Inputs |
 
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Inputs |
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Inputs are grouped together under similar categories, such as Environmental, Section Properties, Material Properties, Load Factors, Resistance Factors and General. The various inputs and their significance are now outlined.
The codes currently supported are as follows:
•DNV-OS-F101 (Submarine Pipeline Systems), October 2013
•DNV-OS-F201 (Dynamic Risers), October 2010
•API-STD-2RD (Dynamic Risers for Floating Production Systems), September 2013
•ISO-13628-7 (Completion/workover riser systems), November 2005
•Environmental File Name. An environmental load is considered to be a load imposed directly or indirectly by the environment. This allows you to specify a list of Flexcom analyses to be included in the code checking calculations. Note that you use this functionality to nominate dynamic analysis keyword files, which are treated as the Environmental load case in terms of the DNV and API code checks.
•Functional File Name. A functional load is a load that is a consequence of the system’s existence and use without consideration of environmental effects. A dynamic analysis is typically preceded by one or more static runs (initial static, offset, current etc.). This input may be used to specify which static run to treat as the Functional load case. If the functional file is not specified it defaults to the analysis immediately preceding the environmental analysis in the restart chain.
•Start Time. This input may be used to exclude the effects of initial solution transients from the code checking calculations.
•End Time. This input, in conjunction with the Start Time, allows you to focus on a particular time segment (e.g. for efficiency reasons) if so desired.
•Set Name. This allows you to specify a list of element sets to be considered for code checking. By default all elements in the designated Flexcom analysis are considered.
•Design Factor. This allows you to specify a numerical factor to be considered for API or ISO code checking. For API code checking, the design format sets limits on loads and load effects to a fraction of the capacity of the component to resist the load or load effect with this factor. The design factor depends on the type of load and can be different for SLS, ULS, and ALS categories. For ISO code checking, the design factor depends on the failure mode and design conditions. Please refer to the ISO code document to select the most suitable value. An appropriate value should be specified per environmental. If not specified, this value defaults to 0.6. This value is not used if specified for the DNV code check, or Method 3 of the API code check.
•Collate. This option allows you to make a summary file of your code check and collates utilizations for the environmental(s) in your output file. By default, this value is set to YES.
•Set Name. The name of the section (i.e. the element set name) whose properties are being defined. Note that any Set Name referenced under the Environmental category must have section properties defined here.
•Material Name. The name of the material associated with the section. The actual material properties themselves are defined under the Material category.
•Alpha C. The flow stress parameter accounting for strain hardening (αc) as per the relevant DNV standard. This value is not used if specified for the ISO code check.
•Diameter and Thickness. The section diameter and wall thickness. If unspecified, these parameters default to the corresponding values used in the Flexcom analysis.
•Tcorr. Corrosion allowance (Tcorr) as per the relevant DNV standard. This value defaults to 0.0 if not specified.
•Alpha Fab. Manufacturing process reduction factor (αfab) as per the relevant DNV standard. This value defaults to 0.85 if not specified. This value is not used if specified for the ISO code check.
•Ovality. The section ovality (fo) as per the relevant DNV standard. This value defaults to 0.005 if not specified.
•Scale Factors. Moment and tension scale factors. If unspecified, these parameters default to 1.0. This value is not used if specified for the ISO code check.
The standard material properties are used for DNV and API code checks.
•Material Name. The name of the material whose properties are being defined. Note that any Material Name referenced under the Section Properties category must have material properties defined here.
•SMYS and SMTS. The Specified Minimum Yield Strength and Specified Minimum Tensile Strength respectively for the material.
•Young’s Modulus and Poisson’s Ratio. Self-explanatory.
•Fy Temp and Fu Temp. The temperature derating factors for the yield stress (Fy,temp) and tensile stress (Fu,temp) respectively, as per the relevant DNV standard.
•Alpha U. The material strength factor (αu) as per the relevant DNV standard. This value defaults to 0.96 if not specified.
The ISO material properties are used for ISO code checks.
•Material Name. The name of the material whose properties are being defined. Note that any Material Name referenced under the Section Properties category must have material properties defined here.
•Rt05. Specified minimum yield strength for 0.5% total elongation at room temperature.
•Rm. Specified minimum ultimate tensile strength at room temperature.
•Elevated Temperature. Used to determine the reduction factor due to temperature.
•Young’s modulus and Poisson’s ratio. Self-explanatory.
•A5. Percentage minimum elongation after fracture.
•Tc. Single load ultimate tension capacity.
•Mc. Single load ultimate bending capacity.
•Pec. Single load ultimate pressure capacity.
Tc, Mc and Pec are used to calculate connector resistance at the start of every section.
The following factors may be applied to API and DNV code checking and are not applied to ISO code checking.
•Functional. The functional factor (γf) as per the relevant DNV standard. This value defaults to 1.1 if not specified.
•Environmental. The environmental factor (γe) as per the relevant DNV standard. This value defaults to 1.3 if not specified.
•Optimise Factors. An option to optimise the load factors to maximise the load effects. The default value of Yes means that the environmental factor is taken as 1/γe if the environmental loading reduces the combined load effects.
The following factors may be applied to API and DNV code checking and are not applied to ISO code checking.
•Material. The material resistance factor (γm) as per the relevant DNV standard. This value defaults to 1.15 if not specified.
•Safety. The safety class resistance factor (γsc) as per the relevant DNV standard. This value defaults to 1.26 if not specified.
The following factor may be applied to API and DNV code checking and is not applied to ISO code checking.
•Usage Factor. The Working Stress Design usage (WSD) as per the relevant DNV standard. This value defaults to 0.75 if not specified.
The reference pressure may be applied to ISO code checking and is not applied to API or DNV code checking.
•Element. The element at which the local internal pressure is to be defined. The reference point is the midpoint of this element.
•Pressure. The local internal pressure from which the internal pressure at the reference point is calculated as per the "Design pressure and design temperature" subsection in the ISO-13628-7 code document.
•*CODE is used to specify the relevant code/procedure to be used in code checking.
•*ENVIRONMENTAL is used to specify a list of Flexcom analyses to be included in the code checking calculations.
•*SECTION PROPERTIES is used to specify section properties to be used in code checking.
•*ELEMENT SETS is used to group individual elements into element sets.
•*MATERIAL is used to specify standard material properties to be used in DNV and API code checking.
•*MATERIAL-ISO is used to specify ISO material properties to be used in ISO code checking.
•*LOAD FACTOR is used to specify load effect factors to be used in code checking.
•*RESISTANCE FACTOR is used to specify resistance factors to be used in code checking.
•*GENERAL is used to specify a general usage factor and an incidental to design pressure ratio to be used in code checking.
•*REFERENCE PRESSURE is used for ISO code checking only to specify the local internal pressure at a particular location.
If you would like to see an example of how these keywords are used in practice, refer to K02 - Worked Example - Complex.