NVA - Modal Test

Experimental Modal Analysis System

NVA-Modal Test is an advanced system for experimental modal analysis of mechanical structures and systems, designed for accurate identification of modal parameters through impact testing with an instrumented hammer or multi-shaker excitation.

The system enables acquisition, processing, and analysis of frequency response functions (FRFs) between the excitation force and the structural response measured by accelerometers, providing a complete solution for research, development, validation, and structural testing activities.

  • NVA-Modal Test is composed of:

    • Multichannel acquisition front-end, also available in portable configurations

    • Modal test transducers (instrumented hammer, accelerometers, strain gauges)

    • Signal generation system for shaker excitation

    • Control computer (notebook or embedded controller)

    • NVA-Modal Test application software for acquisition and analysis

    The system can be implemented on different hardware platforms, ensuring scalability and flexibility according to the number of channels and the application requirements.

    • Compatibility with cDAQ, cRIO, and PXI multichannel systems

    • From 4 to 32 (or more) simultaneous input channels

    • 24-bit A/D converters with high dynamic range

    • Sampling rate up to 51.2 kS/s per channel

    • Programmable anti-aliasing filters

    • Dynamic range greater than 110 dB

    • Integrated power supply for IEPE / ICP sensors (24 V – 4 mA)

    • TEDS support for automatic sensor recognition

    These features ensure reliable measurements even on complex structures and low-response vibration levels.

  • Acquisition and Excitation

    • Free-run or triggered acquisition modes

    • Impact excitation using an instrumented hammer

    • Controlled excitation via electrodynamic shakers

    • Signal generation (sine, broadband, random) up to 8 independent output channels

    Signal Processing

    • Time-domain analysis

    • FFT analysis with selectable windowing

    • FRF calculation and averaging

    • Normal Mode and Frequency Domain Techniques (FDT) analysis

    Modal Parameter Extraction

    • Automatic identification of natural frequencies

    • Calculation of damping factors

    • Curve fitting using autoregressive (AR / ARMA) algorithms

    • Evaluation of:

      • Coherence

      • Real and imaginary parts

      • Measurement quality indicators (MIF, Phase Index)

    • FRF visualization (Magnitude, Phase, Real / Imaginary)

    • Comparative analysis across multiple measurement points

    • Mode shape animation and visualization

    • 2D and 3D representations based on schematic geometry

    • Signal recording for post-processing analysis

    • Export of results to standard formats (TXT, CSV, ASCII)

    • Experimental modal analysis of mechanical structures

    • Identification of natural frequencies and damping ratios

    • FEM model validation and correlation

    • Testing of frames, beams, housings, mechanical components, and industrial structures

    • Vibration analysis in R&D environments

    • Structural testing and diagnostics

    • Academic and research laboratories

    • Complete hardware + software solution

    • High metrological accuracy

    • Scalable channel count

    • Suitable for laboratory and field testing

    • Full integration with the NVA software suite

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