Last Updated: 2022.7
For Internal Pressure
Internal Pressure: The internal design pressure (pressure on the concave side) field represents the gauge pressure. When the Solve for Thickness option is selected, this value represents the input and should not include the static head. When the Solve for Pressure option is selected, this value represents the result. In the latter case, it represents the total internal pressure (design pressure plus the head) that can be sustained by the component and remain code compliant in the absence of any other loadings. The internal pressure value defaults to the value represented on the greater of the cone or cylinder internal pressure. This aspect can be modified if needed.
Static Head: The internal pressure (pressure on the concave side) field represents the result value from the static head of the fluid. The user must determine this value and input it accordingly in the system. The value is then added to the pressure input field, and the sum is used in the internal pressure calculations for the component. This field is not present when the Solve for Pressure option is selected. This defaults to the greater of the cone or cylinder static head. This aspect can be modified if needed.
Axial Load: The axial load field represents the load per unit length on the junction. The check box to the right of the field toggles this value between a tensile load and a compressive load. This value affects the Internal Pressure case only.
For External Pressure
External Pressure: The external pressure field represents the external design pressure (pressure on the convex side). This field is disabled and locked to the value from the cylinder at the junction.
Axial Load: The axial load field represents the load per unit length on the junction. The check box to the right of the field toggles this value between a tensile load and a compressive load. This value affects the External Pressure case only.
Use Custom A: The Use Custom A check box enables the Custom A field for input when it is selected. The Custom A value is used for A in the Line of Support calculations instead of the A value determined by the software.
Custom A: The Custom A field is only available when the Use Custom A check box is selected. This allows the user to determine if an override is needed for the A value that is determined by the software, and instead, use one a value the user has determined from the external pressure charts.
Use Ln Based Interpolation: The Use Ln Based Interpolation check box uses natural log based interpolation instead of straight line interpolation when determining A from the external pressure charts. Both straight line and natural log based interpolation are considered valid, although it's suggested that natural log based is more accurate for the external pressure charts.
Juncture is a line of support: The Juncture is a line of support check box considers the junction as a line of support for the design of the vessel for vacuum. With this consideration, the juncture must pass additional requirements. When the juncture is considered a line of support, the code does not require that the cone required thickness (external pressure) is at least that of the adjacent shell.
Check Cone Pe tr vs. Shell Pe tr: When the junction is not a line of support and the Check Cone Pe tr vs. Shell Pe tr box is selected, the cone tr for the external pressure case must be at least the shell tr for the external pressure case or the junction analysis can fail. Deselect the Check Cone Pe tr vs. Shell Pe tr box to avoid performing this comparison. See UG-33(f) for more information.
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