Remaining Life Assessment
STI Technologies has 23 years of experience in investigation,
analysis and software development
of remaining life. This assessment covers a broad range of
applications including machine tool, office equipment,
automotive, transportation, industrial equipment, aerospace
and the power/utility industries. We determine the remaining
life of critical components through rigorous analysis of
thermal/ mechanical stresses, natural frequencies and mode
shapes, crack initiation, crack propagation and creep. In
addition, we supplement this with a full line of stress and
vibration testing. STI provides a
range of life assessment services with expertise in:
- Stress Corrosion Cracking
- Solid Particle Erosion
- Crack Propagation
- Low and High Cycle Fatigue
- LifeCycle Fatigue Crack Analysis Services
- Probabilistics
- Nuclear Steam Generator Tube Wear and Life Assessment Services
- Customized System Health Management
Stress Corrosion Cracking (SCC)
Using advanced fracture mechanics techniques and SCC crack propagation data, STI has worked successfully with utilities in assessing the remaining life of low pressure disks and axial and radial entry blade attachments subjected to stress corrosion cracking.
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Solid Particle Erosion (SPE)
SPE is often seen in the control stage blade rows for high
pressure rotors. STI provides analysis of the dynamic
stresses, crack propogation and 2D and 3D fracture
mechanics evaluations to obtain remaining life estimates.
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Crack Propagation
The science of fracture mechanics, crack infiltration and
growth are well understood at STI Technologies. Extensive
experience and a broad range of data has gone into the
development of comprehensive STI
software codes for 2D and 3D crack propagation
applications
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Low and High Cycle Fatigue (LCF and HCF)
In fatigue life design, useful life is defined by the cumulative
damage resulting from a combination of infrequent large amplitude
cycles and frequent small amplitude cycles. STI has extensive
experience in measuring and calculating the values for the
unsteady load component and applying these loads to a specific
application list specific applications.
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Lifecycle Fatigue Crack Analysis Services
Spinning Blade Hazard, or the chance of throwing a blade, is
a major concern for both plant operators and plant insurers.
To better address this problem STI has recently developed an
advanced state-of-art fatigue life prediction computer code
called LifeCycle. This software can be applied to accurately
predict the remaining life of turbine blades under known
operating conditions. STI has developed this proprietary code
to solve fatigue problems involving components subject to
complex load sequencing. For additional information on
LifeCycle refer to STI's Your Chance of "Throwing a Blade"
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Probabilistics
What
happens over the life of a product that would increase the
probability of failure over time? Life assessment requires an
understanding of the probability of failure at design, and
the ability to track those changes over time that effect the
probability of failure. STI-Technologies has extensive
experience in determining the remaining life of critical
turbine components - rotors, through rigorous analysis (and
testing) of thermal/mechanical stresses, blade natural
frequencies and mode shapes, crack initiation, crack
propagation and creep for elevated temperature applications.
This expertise is emphasized by a 20 year, successful working
relationship with the U.S. Air Force. For additional
information on probabilistic applications refer to STI's Published Papers on this
Website. For additional probabilistic services provided by
STI refer to " Design
Optimization and Analysis- Probabilistics" on this
Website.
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Nuclear Steam Generator Tube Wear and Life Assessment Services
In nuclear Pressurized Water Reactor (PWR) industry, assessment
of the steam generator tube degradation is an important part
of the maintenance decision-making process. Utility engineers
must conduct a periodic assessment of these tubes based on
current inspection data and projected estimates of wear depth
at the end of the next operating cycle. This assessment allows
the utility engineer to decide a course of action (repair,
reinforce, plug or leave alone) and to determine an efficient
schedule of future preventive maintenance events.
STI Technologies Inc. is able to assist the utility engineer
in making informed maintenance decisions based on analytical
predictions of wear progression and fatigue damamge
accummulation using a new software program developed by the
Electric Power Research Institute (EPRI). For additional
information on STI's nuclear steam genertor tube wear and
life assessment services refer to the STI publication
"Nuclear Steam Generator Services"
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Customized System Health Management
STI develops and supports customized system health
management (health monitoring, diagnostics and prognostics,
quality control) to meet the needs of your critical machines,
where off the shelf CBM systems often prove inadequate. STI
employs a multiple levels of diagnostic/prognostic
information including standard tools (performance models,
trends, alarms, rule bases, etc.), advanced technologies
(fuzzy logic, neural networks, hybrid AI techniques,
probabilistic analysis), and decision-level data fusion
methodologies (heuristic and probabilistic). We will work
with your in-house experts to develop and support customized
CBM systems that apply the best techniques for information
extraction from sensor signals worldwide. An example of a
customized gas turbine monitoring and diagnostic system is
shown.
STI provides initial systems installation consulting and
application specific custom development for the ICHM®20/20, a
wireless data acquisition and processing module produced by
Oceana Sensor. The ICHM® 20/20 is a
revolutionary data acquisition and processing module built on
Bluetooth™ wireless technology and is designed to serve
any type of monitoring and diagnostic application.
The ICHM® 20/20 provides:
- A compact, reliable wireless data acquisition and processing node suitable for high and low bandwidth input signals.
- Industry leading 24 bit ADC at up to 48 kHz sampling frequency for dynamic measurements (including 12 bit ADC for static measurements).
- The ideal platform for remote monitoring and processing of a variety of sensor measurements.
