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Analysis Component

The Analysis component is used to specify the various inputs for a PipeLay analysis. The Analysis component allows you to gather together a set of components of various types, such as pipelines, vessels, waves and so on, from all of those defined in a project file, and to perform various types of analyses using these components. In this example, the Analysis component is named ‘Normal J-Lay Analysis’. The following sections provide a description of the various inputs for the analysis.

 

Properties Tab

The Properties tab allows you to specify the options that are to be applied to all analysis stages of a particular model. In this example, the Model is selected as ‘Model’ and the Contact Modelling option is defined as Simple.  The Tolerance dialog in the Dynamic section has the properties listed in the table below specified.

Table: Dynamic Tolerance Properties

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Installation Stages Tab

The Installation Stages tab is where you define the various stages in your analysis. In this example, there is one static stage and two dynamic stages. Both of the dynamic stages restart from the initial static stage. The regular wave is applied in the first dynamic stage while the random sea is applied in the second dynamic stage. The two tables below list the time variables used in the two dynamic stages. To optimise the analysis run time, No is selected in the Tabular Output drop-down list for the dynamic stages.

Table: Time Variables for Regular Wave Analysis

 

Table: Time Variables for Random Sea Analysis

 

Criteria Tab

On the Criteria tab, you can specify installation criteria for each installation stage that is created in the Installation Stages tab. In this example, criteria are only applied to the initial static stage as the other stages restart from this stage. The table below provides details of the specified criteria. The tolerance parameters are set to their defaults.

 

Table: Criteria Properties for Static Stage

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Fatigue Tab

The fatigue analysis is specified in the Fatigue tab. For this normal J-Lay example, the following options are selected in the Fatigue tab:

▪The Analysis Type is specified as Normal Lay.

▪The Analysis Option is specified as Previous, which means that the fatigue analysis is run as a postprocessing operation after the final dynamic analysis.

▪The Previous Output Format is specified as Database, which means that the database files containing the output from the random sea dynamic analysis are used.

▪The pipeline ‘Line(1)_24’’ Pipe(1)’ is selected from the PipeLine drop-down list.

▪The tower connection point ‘_TensionerVCP(1)’ is selected from the Vessel End drop-down list.

▪Five Vessel Weld Locations are specified, the first location at the vessel connection point, with 12m spacing between each weld location.

▪The S-N Curve component defined previously, ‘S-N Curve’, is associated with the welds in the Weld Properties dialog.

▪The Bending SCF and Axial SCF magnitudes are set to 1.

▪The Allowable Fatigue Damage is set to 0.1.

▪The Cycle Time is set to 1800s and the Pull Length is set to 24m.

 

Summary Postprocessing Tab

You can use the Summary Postprocessing tab to request output from various parameters at crucial locations throughout the installation process. In this example, a number of parameters are selected for summary postprocessing, as detailed in the table below.

Table: Summary Postprocessing

 

Running the Analysis

You are now ready to run the analysis. While the analysis is running, you can observe the analysis progress and check for warnings or errors on the Progress tab.

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