Modal Analysis Dept. of Mechanical Engineering Yungpeng Wang 南臺科技大學 STUST

Modal Analysis 南臺科技大學 STUST 1. Software Name: ME’scope VES 2. Software Structure: Structures Data Blocks Shape Tables Pictures Movies Reports

Structures 南臺科技大學 STUST 1. How to create a structure? Drawing Importing from an external source Tracing from pictures or drawings 2. Limitation: 1000 points

Structures 南臺科技大學 STUST 3. Main Window File → New → Structure 4. Structure Window File → Options → Units → 〈 kg, N, m 〉 Draw → Drawing Assistance Draw → Points → Number Points

Data Blocks 南臺科技大學 STUST 1. How to import measurement data? PC data files of an FFT analyzer Data acquisition system Data collector Recorder

Data Blocks 南臺科技大學 STUST 2. Type of Measurements Imported Time-domain measurements imported Time waveform Auto correlation Cross correlation IRF (Impulse response function)

Data Blocks 南臺科技大學 STUST Frequency-domain measurements imported Linear Spectrum (FFT or time waveform) Auto power spectrum (FFT of auto correlation) PSD (power spectral density) Acoustic intensity Cross power spectrum (FFT of cross correlation) FRF frequency response function (motion/force) Transmissibility (motion/motion) ODS FRF (auto power spectrum with phase relative to a reference) Coherence

Data Blocks 南臺科技大學 STUST 3. Limitation 100 measurement traces 1000 samples per

Data Blocks 南臺科技大學 STUST 4. Main Window File → Import→ Data Blocks 5. Data Blocks Window 〈 Change DOFs 〉 Tools → Assign M#’s 〈 Match Point Numbers and DOFs 〉 Or Structure Window Draw → Assign M#’s 〈 Match Point Numbers and DOFs 〉

Data Blocks 南臺科技大學 STUST 6. Structure Window Edit → Animation Equations 〈 Check Boundary Conditions and Measurement Data 〉 Draw → Animate

Shape Tables 南臺科技大學 STUST 1. How to generate a shape table? Saving during animation Saving the current position in a data block Curve fitting measurements using the Visual Modal or Visual SDM Importing from an external source (for example, FEM) 2. Limitation: 1000 DOFs

Shape Tables 南臺科技大學 STUST 3. Data Blocks Window Modes → Modal Parameters