Introduction

Finite element method is a numerical method for solving problems of engineering and

mathematical physics. Typical problem areas of interest in engineering and mathematical physics

that are solvable by use of the finite element method include structural analysis, heat transfer,

fluid flow, mass transport, and electromagnetic potential.

For problems involving with complicated geometries, loadings, and material

properties, it is generally not possible to obtain analytical mathematical solutions. Hence, we

need to rely on numerical methods, such finite element method, for applicable solutions. In finite

element method, instead of solving for entire body in one operation, we formulate the equations

for each finite element and combine to obtain the solution of the whole body. FEA consists of a

computer model of a material or design that is stressed and analyzed for specific results. It is

used in new product design, and existing product refinement.

Briefly, the solution for structural problems typically refers to determining the

displacements at each at each node and the stresses within each element making up the structure

that is subjected to applied loads.

In this project, I am going to identify and discuss about the finite element method by

using ANSYS method by importing file of the object that has been draw in CATIA software.

The object’s name is Support object, to support some part in Machine part. For the material use

is Aluminum.

Objectives of the project

- To familiar with the import and export file from CATIA to ANSYS

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- To understand how to identify the stress by using Ansys Method

- To know the general steps used in the finite element method.

- To know the various types of elements used in finite element method.

- To summarize some advantages of the finite element method.

DISCUSSION AND ANALYSIS

In this project, the object can be used any type of CAD software that you are familiar

with, ether in SOLID work, Alibree , AutoCad, Catia and so on. The important is that, in other

to import a file from this kind of software to Ansys, you have to save it into stp file.

1. The following object has been draw by using CATIA software.

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The figure 1. Draw by using CATIA software

2. Save the object in figure 1 to stp file then import to Ansys workbench. Select file,

import, chose file that you want to import, select Geometry, choose millimeter, and

generate.

Figure 2. use ansys workbench method

3.Export file from an Ansys workbench method and save it as parasolid tex.

4. Use Mechanical APDL 14.5 Import file that has been save by select import, Parasolid file,

select, ok.

Figure 3. after import file

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5. Select Preprocessors, Add element , solid , 10node 187, apply.

6. Material Property (Aluminum E= 95E9)

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7. Meshing, mash tool, choose smart size, (I am choosing 4 only ) then pick the point that you want (Volume), apply , ok

Figure 4. after mashing volume

8. Solution

Next, we set up an analysis, define displacements and loadings, and solve the

problem.

Click define load , ‘Displacement’, then ‘On Area’. Pick up the location that we

want to fix. (I chose fix point at the four holes at the lower part), apply, choose ALL

DOF to be constrained, then enter 0 into the displacement value box.

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9. Apply pressure in to the top of the work pieces (on area) with the value of Pressure 104.2E6, then solve

Figure 5. apply pressure value.

Figure 6. the read colure indicates the pressure that we have applied and solved

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Figure 7. Deformed and unreformed solution

Figure 8. von Mises stress plot for a solid part subjected to pressure 104.2E6Pa

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Material use Is Aluminum

E= 95E9MPA

σmax = 37.8E6Mpa

σy = 95E6Mpa

From the result above, indicates that the safety factor is not really good. We need to redesign our

part. In this new design, I delete the fillets that have applied on four edges at the top of the part.

The below figure is the news part design.

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By giving the same pressure to news design the value of stress will reduce as show in figure below:

von Mises stress plot for a solid part subjected to pressure 104.2E6Pa

As a result, the safety factor will be obtained as we want.

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To summary, there are many advantages of finite element method, such as it has been

applied to numerous problems, both structural and nonstructural. This method has a number of

advantages that have made it very popular. They include the ability to

1. Model irregularly shaped bodies quite easily

2. Handle general load conditions without difficulty

3. Model bodies composed of several different materials because the element equations are

evaluated individually

4. Handle unlimited numbers and kinds of boundary conditions

5. Vary the size of the elements to make it possible to use small element where necessary

6. Alter the finite element model relatively easily and cheaply

7. Include dynamic effects

8. Handle nonlinear behavior existing with large deformations and nonlinear materials

References:

1. First course in the finite element method Fourth Edition by Daryl L. Logan2. First course in the finite element method Fifth Edition by Daryl L. Logan

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