Softwares available for flexibility calculation/stress analysis
Manual analysis has its limitation on the number and type of supports, the variation in temperature to which the system is subjected and the like. Hence solving a real live size problem is difficult or impossible by the manual methods.
There are number of softwares available to handle complex problems. The first computer analysis of the piping system was done in 1957. The flexibility analysis softwares available as on date are:
- ADL PIPE
- AUTO PIPE
- CAE PIPE
- CAE SAR II
- PIPE PLUS
- TRIFLEX
- QFLEX
The pipe line geometry is feed into system along with the parameter such as the minimum operating temperatures, pipe sizes, bend radii type of branch connections, locations and type of supports. The analysis is done by Finite Element Method. Interpretation of the results to ensure economy, safety etc are the job by a real Piping Engineer.
Data required for flexibility calculations
The following data will be required for the flexibility calculations if it is carried out manually or by the use of software. It is therefore prudent to have this ready before starting.
The direction of coordinates is fixed as below:
- Code of Practice
- Basic Material of Construction of Pipe
- Ambient / Installation temperature
- Number of Thermal Cases
- Flexibility Temperature (See Note)
- Design Pressure
- Outside diameter of Pipe
- Type of construction of pipe
- Nominal Thickness of Pipe
- Manufacturing tolerance
- Corrosion allowance
- Pipe Weight
- Insulation Weight
- Specific Gravity of Contents
- Young’s Modulus at Ambient/Installation Temperature
- Young’s Modulus at Flexibility Temperature
- Thermal Expansion at Flexibility Temperature
- Allowable stress at Ambient/ Installation temperature
- Allowable stress at flexibility temperature
- Bend radius and type of bend
- Branch connection type
- Weight of attachments – Valves and Specialties
- Terminal movements with directions
Note: The code states that the design temperature shall be assumed to be the same as fluid temperature unless calculations or test supports the use of other data.