# Input variables

## Generic variables

These variables can be found in virtually all reports as input variables

Design Pressure – Pc
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 – Do
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 – en
Thickness ‘as is’, meaning it is the design thickness taking into account corrosion and tolerance.
Corrosion – c0
Amount of thickness that accounts for the possible effects of corrosions.
Tolerance – c1
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 stress at operating temperature – S
Stress in the component at which it is still allowed (without failure) to use the component.
Yield strength at operating temperature – Rpt
Stress in the component at which the component starts to plastically deform at operating temperature.
Modulus of elasticity – Et
Tendency to deform (tensile strain) along an axis when opposing forces (tensile stress) are applied along that axis.
Poisson's ratio – ν
(Negative) ratio of transverse to axial strain. An extension (or contraction) in the direction of a load corresponds in a contraction (or extension) in a direction perpendicular to the applied load. The ratio between these two quantities is the Poisson's ratio.
Number of circumferential waves – ncyl
Number of circumferential waves for an unstiffened part of cylinder. The value is an integer ≥ 2 to minimize the value of Pm
Critical strain – ε
Mean elastic strain at collapse
Yield pressure – Py
Pressure at which mean circumferential stress in cylindrical shell midway between stiffeners reaches yield point of material.
Critical pressure – Pm
Theoretical elastic instability pressure for collapse of perfect cylindrical shell
Critical pressure – Pr
Lower bound collapse pressure
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.

# 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: LL′

# Calculation errors

Can't calculate maximum unsupported length for external pressure.
The shell has insufficient strength to determine the unsupported length.