PROCODE: Code Optimization Module for Structural Design
PROCODE optimizes partial safety factors and reliability in code calibration studies. It defines scopes, variables, and functions for structural conditions. Results in improved design parameters.
PROCODE: Code Optimization Module for Structural Design
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Presentation Transcript
The Code Optimisation Module - PROCODE Rolf Skjong & Knut Ronold Det Norske Veritas Rolf.Skjong@dnv.com JCSS Workshop on Code Calibration, March 21-22 2002
PROCODE • PROCODE was developed in the early nineties in the Reliability of Marine Structures Project • .. first use published at OMAE 1992 • …code optimisation • .. has been used extensively in many code calibration studies on ship rules • .. has been used on a project basis on other calibration studies (e.g. Danish Wind Mill design code) • .. is linked to PROBAN • .. use PROBAN for all reliability calculations
PROCODE • Objective • Optimisation of partial safety factors • Control Variables: Partial Safety Factors • Minimum Scatter around a target reliability by minimising the penalty function
PROCODE • SCOPE of code is specified by design cases • External and Internal Conditions are specified separately • External: • External could be environmental conditions (Hs,Tz) • Conditions are associated with a Name-Set • PROCODE take care of the Name-Set and Names that points to the PROBAN variables during execution
PROCODE • Internal: • Relates to structural conditions • Internal could be such as material properties, slenderness measures • Conditions are associated with a Name-Set • PROCODE take care of the Name-Set and Names that points to the PROBAN variables during execution
PROCODE • The scope is defined by the design cases defined by combining external and internal conditions
PROCODE • Variables • X, stochastic • E, environment • D, design situation • , design parameters that may be chosen by the designer
PROCODE • Limit State Function: G(X,E,D,)>0 • Code Check Function: h(x,e,d,,)>= 0 • M failure modes k=1-M • Nk code check functions n=1- Nk • Code check requirements: hnk(x,ei,di, ij, ) >= 0 • Limit State functions: Gk(X,Ei,Di,ij) >= 0 • i,j defining the scope matrix
PROCODE One design Case: Subjected to: With one of the inequalities turning into equality This is generalised to Multiple design cases in PROCODE
PROCODE • Programmable functions • Limit States • Code Checks • Penalty functions • Defined by Data (additional to PROBAN) • Scope (Internal, Internal) • Safety Factor • Design Parameter
PROCODE RESULTS • Code Evaluation (before optimisation starts) • Optimised partial safety factors • Resulting reliabilities • Resulting design parameters (input to cost analysis)
PROCODE Examples • Jack-up, spudcan/punching & tubular members/buckling • Tension Piles/Pull out • Wind turbine rotor blades/fatigue • Ship Structures/Long Series of studies
PROCODE Examples • Wind turbine rotor blades/fatigue • Ronold/C.Christensen “Optimisation of design code for wind-turbine rotor blades in fatigue”. Eng.str. 23(2001) • Previous work on probabilistic design • Wish to develop code valid for variation of designs, locations and materials • Fatigue in rotor blade root - SN approach • Material is fibre-reinforced polyester laminate
PROCODE Examples • Wind turbine rotor blades/fatigue • Scope Parameters • Rotor radius • chord length • section modulus (blade root) • rotor frequency • hub height • material
