5 research outputs found
Automatic phased mission system reliability model generation
There are many methods for modelling the reliability of systems based on component failure
data. This task becomes more complex as systems increase in size, or undertake missions
that comprise multiple discrete modes of operation, or phases. Existing techniques require
certain levels of expertise in the model generation and calculation processes, meaning that
risk and reliability assessments of systems can often be expensive and time-consuming.
This is exacerbated as system complexity increases.
This thesis presents a novel method which generates reliability models for phasedmission systems, based on Petri nets, from simple input files. The process has been
automated with a piece of software designed for engineers with little or no experience
in the field of risk and reliability. The software can generate models for both repairable
and non-repairable systems, allowing redundant components and maintenance cycles to be
included in the model.
Further, the software includes a simulator for the generated models. This allows a user
with simple input files to perform automatic model generation and simulation with a single
piece of software, yielding detailed failure data on components, phases, missions and the
overall system. A system can also be simulated across multiple consecutive missions. To
assess performance, the software is compared with an analytical approach and found to
match within 5% in both the repairable and non-repairable cases.
The software documented in this thesis could serve as an aid to engineers designing
new systems to validate the reliability of the system. This would not require specialist
consultants or additional software, ensuring that the analysis provides results in a timely
and cost-effective manner
Application of a reliability model generator to a pressure tank system
A number of mathematical modelling techniques exist which are used to measure the performance of a given system, by
assessing each individual component within the system. This can be used to determine the failure frequency or probability of failure
of the system. Software is available to undertake the task of analysing these mathematical models after an individual or group of
individuals manually create the models. The process of generating these models is time consuming and reduces the impact of the
model on the system design. One way to improve this would be to automatically generate the model. In this work the procedure to
automatically construct a model, based on Petri nets, for systems undergoing a phased-mission is applied to a pressure tank system,
undertaking a four phase mission
Automatic construction of a reliability model for a phased mission system
There are a number of mathematical modelling techniques available to determine the reliability of any system design, for example Fault Trees, Event Trees etc. These models relate the performance of the system to the performance of the components of which it is comprised and are generally quite difficult to construct. Once constructed the analysis of the models can be performed using commercially available software. This stage of the analysis is well developed and can be performed efficiently. The model construction however is a lengthy process and reduces the impact of the reliability study on the system design. One way of improving this situation would be to automate the construction process. In this work a procedure is developed to automatically generate a reliability model, based upon Petri Nets, for a system undertaking a phased mission
Automated generation of a reliability model for a system undertaking phased missions
There are various mathematical models available to assess the reliability of a given system, these models relate the performance of the system to the performance of the components of which it is comprised and can be used to determine the failure probability or failure frequency of the system in question. Currently there is software available to perform the mathematical analysis of the model but its construction, which is used as input to the software, is undertaken manually. This is quite a lengthy process and can limit the usefulness of the model. One way of improving this situation would be to automate the construction process. In this work a procedure is developed to automatically generate a reliability model, based upon Petri Nets, for a system undertaking a phased mission
Application of a reliability model generator to a pressure tank system
A number of mathematical modelling techniques exist which are used to measure the performance of a given system, by
assessing each individual component within the system. This can be used to determine the failure frequency or probability of failure
of the system. Software is available to undertake the task of analysing these mathematical models after an individual or group of
individuals manually create the models. The process of generating these models is time consuming and reduces the impact of the
model on the system design. One way to improve this would be to automatically generate the model. In this work the procedure to
automatically construct a model, based on Petri nets, for systems undergoing a phased-mission is applied to a pressure tank system,
undertaking a four phase mission