Thermo Coupled Structural & Modal Analysis of a Horizontal Pressure Vessel with using ANSYS Workbench

• Objectives: To Simulate Pressure Vessel for Thermo Coupled Structural & Modal Analysis

• Geometrical Design:

We have an ASME Standard Dimensions of a Pressure Vessel so we made its 3D Model using Autodesk Inventor. Here are the Dimensions of the Pressure Vessel.

This is the 3D Model of Pressure Vessel.

• Problem Statement:

• An ASME Standard Pressure Vessel will be applied with 100 C Fluid Temperatures and 2 Mpa Pressure.
• We will look for FEA for this so we will not consider fluid in the tank but we will provide its physical properties to check how the material behaves.
• 4 Different Materials will be used for this analysis all the loading and boundary conditions will be the same only Material will change.
• An analysis is carried out in Thermo Coupled Structural Analysis.
• In the first phase, PV will be applied with Temperature and then that load will be transferred to the structural deck, and pressure will be applied.
• We will observe various parameters such as Deformation, Stress, and Strain. In the end, we will transfer loads to Modal analysis to observe various modes of failure due to Vibration.

• Material Properties:

For this analysis, 4 Different Kinds of Materials are used for Pressure Vessel, Have a Look at the Mechanical Properties of Materials.

• Types of Analysis to Be Performed:

Thermal Analysis: PV will be applied with Temp and Convection Coefficient; Results will be imported to Structural Analysis.

Structural Analysis: Imported Body Temperature, Pressure, and Standard Earth Gravity will be applied to check Deformation, von misses Stress and Strain

Modal Analysis: Structural Steel Model deck will be transferred to Modal analysis to check various modes of failure.

• Mesh Criterion:

Type Of Elements: Tetrahedrons

Mesh Method: Patch Conforming Method

Size of Elements: 100 mm

1) Mesh Model:

2) Mesh Quality Checks:

A) Element Quality:

B) Jacobian Ratio:

C) Mesh Metric:

• Symmetry Region:

For this analysis we will use only half a portion of the Pressure Vessel Model, It will lead to less computational time.

The Geometry is Imported in Design Modeler, and using the Slice tool model is cut down in two halves.

• Thermal Analysis:

• In First Phase Pressure Vessel Body is applied with 100 0C Temperature in the inner side.
• With this constraint, one more constraint is applied to the PV body.
• Convection Coefficient is applied at an outer portion of the body with 5e-006 W/mm2 0C
• Body is to assumed to be resting in the open air.

1) Body Temperature:

2) Convection:

• Results (Thermal)
• Analysis carried out with the boundary conditions shown before.
• Due to Convection, there is a distribution of temperature all over the body.
• Different Values of temperatures found for different materials.
• For results, we have observed Temperature Distribution and Heat Flux.
• The Results then exported to structural analysis deck.

1) Temperature

2) Heat Flux

• Structural Analysis

• Once phase one gets completed, Body Temperatures from the thermal analysis will be imported.
• With Imported results, as per our problem statement, 2 Mpa pressure will be applied to pressure vessel
• As we have mentioned earlier we will be using 4 different materials for this project.
• We will add materials one by one and will observe the results. Standard Earth Gravity is applied in Negative Y Direction.
• Bottom Support Legs are made fixed from bottom, The entire nozzle end surface also kept as fixed. Large Deflection is kept on for this analysis.
• Auto Time stepping to program default.
• The step end time is taken as 1 sec.
• All other parameters kept default.

1) Imported Body Temperatures

2) Pressure

3) Standard Earth Gravity

4) Fixed Support

Results (Structural):

1) TD

2) ES

3) EES

Post Process Results Summary;

• Modal Analysis for Case 1
• Thermo Structural Analysis performed for first case.
• The results we obtained from this simulation
• These results are now exported for Modal Analysis.
• Modal Analysis is used to check the frequencies at which a model can vibrate.
• Modal deck is connected with Structural Deck.
• Total 6 Mods of Vibration Observed.
• For this analysis we have taken only case 1 for consideration.

• Modal Results:

Video Section:

• Full Project Step by Step 

Thermo Coupled Structural Analysis of a Horizontal Pressure Vessel || ANSYS Workbench

• Results

Pressure Vessel FEA || Results || ANSYS Workbench

Conclusions:

• Analysis is carried out in 3 Phases, Thermal Structural, and Modal.
• Total Deformation value is maximum in Aluminum Alloy
• Equivalent Stress value is max in Structural Steel
• Equivalent Elastic Strain is max in Aluminum Alloy.
• Structural Steel, Aluminum and Nickel Alloy Materials shows similar material properties so obtained values of deformation stress and strain are similar.
• This pressure vessel is analyzed for 2 Mpa pressure at 100 0C Temperature, but it can be analyzed for further more values.
• After Modal analysis is done, the values of Effective Mass is observed.
• Modal analysis is carried out to obtain values for natural frequencies, which can be used for the stability of a component.
• Vibration due to load will have an impact on the structure, so external dampers can be used to reduce the vibrations.
• The purpose of this analysis was to observe values of stress-strain, deformation, and modal frequencies.