Pipeng Toolbox : Hot Pipe Hobbs Buckling Calculators Blank User
Short Cuts
GO
Main ±
Beams ±
References ±
Fluid Flow ±
Fluid Properties ±
Maths ±
Materials ±
Pipelines ±
Soils ±
Subsea ±
Demo

Hot Pipeline Hobbs Lateral And Upheaval Buckling

Calculate high temperature pipeline lateral and upheaval buckling inititation temperature from initial out of straighness using the Hobbs method.

The Hobbs method is suitable for pipelines lying on the seabed. It should not be used for buried pipelines. The buckle initiation temperature can be calculated for lateral buckling modes 1 to 4, and upheaval buckling mode. The post buckling mode is indicative only, and is not valid outside the elastic range.

Change Module :

[FREE] tools are free in basic mode with no login (no plots, tables, goal seek etc). Login or Open a free account to use the tools in plus mode (with plots, tables, goal seek etc).
[PLUS] tools are free in basic CHECK mode with Login or Open a free account (CHECK values no plots, tables, goal seek etc). Buy a Subscription to use the tools in plus mode (with plots, tables, goal seek etc).
Try plus mode using the Plus Mode Demo tools with no login.   Help Using The Pipeng Toolbox (opens in the popup workbook)

Links : ±
CALCULATOR : High Temperature Pipeline Hobbs Lateral And Upheaval Buckling Model (Multi Layer Pipe) [PLUS]   ±

Calculate Hobbs upheaval and lateral buckling load and buckling temperature from initial out of straightness for multi layer pipelines.

Buckle conditions can be calculated for either buckle initiation, or post buckle for the selected buckle mode. The global axial load should be the same for buckle initiation and post buckle. Buckling should be checked for lateral buckling modes 1, 2, 3 and 4, and for upheaval buckling. The lowest buckling temperature should be used. Post buckle results are indicative only. The model is not valid outside the elastic range. This calculator is suitable for unburied pipelines lying on the sea bed. It should not be used for buried pipelines.

Tool Input

  • schdtype : Line Pipe Schedule Type
  • diamtype : Line Pipe Diameter Type
    • ODu : User Defined Outside Diameter
    • IDu : User Defined Inside Diameter
  • wtntype : Line Pipe Wall Thickness Type
    • tnu : User Defined Wall Thickness
  • wltype : Pipe Unit Weight Type
  • sectype : Cross Section Type
    • OODu : User Defined Outer Diameter Including Coatings)
    • Zu : User Defined Pipe Z Modulus
    • EIu : User Defined Pipe E x I
    • EAu : User Defined Pipe E x A
    • EAαu : User Defined Pipe E x A x alpha
    • νu : User Defined Pipe Poisson's Ratio
    • WLu : User Defined Pipe Total Weight Per Length
  • buckmode : Buckle Mode
  • buckstage : Buckle Stage
  • WTi : Pipe Liner Wall Thickness
  • ρi : Pipe And Liner Density
  • Ei : Pipe And Liner Elastic Modulus
  • αi : Pipe And Liner Thermal Expansion Coefficient
  • νi : Pipe And Liner Poisson's Ratio
  • WTo : Pipe Coating Wall Thickness
  • ρo : Pipe Coating Density
  • Δi : Initial Out Of Straightness
  • Ta : Ambient Or Installation Temperature
  • Pi : Internal Pressure
  • Nin : Installation Load
  • ρf : Internal Fluid Density
  • ρb : External Fluid Density
  • μa : Axial Friction Factor
  • μl : Lateral Friction Factor

Tool Output

  • ΔT : Delta Temperature At Buckle Inititation
  • Δb : Buckle Amplitude
  • ν : Pipe Poisson Ratio
  • BM : Maximum Bending Moment (Elastic)
  • EA : Pipe E x A
  • EAα : Pipe Expansion Modulus
  • EI : Pipe E x I
  • Fab : Buckle Axial Load
  • Fag : Global Axial Load (Away From Buckle)
  • IID : Pipe Inside Diameter Including Liner
  • Lb : Buckle Half Wave Length
  • Ls : Buckle Slip Length
  • OD : Line Pipe Diameter
  • OD/tn : Line Pipe Diameter Over Wall Thickness Ratio
  • OOD : Pipe Outer Diameter Including Coatings
  • SB : Maximum Bending Stress (Elastic)
  • Tb : Buckle Inititation Temperature
  • W : Total Pipe Weight Per Unit Length
  • Z : Pipe Z Modulus
  • cvg : Convergence Check
  • mlb : Buoyancy Unit Mass
  • mlc : Contents Unit Mass
  • mlp : Pipe Unit Mass Including Liner And Coating
  • tn : Line Pipe Thickness