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Step 6: Results

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Let first look at Total Deformation. Under Solution (A6), click on Total Deformation. The Total Deformation plot is then shown in the Graphics window.

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You can also animate the deformation by clicking play button right under Graphics window.

Bending Stress

Now let's look at the stress on  the beam. Let's expand Beam Tools and click on Direct Stress.

https://confluence.cornell.edu/download/attachments/112041751/Direct%20Stress.png

The direct stress is the stress component due to axial load encountered by the beam element. Since there is not axial load, we expect a direct stress of zero value throughout the beam.
 
Next let's look at the  Maximum Bending Stress of the beam. Click onMaximum on Maximum Combined Stress.
Image Added
 

https://confluence.cornell.edu/download/attachments/112041751112041761/Direct%20StressMaximum%20Bending%20Stress.png

Maximum Combined Stress is combination of direct stress and maximum bending stress. Since we have pure bending problem, the maximum combined stress will be the maximum bending stress. 
We expect a pure bending stress in the central region between the two applied forces. The stress is tensile on the bottom surface and compressive on the top surface as expected. Elementary beam theory predicts the bending stress as σ_xx =My/I. Here

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For this geometry, we expect the neutral axis to be at y =h/2 =0.025 m. So the max value of σ_xx= M*(h/2)/I = 9.6e5 Pa. This is reasonably close exact solution to both the maximum value of tensile and compressive stresses from the computational solution. We have a relatively stubby beam; the agreement with beam theory should improve as the length/height ratio of the beam is increased. Also, the FEA solution perhaps can be made more accurate by refining the mesh. This is left as an exercise to the reader.

Force Reaction, Moment Reaction

If we click on the Force Reaction, we see that the force reaction at point A and B is 4000, which is what we are expecting. The moment reaction at A and B is also zero, as expectedNote: We see stress concentration appears around the region of the point force and point displacement. A force and displacement applied to a vertex is not realistic and loads to singular stresses (that is , stresses that approach infinity near the loaded vertex). We should disregard stress values in the vicinity of the loaded points.

Go to Step 7: Verification & Validation

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