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ModalVIEW - modal testing & analysis tool

 

1. Overview

2. Features

3. Hardware system

 

Overview

ModalVIEW software is designed for you to easily acquire multi-channel sound or vibration signals from a running machine, or the static or dynamic loading of a structure by utilizing data acquisition hardware. After obtaining a set of time histories, it can animate the response of a structure and show you the structure's vibration behavior at once. It helps you to extract and visualize useful modal parameters information from acquired time- and frequency-domain experimental data. ModalVIEW software is developed under National Instruments' LabVIEW, an open environment designed to make interfacing with any measurement hardware rapidly and simple. ModalVIEW software is compatible with any dynamic signal acquisition (DSA) hardware of National Instruments including plug-in boards, USB devices, and PXI systems and speed your time to perform experimental measurement. With ModalVIEW software, a low cost modal testing and modal analysis tool, you can also leverage your structural testing capabilities by utilizing existing investment in NI DSA hardware.

ModalVIEW software is developed according to the LabVIEW development guidelines and is certified by National Instruments as Compatible with LabVIEW.

 

Features

Data management

Integrated data management organizes different type of experiment data into a project. Each data in the project can be easily accessed and viewed. Data management in project makes processing large experimental data sets much easier and reduces your test time.

 
 

Data acquisition

Most popular National Instruments multi-channel DSA hardware can be seamlessly connected. Data acquisition supports free run and external trigger acquisition modes. Post-processes such as windowing, FRF average are supported. Acquired time waveform and averaged FRF can be displayed at the same time. Acquired data block can be previewed and processed before being saved into data file. Designed test plan guides you to perform the whole test step by step. Graphically indicated measurement points on a connected structure guide you to correctly arrange sensors and finish test process.

 
 

3D modeling

Basic structure blocks including plate, triangle, circle, cube, cone, cylinder and sphere are provided to help you rapidly build your experimental structure. Structure display can be interactive rotated, elevated, zoomed and paned in the 3D view with a cursor operation. Measurement points and directions can be displayed on the model structure. Structure model can also be imported from UFF or ASCII file format.

 
 

ODS & mode animation

Model structure can be directly animated from time or frequency domain data measurements or modal shape table. Animation shape data can be interpolated for unmeasured points from near measured data. Deformed and un-deformed shape can be display together. Animation speed and amplitude can be controlled. Structure animation can be documented into an AVI file.

 
 

Modal analysis

MDOF polynomial curve fitting method (Rational polynomial fit, RPF) provides you a quick insight into natural frequency, damping ratio and modal shape with minimum interaction. With residual effects compensation, out of band modes are taken into account to guarantee estimation accuracy. Advanced analysis method (Least square complex frequency-domain, LSCF) are also provided, which involves two steps: identifying mode location from generated stabilization chart; estimating modal shape based on selected modes. Stochastic subspace identification (SSI) method is also included for operational modal analysis (OMA). Mode locations can be identified automatically or selected manually with your expert skills. FRF can be synthesized from estimated modal parameters to verify analysis results. Mode shape result can be compared with modal assurance criterion (MAC). Complex mode can be further converted into real mode.

 
 

Order-based OMA

A new order-based operational modal analysis (OMA) method to identify modal parameters from response measurements of rotation machine structure in operating state. The order spectrum of time vs. frequency and rpm vs. frequency plot are available for easy detection and selection of orders and resonances. Advanced order tracking method is combined with LSCF frequency domain estimation to solve noise and vibration applications relying on engine running up/down as a useful excitation.

 
 

Hardware system

ModalVIEW uses dynamic signal acquisition (DSA) hardware of National Instruments as data acquisition front-ends enabling applications from 4 to hundreds of input channels. DSA hardware are designed specifically for applications requiring audio, noise, and vibration measurements with 24-bit A/D resolution, AC/DC coupling, IEPE conditioning, anti-aliasing filters and support multiple sensors, such as microphones and acceleration sensors, The selected NI DSA devices can be synchronized between channels and on up to thousands of channels. It supports multiple interfaces including USB, PCI, PXI and Compact RIO.

Supported DSA hardware

<NI 9233, NI 9234>

• 24-Bit ADC Resolution
• 102 dB Dynamic Range
• AC-coupled with IEPE for Microphones and Accelerometers
• Direct BNC Connectivity
• Anti-aliasing Filters

<NI 4431, NI 4432>

• 24-Bit ADC Resolution
• 100 dB Dynamic Range
• 102.4 kS/s Maximum Sampling Rate
• Software Selectable AC / DC Coupling per Channel
• Software Selectable IEPE for Microphones and Accelerometers
• Anti-aliasing Filters
• Portable bus-powered device for USB
• Analog output for excitation

<NI 4461>

• 24-Bit ADC Resolution
• 118 dB Dynamic Range
• Software Selectable IEPE for Microphones and Accelerometers
• Differential Input Mode
• Software Selectable AC / DC Coupling per Channel
• Anti-aliasing Filters

<NI 4472>

• 24-Bit ADC Resolution
• 110 dB Dynamic Range
• 102.4 kS/s Maximum Sampling Rate
• Software Selectable AC / DC Coupling per Channel
• Software Selectable IEPE for Microphones and Accelerometers
• Anti-aliasing Filters

<NI 4498>

• 24-Bit ADC Resolution
• 113 dB Dynamic Range
• 204.8 kS/s Maximum Sampling Rate
• Software Selectable AC / DC Coupling per Channel
• Software Selectable IEPE for Microphones and Accelerometers
• Anti-aliasing Filters

 

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Last updated April 28th, 2018