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AppendicesLiterature: Selected papers 1. Introduction - Overview of STRURELThe necessity to analyse and to verify probabilistically the reliability of technical components and systems has evolved in several areas such as offshore and marine engineering, nuclear and aerospace engineering and in the wide field of civil engineering. A reliability question always arises if there is some random demand on a random capacity of a system and where demand and capacity depend on a number of random variables or random processes. The same concepts are applicable when designing service systems, in econometrics and in many other fields. The program system STRUREL has been developed to perform the computational tasks in a user friendly environment based on the most recent theoretical findings. It originated from applications in structural reliability but can be interpreted as a general uncertainty manipulator and, thus, is applicable in many fields. STRUREL consists of several independent but highly interrelated programs which are: STATREL: A module for the reliability-oriented statistical analysis of data including simulation and analysis of time series COMREL: A module for time-invariant and time variant reliability analysis of components with many alternative analysis methods SYSREL: A module for the reliability analysis of systems PERMAS-RA: A module combining COMREL with the FE-code PERMAS (by Intes GmbH) All programs have a user friendly graphical interface on PC´s. The graphical user interface includes a rich HELP facility not only for operating the programs but also on theoretical concepts. The user can work either with a Symbolic Processor to formulate his problem or can write a Fortran program and compile and link it with the reliability algorithms. 2. How STRUREL Programs Work TogetherGeneralThe STRUREL software covers the preparatory steps, all computational tasks and many post processing options in technical reliability, decision making under uncertainty and statistical analysis. The programs have applications in structural engineering and code making, in the nuclear power plant, offshore, ship and aerospace industry, in hydrology, operations research, financial planning and statistics. Input to the STRUREL programs is rather short in terms of failure criteria and stochastic models for the basic random variables. Fully interactive input and a rich online help function facilitate setting up the input data. The programs come with a rich set of examples and an exhaustive technical reference in the printed manuals. The STRUREL programs provide short and clear result files but in case of problems a detailed error traceback can be generated. From parameter studies one can compute and plot failure probability, reliability, partial safety factors, hazard functions, expected cost and, of course, various sensitivity measures. Report writing is fast and simple by versatile formatting, export and print options like export to Clipboard or write to *.wmf, *.bmp files. True Type Fonts are used throughout all plots. STATREL The first module in the sequence of the STRUREL system is STATREL for the statistical analysis of data. For all models included in other STRUREL modules STATREL performs parameter estimation by different methods, confidence interval and quantile estimation as well as hypothesis testing including tests for sample validity, distribution functions and parameters. STATREL also provides rich facilities for simulation and analysis of random processes. Import of data from spreadsheet programs like Excel and export of stochastic models to COMREL and SYSREL is possible. COMREL Both the time invariant COMREL-TI and the time variant COMREL-TV for componental reliability analysis can deal with arbitrary dependence structures in the stochastic model (Rosenblatt-, Hermite and Nataf-models). The full set of stochastic models offered by STATREL is supported (44 models) and can be inputted either in parameter form or in terms of the first two moments and additional parameters if necessary. In COMREL-TI and COMREL-TV several failure criteria can be defined in one job and be analysed one after another in one job. For larger sets of failure criteria one may use predefined 'Archives' of stochastic models and state functions connected to predefined 'Reliability Processors'. SYSREL System reliability evaluation with multiple failure criteria is covered by SYSREL. System modelling includes not only the representation by a (minimal) set of parallel systems in series but also the important case of conditional events (observations). The features for stochastic modelling are the same as in COMREL. The interface to the failure criteria is essentially the same as in COMREL making it straightforward to check the failure criteria individually in COMREL before using them in a system reliability analysis. |
