Transcript divers_Shaker Introd..

Shaker training
March 2011
Renard Klubnik
Applications engineer
The information contained in this document is the property of Meggitt Sensing Systems and is proprietary and/or copyright
material. This information and this document may not be used without the express authorization of Meggitt Sensing
Systems. Any unauthorized use or disclosure may be unlawful.
Information contained in this document is subject to U.S. Export Control regulations, specifically the (choose as
appropriate) International Traffic in Arms Regulations and / or Export Administration Regulations. Each recipient of this
document is responsible for ensuring that transfer or use of any information contained in this document complies with all
relevant (choose as appropriate) International Traffic in Arms Regulations and / or Export Administration Regulations.
Introduction to shakers
Where do shakers fit in the test market?
Reaction mass shakers
– Excite a structure, not shake it
– Modal testing
– Not for shake testing
No envelope performance curves like MIL 810G
– Transfer function measurement – built in impedance head
Point impedance
Transfer impedance
– Ability to measure is a function of the readout equipment
and mechanical impedance of test structure
– Characterize the unit under test, not vibrate it
– Identify natural frequencies and amplification factor
Trunion mounted shakers
– Test article testing
Page 2
© Meggitt Sensing Systems. Proprietary. 15 February 2010
Application of shakers
Used in determining mechanical
impedance
Measure the dynamic properties of
structures and materials
It is the complex ratio of applied
force to resulting velocity
It is frequency related
– Sine
– Random
Similar properties for acceleration
and displacement components are
shown in the adjoining chart
Usually done by transfer function
measurements of two channel
analyzers and supporting software
Easier setup than trunion mounted
designs
Page 3
© Meggitt Sensing Systems. Proprietary. 15 February 2010
Primary applications
Why/where are the shakers used?
Understand the mechanics of a test
object
– Simulate external forces
Test electrical components
circuit boards
sub assemblies
Determine mode shapes
– Assess structural response under
different forms of excitation
Sine
Random
Impulse
– Determine a test objects resonant
frequencies
– Medical – bones
Page 4
© Meggitt Sensing Systems. Proprietary. 15 February 2010
Reaction mass shakers – Operation principle
Operates on reaction mass principle
A reaction force is generated which excites
the test structure
– An AC electrical voltage is applied to
the coil
– Alternating magnetic field causes
relative movement between the
permanent magnet outer shell and
inner coil
– Like poles of magnet repel each other
Two reaction mass shaker types
– Electromagnetic shakers
– Piezoelectric shakers
Page 5
© Meggitt Sensing Systems. Proprietary. 15 February 2010
Permanent magnet
Permanent magnet
Typical electromagnetic shaker
Electromagnetic shaker
Operates similarly to a loud speaker
A coil is driven within a permanent magnet
field
The dynamic electromagnetic coil field
‘pushes’ against the heavier outer permanent
magnet shell
Coil is attached to the structure
Heavy ring-shaped magnets are suspended
around the coil
Force generated is proportional to input
current
Powered by conventional methods (audio
power amplifier)
Page 6
© Meggitt Sensing Systems. Proprietary. 15 February 2010
Piezoelectric shakers
Utilize piezoelectric ceramic disks which
change thickness proportional to an applied
voltage
Ceramic disks are sandwiched between a
heavy mass and a light fixture which
attaches to the test structure
Although displacement is small, the use of
multiple disks and high drive voltages
produces large forces at high frequencies
Must be driven by high voltage which is
provided by an impedance matching
network between the power amplifier and
shaker
Impedance matching network steps up the
power amplifier output drive voltage to a
much higher level for the drive voltage of
the shaker
Page 7
© Meggitt Sensing Systems. Proprietary. 15 February 2010
Reaction mass shakers
Page 8
© Meggitt Sensing Systems. Proprietary. 15 February 2010
Reaction mass electrodynamic shaker systems
Reaction mass shakers
Open or closed loop measurements
Attach shaker directly to test object
Contact unit under test with built in force gage
Stingers not used
Page 9
© Meggitt Sensing Systems. Proprietary. 15 February 2010
Shaker systems, impedance heads and amplifiers
F3
Electrodynamic design
Nominal 1 lb force output
25 – 10000 Hz
2.26” diameter
Z602WA impedance head or
dummy plug
F4
Electrodynamic design
Nominal 10 lb force output
10 – 7500 Hz
5.10” diameter
Z820WA impedance head or
dummy plug
Materials testing application
Page 10
© Meggitt Sensing Systems. Proprietary. 15 February 2010
F3 shaker
Page 11
© Meggitt Sensing Systems. Proprietary. 15 February 2010
F4 shaker
Page 12
© Meggitt Sensing Systems. Proprietary. 15 February 2010
Shaker systems, impedance heads and amplifiers
F5B
Electrodynamic design
Nominal 0.4 lb force output
10 – 10000 Hz
1.35” diameter
Z11 impedance head
F10
Electrodynamic design
Nominal 20 lb force output
5 – 2000 Hz
8.25” diameter
Z820WA impedance head or
dummy plug
Page 13
© Meggitt Sensing Systems. Proprietary. 15 February 2010
F5
Page 14
© Meggitt Sensing Systems. Proprietary. 15 February 2010
F10
Page 15
© Meggitt Sensing Systems. Proprietary. 15 February 2010
Piezoelectric shaker systems
Piezoelectric performance
Below resonance, system output is displacement
controlled – ~1 micron per 1000 volts
Above resonance, output is force controlled
Open or closed loop testing
Output of shaker is dependent on the mechanical
impedance of the specimen
At higher frequencies shaker is lower impedance
Page 16
© Meggitt Sensing Systems. Proprietary. 15 February 2010
Shaker systems, impedance heads and amplifiers
F7
Piezoelectric design
Nominal 100 lb force output
500 – >20000 Hz
2.20” diameter
Impedance head built in
Requires impedance matching network
F7-1
Piezoelectric design
Nominal 10 lb force output
1 – 80000 Hz
2.20” diameter
No impedance head
Requires impedance matching network
Page 17
© Meggitt Sensing Systems. Proprietary. 15 February 2010
F7 and F7-1 comparison
F7 with impedance head Z7
The Z7 is an integral part of the F7
Page 18
© Meggitt Sensing Systems. Proprietary. 15 February 2010
F7-1 (has no measurement electronics)
Construction of F7 and F7-1
F7 without
impedance head
Page 19
© Meggitt Sensing Systems. Proprietary. 15 February 2010
F7-1
F7 – testing to 20 kHz
Page 20
© Meggitt Sensing Systems. Proprietary. 15 February 2010
F7-1 testing to 80 kHz
Page 21
© Meggitt Sensing Systems. Proprietary. 15 February 2010
Shaker systems, impedance heads and amplifiers
F4/F7
Combination design for low and high
frequency
Nominal 10 lb force output
10 – >20000 Hz
Requires two power amplifiers for
continuous sweep
Requires impedance matching network for
F7 shaker
Page 22
© Meggitt Sensing Systems. Proprietary. 15 February 2010
F4/F7 assembly
Page 23
© Meggitt Sensing Systems. Proprietary. 15 February 2010
F4/F7 completed assembly
Page 24
© Meggitt Sensing Systems. Proprietary. 15 February 2010
F4/F7
Two power amplifiers if continuous sweep is desired
One matching network
Page 25
© Meggitt Sensing Systems. Proprietary. 15 February 2010
Trunion mounted shakers
Page 26
© Meggitt Sensing Systems. Proprietary. 15 February 2010
Special order shakers: D60H, D60L, D125
D60H, D60L, D125
Page 27
© Meggitt Sensing Systems. Proprietary. 15 February 2010
Shaker performance
Shaker response is payload sensitive
Mass on shaker causes lowering of resonant frequencies
Customer will have to estimate response with his payload
Payload can contribute additional resonances
Page 28
© Meggitt Sensing Systems. Proprietary. 15 February 2010
D125 testing turbine blade
Requires items
Fixturing
Control accelerometer
Measurement accelerometer
Controller – sine or random
Page 29
© Meggitt Sensing Systems. Proprietary. 15 February 2010
Amplifiers and accessories
Page 30
© Meggitt Sensing Systems. Proprietary. 15 February 2010
Impedance heads
Used to measure shaker effect
Force transducer
Accelerometer
Positioned between shaker and test article
Option on F3
– Z602WA
Option on F4
– Z820WA
Option on F5
– Z11
Built in on F7
Option on F10
– Z820WA
Page 31
© Meggitt Sensing Systems. Proprietary. 15 February 2010
Impedance heads
Z11 (F5B)
Charge output
Z602WA (F3)
IEPE power
Z820WA (F4 F10)
IEPE power
Page 32
© Meggitt Sensing Systems. Proprietary. 15 February 2010
Amplifiers
PA8HF
Low noise and low distortion over its entire range
of operation
Designed for small and medium size
electromagnetic and piezoelectric shakers
Page 33
© Meggitt Sensing Systems. Proprietary. 15 February 2010
PA8HF specifications
Page 34
© Meggitt Sensing Systems. Proprietary. 15 February 2010
Matching network needed for piezoelectric shakers
N7FS, N8FS, N8FHS Matching network
Electrical interface between amplifiers and
piezoelectric shakers
Provide voltage step to drive shakers at full
voltage levels
Lower voltage levels at higher frequencies to
better match reactive loads
Page 35
© Meggitt Sensing Systems. Proprietary. 15 February 2010
How to choose the right shaker for the application?
Determine the application
Modal
Test article testing
Modal testing
Determine frequency range
Evaluate size and shape of test article
Estimate stiffness of test article
Explore measurement options
Test article testing
Determine frequency range
Evaluate size and shape of the test article
Determine desired amplitude test range
Consider shaker performance with additional payload
Page 36
© Meggitt Sensing Systems. Proprietary. 15 February 2010
Sample configurations
F3 (needs to have dummy plug or Z602WA)
Signal source side
– F3 (includes cable to mate with PA8HF)
F3/dummy plug or F3/Z602WA
– PA8HF if signal source can’t deliver 10 watts
– *Signal source (sine oscillator, random noise generator)
– *Cable to connect either the PA8HF or F3 to the signal source
Measurement side
– With Z603WA Impedance head (2 x microdot to BNC cables supplied)
2 x IEPE power supplies (P704B)
– *Other accelerometers for test article measurement
* - designates additional required instrumentation available from other sources
Page 37
© Meggitt Sensing Systems. Proprietary. 15 February 2010
Sample configurations
F5
Signal source side
– F5 (includes cable to mate with PA8HF)
– PA8HF if signal source can’t deliver 3 watts
– *Signal source (sine oscillator, random noise generator)
– *Cable to connect either the PA8HF or F5 to the signal source
Measurement side
– Optional Z11 Impedance head (2 x 5-44 to BNC cables supplied)
2 x charge converters required (CC701)
– Other accelerometers for test article measurement
* - designates additional required instrumentation available from other sources
Page 38
© Meggitt Sensing Systems. Proprietary. 15 February 2010
Sample configurations
F4 (needs to have dummy plug, Z820WA or F7)
Signal source side
– F4 (includes cable to mate with PA8HF)
F4/dummy plug or F4/Z820WA or F4/F7 (see separate page)
– PA8HF if signal source can’t deliver 100 watts
– *Signal source (sine oscillator, random noise generator)
– *Cable to connect either the PA8HF or F4 to the signal source
Measurement side
– With Z820WA Impedance head (2 x BNC to BNC cables supplied)
2 x IEPE power supplies (P704B)
– *Other accelerometers for test article measurement
* - designates additional required instrumentation available from other sources
Page 39
© Meggitt Sensing Systems. Proprietary. 15 February 2010
Sample configurations
F4/F7
Signal source side
– F4 (includes cable to mate with PA8HF)
– F7 (includes cable to mate with N7FS)
– 2 x PA8HF if signal source can’t deliver 100 watts and customer wants
full bandwidth coverage at the same time
– N7FS matching network (includes cable to mate with PA8HF)
– *Signal source (sine oscillator, random noise generator)
– *Cable to connect the PA8HF to the signal source – user configured
Measurement side
– Z7 Impedance head, included (2 x microdot to microdot cables
supplied)
2 x charge converters required (CC701)
2 x IEPE power supplies (P704B)
– *Other accelerometers for test article measurement
* - designates additional required instrumentation available from other sources
Page 40
© Meggitt Sensing Systems. Proprietary. 15 February 2010
Sample configurations
F7
Signal source side
– F7 (includes cable to mate with N7FS)
– 1 x PA8HF
– N7FS matching network (includes cable to mate with PA8HF)
– *Signal source (sine oscillator, random noise generator)
– *Cable to connect the PA8HF to the signal source
Measurement side
– Z7 Impedance head, included (2 x microdot to microdot cables
supplied)
2 x charge converters required (CC701)
2 x IEPE power supplies (P704B)
– *Other accelerometers for test article measurement
* - designates additional required instrumentation available from other sources
Page 41
© Meggitt Sensing Systems. Proprietary. 15 February 2010
Sample configurations
F7-1
Signal source side
– F7-1 (includes cable to mate with N8HFS)
– 1 x PA8HF
– N8HFS matching network (includes cable to mate with PA8HF)
– *Signal source (sine oscillator, random noise generator)
– *Cable to connect the PA8HF to the signal source
Measurement side
– *Other accelerometers for test article measurement
* - designates additional required instrumentation available from other sources
Page 42
© Meggitt Sensing Systems. Proprietary. 15 February 2010
Sample configurations
F10 (needs to have dummy plug, Z820WA or F7)
Signal source side
– F10 (includes cable to mate with PA8HF)
F10/dummy plug or F10/Z820WA or F10/F7 (see separate page)
– PA8HF if signal source can’t deliver 100 watts
– *Signal source (sine oscillator, random noise generator)
– *Cable to connect either the PA8HF or F10 to the signal source
Measurement side
– With Z820WA Impedance head (2 x BNC to BNC cables supplied)
2 x IEPE power supplies (P704B)
– *Other accelerometers for test article measurement
* - designates additional required instrumentation available from other sources
Page 43
© Meggitt Sensing Systems. Proprietary. 15 February 2010
Sample configurations
F10/F7
Signal source side
– F10 (includes cable to mate with PA8HF)
– F7 (includes cable to mate with N7FS)
– 2 x PA8HF if signal source can’t deliver 100 watts and customer wants
full bandwidth coverage at the same time
– N7FS matching network (includes cable to mate with PA8HF)
– *Signal source (sine oscillator, random noise generator)
– *Cable to connect the PA8HF to the signal source – user configured
Measurement side
– Z7 Impedance head, included (2 x microdot to microdot cables
supplied)
2 x charge converters required (CC701)
2 x IEPE power supplies (P704B)
– *Other accelerometers for test article measurement
* - designates additional required instrumentation available from other sources
Page 44
© Meggitt Sensing Systems. Proprietary. 15 February 2010
The information contained in this document is the property of Meggitt Sensing Systems and is proprietary and/or
copyright material. This information and this document may not be used or disclosed without the express authorization
of Meggitt Sensing Systems. Any unauthorized use or disclosure may be unlawful.
The information contained in this document may be subject to the provisions of the Export Administration Act of 1979
(50 USC 2401-2420), the Export Administration Regulations promulgated thereunder (15 CFR 730-774), and the
International Traffic in Arms Regulations (22 CFR 120-130). The recipient acknowledges that these statutes and
regulations impose restrictions on import, export, re-export and transfer to third countries of certain categories of data,
technical services and information, and that licenses from the US Department of State and/or the US Department of
Commerce may be required before such data, technical services and information can be disclosed. By accepting this
document, the recipient agrees to comply with all applicable governmental regulations as they relate to the import,
export and re-export of information.'
Page 45
© Meggitt Sensing Systems. Proprietary. 15 February 2010