김경종
68 lines
3.0 KiB
Markdown
68 lines
3.0 KiB
Markdown
---
|
|
type: concept
|
|
title: "Midas FEA Linear Dynamics and Buckling Analyses"
|
|
created: 2026-06-02
|
|
updated: 2026-06-02
|
|
address: c-000151
|
|
aliases:
|
|
- MIDAS FEA modal analysis
|
|
- MIDAS FEA time history analysis
|
|
- MIDAS FEA response spectrum analysis
|
|
- MIDAS FEA linear buckling analysis
|
|
tags:
|
|
- concept
|
|
- finite-element-method
|
|
- dynamics
|
|
- eigenproblems
|
|
- buckling
|
|
- midas-fea
|
|
status: current
|
|
related:
|
|
- "[[Midas-FEA-Analysis-Manual|Midas FEA Analysis Manual]]"
|
|
- "[[Direct Time Integration Methods]]"
|
|
- "[[Finite Element Eigenproblem Solvers]]"
|
|
- "[[Geometric Stiffness Matrix]]"
|
|
- "[[Dynamic Buckling Analysis]]"
|
|
sources:
|
|
- "[[Midas-FEA-Analysis-Manual|Midas FEA Analysis Manual]]"
|
|
source_refs:
|
|
- source: "[[Midas-FEA-Analysis-Manual|Midas FEA Analysis Manual]]"
|
|
raw_path: ".raw/MidasFEAAnalysisManual/"
|
|
raw_files:
|
|
- "MidasFEAAnalysisManual_002.md"
|
|
- "MidasFEAAnalysisManual_036.md"
|
|
- "MidasFEAAnalysisManual_038.md"
|
|
- "MidasFEAAnalysisManual_039.md"
|
|
md_indices:
|
|
- 2
|
|
- 36
|
|
- 38
|
|
- 39
|
|
match: "heuristic-heading-keyword"
|
|
confidence: high
|
|
---
|
|
|
|
# Midas FEA Linear Dynamics and Buckling Analyses
|
|
|
|
## Definition
|
|
|
|
Midas FEA linear dynamics and buckling analyses are the manual's linear static, modal, time history, response spectrum, and eigenvalue buckling procedure family.
|
|
|
|
## How It Works
|
|
|
|
Linear static analysis solves the assembled stiffness equation with loads, boundary conditions, coordinate transformations, and singularity checks. The manual also warns that nonlinear member cases such as tension-only or compression-only links use internal iteration, so their results should not be combined as if they were purely linear load cases.
|
|
|
|
Modal analysis solves `K phi = lambda M phi` and reports mode shapes, participation factors, effective modal mass, and modal direction factors. Lanczos and subspace methods are described, including shift-invert ideas, rigid-mode handling, and Sturm sequence checks for missed eigenvalues.
|
|
|
|
Time history analysis is organized through mode superposition and direct integration, with damping models such as Rayleigh damping and modal damping. The manual gives a practical time-step accuracy rule: choose a step small enough relative to the highest mode of interest and the load time interval.
|
|
|
|
Response spectrum analysis approximates a multi-degree-of-freedom response through modal single-degree-of-freedom spectra and modal combination rules such as ABS, SRSS, and CQC. Linear buckling analysis forms a geometric stiffness contribution from a pre-buckling stress or internal force state and solves an eigenvalue problem for critical load factors and modes.
|
|
|
|
## Connections
|
|
|
|
- [[Finite Element Eigenproblem Solvers]] covers modal and buckling eigenvalue algorithms.
|
|
- [[Direct Time Integration Methods]] covers transient dynamics and direct integration.
|
|
- [[Geometric Stiffness Matrix]] connects internal stress to buckling stiffness.
|
|
- [[Dynamic Buckling Analysis]] extends stability thinking to time-dependent loading.
|
|
|