Input variables
Generic variables
These variables can be found in virtually all reports as input variables
- Design Pressure – P
- Pressure assumed to be present in the component according to the design terms
- Design Temperature – T
- Temperature assumed to be present in the component according to the design terms
- Material
- Name of selected material used for the construction of the component
Specific variables
These variables are component specific
- Outside Diameter – D
- Outside diameter of the attached part. The diameter runs from the outside of the wall to the opposite outside of the wall, through the center of the circle.
- Nominal Thickness – tn
- Thickness ‘as is’, meaning it is the design thickness taking into account corrosion and tolerance.
- Corrosion – c
- Amount of thickness that accounts for the possible effects of corrosions.
- Tolerance – tol
- Tolerance in thickness for production
- Infinite length – L′
- The unsupported lenght of the shell is infitely long, meaning the external pressure can not collapse the shell.
- Maximum unsupported length – L
- Maximum length of the straight part of the pipe that is unsupported.
Pipe
Calculated Values
- Allowable Operating Stress – So
- Stress in the component at which it is still allowed (without failure) to use the component.
- Allowable stress at 20 °C – Sa
- Stress in the component at which it is still allowed (without failure) to use the component at 20 °C ambient temperature.
- Yield strength at operating temperature – Sy
- Stress in the component at which the component starts to plastically deform at operating temperature.
- Allowable Operating Stress thick shells – S
- Stress in the component at which it is still allowed (without failure) to use the component.
- Allowable buckling stress thin walled or thick walled shell – B, B′
- Maximum compressive stress causing instability in the structure.
- Modulus of elasticity – E
- Tendency to deform (tensile strain) along an axis when opposing forces (tensile stress) are applied along that axis.
- Maximum Allowable Pressure – Pa
- The maximum pressure at which the component can be used in operation. This value should be larger than the design pressure.
Scope errors
- Temperature is out of scope for material
- The material properties are not available at the design temperature.
Errors
- Can’t find material ‘MaterialName’ in database
- Material could not be found in database. Select an existing material name, or select another material via the material selection window.
Remarks
- Restricted unsupported length: L = x mm
- The unsupported length is restricted to a maximum: L ≤ L′
- Yield strength taken as: Sy = 2 B′
- This is applicable for thick walled shells with unknown yield stress according ASME II part D table Y-1.
Calculation errors
- Can't calculate maximum unsupported length for external pressure.
- The shell has insufficient strength to determine the unsupported length.