structural analysis of Ibeam subjected to Uniform varying load, Includes the step by step procedure for analysis.

1. INTRODUCTION:
I-beam consists of 2 horizontal planes, known as the flanges, connected by one vertical
component or the web. The shape of the flanges and the web create I or H cross section. Most
I beams use structural steel but some do use aluminium. They have a wide range of
application such as building framing, bridges and general structural purposes.
Builder needs to consider the following:
 Deflection: Thickness to minimize the deformation of the beam.
 Vibration: A certain mass and stiffness are selected to present vibrations in the
building.
 Bend: The strength of the I beam’s cross section should yield stress.
 Buckling: The flanges are chosen to present buckling locally, sideways or torsionally.
 Tension: The builder chooses an I-beam with a web thickness that won’t fail, buckle,
and ripple under tension.
I-beams are the choice shape for structural steel builds because of their high functionality.
The shape of I beams makes them excellent for unidirectional bending parallel to the web.
I-beam structures.
The structural analysis on Ansys is started with the engineering data sources. General
nonlinear methods is selected and structural steel Nonlinear is selected.
A nonlinear analysis is where nonlinear relation holds between applied forces and
displacement. Nonlinear effects can originate from geometrical non linearity’s and contact.
These effects results in stiffness matrix which is not constant during the load application.
The yield strength of structural steel is 250Mpa and the tangent modulus is 1450 Mpa.
ANALYSIS OF AN I BEAM SUBJECTED
TO UNIFORM VARYING LOAD

2. Selection of materials and type of analysis
Geometry:
I-beam W4x4 from is taken as the component for analysis.
I-beam details
In the design modeller, I section is selected and the values for the I-beam are plugged into
from and the sketch is extruded to 500mm and is chamfered at the 4 edges.
 Chamfering provides external strength to external corners (removes stress
concentration)
 Applied to the outer edges to break the corner.ie remove sharp edges which may hurt
the person handling it.

3. Extruded image of the I-beam
Modelling:
Here the material of the I-beam is assigned as structural steel nonlinear.
Meshing:
Fine meshing is selected, element size is defined to be 5 mm and mesh is generated. Since
the case is loading and unloading, the number of steps is selected to be 2. Time stepping is
selected to ‘ON’. Initial sub steps, minimum sub steps are assigned to 30, Maximum sub
steps is chosen to be 100. Large deflection is selected to ON.
Mesh with 12600 elements and fine face meshing

4. Mesh parameters
The reason why sub step is considered is to understand the plastic deformation better. These
sub steps will breakdown the load even more. For plastic deformation, large deflection is
preferred.
Boundary conditions:
Fixed support is inserted at one end of the beam. Pressure is inserted on the top face of the
beam. Magnitude for this selected as tabular as it is uniformly distributed. The tables are
corrected for time values of different loading and unloading conditions. 4Mpa is selected at
interval 2, and is distributed along Z axis for interval 0,1 and 2 .

5. Boundary conditions applied to the I-beam
This model is then run for force convergence, it took a long time and created a huge file.
Convergence value is less than criterion value, which suggests a right result.
Force Convergence Value:
This is the unbalanced "error" force that is a result of the changing stiffness of the model
caused by either geometric, material or contact nonlinearities. The residual is the difference
between the applied load and the summation of internal forces of the equilibrium
iteration. The program calculates this automatically with no user input required. Tracking
rate of change in residual vs. changes in solution settings is an excellent way of optimizing
solution efficiency.

6. Results:
Stress is inserted to be equivalent to equivalent von Moises. Strain is selected to be equivalent
total. They are then evaluated.
Von Moises stresses on the I-beam, 314.61 being maximum stress which is more than yield stress,
therefore there is deformation in the I-beam.
Stresses are seen mostly in the fixed end and the free end is free from all the stresses.

7. Total strain is seen highest on the edges of the fixed end and seen least in the point farthest from the fixed
end.
Stress vs time graph for the loading and the unloading cycle, at <250 Mpa is beam is seen to fail which is
true due to the fact that 250 Mpa is the yield strength.

8. Strain vs time graph, the beam shows significant deformation from time 0.8sec and at unloading
condition the strain seems to reduce by a small amount.
Graph between stress and strain for loading and unloading condition

9. Summary of all the results
A mesh node is created to find the maximum and the minimum stress and strain at a given
point.The 2 values are selected and plot is generated between the maximum strain and the
maximum stress. All the other values such as time are omitted in the plot parameters.
Challenges in doing the mini project:
 Since the allocated disk space is low, most of the Ansys files crash before saving. I
had to use a hard disk to save all my data.
 Creating a uniform distributed load was a difficult task that needed some research.
Object Name Equivalent Stress
Equivalent Total
Strain
Equivalent Stress 2
Equivalent Total Strain
2
State Solved
Scope
Scoping Method Geometry Selection
Geometry All Bodies 1 Node
Definition
Type
Equivalent (von-Mises)
Stress
Equivalent Total
Strain
Equivalent (von-Mises)
Stress
Equivalent Total Strain
By Time
Display Time Last
Calculate Time History Yes
Identifier
Suppressed No
Integration Point Results
Display Option Averaged
Average Across
Bodies
No
Results
Minimum 1.0493e-004 MPa 7.2653e-010 mm/mm 30.737 MPa 5.6156e-002 mm/mm
Maximum 314.61 MPa 0.12072 mm/mm 30.737 MPa 5.6156e-002 mm/mm
Minimum Occurs On Solid
Maximum Occurs On Solid
Minimum Value Over Time
Minimum 1.0493e-004 MPa 7.2653e-010 mm/mm 11.648 MPa 5.8242e-005 mm/mm
Maximum 2.9884e-002 MPa 2.507e-007 mm/mm 331.86 MPa 5.7662e-002 mm/mm
Maximum Value Over Time
Minimum 21.721 MPa 1.086e-004 mm/mm 11.648 MPa 5.8242e-005 mm/mm
Maximum 424.66 MPa 0.12216 mm/mm 331.86 MPa 5.7662e-002 mm/mm
Information
Time 2. s
Load Step 2
Substep 4
Iteration Number 64

10. Further work:
With more computational cost time, an increased mesh will better the existing results and
also increased loading and unloading time steps could better the result. Meshing using
different shapes can be experimented to see the results.
References:
1. https://caeai.com/blog/stress-analysis-convergence-tips-dummies
2. http://www.soscoqatar.net/productdisplay.aspx?cid=5
3. http://www.padtinc.com/blog/the-focus/to-use-large-deflection-or-not-that-is-the-
question
4. https://www.femto.eu/stories/linear-non-linear-analysis-explained/
5. https://blog.swantonweld.com/i-beams-in-structural-steel-construction