R-Code

The R-code software was written to support the calculations for cracked body structural assessments following the R5 and R6 Procedures. However failure assessment diagram methods based on R5 and R6 methodology have been widely adopted around the world including the American ASME, Swedish, French, Chinese and Japanese national procedures as well as the British BS 7910 standard. The R-Code software can therefore be of great help with all the above. 

The software can calculate the stress intensity factor and collapse loads for a wide variety of geometries, for high order through section stress variations. Integrated crack opening, area and gas flow calculations can be performed, for penetrating defects, to aid leak before break analyses. Many other features are available to all geometries including fatigue crack growth, treatment of residual stresses and temperature dependent materials. Facilities for calling Visual Basic^© functions, subroutines and external programs enable user specified features such as collapse solutions. These powerful features give the user access to internal information through ‘public variables’ and provide an additional route for user specified output. 

The R-Code program includes: - 

Stress Intensity Factor and Limit Load solutions for over 100 geometry crack combinations

Integrated crack and gas flow calculations for ‘leak before break’ analysis

Automatic sensitivity analysis

·QA tracking of all data

Interactive result presentation plus tabular postprocessor with interface to standard spreadsheet formats

Temperature dependent materials

Visual Basic^© interpreter and use of external subroutines

Option for user defined Stress Intensity factors and collapse solutions

Novice and Expert User modes

User defined input and output units and data checking

Reference state methods for user defined geometries

Materials Database Facility

R-Code features for High Temperature Use (R5)

In addition to the features already mentioned, high temperature assessments will take account of time dependent material properties and behaviour. The program accessed in R5 mode may be used to perform assessments taking account of creep and fatigue crack growth.  Several creep strain equations are incorporated plus the Visual Basic^© route for users’ own equations. Allowance can be made for crack incubation and any stress redistribution using a number of different methods. Continuum damage may be evaluated in terms of life fraction or ductility exhaustion methods and checks can be made for crack stability under short term loading. The results may be looked at in the post processor and include not only the crack depth but also the creep and fatigue contributions plus growth rates and parameters such as C*, C(t) and rupture time. 

R-Code features for Low Temperature Use (R6) 

R-Code used in R6 mode has a number of features that do not apply to the R5 mode. Assessments can be undertaken for both of the R6 analysis types, initiation and tearing.  Material properties may also vary with temperature or radiation dose where these may vary through the section for non-fatigue calculations. For fatigue calculations these may vary with time or position. Sensitivity studies can be undertaken with a large choice of sensitivity variables. 

R-Code and finite element analyses 

Finite element results can be used directly by R-Code for transferring the uncracked body stress distributions. In R-Code (R6 mode) stresses and strains may also be required from an elastic-plastic analysis of the uncracked body; especially if the secondary stresses are high when compared to the primary ones. This facility uses a modification to the previous theory that gives less conservative results.