Casing Burst & Collapse Biaxial Stress Calculator

Compute API TR 5C3 internal yield (burst) pressure, nominal collapse resistance, and tension-adjusted collapse derating factor based on von Mises ellipse.

Casing Geometry & Steel Grade

Outside Diameter OD (in):

Nominal Wall Thickness t (in):

Minimum Yield Strength YS (psi): P110=110k, L80=80k, N80=80k

Nominal Collapse Rating Pc0 (psi):

Axial Tensile Load F_a (lbf):

Design Safety Factor SF Target:

Calculated Casing Limits

Barlow Burst Yield Rating:

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Derated Collapse Rating (Pc):

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Biaxial Derating Factor:

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Axial Stress / Yield Ratio:

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Pipe Cross-Section Area:

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Maximum Allowable External Press:

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API TR 5C3 & ISO 10400 Casing Mechanics

In deepwater, HPHT, and heavy casing string designs, casing is subjected to simultaneous axial tension and external hydrostatic pressure. Under the maximum shear stress or von Mises yield criterion, axial tension significantly reduces the casing's resistance to collapse.

1. API Barlow Internal Yield Pressure (Burst)

P_burst = 0.875 × (2 × YS × t) / OD

Where 0.875 represents the standard API 12.5% minimum wall thickness manufacturing tolerance allowance.

2. Biaxial Collapse Reduction Factor

R = √(1 - 0.75 × (σ_a / YS)²) - 0.5 × (σ_a / YS)
P_c(derated) = P_c0 × R