Structural Analysis of a Truss Using ANSYS Workbench

 Trusses are widely used in structural engineering due to their ability to efficiently distribute loads while maintaining a lightweight design. These structures are commonly found in bridges, towers, and roofs, where stability and strength are critical.

In this blog, we will analyze a truss system using ANSYS Workbench, a powerful Finite Element Analysis (FEA) tool. We will define the material properties, apply boundary conditions, and simulate the structural behavior of the truss under given loads. By following this step-by-step process, you will gain a clear understanding of how to use ANSYS Workbench for truss analysis.

The following entities are gonna find in this blog namely Stress, Total deformation, Total bending moment.

Step 1 : Assign the required material and create a geometry

            To solve problems related to beams and trusses open the workbench and choose static structural analysis . If you want to assign a new material with the required properties , open up the engineering data option which will shown on the screen once you double clicked static structural. Here, I am not gonna change the material which is not necessary for my use and am going to leave this area and jump to geometry. If you do not assign any material and its property , a random material is chosen named structural steel though we are working on structural analysis.

            You can create your own geometry or you can import from other software like Solid works , Mechanical APDL etc.. by saving the imported geometry in the form of .step , .iges , .sldprt , etc...

In this blog , I create my own geometry with the required dimensions that was mentioned in it.

 Once you created the geometry we should assign cross section and i chose a circular section because it has high strength to weight ratio , better resistance to Buckling , Uniform load distribution etc...

Then move on to the mechanical modal where assigning the boundary conditions and bringing up the results were done .

Once you open up the mechanical modal the first step is meshing . Before that what is meshing ? why we want to mesh? Why can't we solve problems without mesh? So there are many questions that can come across so let me give you a single solution . Meshing is a process of dividing a complex geometry into a simpler one i.e., we can't solve the problem by taking the whole problem into a single one instead we can split up into multiple ones and we can solve each and every element . That's why we call nodes and elements . These two parameters are important in Finite Element Analysis (FEA). By solving into each and every element it enhances accuracy, reduces computation time etc..

So once you open mechanical modal the first step is to generate mesh . Once you generated mesh, then assign the boundary conditions.

The above image shows the first boundary condition that the fixed support that is located in the left bottom of the truss . If you are new to Workbench and do not know how to assign boundary conditions , let me guide you . Right click on the static structural → Insert →Fixed Support , since it has fixed end on one side.

These two image shows two different conditions and it implies a roller support . Since we can't assign roller support directly and by choosing both Displacement and Fixed rotation we can assign it indirectly. If you see the image in displacement i chose only x-direction to move freely and i have locked both y and z directions because in roller support the roller can move only in positive x-direction or negative x-direction and there is no possible to move towards y or z directions. So I arrested both directions by assigning zero newtons to each.

And the second image represents the fixed rotation and we have arrested all three directions to ensure that the roller shouldn't rotate in any axis and our only intention is to fulfill the performance of roller support. Once assigning these two conditions we can perform on roller support in workbench.

The next step assign the forces that acts on the truss by right clicking on static structural → Insert →Force. 

                                       

                                    

Choose the required location that the force acts on the truss. In the side bar , choose the negative y direction so that the force acts towards downward.

After assigning all the boundary conditions , select the required solution by right clicking on Solution →Insert →Deformation , Beam tool(stress) etc.. according to our requirements. 

                              

Once you assigned all the required solutions click on the Solve button which is in the Home bar in the top screen to calculate the results. 

This takes some time to solve and it solves we can define the answer. Once it was completed, we can go through the results.

Deformation

Maximum Deformation (🔴 - Red Zone)

• The highest deformation is 3.0932e-7 m (0.309 µm), which occurs at the middle diagonal members of the truss.
• These members experience the most displacement, indicating they are under the highest bending or axial stresses.

Minimum Deformation (🔵 - Blue Zone)

• The lowest deformation is 0 m, seen at the fixed support on the left side.
• This means the constraints are correctly applied, preventing movement at the support.

Color Distribution Analysis

• The outermost top members show moderate deformation, transitioning from green to yellow, suggesting they undergo some bending.
• The bottom members remain relatively stable, meaning they mostly experience tension or compression rather than bending.

Stress

Maximum Stress (🔴 - Red Zone)

• The highest stress is +2642.4 Pa, which occurs at one of the diagonal members near the middle joint.
• This suggests that this member is experiencing the highest tensile force (pulling apart).

Minimum Stress (🔵 - Blue Zone)

• The lowest stress is -3394.7 Pa, located at the leftmost diagonal member.
• Negative stress indicates compression, meaning this member is being pushed inward.

Stress Distribution Analysis

• The top horizontal members are experiencing mild stress (mostly green/yellow), meaning they act as stabilizing elements.
• The bottom members show a mix of compression and tension, which aligns with typical truss behavior.
• The diagonal members are under the highest stress, playing a crucial role in load transfer.

Bending Moment

Maximum Bending Moment (🔴 - Red Zone)

• The highest bending moment is 1.5183 N·m, which occurs at the rightmost inclined member.
• This suggests that this member experiences the most significant bending forces, possibly due to an uneven load distribution.

Minimum Bending Moment (🔵 - Blue Zone)

• The lowest bending moment is 0.0028336 N·m, found at the left support region.
• This indicates that the support effectively resists bending forces.

Bending Moment Distribution Analysis

• The top and bottom horizontal members show relatively low bending moments, confirming that they mainly resist axial forces.
• The diagonal members experience moderate bending, indicating structural load transfer across the truss.
• The rightmost inclined member is under the highest bending moment, meaning it could be a potential weak point in the design.

Conclusion :

                *The truss structure is efficient in load distribution, but slight modifications in member thickness or material selection may improve its strength.

                *The stress and deformation values indicate that the truss is structurally sound under the given loading conditions.

                *Further optimization can be done by refining the design, changing the boundary conditions, or using a different cross-section.