Analysis Component |
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Analysis Component |
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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 S-Lay Analysis’. The following sections provide a description of the various inputs for the analysis.
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
Property |
Value |
Tolerance Measure |
0.001 |
Maximum Number of Iterations |
1000 |
Small Torque Value |
1 x 106 Nm |
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
Property |
Value |
Time Step Type |
Fixed |
Start Time |
0 s |
End Time |
50 s |
Time Step |
0.05 s |
Ramp Type |
Non-linear |
Ramp Time |
20 s |
Table: Time Variables for Random Sea Analysis
Property |
Value |
Time Step Type |
Fixed |
Start Time |
0 s |
End Time |
3700 s |
Time Step |
0.05 s |
Ramp Type |
Non-linear |
Ramp Time |
100 s |
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 other tolerance parameters are set to their defaults.
Table: Criteria Properties for Static Stage
Property |
Value |
Criteria |
Tension |
Component Type |
Tensioner |
Minimum Value |
5000 kN |
Maximum Value |
5001 kN |
Iterate On - Type |
Seabed Connection Point |
Iterate On - Name |
Seabed Connection |
Iterate On - Vector |
Global Y |
Tolerance – Max Iterations |
200 |
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
Type |
Component |
Parameter |
Criteria |
Pipeline(1) |
Tension - Start |
Criteria |
Lay Vessel(1) |
Tip Separation |
Criteria |
Pipeline(1)_24’’ Pipe(1) |
Bending Strain |
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.