Calculate trigger upheaval buckling inititation temperature from trigger height for multi layer pipelines.
The trigger should be designed so that the trigger upheaval buckling initiation temperature is less than the lateral buckling initiation temperature for all four lateral buckling modes. Buckle conditions can be calculated for either lateral buckle initiation for the selected lateral mode, trigger upheaval buckling inititation, or trigger post upheaval buckle. Use the Result Plot option to display the buckling initiation temperature versus lateral out of straightness or buckle trigger height. Or use the goal seek option to calculate the required trigger height for each lateral buckling mode. The buckle trigger height should be the maximum required height for all four lateral buckling modes.
The trigger post buckle is calculated for an upheaval buckle and is indicative only. The post buckle is a combined lateral and upheaval buckle. Finite element analysis (FEA) is recommended for post buckle analysis. The global axial load should be the same for the lateral mode buckle initiation, upheaval trigger buckle initiation, and upheaval trigger post buckle. The calculation is valid in the elastic range only. The calculator is suitable for unburied pipelines lying on the sea bed. It should not be used for buried pipelines.
Tool Input
- lattype : Goal Seek Lateral Buckling Mode
- 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
- Δl : Lateral Out Of Straightness
- Δt : Buckle Trigger Height
- 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