As the fabricators are responsible for the design of pressure vessel, they had to validated their design. The validation can be performed either by calculations or FEA evaluation
- ASME BPVC Section VIII, Division 1 – Design by Rule
- ASME BPVC Section VIII, Division 2 – Design by Analysis
ASME BPVC Section VIII, Division 1 – Design by Rule
This incorporates the methodology to perform the validation through analytic calculation to evaluate the adequate requirements of the pressure vessels like – Shell thickness, Nozzle requirements, RF pad requirements etc. They are applicable to chemical reactors, accumulator tanks, autoclaves, chemical adsorption vessels, heat exchangers, vacuum chambers etc.
ASME BPVC Section VIII, Division 2 – Design by Analysis
When the geometry or the load become complex and tedeous to handle or to evaluate the stress propagation and distribution on the pressure vessel, we shall use Division 2. In this method, the pressure vessel is validated through FEA codes and tools for combinations of load conditions to quantify the structural integrity of the vessel and adequacy of material and strength in all regions of the vessel.
As a part of Heavy engineering services, Graphler has an extensive experience in Pressure vessel analysis services and Storage tanks to validate through the FEA services to quantify the parameters meet out the requirements as per Design by analysis.
How Pressure vessel analyses shold be precessed for analyses
CAD Conversion/Development and Simplification:
From the drawings provided by the fabricator, the 2D CAD to 3D CAD conversion are made with the elements which are required for the analysis and other miscellaneous elements are excluded. Complex geometrical features are simplified and debugged for better mesh strategies.
FE Meshing:
On completion of geometry simplification, the type of mesh – Solid or Shell, stategy of meshing and Quality parameters are set to get the best results. Through experience and specialization, the parameters are set based on the stress gradient, load path, structural discontinuity and shell to size factors. The process are architected for best result accuracy and precision in various load cases
Boundary Conditions :
The constraints and loadings shall be provided based on the Load cases such that no peak stresses, singularities and over constraint the vessel.
Load cases and Analyses :
The Pressure vessels are evaluated for various combinations of loads based on the operation, location and safety parameters. Some of the load cases are as follows
- Internal Pressure
- External Pressure
- Temperature
- Thermal Shock Loads
- Mechanical Shock Loads (Impact, deflagration)
- Acceleration (Transport – Sea, Road or Air)
- Vibration Load
- Seismic vibration (Earthquake)
- Wind Load
- Cyclic Loads
- Lifting
Based on the requirements and pressure vessel type and analyses, one of the following methodology is abided to validate the structural integrity of the pressure vessel
- Elastic stress Analysis Method
- Elastic-plastic Analysis Method
- Limit load Analysis Method
Evaluation of Results & Documentation :
On Completion of the analyses , the results of displacement, stress, strain, mode and Temperature are extracted and the are interpreted anc compared with the acceptance creteria of ASME Section VIIN division 2. Through stress linearization method the stresses are compared in case of elestic stress method.
The results and plots are documented as per the requesites of ASME process for assesments.
3D model Detailing & Fabrication Drawings:
On completion of the analysis the necessary changes are made and detailed 3D model are developed with all structural accessories and additional equipments. Then 2D fabrication drawings are generated as per the fabricator’s format and delivered.
We at, Graphler Technology Solutions provide expert FEA services- Pressure Vessel Analysis Services, CAD Conversion Services with engineering prospects and quality. With our expertise in Structural analysis, CFD analyses , Product design and development and Product Animation Services – we offer the best solutions to build, develop and optimize the products.
