Reliability and Maintainability
Program Plan
Reliability Allocation, Prediction &
Analysis
Reliability Models
Failure Mode Analysis
Testability Analysis
Fault Tree Analysis
R & M Test Planning
Reliability, Availability,
Maintainability and dependability
RMA are our bread and butter. Our
experts will be happy to support the
planning, requirements definition,
allocation as well the analyses and
engineering tasks. We can support
your RMA team if you have one, or
manage the program entirely. Either
way, we guarantee peace of mind.
Our team are involved not only in traditional consulting but also are in
the forefront of R&D efforts in the
fields of RMA engineering and RMA
methodology and tool development. We
can therefore analyze your system and
requirements using best current
practices and propose the most
effective path to completing the RMA
tasks.
Reliability & Maintainability
Program Plan
To ensure reliability goals are met,
at the lowest cost, requires a
comprehensive R&M program plan that
includes all lifecycle phases. The
plan defines all the tasks and
organizational structure needed to
satisfy the RMA requirements and
constraints for each stage of product
lifecycle. A good R&M plan includes
not only an understanding of
reliability and maintainability
engineering practices, it requires a
good understanding of your system: the
physical elements and processes that
may influence R&M metrics, planned
usage and customer requirements and
constraints. Our team includes R&M
engineers, physicists, mathematicians
able to model complex systems, as well
as safety engineers that can review
the plans and include required safety
input.
Reliability Allocation, Prediction &
Analysis
SoHaR's reliability experts have
performed hundreds of reliability
predictions and analyses that have
formed the basis for reliability
assessments, allocation and design
changes. Our team performs reliability
prediction for electronic and
non-electronic parts according to any
of the existing reliability standards
and manufacturer in-house data.
Reliability calculations are based on
electrical/thermal stress analysis.
The output is a report with a
breakdown of MTBF and MTBCF numbers
per system, unit, board and component
levels.
See also the RAM Commander
Reliability prediction module.
Reliability Prediction Methods
-
MIL-HDBK-217
-
217 Plus
-
SR332 - Telcordia 2001
-
RDF 95 - French Telecom
-
IEC 62380 (RDF 2003)
-
UTEC 80810 - (CNET 2000)
-
FIDES Guide 2004
-
SN29500.1 - Siemens
-
HRD - British Telecom
-
ALCATEL
-
RADC 85-91
-
NSWC 98
-
GJB299 - Chinese Reliability
-
GJB 1391,1392 - Chinese FMECA
-
CJB/Z35 - Chinese Derating
-
Stress/Strength
For more information about these
methods please also see
reliability prediction for
electronic and non-electronic parts.
Reliability
Models
Often we will be required to develop a
reliability model that can accurately
and completely take into account fault
tolerance, recovery, redundancy and
degraded states. We use such methods
as
Reliability Block Diagrams (RBD),
Markov models and Petri Nets, as well
as Monte Carlo Simulations. For most
systems, information about
availability can only be obtained from
a well developed reliability model
that includes also recovery and repair
information.
Analysis of the models provides
outputs including: Reliability,
Availability (including degraded
states, partial availability, and
average downtime) as well as MTBF and
Mean Time Between Critical Failures (MTBCF).
See also the
RAM Commander Reliability
Block Diagram and Markov
Chains modules.
Failure Mode Analysis
Failure Mode and Effect Analysis (FMEA)
is an engineering technique for
systematic identification and
elimination/mitigation of known and/or
potential problems of a system. The
FMEA lists all known failure modes and
analyzes them for their potential
effects.
Failure Mode and Effects Criticality
Analysis (FMECA) allows us to focus on
the critical failure modes and analyze
their probabilities of occurrence.
FMEA is an ongoing process that should
start as early as the first design
review and continue throughout the
life of the product. An FMEA will
usually evolve into a FMECA once
design details solidify and the
accuracy of prediction will increase
when testing and field data can be
added at later stages.
SoHaR's
reliability team will follow your
product lifecycle to ensure an
effective FMECA according to the
MIL-STD-1629A requirements, and
process/design FMEA fully compliant
with QS 9000 guidelines.
See also the
RAM Commander
FMECA and
Design/Process FMEA modules.
Testability
Analysis
Testability
analysis is
a widely used method for the evaluation of
qualitative and quantitative characteristics of
BIT/BITE design, such as Fault Detection
probability, BIT coverage, Fault Isolation
resolution and False Alarm probability. SoHaR's R&M
and safety engineers performs testability analysis
in conjunction with FMECA.
When reviewed and analyzed in conjunction with the
FMECA the focus is on how well the BIT/BITE design
deals with severe failure modes, and the context is
naturally safety-oriented.
Fault Tree Analysis
Fault tree analysis (FTA)
is a
systematic, deductive, top-down method
of analyzing system design and
performance. It involves specifying a
top event to analyze (such as
catastrophic system behavior),
followed by identifying all of the
associated elements in the system that
could cause that top event to take
place. It clearly identifies fault
relationships and provides a clear
approach for predicting the
probability that a top-level event
will occur. The results of a FTA
provide crucial input to the
Reliability analysis as well as to
Safety assessments and Probabilistic
Risk Assessments (PRA)
Fault Trees provide
a convenient symbolic representation
of the combination of events resulting
in the occurrence of the top event.
SoHaR has performed FTA on a large
variety of systems and has experience
not only in accomplishing the analysis
but also identifying the crucial
elements requiring the analysis.
See also the
RAM Commander
Fault Tree Analysis (FTA)
module and Event
Tree Analysis (ETA)
module.
Reliability &
Maintainability Test Planning
Efficient and cost-effective R&M test
strategies are essential for the
achievement of R&M design and
performance goals. The SoHaR R&M team
of experts will establish an R&M
test planning strategy
that will include the types of tests,
test schedule, amount of risk to be
tolerated, while taking into
consideration schedule and budget
constraints.
