Type 8761

PULSE Operational Modal Analysis

Software for post-measurement modal analysis of structures under actual operating conditions and where it is difficult to artificially excite the structure.

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This PULSE software performs modal analysis by post-processing data from measurements on only the output of the structure. Because there is no need to measure the input forces, it is ideal for testing under actual operating conditions, and in situations where it is difficult or impossible to control an artificial excitation of the structure. This makes the setup and measurement procedure simple and fast, as only accelerometers are used – with no hammer or shaker excitation. Downtime is further reduced with in situ testing, during normal operation.

USE SCENARIOS

  • Testing civil engineering structures that are loaded by uncontrollable and unmeasurable ambient forces, such as waves on offshore structures, wind load on buildings, and traffic load effects on bridges
  • Capturing real-life modal parameters of mechanical structures such as aircraft during flight, full vehicles on test tracks, running trains and operating machinery during actual operating conditions
  • Testing of large mechanical structures that are difficult to excite artificially, such as ships and submarines
  • Estimation of modal parameters to be used for finite element (FE) model correlation and model updating, or for design verification, benchmarking, troubleshooting and quality control

CAPABILITIES

This operational modal analysis (OMA) software contains powerful algorithms for accurate modal identification and is yet very easy to use with its task-oriented user interface, intuitive workflow and high degree of automation, including automatic mode estimation. The software is available in Light, Standard and Pro versions.

  • Determining the modal parameters (natural frequencies, damping ratios and mode shapes) of structures in operation
  • Modal parameter identification using actual boundary conditions, actual spatial and frequency distributions of forces and actual force and response levels
  • Automatic identification and suppression of deterministic signals (harmonic components) 
  • Powerful time domain (Pro only) and frequency domain algorithms 
  • Crystal clear stabilization diagrams to discriminate between physical modes and computational modes (Pro only)
  • Modal assurance criterion (MAC) plots and tables
  • Complexity plots and mode normalization
  • Time and frequency domain ODS analysis
  • Fast stochastic subspace identification (SSI) analysis of large amounts of data files without user interaction (batch processing mode; Pro only)
  • Export of animations using AVI movie files
  • Reporting in Microsoft® Word and Microsoft Excel®
  • Structural Health Monitoring (SHM) options (Pro only)

The core technology behind the operational modal analysis software is protected by patents. This includes the efficient and powerful frequency domain decomposition (FDD), enhanced frequency domain decomposition (EFDD) and curve-fit frequency domain decomposition (CFDD) algorithms. In addition, there are four unbiased time domain SSI techniques: principal components (PC), unweighted principal components (UPC), extended unweighted principal components (UPCX) and canonical variate analysis (CVA).

ADDITIONAL CAPABILITIES

REQUIREMENTS

The software can be used as a stand-alone package, by importing time data in standard UFF formats. However, together with PULSE Modal Test Consultant Type 7753 they form a highly integrated measurement and analysis system.