# Vibration Data: Van - Front Wheel Hub

## General Information

**Contact:**Gyorgy Szarka [additional processing by Dr Alex Weddell]

**Institution:**University of Bristol

**Parameter:**Vibration, 3-axis

**Specific Location:**Data Logger is cable-tied to the wheel (diameter 0.7 m) in an angle of approximately 35 degrees.

**Data Duration:**00d 00h 04m 59s

**Sampling Frequency:**2048 Hz

**Description:** The selected car is a commercial vehicle (VW Transporter van) with a 5-cylinder diesel engine. The engine speed is relatively low, varying between 1500-2500 rpm. The van was driven around a set of roundabouts and straights for approx. 5 minutes, the maximum speed on the straight road was 40 mph.

The data streams are included in .mat file, titled with the location of each data segments. There are 7 columns of data that represent: time (in seconds), x-axis raw data (in mV), y-axis raw data (in mV), z-axis raw data (in mV), x-axis acceleration (in g), y-axis acceleration (in g), and z-axis acceleration (in g).

Features:

a) The sensor is saturated at speeds higher than ~25 mph so the data for those parts cannot be used

b) Starting from stand-still 27 - 33 seconds

c) Going around a roundabout 86.3 - 97.3 seconds

d) Stopping: 298 - 306 seconds

**Acknowledgment:** This work was supported by the Engineering and Physical Sciences Research Council (EPSRC) under grant number EP/G067740/1 "Next Generation Energy-Harvesting Electronics: Holistic Approach"

## Detailed Test Information

**Original Filename:**CarVib_WheelHub.mat

### Test Equipment:

Custom data logger based on ADXL325 MEMS 3-axis accelerometer### Calibration Parameters:

**X:**210 mV/g, zero-g reading 1812 mV

**Y:**210 mV/g, zero-g reading 1797 mV

**Z:**210 mV/g, zero-g reading 1810 mV

### Axis Directions:

**X:**tangential, clockwise

**Y:**radial, pointing outwards

**Z:**tangential, pointing away from the car

### Downloads/Links

Data MAT file (zipped)## Graphical Test Results

### Peak Acceleration Frequency and Amplitude

### FFT at Maximum Vibration Amplitude

### X-axis Vibration Characteristics

### Y-axis Vibration Characteristics

### Z-axis Vibration Characteristics

## Automated Analysis

### Processing Parameters

Sample rate: 2048 HzDuration: 299 s

Settling time: 10 s

FFT interval: 1 s

FFT length: 1 s

Number of FFTs performed: 289

### Results

Highest mean vibration axis: X*X-axis*

Max Accel Ampl: 999.3 m

*g*_{peak}at 44.0 Hz at 230 s

Time Peak Accel Ampl above 50% of Max Ampl: 7.0 s (2.4 %)

Peak Accel Freq Range (above 50% of Max Ampl): 41.0 ... 49.0 Hz

Mean Accel Freq (above 50% of Max Ampl): 44.4 Hz

Mean Peak Acceleration Ampl (whole test): 109.1 m

*g*_{peak}

Mean Peak Acceleration Freq (whole test): 149.5 Hz

*Y-axis*

Max Accel Ampl: 313.3 m

*g*_{peak}at 44.0 Hz at 10 s

Time Peak Accel Ampl above 50% of Max Ampl: 3.0 s (1.0 %)

Peak Accel Freq Range (above 50% of Max Ampl): 29.0 ... 29.0 Hz

Mean Accel Freq (above 50% of Max Ampl): 29.0 Hz

Mean Peak Acceleration Ampl (whole test): 19.4 m

*g*_{peak}

Mean Peak Acceleration Freq (whole test): 212.8 Hz

*Z-axis*

Max Accel Ampl: 305.7 m

*g*_{peak}at 44.0 Hz at 197 s

Time Peak Accel Ampl above 50% of Max Ampl: 60.0 s (20.8 %)

Peak Accel Freq Range (above 50% of Max Ampl): 19.0 ... 220.0 Hz

Mean Accel Freq (above 50% of Max Ampl): 67.8 Hz

Mean Peak Acceleration Ampl (whole test): 84.2 m

*g*_{peak}

Mean Peak Acceleration Freq (whole test): 86.1 Hz