Part IV
Modelling Guide
A. Building a model
A model represents the pipe centerline, with sizes, materials, components, supports and loads attached. SWBPIPE does not supply missing engineering inputs. A required value that is absent stops the solve. The diagnostic identifies the missing input.
1.Units and geometry.
Every quantity has an entered unit. Consumed values are converted to SI for the solve. The node table defines the model geometry, and the drawing follows those rows.
Put nodes at every change of direction, support, component and branch. Also put nodes at every change of size, material or temperature, and wherever you want a result. Long straight runs need no intermediate nodes for accuracy under the exact beam assumptions of end loads and consistent span loads. Intermediate nodes provide intermediate results.
Nodes are entered with absolute coordinates. Readouts offer Entered, SI and US display units where conversion is available. Editing retains entered units. Display preferences do not change the model’s authored units (Status).
2.Pipe sizes.
Each pipe has its nominal outside diameter and wall thickness, entered directly or through a defined section. For weight, give pipe, contents and insulation densities, and the insulation thickness. For the exact route, the allowance definitions also determine the pressure bore and contents area; identify the section basis below.
There are no pipe schedule tables to select from (Status). Exact-contract sections require explicit corrosion allowance and use nominal wall for stiffness and metal mass. The entered mill tolerance and corrosion allowance reduce the stress section and pressure bore. Stress rows identify both section bases. The pressure-free route retains its single wall-minus-mill-tolerance basis. Check the route before applying an allowance workaround (Status).
3.Materials.
Material inputs depend on the selected model contract. The ordinary route uses entered elastic and shear moduli and thermal expansion data. Enter these properties at the temperatures you need. When an ordinary case selects a temperature basis, it uses one named point or supported interpolation. It never extrapolates.
Exact pressure and model 0.6.0 load/reference states require explicit elastic modulus E and Poisson ratio ν. These routes derive the shear modulus.
Model 0.6.0 selects each member’s actual material basis explicitly. It uses base properties, an exact point or supported temperature interpolation. It refuses extrapolation. Installation, operating temperature and thermal/fit definitions are explicit states. Recorded shear modulus and expansion data do not substitute for E/ν. For a code range, the reference modulus basis is the value required by that code (Part II D).
4.Open, save and reopen.
The native desktop opens a model document through File > Open Model Document. A solve request containing separate model and material objects is not a desktop model document. File and shape checks refuse unsupported documents by name. A refused file or cancelled chooser leaves the session unchanged. Browser preview cannot open model files.
- Open the model document. Resolve any named file or shape refusal before solving.
- Check geometry, quantities, components, restraints, material states and load sources.
- Select the solver mode and solve. Read the standing, coverage, diagnostics and solve proof.
- Save the document as a local project. Examine the stored project and revision before any requested replacement.
- Choose Replace, Save as a new project, or Cancel. Cancel keeps the stored project.
- Reopen the saved project. Check its model and result standing before continuing.
Saving the same project needs no replacement prompt while its stored revision still matches this session’s last open or save. Another writer’s change requires a prompt. The store checks that revision and writes the project in one transaction. A further change before Replace is refused and prompts again. A timed-out write fails visibly.
Save as a new project assigns a new project ID. Its model hash changes, and the old ID’s solved run is not carried over. Opening a document adopts its entered data without filling missing engineering values. Saving can apply the declared persistence normalization. Reopening saved results does not establish current numerical eligibility.