Planes, trains and automobiles – while we have experience across those sectors, this particular project focuses on a complex industrial system where upset conditions could trigger a significant dynamic event.
In certain scenarios, transient events can lead to cascading failure, fatigue damage, overloading, or even rupture. Accurately predicting and mitigating these risks is critical to process safety and long-term operational reliability.
The Right Tool for the Right Scenario
For most piping and pipeline projects, industry professionals rely on CAESAR II, a tool we use daily at DOCAN. However, when dealing with highly transient, time-dependent dynamic scenarios, we turn to ROHR2 (R2).
In our experience, ROHR2 is one of the most capable solvers available for true transient events. It is particularly powerful when analysing:
- Real-time-based dynamic loading
- Plastic and buried piping systems
- Integrated piping, vessel, and structural models
- Complex support and boundary conditions
(“Rohr” translates to “pipe” in German – an appropriate name for such a specialised tool.)
Fully Integrated System Modelling
In this case, our model incorporated:
- A large vessel
- The downcomer
- A header system
- Associated supporting structure
- Pipe supports
- An expansion loop
- A terminating drum
All stress intensification factors (SIFs) and flexibility factors (K values) were correctly applied. We completed full stress checks in accordance with ASME B31.3, with particular focus on the occasional load case.
Given the event’s transient nature, we performed a time-based dynamic analysis in ROHR2. From the resulting complex time histories, we conducted a rainflow fatigue analysis using the fatigue-counting methodologies defined in ASME B31.3.
We also extracted the system’s frequency response using appropriate transforms, enabling us to identify potential excitation frequencies that could drive damaging dynamic behaviour.
The Outcome
The result?
- A confident and defensible process safety case
- Clear identification of any risks
- Simple, pragmatic engineering solutions, where required
What Sets DOCAN Apart
A key differentiator is our ability to integrate the entire system, piping, vessels, and supporting structures, into a single coherent model. This allows us to:
- Perform true coupled dynamic analysis
- Assess system-wide interactions
- Implement and test design changes rapidly within a single environment
This work is delivered by DOCAN’s expert Mechanical and Plant Team, using some of the most advanced analysis technology available. Want to work with DOCAN? Contact us here, or call us on +44 01606 212 330.