorithm
• Ordinary Eigenvalues
• One Way to Get Bad Eigenvalues
• Another Way to Get Bad Eigenvalues
• Quick (and Dirty) Modal Damping
• Eigenvalues of the Stiffness Matrix

PFEM

PFEM has not been migrated from OpenSees yet.

• The PFEM in OpenSees
• Just Fillin’ Up the Tank
• Sloshing Around
• Hydrostatic Loading on a Wall

Less common problems

• Solving when all DOFs are constained: Most Solvers Can Be Marplots