56 lines
2.2 KiB
Markdown
56 lines
2.2 KiB
Markdown
---
|
|
type: concept
|
|
title: "Finite Element Eigenproblem Solvers"
|
|
complexity: advanced
|
|
domain: computational-mechanics
|
|
aliases:
|
|
- eigensystem solution
|
|
- finite element eigenvalue analysis
|
|
- modal analysis
|
|
created: 2026-05-28
|
|
updated: 2026-05-28
|
|
address: c-000015
|
|
tags:
|
|
- concept
|
|
- finite-element-method
|
|
- eigenproblems
|
|
status: current
|
|
related:
|
|
- "[[Finite Element Method]]"
|
|
- "[[Direct Time Integration Methods]]"
|
|
- "[[Static Equilibrium Equation Solvers]]"
|
|
- "[[Dynamic Buckling Analysis]]"
|
|
- "[[Geometric Stiffness Matrix]]"
|
|
- "[[BLZPACK]]"
|
|
sources:
|
|
- "[[Finite Element Procedures]]"
|
|
- "[[Dynamic-Buckling-Analysis-of-Shell-Structures-using-Finite-Element-Method]]"
|
|
---
|
|
|
|
# Finite Element Eigenproblem Solvers
|
|
|
|
## Definition
|
|
|
|
Finite element eigenproblem solvers compute eigenvalues and eigenvectors of matrix systems such as `K phi = lambda M phi`, commonly used for free vibration, buckling, modal reduction, and stability analysis.
|
|
|
|
## How It Works
|
|
|
|
The source introduces eigenvector properties, shifting, zero-mass effects, standard-form transformations, Rayleigh-Ritz approximations, component mode synthesis, error bounds, and solution methods including inverse iteration, forward iteration, Rayleigh quotient iteration, Jacobi transformations, Householder-QR, polynomial iteration, Sturm sequence techniques, Lanczos iteration, and subspace iteration.
|
|
|
|
The dynamic buckling thesis adds an implementation example: [[BLZPACK]], based on Block Lanczos, is used for vibration and buckling eigenvalue analyses in a shell dynamic buckling program.
|
|
|
|
## Why It Matters
|
|
|
|
Large finite element models can have many degrees of freedom, but engineering decisions often require only selected modes or eigenvalues. Solver choice determines whether the analysis can efficiently find the physically relevant part of the spectrum.
|
|
|
|
## Connections
|
|
|
|
- [[Direct Time Integration Methods]] can be contrasted with mode superposition.
|
|
- [[Static Equilibrium Equation Solvers]] shares matrix factorization and conditioning concerns.
|
|
- [[Finite Element Program Implementation]] must support sparse matrix operations and vector iteration workflows.
|
|
|
|
## Sources
|
|
|
|
- [[Finite Element Procedures]]
|
|
- [[Dynamic-Buckling-Analysis-of-Shell-Structures-using-Finite-Element-Method]]
|