Pipeng Toolbox : Hobbs Buckling Modules Blank User
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Pipeline Hobbs Buckling Modules

Links : ±
CALCULATOR MODULE : Hot Pipeline Hobbs Lateral And Upheaval Buckling   ±
CALCULATOR MODULE : Hot Pipeline Upheaval Buckling   ±

Calculate high temperature pipeline upheaval buckling using either the Hobbs method, the Pipeng method, or the LRSTAR method.

The Hobbs method can be used for used for pipelines lying on the seabed. The LRSTAR and Pipeng methods are suitable for buried pipelines, and have been developed using the results from finite element analysis (FEA). The LRSTAR method uses a cubic spline fit for the dimensionless Richards length number and Richards weight number. The Pipeng method uses a simple mathematical relationship between the Calladine Length number and the Calladine load number based on beam theory.

The Hobbs method calculates the initiation temperature from the global axial load, the load outside the slip zone, and hence accounts for the expansion of the pipe prior to buckling. The Pipeng method and LRSTAR method calculate the initiation temperature from the axial load in the buckle, and do not account for the expansion of the pipe prior to buckling. The Pipeng method and LRSTAR method are therefore slightly conservative. In addition, the LRSTAR method includes a built in design factor. The LRSTAR method is therefore more conservative than the Pipeng method.

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CALCULATOR MODULE : Hot Pipeline Lateral Buckling   ±
CALCULATOR MODULE : Hot Pipeline Upheaval Buckling Trigger   ±

Calculate high temperature pipeline upheaval buckling trigger height using Hobbs method.

Upheaval buckling triggers are used to initiate controlled buckling of high temperature high pressure pipelines. The trigger height should be designed so that the upheaval buckling initiation temperature is lower than the lateral buckling initiation temperature for all four lateral buckling modes. The triggers should be spaced according to the buckle initiation slip length. Use the Result Plot option to display the buckle initiation temperature versus either lateral out of straightness or trigger height, and use the goal seek option to calculate the required trigger height.

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