Structural and modal analysis
SignalCalc 900 Provides a Complete Modal Data Acquisition Solution for Small or Large Structural Tests
In a modal study, a common transfer function measurement is the Frequency Response Function (FRF). FRF measurements are used extensively in the modal analysis of mechanical systems. The frequency response function is a complex value and includes both a real and imaginary component that can be resolved into magnitude and phase.
Similar to the FFT Analyzer, the FRF is a characteristic of a system that has a measured response resulting from a known input. The known input could be exciting a structure with an impact hammer or with a modal shaker. The response could be the vibration from a transducer such as an accelerometer, velocity probe, or a displacement sensor that is attached to the structure. It is most common to measure and calculate accelerance frequency response functions. Accelerance is acceleration per unit force, mobility is velocity per unit force and compliance is displacement per unit force.
Modal measurements are typically done with an impact hammer or with a modal shaker. Both require special signal processing features such as pre-triggering, special windowing functions, source triggering, preview capture, etc. which are standard features in the SignalCalc 900 Analyzer suite.
The software also provides an automated book-keeping scheme that tags each measurement with structural geometry information that can be easily exported to modal animation or curve fitting applications.
Transfer Function Measurements
>140 dB dynamic range
Useful for high signal-to-noise measurements and is imperative for high Q structures such as turbine blades
Transfer Function Measurements
TRFs based on H1, H2 and Hv (opt 71) techniques are provided to account for the presence of noise on the input/output channels
Rectangular, Hanning, Flat Top, Force, Exponential Windows
Minimize spectral leakage as needed for your setup
Preview Average mode
Examine time and frequency domain views of impact hammer data before accepting into the measurement
Up to 51,200 frequency lines of resolution
Isolate closely spaced modes
Structural Geometry Information
Easily assign Rectangular, Cylindrical or Spherical coordinates to measurements
Programmable sequencer to tag point and direction
Automate the tagging of point/direction when taking many measurements – Particularly useful during an Impact Hammer test when roving the hammer across different locations
File Export to modal analysis or animation programs
Automatically or manually export to MEscope, UFF, Matlab, SDF, ASCII/CSV
Shaker Excitation and MIMO Analysis
Shaker Testing Excitation
SignalCalc 900 offers a large range of output (DAC) signals to cater to variety of measurement situations – Random, Burst Random, Pseudo Random, Sine, Swept Sine, Square, Swept Square, Chirp, Impulse, etc.
Multi Output Multi Input Analysis (opt 71)
Analyze modal properties in complex structures by exciting with multiple shakers at different locations simultaneously. Excitations from different DAC channels are uncorrelated ensuring highest quality transfer functions
Custom Reports and Data Review/Export
Fully Customizable Plots
Include readouts including test parameters, customer and test article name, operator, test time, etc
Data from one or more runs/saves can be overlaid in Review Mode within seconds. The overlaid plots can be placed in a report.
Data can be exported automatically during or after a test
Create Custom Report Templates in Word
Create a report template in Microsoft Word and have SignalCalc 900 populate the report parameters, plots, and images automatically after each test (DP900-68)
Images and Media
Attach images of the test article or setup and have them printed in the report
Generate Reports Anywhere
Generate Reports on the PC that conducted the test, or on any networked PC
1 Measurement Saves
Review panel provides a quick way to browse through the individual saves or overlay them for comparison
2 Modal Damping
A single degree of freedom circle fit method is provided to identify natural frequencies and estimate damping values
3 Hammer Impact
Pre-trigger delay provides a way to display the complete impact hammer signal