김경종
52 lines
2.5 KiB
Markdown
52 lines
2.5 KiB
Markdown
---
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type: concept
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title: "Midas Civil Dynamic and Seismic Analysis"
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created: 2026-06-02
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updated: 2026-06-02
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address: c-000162
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aliases:
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- MIDAS Civil dynamic analysis
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- midas Civil seismic analysis
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tags:
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- concept
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- finite-element-method
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- midas-civil
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- dynamics
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- seismic-analysis
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status: current
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related:
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- "[[Midas-Civil-Analysis-Reference|Midas Civil Analysis Reference]]"
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- "[[midas Civil]]"
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- "[[Direct Time Integration Methods]]"
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- "[[Finite Element Eigenproblem Solvers]]"
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- "[[Midas FEA Linear Dynamics and Buckling Analyses]]"
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sources:
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- "[[Midas-Civil-Analysis-Reference|Midas Civil Analysis Reference]]"
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---
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# Midas Civil Dynamic and Seismic Analysis
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## Definition
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Midas Civil dynamic and seismic analysis is the set of modal, damping, response-spectrum, and time-history procedures described in the [[Midas-Civil-Analysis-Reference|Midas Civil Analysis Reference]].
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## How It Works
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Free vibration is treated through eigenvector analysis and Ritz vector analysis. Ritz vectors are generated from initial load vectors and repeated static analyses that include inertia effects, so fewer load-relevant vectors can capture response than a broad eigenmode extraction.
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Damping options include proportional and nonproportional forms: mass/stiffness/Rayleigh damping, strain-energy proportional damping, mode damping, element Rayleigh damping, and General Link damping. Response spectrum analysis decomposes an MDOF structure into modal SDOF responses and combines modal contributions using rules such as SRSS and CQC. Time-history analysis supports mode superposition and direct integration, with direct integration needed when stiffness or damping is nonlinear.
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## Solver Development Notes
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- Modal analysis requires consistent mass, stiffness, eigen extraction, normalization, and modal participation output.
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- Ritz vectors add a load-dependent reduced basis, so the initial load-vector contract is part of the input schema.
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- Rayleigh damping needs mode-frequency selection and safeguards against excessive damping after yielding.
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- Multi-support seismic input requires support-specific ground-motion histories and constraint-compatible load assembly.
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## Connections
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- [[Finite Element Eigenproblem Solvers]] covers modal extraction.
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- [[Direct Time Integration Methods]] covers Newmark-style transient solution.
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- [[Midas FEA Linear Dynamics and Buckling Analyses]] provides a sibling product comparison.
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- [[Nonlinear Newmark-Beta Integration]] is relevant when nonlinear time stepping is added.
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