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.

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. Corrosion and other allowances reduce the section for stress only.

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 0.4.0 load/reference states require explicit elastic modulus E and Poisson ratio ν. These routes derive the shear modulus.

Model 0.4.0 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).

Model each support as built, with its actual physical behavior. A shoe on a steel beam is a rest with friction. Lugs may also make the shoe a guide. A rod hanger carries tension only. A trunnion on a beam is a stub from the centerline to the support point, with a rest at its end.

A model needs enough restraint to prevent rigid-body movement in every direction. When numerical checks detect a mechanism or insufficient restraint, the solve is blocked. Diagnostics identify the detected problem. A solved result does not prove physical stability. Examine the largest movement and rotation in every case. Read the numerical admission and coverage limits.

Build the basic loads first. Then construct the cases needed for the code check. The following tables describe a line with one operating condition.

Each operating condition has its own OPE case. The expansion range is formed between the extreme states. Part II C and D explain this distinction.

SWBPIPE supplies no code tables. Enter flexibility factors, SIFs, component dimensions and allowables from the applicable codes and catalogs. For the B31 codes, use ASME B31J for SIFs and flexibility factors. Use owner and manufacturer data for components and hangers. The classical forms in Part II E provide a comparison for entered data.

The ordinary curved-bend mode uses k in stiffness. With mechanics_geometry_only bend markers or tee/branch records, the ordinary route can publish a separate user equal-factor intensified bending measure. It applies at adjacent straight member ends; tee/branch ends must match the declared header or branch pipe reference. Each end uses its member section modulus and the corresponding positive user-entered SIF.

A realized curved-bend component supplies no such measure on its arc or straight neighbors. This measure never multiplies stress by k and is not a code stress. User formula criteria can evaluate intervals, but a formula gate is not standards approval. SWBPIPE supplies no built-in code classification or allowable. The code check is made in the program used for validation (Part V).

You can keep material, section, component and hanger data in private libraries. You can keep projects in a local store. These local data remain on your machine.

Check the model before reading its results. Short diagnostic runs can reveal model errors.

• Movements first. Look at the largest displacement and rotation in every case. Meters of movement or whole radians of rotation indicate a possible mechanism or unit error. Investigate these values (Status).
• Weight balance. In the weight case with every rest acting, the vertical support loads add up to the total weight entered.
• Free growth. Hold the line at one anchor only and apply the thermal case. For uniform unconstrained thermal strain, each node should move by αΔT times its position vector from the anchor. Member forces should be zero. Other restraints, nonuniform strain or imposed boundary motions change this expectation.
• Order of magnitude. Compare the thermal load on a leg with the guided-cantilever estimate of Part II A. A result ten times larger or smaller needs explaining.
• Support states. In each nonlinear case, read which rests have lifted off, which gaps have closed and which shoes slide. Ask whether the line would behave that way.
• The validating program. The final check is the model in the program you validate in, compared result by result (Part V C).