NVH, Fatigue, and Frequency Domain Analysis
Instructor
- Yun Huang, Ph.D.
NVH, Fatigue, and Frequency Domain Analysis
Syllabus
This course is recommended for attendees who want to run NVH or other frequency domain vibration, fatigue and acoustic simulation problems with LS-DYNA®. This course is useful for applications including vehicle NVH, aircraft / spacecraft vibro-acoustics, engine noise simulation, and machine vibration testing and simulation. This course introduces you to the frequency domain vibration, fatigue and acoustic features of LS-DYNA and gives a detailed look at the application of these features to vehicle NVH simulation and durability analysis.
Content
-
Introduction
- NVH theory and lab testing technology
- Overview of LS-DYNA frequency domain features and applications
- Frequency domain analysis vs. time domain analysis
- Fourier transform
-
FRF
- Modal superposition method
- Damping (viscous damping, structural damping)
- Nodal force / resultant force FRF
-
SSD
- Large mass method
- Equivalent Radiated Power (ERP)
- Mode expansion with LS-PrePost®
- Mode contribution expansion plot
- Direct SSD
-
Random vibration with PSD loading
- Correlated and uncorrelated multiple excitation
- Acoustic waves
- Pre-stress condition
-
Acoustics
- BEM, FEM
- Vibro-acoustics
- Incident waves
- Acoustic panel / element contribution analysis
- ATV and MATV
- Frequency weighted SPL (dB)
- Radiated sound power, radiation efficiency
- Acoustic eigenvalue analysis
-
Response spectrum analysis
- Input earthquake spectrum
- Modal combination methods (SRSS, CQC, etc.)
- Multi-input spectra
- DDAM
-
Fatigue
- Fatigue theories
- Fatigue analysis in harmonic / random vibration environment
- Miner's rule
- Dirlik Method
- Time domain fatigue (based on stress / strain)
- Multiaxial fatigue
- Mean stress correction
-
Advanced topics
- Statistical Energy Analysis (SEA)
- Brake squeal analysis
- NVH analysis based on IGA
-
Auto NVH examples
- FRF on BIW
- Noise Transfer Functions (NTF)
- Vehicle interior noise
- Muffler Transmission Loss Analysis
-
Workshop
- Hands-on exercise
- Post-processing of binary and ASCII databases (d3ssd, d3acs, d3ftg, nodout_ssd, elout_ssd, etc.)