major differences between halt and ed
TRANSCRIPT
Major Differences between
Random Vibration Tables and
Electro-Dynamic Shakers
Overview
Overview
• Random Vibration (HALT)
Overview
• Random Vibration (HALT)
Highly Accelerated Life Test
Overview
• Random Vibration (HALT)
Highly Accelerated Life Test
The test article is subjected to all 6 possible axes of motion (X, Y, Z, Roll, Pitch, and Yaw) at the
same time. This is subject to the limits of Newtonian Physics, where an object can only move in one
direction at any instant.
Overview
• Random Vibration (HALT)
Highly Accelerated Life Test
The test article is subjected to all 6 possible axes of motion (X, Y, Z, Roll, Pitch, and Yaw) at the
same time. This is subject to the limits of Newtonian Physics, where an object can only move in one
direction at any instant.
Why? The Goal of HALT testing is to quickly find failures in a design. The
cause of the failure is then determined and the design is strengthened
and testing continues until failures occur at levels of stress higher than a
product sees in usual service.
Overview
• Random Vibration (HALT)
Highly Accelerated Life Test
The test article is subjected to all 6 possible axes of motion (X, Y, Z, Roll, Pitch, and Yaw) at the
same time. This is subject to the limits of Newtonian Physics, where an object can only move in one
direction at any instant.
Why? The Goal of HALT testing is to quickly find failures in a design. The
cause of the failure is then determined and the design is strengthened
and testing continues until failures occur at levels of stress higher than a
product sees in usual service.
When? Usually during product
development, but can also
be done later to improve the
design.
Overview
Overview
• Electro-Dynamic (ED)
Overview
• Electro-Dynamic (ED)
May be used for the same purpose as HALT
Overview
• Electro-Dynamic (ED)
May be used for the same purpose as HALT
Major Difference?
Overview
• Electro-Dynamic (ED)
May be used for the same purpose as HALT
Major Difference?
Limited to ONE axis of motion,
unless multiple tests are used
to move an object in 2 or 3
axes.
Overview
• Electro-Dynamic (ED)
May be used for the same purpose as HALT
Major Difference?
Limited to ONE axis of motion,
unless multiple tests are used
to move an object in 2 or 3
axes.
Other Key
Differences
Overview
• Electro-Dynamic (ED)
May be used for the same purpose as HALT
Major Difference?
Limited to ONE axis of motion,
unless multiple tests are used
to move an object in 2 or 3
axes.
Other Key
Differences Frequency
Overview
• Electro-Dynamic (ED)
May be used for the same purpose as HALT
Major Difference?
Limited to ONE axis of motion,
unless multiple tests are used
to move an object in 2 or 3
axes.
Other Key
Differences Peak Frequency
Overview
• Electro-Dynamic (ED)
May be used for the same purpose as HALT
Major Difference?
Limited to ONE axis of motion,
unless multiple tests are used
to move an object in 2 or 3
axes.
Other Key
Differences Peak Frequency Motion
Overview
• Electro-Dynamic (ED)
May be used for the same purpose as HALT
Major Difference?
Limited to ONE axis of motion,
unless multiple tests are used
to move an object in 2 or 3
axes.
Other Key
Differences Peak Frequency Motion Fixturing
Overview
• Electro-Dynamic (ED)
May be used for the same purpose as HALT
Major Difference?
Limited to ONE axis of motion,
unless multiple tests are used
to move an object in 2 or 3
axes.
Other Key
Differences Peak Frequency Motion Fixturing Displacement
Overview
• Electro-Dynamic (ED)
May be used for the same purpose as HALT
Major Difference?
Limited to ONE axis of motion,
unless multiple tests are used
to move an object in 2 or 3
axes.
Other Key
Differences Peak Frequency Motion Fixturing Displacement Test
Design
Key
Differences Peak Frequency Motion Fixturing Displacement Test
Design
HALT ED
Key
Differences Peak Frequency Motion Fixturing Displacement Test
Design
HALT Wide band FIXED
frequency response to create
the PSD energy.
ED
Key
Differences Peak Frequency Motion Fixturing Displacement Test
Design
HALT Wide band FIXED
frequency response to create
the PSD energy.
Approximately 20HZ to 12kHz with fairly flat average power.
ED
Key
Differences Peak Frequency Motion Fixturing Displacement Test
Design
HALT Wide band FIXED
frequency response to create the PSD
energy.
Approximately 20HZ to 12kHz with fairly flat average power.
ED PSD is programmed into the controller to achieve a given
PSD curve.
Key
Differences Peak Frequency Motion Fixturing Displacement Test
Design
HALT
Wide band FIXED frequency response to create the PSD
energy.
Approximately 20HZ to 12kHz with fairly flat average power.
ED
PSD is programmed into the controller to achieve a given
PSD curve.
Typically the energy is concentrated in a given area of interest for the test, and is
usually based on empirical measurements of the
environment that the unit under test will need to endure
during its lifecycle.
Key
Differences Peak Frequency Motion Fixturing Displacement Test
Design
HALT ED
Key
Differences Peak Frequency Motion Fixturing Displacement Test
Design
HALT The peak for any
individual random shock impulse is typically 10X the average providing
more headroom for any individual shock pulse.
ED
Key
Differences Peak Frequency Motion Fixturing Displacement Test
Design
HALT The peak for any
individual random shock impulse is typically 10X the average providing
more headroom for any individual shock pulse.
This is due to the shock hammers under the table
that produce shock waves.
ED
Key
Differences Peak Frequency Motion Fixturing Displacement Test
Design
HALT The peak for any
individual random shock impulse is typically 10X the average providing
more headroom for any individual shock pulse.
This is due to the shock hammers under the table
that produce shock waves.
ED Due to the differences in the way the table works it is unable to achieve large instantaneous
shock pulses.
Key
Differences Peak Frequency Motion Fixturing Displacement Test
Design
HALT ED
Key
Differences Peak Frequency Motion Fixturing Displacement Test
Design
HALT 6 degrees of
freedom motion, X, Y, Z, Pitch, Roll and Yaw
ED
Key
Differences Peak Frequency Motion Fixturing Displacement Test
Design
HALT 6 degrees of
freedom motion, X, Y, Z, Pitch, Roll and Yaw
ED
Single axis at a time only.
Key
Differences Peak Frequency Motion Fixturing Displacement Test
Design
HALT 6 degrees of
freedom motion, X, Y, Z, Pitch, Roll and
Yaw
ED
Single axis at a time only.
One must shift the orientation of the part on axis at a time X, Y and Z
only.
Key
Differences Peak Frequency Motion Fixturing Displacement Test
Design
HALT ED
Key
Differences Peak Frequency Motion Fixturing Displacement Test
Design
HALT
Fixtures are much lighter
than ED shaker fixtures.
ED
Key
Differences Peak Frequency Motion Fixturing Displacement Test
Design
HALT
Fixtures are much lighter than ED shaker fixtures.
ED
Sometimes massive to accommodate a heavier load with
more displacement.
Key
Differences Peak Frequency Motion Fixturing Displacement Test
Design
HALT ED
Key
Differences Peak Frequency Motion Fixturing Displacement Test
Design
HALT
Displacement is on the order of millimeters, and not controllable.
ED
Key
Differences Peak Frequency Motion Fixturing Displacement Test
Design
HALT
Displacement is on the order of millimeters, and not controllable.
ED
Can move more than one inch,
typically about ½ cm.
Key
Differences Peak Frequency Motion Fixturing Displacement Test
Design
HALT ED
Key
Differences Peak Frequency Motion Fixturing Displacement Test
Design
HALT Discovery test to rapidly find weaknesses using
accelerated stress conditions.
Find a weakness… Improve the weakness
ED
Key
Differences Peak Frequency Motion Fixturing Displacement Test
Design
HALT Discovery test to rapidly find weaknesses using
accelerated stress conditions.
Find a weakness… Improve the weakness
There are many books and consultants available
on the subject of test design.
ED
Key
Differences Peak Frequency Motion Fixturing Displacement Test
Design
HALT Discovery test to rapidly find weaknesses using
accelerated stress conditions.
Find a weakness… Improve the weakness
There are many books and consultants available
on the subject of test design.
ED
There are standards and MIL Specs written around
this type of testing.
Key
Differences Peak Frequency Motion Fixturing Displacement Test
Design
HALT Discovery test to rapidly find weaknesses using
accelerated stress conditions.
Find a weakness… Improve the weakness
There are many books and consultants available
on the subject of test design.
ED
There are standards and MIL Specs written around
this type of testing.
The test engineer may often have the specs or standards imposed by a
customer
Additional Differences
HALT ED
Additional Differences
HALT ED
Additional Differences
HALT ED
Can achieve a more severe
test.
Can use larger parts such as
motor housings or castings.
Additional Differences
HALT ED
Conclusion
• Neither HALT or ED shakers are necessarily
better than the other. It all depends on the
specific product and test being run.
Conclusion
• Neither HALT or ED shakers are necessarily
better than the other. It all depends on the
specific product and test being run.
• In some cases, the test results from an ED
Shaker table can be correlated to a HALT
chamber table by running HALT discovery
testing after finding destruct points with an
ED Shaker, but it depends on the type of
part being tested.
For more information,
please contact
Cincinnati Sub-Zero or visit
www.cszindustrial.com