KEVOS® MAKEOS · Strength
Pressure Cylinder Wall Stress
What stresses does internal pressure cause in this tube or cylinder wall?
Hoop, radial and longitudinal stresses in a cylinder under internal pressure by Lamé’s thick-wall equations, with the thin-wall estimate and a von Mises safety factor.
Open the calculatorRuns in your browser. No account needed.
How this tool works
Inputs, units and where to find them
| Input | Unit | Typical source |
|---|---|---|
| Inside diameter | mm | Bore of the tube or cylinder. |
| Wall thickness | mm | Minimum wall thickness after tolerances, corrosion and machining allowances. |
| Internal pressure (gauge) | MPa | Maximum working (or test) gauge pressure; 1 MPa = 10 bar. |
| Ends | choice | Closed if the pressure on the end caps is carried by this wall (e.g. a capped cylinder). |
| Yield strength | MPa | Minimum yield strength from the material certificate or specification, not a typical value. |
| Required safety factor | Factor of safety required by your design code, customer specification or company standard. |
Method and formulas
- ro = ri + t. Hoop at bore σθ = p(ro² + ri²) ÷ (ro² − ri²); radial σr = −p.
- Longitudinal (closed ends) σz = p ri² ÷ (ro² − ri²).
- Thin wall σθ ≈ p d_mean ÷ 2t; von Mises from the three principal stresses at the bore.
- Example: 80 mm bore, 10 mm wall at 25 MPa gives a bore hoop stress of 113.89 MPa and a factor of 2.9514.
Limitations
- Elastic stresses away from ends, ports and welds; these features raise local stress.
- Pressure equipment must be designed to its code (e.g. AS 1210 or ASME VIII), which sets allowable stresses and thicknesses.
- Example values are illustrations. Replace them with values for your actual task.
Typical uses
- Check hydraulic cylinder barrels, tubes and pipes
- Compare thin-wall and thick-wall results
- Screen a wall thickness before code design
Who it is for
- Design engineers
- Structural and mechanical engineers
- Engineering students
What you get
- Hoop stress at the bore (Lamé)
- Longitudinal and radial stress
- Thin-wall hoop stress
- von Mises stress and safety factor
Interpreting the result
- If the thin-wall result is much lower than Lamé, the wall is thick and the Lamé result governs.
References
- Machinery’s Handbook, 29th edition (Industrial Press, 2012), printed pp. 290–294. Topic reference; no source tables or recommended settings are reproduced.
WORKOS tools are screening and decision-support utilities. Verify important financial, engineering, safety, legal or operational decisions using appropriate professional standards and your organisation’s approved data.
