How to calculate stress in FEA of regulating valves

The regulating valve is a key actuating element in industrial fluid control systems, widely used in industries such as oil, chemicals, and electricity. During its operation, components such as the valve body, cover, and core often bear complex loads, such as internal pressure, temperature stress, and fluid impact. To ensure the safe and reliable operation of the regulating valve under various working conditions, it is necessary to perform strength analysis on its key components. Finite Element Analysis (FEA), as an efficient numerical simulation method, has become an indispensable tool in modern engineering design.

FEA (Finite Element Analysis) evaluates the mechanical properties of the structure by discretizing the complex structure into a large number of simple elements, establishing a mathematical model, and solving the displacement, strain, and stress of each node, thus assessing the mechanical properties of the structure. In the design of regulating valves, the application of FEA for stress calculation mainly includes the following steps:

1. Establish Geometric Model
Firstly, according to the actual structural drawing of the regulating valve, build a three-dimensional geometric model in CAD software. The model should include key components such as the valve body, valve seat, valve core, and valve rod, and consider the sealing structure and connecting flange if necessary.

2. Mesh Generation
Divide the geometric model into a finite number of elements to form a finite element mesh. The mesh density should be locally refined in the stress concentration areas (such as the valve passage diameter change area, the contact area between the valve core and the valve seat) to improve the calculation accuracy.

3. Material Property Definition
Input the corresponding material parameters such as elastic modulus, Poisson's ratio, yield strength, and density according to the material of different components (such as cast steel, stainless steel, cast iron, etc.).

4. Load and Boundary Condition Setting
Apply appropriate boundary conditions and loads according to the actual working conditions:

- Pressure load: such as the pressure on the internal surface of the valve body by the medium;
- Thermal load: such as temperature difference stress caused by high-temperature fluids;
- Mechanical load: such as the torque or thrust transmitted by the valve rod;
- Constraint conditions: such as fixed supports at the flange connection.

5. Solution and Calculation
Use FEA solvers (such as ANSYS, ABAQUS, SolidWorks Simulation, etc.) for calculations to obtain the displacement, strain, and principal stress distribution of each node.

6. Result Analysis and Verification
Analyze the calculation results, focusing on the maximum stress value in the stress concentration areas, and compare it with the allowable stress of the material to judge whether the structure meets the strength requirements. Usually, it is evaluated according to relevant standards such as ASME, GB, or EN.

7. Optimize Design
If some areas have excessive stress or structural redundancy, optimization and re-analysis can be carried out by modifying the geometric shape, adjusting the wall thickness, or replacing materials and other methods.

Summary
The use of FEA technology for stress calculation of regulating valves not only improves the accuracy and efficiency of design but also effectively reduces the cost of testing and development cycle. With the development of computer technology, FEA has become an important means for structural strength analysis of regulating valves, providing a solid guarantee for the safety and reliability of valve products. In the future, combined with advanced technologies such as multi-physical field coupling analysis and topology optimization, FEA will play a more extensive role in the design of regulating valves.