We Have Numbers Of Free Samples

Table of Content

1. Specifications of Client for Bracket
2. Constraints Applied to FEA Model
3. Load Application
4. Material Properties
5. Analysis Results
6. Result Discussion
7. Modified Bracket Model
8. Analysis Results for Modified Model
9. Comparison of Specifications and Modified Design of Bracket
10. References

List of Figures

• Fig-1 Bracket
• Fig-2 Meshed Geometry
• Fig-3 Bracket Fixed Support
• Fig-4 Force Application
• Fig-5 Total Deformation of Bracket
• Fig-6 Equivalent (Von-Mises) Stress
• Fig-7 1st Frequency
• Fig-8 Meshed New Geometry
• Fig-9 Total Deformation of modified Bracket
• Fig-10 Equivalent (Von-Mises) Stress
• Fig-11 1st Frequency of Modified Model

List of Tables

• Table-1 Client’s Specifications
• Table-2 Analysis Result
• Table-3 Analysis Result for modified design
• Table-4 Weight Comparison

1. Specifications of Client for Bracket

There are so many designs to prepare full assembly of automotive parts. Thousands of parts are used in automotive assembly. Here a bracket made of aluminum material by casting process is taken for the design and analysis process. It is used as a mounting bracket in front wheel drive passenger cars.

In mass production or high volume manufacturing every new design aspect needs to be evaluated for stresses and vibration. If we simulate the stress and vibration from the result we can optimize the design for material, weight and etc. which can provide the benefit in cost of product.

Fig-1: Bracket

But design needs to withstand the allowable stress and vibration condition without any failure. Finite element modelling is processed on the bracket for initial design state and ensured to the design criteria of client as shown in table-1:

Table-1 Client’s Specifications

Client also requires technical report, analysis in detail, statement of possibility for design under given specifications and recommendation how to improve the design and reduce its weight. If there is any improvement, it should be taken into account that part is made from mould casting.

2. Constraints Applied to FEA Model

For finite element analysis simulation there are some concepts to understand:

• Meshing or discretization

  The model is converted in the small element size. The reason for the partition in small elements is that the partial differential equations can be easily solved for the geometry analysis. Meshing type depends on the type of analysis and geometry conditions and also quality of meshing and sizing.

  

  Fig-2: Meshed Geometry

From the figure-2 we can see the meshing of bracket geometry in small parts.

Number of elements: 52498
Number of nodes: 202516

For high quality analysis element and orthogonal quality must be > 0.75 otherwise it will be considered as low quality mesh. And low quality mesh is not good result.

• Constraints

  First of all, we need to define the constraints that provide the original degree of freedom of the object. Two holes are fixed constraints as after bolting they don’t have any degree of freedom for movement.

  

  Fig-3: Bracket Fixed Support

In figure-3 fixed support for the bracket is visible at the hole sections for bolting purpose.

3. Load Application

As per the client’s specifications loads are applied as shown in the below figure-4.

Figure-4: Force Application

Force in the other sense load is applied to the bracket face as shown in above figure with the magnitude and direction of:

Y-direction: 20kN (Vertically downward direction)

X-direction: 10kN (Positive direction)

Both forces acting on the bracket as shown in the above figure-4 by indicating A as Y-directional load and B as a X-directional load.

4. Material Properties

The material used is Aluminium 204.0-T4 and its properties are:

Physical Property:

Density: 3000 kg/m3

Mechanical Property:

Young’s Modulus – 71 GPa

Poisson Ratio – 0.33

Ultimate Tensile Strength (UTS) – 340 MPa

Ultimate Yield Strength – 220 MPa

5. Analysis Results

After applying boundary conditions like fixed support at two holes and load is applied in X and Y direction as specified, to gain with effort the results of analysis as under:

Total Deformation

Fig-5 Total Deformation of Bracket

As we can see from the figure-5, the maximum total deformation for the bracket is 0.4814 mm while minimum is 0 mm. Red colour sign show maximum deformation and dark blue colour.

Equivalent (Von-Mises) Stress

Fig-6 Equivalent (Von-Mises) Stress

From figure-6, stress distribution in the bracket is show. Maximum stress value is 277.96 MPa and minimum value is 0.026 MPa. From material property we have ultimate tensile strength of Aluminum 204 T4 is 340 MPa which is greater than our maximum equivalent stress hence the design is safe.

Frequency (Modal) Analysis

Fig-7 1^st Frequency

After modal analysis 6 mode frequencies are as under:

Mode-1           1059.7 Hz
Mode-2           2111.9 Hz
Mode-3           2251.1 Hz
Mode-4           3844.7 Hz
Mode-5           3844.7 Hz
Mode-6           5640.3 Hz

The first mode frequency is 1059.7 Hz which is greater than 800 Hz as per client’s requirement, shown in figure-7.

6. Result Discussion

Table-2, shown below, provides us the summary of results obtained from analysis:

Table-2 Analysis Result

• From the table we can conclude that maximum equivalent or Von-Mises stress is 277.96 MPa which is less the ultimate tensile strength of the given material which is 340 MPa. Hence the design is safe.
• The modal frequency in first position is 1059.7 Hz which is greater than the 800 Hz as specified by client.

In this analysis the mesh is quadratic which provides more accuracy of the result. Furthermore, the mesh quality is 0.85 which is greater than 0.75 hence the analysis is high quality analysis.

7. Modified Bracket Model

After applying some modification like material removal from upper side and middle wall new geometry is meshed as shown in below figure-8.

• Meshing or discretization
  

  The model is converted in the small element size. The reason for the partition in small elements is that the partial differential equations can be easily solved for the geometry analysis. Meshing quality depends on the type of analysis and geometry conditions. The accuracy that can be obtained from FEA model is directly related mesh quality. This process of mesh refinement is key step in validating nay finite element model.

  

  Fig-8: Meshed New Geometry

From the figure- we can see the meshing of bracket geometry in small parts.

Number of elements: 75981
Number of nodes: 45655

All constraints, loads and material is same as applied on the initial design.

8. Analysis Results for Modified Model

After applying boundary conditions like fixed support at two holes and load in X and Y direction as specified, we to gain the results of analysis as under:

Total Deformation

Fig-9 Total Deformation of Modified Bracket

As we can see from the figure-9, the maximum total deformation for the bracket is 0.51 mm while minimum is 0 mm. Red colour shown maximum deformation and dark blue colour shown minimum value.

Equivalent (Von-Mises) Stress

Fig-10 Equivalent (Von-Mises) Stress

From figure-10, stress distribution in the modified bracket is shown. Maximum stress value is 235.91 MPa and minimum value is 0.0193 MPa. From material property we have ultimate tensile strength of Aluminium 204 T4 is 340 MPa which is greater than our maximum equivalent stress hence the design is safe.

Fig-11 1^st Frequency of Modified Model

Frequency (Modal) Analysis

After modal analysis 6 mode frequencies are as under:

Mode-1           989.20 Hz
Mode-2           2064.1 Hz
Mode-3           2180.0 Hz
Mode-4           3798.2 Hz
Mode-5           4914.1 Hz
Mode-6           5562.4 Hz

The first mode frequency is 989.20 Hz which is greater than 800 Hz as per client’s requirement, shown in figure-11.

9. Comparison of Specifications and Modified design of Bracket

Table-3 Analysis Result for modified design

• From the table-3, we can conclude that maximum equivalent or Von-Mises stress is 235.91MPa which is less the ultimate tensile strength of the given material which is 340 MPa. Hence the design is safe.
• The modal frequency in first position is 989.20 Hz which is greater than the 800 Hz as specified by client.

Table-4 Weight Comparison

In table-4 weight comparison is provided between the initial and modified design of the bracket. Due to material removal from the modified design its weight reduced from initial design but its functioning is under given a criterion that is design is safe even after the removal of material.  It will directly affect the product cost as well.