# Final Report Finite Element Methode Chair ```FINAL REPORT
FINITE ELEMENT METHOD
CHAIR ANALYSIS
CATIA V5 AND ANSYS 18
Presented to
Lecture:
Dr.Eng. Azhari Sastranegara, B. Eng., M. Eng.
Sudent:
Ririn Handayani
003201700008
President University
December 31st 2019
Abstract
Chairs are a tool that we always meet in our activities every day. We will
find seat even we will always use the chairs to perform daily activities. The
average person uses chairs approximately 2-3 times per day. In the community
there are many kinds of chairs ranging from many materials. Now days most
people tend to prepare use chair that has enough strength, material that mind is
structural steel for applying material in the chair that we analyzed in ANSYS 18,
with reference maximum weight 120 kg, safety factor 1 and confortable to use
based on 3D design using Catia V5 with price estimation could not over to \$100,
beside the design with agronomical aspect and drawing of design result simulation
of analysis and the model to projection view. Thus this is one of the applications
of finite element method in objects in daily life to the chair.
Keywords: Finite Element Method, Design, Analysis.
Introduction
FEM standard for Finite Element Method, the most basic concept of FEM
is solving a problem is by dividing the object of analysis into finite small parts.
Finite Element is one of the numerical methods that utilize matrix operations to
solve physical problems. Another method is the analytical method, which requires
a mathematical equation that is a model of physical behavior. The more complex
physical behavior (due to the complexity of geometric shapes, the number of load
intersections, constrains, material, properties, etc.) the more difficult or even
impossible to build a mathematical model that can represent the problem, an
alternative method is to divide the case into small simple parts which in this small
part we can build a simpler mathematical model. Then the interaction between
these small parts is determined based on physical phenomena to be resolved. This
method is known as the finite element method, because we divide the problem
into a number of specific elements (finite) to represent the problem that the actual
number of elements in infinite (Continuum).
Analysis Purpose
1. Make a chair design using Catia V5 based on agronomical chair
2. Simulates the state of the chair and it is characteristic with some
assumptions.
3. Make an analysis using Ansys 18 of the characteristic of the chair with
applied structural steel as a material.
4. To find out the strength of the chair before the actual manufacturing stage
and by providing price assumptions.
5. Make drafting of the projection view to find out the point and location of
Research Methodology
In doing this analysis, we need to combine the type of application system
between Catia V5 and ANSYS 18, where the design and chair modeling stages are
carried out in Catia V5 while the analysis and calculation are done at ANSYS 18,
so the final results will be presented in this study. However, we can describe the
steps taken in conducting research and analysis of the chair that we expect as
below.
1. Chair Design using Catia V5.
In this case we using part design to make the model of the chair from 2
dimensions, then make workbench to make 3D part. However, the result of design
also the part of step model in Catia V5 can show below.
Form the figure the chair type that used for hair style seat, then in accordance
with aspect of agronomic for hair style seat. Where the plane that we have been
applying several plane to made for every part. Moreover, continue to next step for
analysis the design that have made it is ANSYS 18.
2. Analysis design use ANSYS 18.
To apply the design from other application to ANSYS 18, need to convert
system to alter with the analysis part command in ANSYS 18. The way that
applied is save as the design for Catia V5 and change the folder type from it is
STP file, then it can apply to the ANSYS 18.
Furthermore, the step to do the analysis for the chair, firstly we need to
know how to operate the command in ANSYS 18. Moreover, the step will
describe below.
a. ANSYS 18 Command Apply
For the first step after apply the design from Catia V5 we need to import the data
design that we made, then choose Static Structural and Geometry to import the
data and assume some material that we want to apply fro the chair.
b. Apply material for ANSYS 18
In this section we need to open the Engineering Data to apply the material for the
chair. However, the material that we input is Structural steel based on
www.mcmaster.com as a reference for the material, and the material has 1” (inch)
has \$6.95 then we can apply the material with the base of the chair around 7 part
from the material that we used. Then the total is 7x6.24 is \$ 43.68 + seat \$28 =
\$71.68 chair price, then we can conclude the price is lower then \$100.
Furthermore, show the ANSYS system for material apply.
The data material that had applied for the analysis chair is become of reference to
find the meshing for deformation stress, equivalent elastic and also for the
equivalent stress include tool stress for the safety factor to find the result for the
chair before applied to the chair before to the reality.
c. Model and Static Structural
Simulate All the model and static structural aspects of your product. Conduct with
linear static analyses that reveal stresses or deformations, modal analyses that
determine vibration characteristics, and advanced transient nonlinear studies that
focus on dynamic effects and complex behaviors. For the chair analysis cn show
for the model result after converting from Catia V5.
-
Model ANSYS 18 for chair
(Geometry Model)
After the model checked for the meshing of the chair model.
(Mesh of the Model chair)
Meshing is defined as the process of dividing the whole component into a
number of elements so that whenever the load is applied on the component it
distributes the load uniformly called as meshing.
-
Static Structural
Static structural used to make Fixed Support and Force for the object that we
analysis.
(Fixed Support)
Fixed supports can resist vertical and horizontal forces as well as a
moment. Since they restrain both rotation and translation, they are also known as
rigid supports. This means that a structure only needs one fixed support in order to
be stable.
(Force)
The force that would be needed to cause the bolt to displace to get a loaddisplacement curve from ANSYS 18.
d. Solutions for the Chair Analysis
-
Total Deformation Von Mises
However, we can find the total deformation of the chair from the data input from
the material input with yield strength 1, 2 pa for the structural steel and young
modulus 2E+11 pa to input to the formula. Then the result in ANSYS 18.
From the analysis we can obtain the result that we found it is 76555.7 mm or
0,750-4 Mpa, comparing to the yield strength this is more rigid material
-
Equivalent Von Misses Elastic Strain
It is supposed that strain energy w at a per-unit volume is a function of
total equivalent strain. Equivalent choices may be made for the expression of
a strain field depending on whether in the case of elastic deformation the response
function linking strain to the deforming stress is the compliance tensor of the
material. Then the formula and result from ANSYS show below.
From that figure that we made in ANSYS 18 it will show the Von Misses of
the equivalent elastic strain is 3,036 Mpa, then we can see that more than young
modulus that we used.
-
Equivalent Stress
Von Misses stress is a value used to determine if a given material will yield or
fracture. It is mostly used for ductile materials, such as metals. It same with elastic
formula to assume the value. Then calculating and simulate in ANSYS 18.
From that figure that we made in ANSYS 18 it will show the Von Misses of
the equivalent stress is 55387 Mpa then we can see that more than young modulus
that we used.
-
Tool Stress or Safety Factor
In engineering, a factor of safety, also known as safety factor, expresses how
much stronger a system is than it needs to be for an intended load.
For the reference of FOS (Factor of Safety)
From the safety factor reference we can conclude the material of structural steel
that we have use is around 4-6. But on that case in ANSYS we see the result is
around 0,451357 KN/mm2 then in 4,051357 Mpa. Then is quite near with the
reference material factor of safety.
Conclusion
In the results that have been achieved we can conclude there are some challenges
in the results of converting from two different applications where the desired
results do not match properly. However, in this convert process the authors
continue to strive to provide the best calculation of some formulas used so that
the results of the analysis of deformation, strain and stress can be read properly. in
this case the safety of this chair reaches 4 where it is adjusted with the FOS
reference which is 4-6, but basically this depends on the material used, due to the
use of structural steel so the results are so. The use of structural steel material is as
an estimated cost of sales for this chair so we get a sales fee of \$ 71.68 and this is
considered quite cheap because it is under \$ 100. This proves the benefits of using
analytical design applications on objects that are often encountered in everyday
life.
APPENDIX
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