Executive Summary by K6p19B


									Executive Summary

Chapter 1 reviews the structural reliability design process and presents the general
procedure of structural reliability analysis. An overview of uncertainties and failure
modes is given, including objective uncertainties and subjective uncertainties. A
detailed description of the associated reliability concepts, definitions and notations is
given. Finally, the benefits and drawbacks of using probability-based design methods
are listed and the role of reliability analysis in a general probability design procedure
is represented.
In chapter 2, the basic theories and methods of reliability are presented in detail.
Analytical methods (approximate methods) are introduced. The direct integration
method is presented, including the techniques of standardized integral region, joint
probability density function, multivariate integration and advanced method of
integration. Monte Carlo simulation methods and response surface methods are
presented, including basic theory, with simplifications for large systems, iterative
solution scheme and response surface and finite analysis etc. Suggestions are given
for choosing reliability methods.
In chapter 3, the general procedure for modelling of a physical problem in a
probability manner is presented, with guidance on identification of the problem. Then,
to ensure the safety of the designed structure, all significant modes of failure for the
structure are identified. The sensitivity analysis method and an overview of
uncertainties and probabilistic distributions are given. The concept of system
reliability is introduced, and the calculation methods of system reliability are
In chapter 4, loads on marine structures are introduced.
In chapter 5, the procedure of calculating reliability of ship structure is introduced in
detail, including identity of failure modes, calculation of loads and strength of ship
structures, establishment of limit state functions, etc. Time-variant computations are
outlined. Fatigue reliability is introduced.
In chapter 6, reliability assessment and reliability based design code are introduced.
The general method of determining partial safety factors is derived, followed by a
demonstration of how partial safety factors are determined, calibrated, and used in
new designs that have uniform safety. Finally an illustration is given of how
probability based methods can be used to develop and calibrate codes (or design
criteria) in order to produce designs with uniform safety (target safety index) over a
wide range of the basic parameters involved in the design.
In chapter 7, the use of QRA combined with SRA is outlined, and integrated
approaches for SRA methods and QRA are presented on the basis of the classical
Bayesian approach and the fully Bayesian approach, respectively. Risk analysis
methodology is introduced, starting with the PHA which is often preferred in a safety
context, and continuing with FMEA.

It is accepted that this document has been written with more detail than would
necessarily be needed for a guideline document for industrial use and would probably
also need further examples and illustrations to enhance such use. Further drafting and
development, needed for final publication, will be a further ASRANet activity under
the relevant task group.

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