TS 1033190 - Vibration Analysis Training
Vibration Analysis Training - Updated 8/2018
Click on the PowerPoint file in the attachments section of this document to view the training file.
Note: This updated Vibration Analysis includes Smart Phone and other mobile devices.

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Vibration Analysis
Jody Adams

Daimler Trucks

Course Intent
 This course is designed to educate DSM’s, technicians, and anyone else
wanting to understand the fundamentals of vehicle vibrations regardless
of the Vibration Analyzer used.
 You will be taught how to collect vibration data, rapidly identify the source
of the vibration, validate the complaint and more importantly know what
is not causing the problem reducing the warranty costs and promoting
Uptime.
 You will be provided the component tests and troubleshooting sequence
for a specific vibrations classification and order.

Daimler AG

Title of presentation / Department / Date

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Agenda
 Noise, Vibration, & Harshness
 Vibration Characteristics
 Fatigue Due To Vibration
 Drivers Experience
 Drivers Interview
 Primary Sources & Classifications
 Evaluation tools
 EVA/Smart Phone/IPad Set Up, Calibration, & Test Drive
 Vibration Source Diagnostics (Wheel end, Driveline, Engine)
 Service Related Bulletins
 Data Analysis Review

Daimler AG

Title of presentation / Department / Date

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Difference Between Noise, Vibration, & Harshness
 Noise – sound heard but not necessarily felt. Noise can be caused by a
vibration. Examples would be a rattling shifter which may be caused by
improper driveline angles but the result is shifter rattle.

 Vibration – repeated movement felt by the driver at the Steering wheel,
floor, or seat. Vibration can be measured with an accelerometer and the
potential source revealed.
 Harshness – a distinct jolt felt by the driver from an input on the road or
terrain. It often feels like the suspension is not doing it job. It may be
caused by improper ride heights, or worn out components such as
suspension components or mounts.

Daimler AG

Title of presentation / Department / Date

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Vibration Basics
All automotive vibrations have 3 basic components
Source – Most of the time it is a rotating component
(wheel end, driveline, or engine) component out-of-round
or out-of-balance. Engines have vibrations that are a natural
part of an engine running. Transfer paths must be checked first.
Transfer Path – is anything that is connected to, or touches
the vibration source. It can be suspension system components,
mounts, exhaust system, running boards etc.
Receiver – is the part in or around the cab (occupants compartment)
that the driver sees, feels or hears is vibrating. It can be the floor,
seat, steering wheel, sun visor, dash mirrors, shifter etc.

Daimler AG

Title of presentation / Department / Date

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Vibration & Measuring Device/Accelerometer
 A vibration is a repetitive motion back and forth relative to a fixed central
position.
 All truck vibration issues will be due to engine, driveline, or tire orders.
 Vibrations are measured by an electromechanical device called an
accelerometer which measures change in velocity or the force of
acceleration caused by gravity or movement over time.
 Accelerometers for vehicle testing are typically a Piezo-Electric or MEMS
type

Daimler AG

Title of presentation / Department / Date

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Piezo-Electric Accelerometer

Mass
Crystal

 Piezo-Electric are crystal based (man made or natural)
 The basic principle of operation behind a Piezo-Electric accelerometer crystals
produce a charge when they are compressed, flexed or subjected to shear force. The
charge output is converted by electronics.
Daimler AG

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MEMS Accelerometer
Z

Y

X

 MEMS = Micro-Electro-Mechanical Sensors
 The basic principle of operation behind the MEMS accelerometer is the displacement of a
small proof mass etched into the silicon surface of the integrated circuit and suspended by
small beams.
 Found in Smart Phones can measure all 3 axis as well as pitch, roll and yaw.
 MEMS accelerometer are not affected by temperature and more accurate than a Piezo type
Daimler AG

Title of presentation / Department / Date

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Vibration Characteristics
 Vibration Characteristics:
1. Frequency is the number of repetitive motions that can be heard or felt
in a given time, usually in 1 second. The measurement
of cycles occurring in one second is called Hertz (Hz).
 Frequency of rotating components can be determine and calculated by Mathematics.
Tire example
Natural Hz

= 10 Hz
514 TRPM x 70 mph
60 seconds x 60 minutes

=
Rear axle ratio X Tire Natural Hz
3.07 X 10 Hz = 30.7 Hz @ 70mph

Daimler AG

Driveshaft Natural Hz

Title of presentation / Department / Date

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Vibration Characteristics
2. Amplitude is the strength level or severity of the disturbance of the
vibration. It is defined as the distance from the center of the motion
to either extreme. The measurement is in G’s.

G’s

= Hz
Daimler AG

Title of presentation / Department / Date

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Vibration Characteristics

3. Resonance – natural frequency of a component or combination of
components (assembly). Resonance amplifies the vibration. When a
component is near it’s natural frequency it will vibrate at the slightest
force. Vehicle applications are designed so that they don’t occur during
highway cruising speeds.

Daimler AG

Title of presentation / Department / Date

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Human Body Sensitivity to Vibration
 Whole body vibration can cause operator fatigue.
 ISO 2631 indicates highest susceptibility is between 4 Hz and 8 Hz.

1 meter/second2 =0.1019g’s

Acceleration (m/s^2, rms)

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Vibration Exposure Criteria for Fatigue, Vertical, Seated,
Whole-Body
24 hour
16 hour
8 hour
4 hour
2.5 hour
1 hour
25 min
16 min
1 min

1

80.00

63.00

50.00

40.00

31.50

25.00

20.00

16.00

12.50

10.00

8.00

6.30

5.00

4.00

3.15

2.50

2.00

1.60

1.25

1.00

0.1

Third-Octave-Band Frequency
Daimler AG

Title of presentation / Department / Date

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IS0 2631 Exposure Guideline

Daimler AG

Title of presentation / Department / Date

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Drivers Experience to Vibration
 Drivers experience vibration in three ways:
1. What the driver feels:
a. shaking steering wheel
b. shaking seat
c. shaking floor

Note: if the vibration is felt in the steering wheel the source is coming from
the front of the vehicle. If the vibration in felt in the floor or seat the
source is coming from the rear of the vehicle.

Daimler AG

Title of presentation / Department / Date

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Driver Experience to Vibration
2. What the driver sees:
a. rattling or shaking gear shift lever
b. shaking mirrors
c. water or fluid in bottle of cup holder
3. What the driver hears:
a. rattling dash
b. loose change rattling in cup holder
c. rattling shifter

Daimler AG

Title of presentation / Department / Date

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Categories of Vibrations
Vehicle Speed Related Vibrations: A vehicle speed related vibration will
usually always occur at the vehicle same speed regardless of the engine
RPM. This type of vibration cannot be detected with the vehicle stopped.
Engine Speed Related Vibrations: An engine speed related vibration will
usually always occur at the same engine RPM speed regardless of the
vehicle speed. This type of vibration can usually detected with the vehicle
stopped, although sometimes it may only show up under a load.

Daimler AG

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Drivers Interview

 In order to evaluate the drivers complaint, critical questions need to be
ask:
1. When did the vibration first occur?
a. after a component change
b. since new
c. check warranty repair history
2. When is the vibration felt, seen, or heard?
a. certain speed
b. certain rpm
c. certain road surfaces
d. does the vibration disappear when the clutch is engaged?
Daimler AG

Title of presentation / Department / Date

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Vibration Questionnaire
VIN # ________________________ Mileage _________________
Customer Name ________________________
What mileage was the vibration first noticed? ______________
Where any repairs made prior to noticing the vibration? Yes ___ No ___
Where is the vibration felt?
Steering Wheel _____
Seat ______
Floor ______
Other ______ explain ____________________________________
What speed range is the vibration in MPH? __________________________
What RPM range is the vibration felt? ______________________________
Does this condition happen in: Bobtail ____ With Trailer ____ Both ___
What type of road surface is the driver experiencing the problem?
Asphalt _____
Concrete _____
Dirt _____
Does the vibration disappear when the clutch pedal is depressed? ________
Is there any visual evidence of leaky transmission output seals? Yes ____ No ____
Is there any visual evidence of leaky differential? Yes____ No ____
Has driver altered the cab or suspension height adjustments? Yes ____ No ____
Has this vehicle been to any other shops for this condition? Yes ____ No ____
Visually inspect tires. Check the item(s) that the tires display.
Under inflation _______
Dry Rot _______
Gouges in tire side wall ______
Wheel damage _____
Chunks Missing out of tread _____
Flat spotted tires _____
Unusual tire wear patterns ____
Daimler AG

Title of presentation / Department / Date

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Vibration Orders & Classifications
 Vibrations are classified into orders. Orders are periods which the
vibrations occur in relationship per revolution of a component. They are
classified as 1st, 2nd, 3rd, 4th, and so on.



1st order vibrations creates one shake per component revolution.
1st order vibrations will always be excessive run out or an out of
balance condition.
As the flat spot rotates
and contacts the ground
it will create a shake


Daimler AG

2nd order vibration creates two shakes per component revolution.
Title of presentation / Department / Date

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Source of Vibrations by Classifications of Orders







Tire/Wheel orders 1st, 2nd, & 3rd
causes: Wheels, hubs, drums, rotors and tire assemblies
Driveline or Propeller shaft 1st order
causes: Drive shaft, park brake drums, yokes & phasing
Driveline or Propeller shaft 2nd order
causes: U-joints, phasing, working angles, dynamic bearing load
Engine orders
causes: Engine mounts, exhaust, crankshaft, dampers, etc.
The trend of conditions is over a 15 year period
Tire/Wheel End (90%)
Driveline/Drive train (8%)
Engine/Exhaust (2%)

Daimler AG

Title of presentation / Department / Date

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Vibration Analysis & Confirmation

 Before Test Driving vehicle make sure the tires are inflated to the proper
specification
 Make sure suspension and cab air ride height are set correctly.
 Inspect the driveline to make sure vehicle is safe to drive.
 Test drive the vehicle using a reputable Vibration Analyzer to
validate & identify the source and classify the order of the vibration.
 Sometimes preparing the vehicle fixes the problem

Daimler AG

Title of presentation / Department / Date

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Evaluation Tools
 Vibration Analyzer tools will minimize troubleshooting time.

 If using a tool such a the Kent Moore EVA (J-38792-A) Vibration Software
(J-38792-VS) will also be needed to locate and identify the primary
source of vibration.
 Always make sure the most current operating software is used
Kent Moore EVA is Version 3.0 memory cartridge Kent-Moore
part # J-38792-60.
 Other Vibration analyzing tools are the MTS 4100, Eaton DVA MD-300,
or Smart Phone such as IPhone with appropriate vibration software app.
Daimler AG

Title of presentation / Department / Date

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Vibration Evaluation Tools

Sirometer

MTS 4100
Daimler AG

Resonant Reed Tachometer

Eaton DVA MD-300

Kent Moore EVA2

Picoscope NVH Kits
Title of presentation / Department / Date

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Vibration Evaluation Tools Smart Phone for Vibration Diagnosis

 Phone with NVH App can be used to locate the Vibration order
 Set Up and Use will be covered later in this presentation
Daimler AG

Title of presentation / Department / Date

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Vibration Evaluation Tools
Tool

Advantage

Disadvantage

Sirometer

In expensive, easy to use

Limited usage, doesn’t register g’s, no accelerometer