Question

It may become necessary to analyze pipe cross‑sections as surface models in plant engineering in particular, but also when analyzing details of structural systems. For this purpose, RFEM offers the option to create pipe cross‑sections automatically by means of a line.

In RFEM 5 and RSTAB 8, it is possible to assign nonlinearities to member hinges. In addition to the nonlinearities "Fixed if" and "Partial activity", you can select "Diagram". If you select the "Diagram" option, you have to specify the according settings for the activity of the member hinge. For the individual definition points, it is necessary to specify the abscissa and ordinate values (deformations or rotations and the according internal forces) that define the hinge.

Piping systems are exposed to a variety of loads. One of the most decisive is internal pressure. This article will, therefore, deal with the stresses and deformations resulting from a pure internal compression load in the pipe wall or for the pipe.

After modeling piping systems in RFEM using RF‑PIPING and defining loads as well as load and result combinations, you can carry out pipe stress analysis in the RF‑PIPING Design add‑on module.

You can select all or only some pipelines and loads, load or result combinations for piping design. The material library provides various materials according to EN 13480‑3, ASME B31.1‑2012, and ASME B31.3‑2012 standards.

After the calculation, the results are displayed in clearly arranged windows; for example, by cross‑section, by pipeline, or by members. You can also display the design ratio graphically on the entire model in RFEM. This way, you can quickly recognize critical or oversized areas of the cross-section.

In addition to the input and result data, including design details displayed in tables, you can add all graphics into the printout report. This way, comprehensible and clearly arranged documentation is guaranteed. You can select the report contents and extent specifically for the individual designs.

• Design according to EN 13480-3, ASME B31.1-2012, and ASME B31.3-2012
• Check of the minimum required wall thickness of the pipes, taking into account manufacturing allowances, corrosion, and welding factor
• Analysis of stresses due to sustained loads, sustained and occasional loads as well as due to thermal expansion
• Result documentation with tables and graphics in the RFEM printout report

• Graphical input of piping systems and piping components
• Illustrative visualization of piping systems and piping components in RFEM graphic window
• Comprehensive libraries for piping cross‑sections and materials
• Comprehensive libraries for flanges, reducers, tees, and expansion joints
• Consideration of piping structure (insulation, lining, tin‑plate)
• Automatic calculation of stress intensification factors and flexibility factors
• Specific piping action categories for load cases
• Optional automatic combinatorics of load cases
• Consideration of material properties (modulus of elasticity, coefficient of thermal expansion) either during operating temperature (default setting) or during reference (assembly) temperature of material
• Consideration of strain and uplift due to pressure (Bourdon effect)
• Interaction between the supporting structure and the piping system