Linear dynamics in 3DEXPERIENCE Mechanical Scenario Creation App or ABAQUS refers to the study of structural response under dynamic loading while assuming linear material behavior, small deformations, and small strain. Abaqus provides several procedures to perform linear dynamic analysis efficiently.
Types of Linear Dynamic Analyses in Abaqus
Abaqus offers multiple linear dynamic analysis techniques, primarily using modal methods to reduce computational cost:
1. Natural Frequency Extraction (Eigenvalue Analysis)
- Used to determine the natural frequencies and mode shapes of a structure.
- Conducted using the FREQUENCY step in Abaqus.
- Methods:
- Lanczos (default, best for large models)
- Subspace iteration (efficient for small models)
- AMS (Automatic Multi-level Substructuring, for very large models)
2. Mode-Based Dynamic Analyses
- Utilizes eigenmodes extracted from frequency analysis to reduce computational effort.
- Modal Transient Analysis (STEADY STATE DYNAMICS, TRANSIENT FREQ.)
- Solves dynamic equations using mode superposition.
- Suitable for systems where damping is proportional.
- Computationally efficient compared to direct transient analysis.
- Steady-State Dynamics
- Used for harmonic loading (e.g., sinusoidal loads at different frequencies).
- Employs frequency domain analysis.
- Response Spectrum Analysis
- Used for seismic or shock load evaluations.
- Computes maximum response based on predefined response spectra.
3. Direct Integration Methods
- Implicit Direct Integration (DYNAMIC, IMPLICIT)
- Solves equations using step-by-step integration.
- Suitable for cases with significant damping or non-proportional damping.
- Explicit Direct Integration (DYNAMIC, EXPLICIT)
- Usually used for nonlinear problems but can be used in linear dynamic studies.
4. Random Response Analysis
- Used when loads are defined as power spectral density (PSD).
Applied in vibration and noise analysis.
Abaqus Linear Dynamics is used across industries to analyze vibrations, dynamic loads, and frequency response:
- Aerospace & Defense: Aircraft vibration, missile launch dynamics, rotor stability.
- Automotive: NVH analysis, crashworthiness, suspension behavior.
- Civil Engineering: Seismic analysis, skyscraper and bridge vibrations.
- Energy: Wind turbine blades, nuclear plant piping, hydroelectric structures.
- Marine & Offshore: Ship hull vibrations, oil platform stability, propeller dynamics.
- Electronics: PCB reliability, appliance noise reduction, speaker analysis.
- Manufacturing: Machine tool vibration, crane dynamics, robotic arm stability.
EduSpace link for linear dynamics course:
