SAE J1490_201105

1 Scope
    1.1 Purpose
2 References
3 Definitions
    3.1 Vibration Measurement Axis Reference
    3.2 Terminology
          3.2.1 Overlap Processing
          3.2.2 PSD
          3.2.3 Ride Vibrations
          3.2.4 RMS
          3.2.5 Seat Pad
          3.2.6 Signal-to-Noise Ratio
          3.2.7 Spectrum
          3.2.8 Test Section
          3.2.9 Transverse Sensitivity
          3.2.10 Windowing
    3.3 Letter Symbols
4 General Test Design
5 Test Preparation and Documentation
    5.1 Vehicle
    5.2 Test Site
    5.3 Operator
    5.4 Operating Conditions
6 Subjective Ride Evaluations
7 Instrumented Ride Vibration Measurements
    7.1 Measurement Instrumentation
          7.1.1 Accelerometers and Signal Conditioning
          7.1.2 Acceleration Data Recording
          7.1.3 Instrumentation Data Sheet
    7.2 Accelerometer Location
    7.3 Data Analysis
          7.3.1 Stationary of Data
          7.3.2 Acceleration Measures
                  7.3.2.1 g(rms)
                  7.3.2.2 Weighted g(rms)
                  7.3.2.3 1/3 Octave Peak g(rms)
                  7.3.2.4 ISO 1/3 Octave Peak
                  7.3.2.5 Exceedance
                  7.3.2.6 Absorbed Power
          7.3.3 Data Analysis Parameters
                  7.3.3.1 Data Duration
                  7.3.3.2 Prepossessing Filters
                  7.3.3.3 Sampling Frequency
                  7.3.3.4 Sampling Accuracy
                  7.3.3.5 Sampling Window
                  7.3.3.6 Frequency Resolution
                  7.3.3.7 Overlap Percentage
                  7.3.3.8 Precision of Spectral Estimates
8 Data Presentation
    8.1 Graphic Presentation
          8.1.1 Power Spectral Density
          8.1.2 Square Root of Power Spectral Density
          8.1.3 Time Domain Histogram
    8.2 Ride Measures Presentation

Gives a uniform procedure for measuring ride vibrations for all Class 7 and 8 commercial vehicles, including combination vehicles and straight trucks.