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Numerical and Experimental Modal Analysis of Car Door with and without Incorporating Visco-elastic Damping
Available online at www.sciencedirect.com
ScienceDirect Materials Today: Proceedings 5 (2018) 22237–22244
www.materialstoday.com/proceedings
ICASE_2017
Numerical and Experimental Modal Analysis of Car Door with and without Incorporating Visco-elastic Damping Basanth Kumar Ba, Chandru B. Ta*, Suresh.P. Mb, Maruthi.B.Hc b
a EWIT, Visvesvaraya Technological University, Bengaluru, India ACS college of Engg., Visvesvaraya Technological University, Bengaluru, India c EWIT, Visvesvaraya Technological University, Bengaluru, India
Abstract Analysis of Noise, vibration and Harshness (NVH) of the car door was carried out, the door component is a very vital body in the passenger car, it not only provides safety against the outside obstacles which are disturbing driver and occupants and it also protects from wind and also offers aerodynamic effects while in motion, door will vibrate due to wind force and by the less strong weak reinforcement, this can be overcome by adding some Vibration Dampers. Initially numerical analysis is conducted for conventional car door for without and with viscoelastic damping material at free – free condition. In the next step, Experimental modal analysis is carried out for automotive car door for without and with viscoelastic damping at same condition. Natural frequencies and mode shapes were collected at both methods and compared together; Hence, it proved that component with viscoelastic damping material one was better than conventional one. © 2018 Elsevier Ltd. All rights reserved. Selection and/or Peer-review under responsibility of International Conference on Advances in Science & Engineering ICASE - 2017. Keywords: Noise vibration harshness, Aerodynamic, Reinforcement, ME scope, FE analysis, stiffeners
1. Introduction The superior function of the door is to decrease the hazard caused during the side impact and also to prevent the passenger being ejected while vehicle collision.
* Corresponding author: Tel: +91 9448170148 E-mail address: [email protected] 2214-7853 © 2018 Elsevier Ltd. All rights reserved. Selection and/or Peer-review under responsibility of International Conference on Advances in Science & Engineering ICASE - 2017.
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Basanth Kumar et.al. / Materials Today: Proceedings 5 (2018) 22237–22244
As well as with these important parameters of the door opening, comfortable entry into the passenger compartment includes. Generally, doors are expensive but many manufacturers simplify them and reduced to lower number of cost. Doors are designed with bore type cross section. Stiffness is an important parameter for any kind of door because the concentrated force from hinge and door locks must be equally distributing throughout the complete door, such that there must be any chance to local distribution. In addition to this stiffness ensures the tightness with the surrounding frame. Globalization and liberalization made a drastic change in an industrialized nation. In turn caused number of business start working towards automobile vehicle and took off number of variations in it and postured difficulties, which leads to the achievement of bigger populace at greater part of nation. In the meantime, greater nation opened up themselves, welcomed other nations to contribute them in order to fulfil their financial structure enhancing per capita wage. The virtue of the above situation got changed the nation and opened up substantial road. Thus the per capita impiety of the nation expanded and turned into an aid for the makes and commercial ventures of the customer durables. The above reflected in expanded vitality requests and prompted the issue global energy crisis. The government gathered intending to the vitality issue by defining control and arrangements; one such is fuel productive vehicle. Now a day’s car business is growing very well in any nation, per the customer requirements. Thus vibration plays a vital role in automobile industry. In particular, carefully examining the vibration related an issue is enhanced to decide the vibration delivered on the segment because of different reason. For example, transmission of power from one segment to another segment or running state motor. In general examining vibration issues found its application in automobile industry. Automobile industry considered these vibrational issues and investigated seriously sort to accomplish the object of fuel effective vehicle. These serious ileostomies increased the quality of the vehicle, in turn achieved the wellbeing and solace of the customer. 2. Literature review Suresh PM et al [1] carried out the modal analysis of conventional and sandwich constructed passenger car door. Their results showed that the sandwich car roof properties were better than the conventional car roof. Daniel James et al [2] the paper described, to compete in the modern automotive industry the CAE analysis must be one of the important tool and it has been increasingly in effective manner and it has to be performed using standard method. Chrysler group LLC and Beta CAE worked together to developed a template for performing door durability using ANSA task manager. These templates were developed to automate routine tasks, reduce duplication of effort, increase quality, and facilitate standardization of the processes. Stenti. A et al [3] the paper showed, generally complex structure will be connected via different types joints such as joints, seals, gaskets etc. In their paper their concern the structure – borne vibrations transmission of a highly nonlinear joint, mainly they were concerned about car door weather seal. In order to investigate the seal, they developed a nonlinear FE model and it is being analysed. Thus they mainly focused on the seal stiffness contribution. 3. Objectives and Methodology 3.1. Objectives Today we come across with many of new modified structures, components, machines or machine elements etc., when these things are affected by vibration or vibration related problems results in fracture, fatigue and failure in the component or structure. The components of structure may be beams, body, frame etc., Because of this it is necessary that every component or structure has to be analyzed in order to avoid resonance. There are several ways and several methods to analyze, such as Finite Element Analysis (FEA), Experimental analysis and by harmonically. Present work concentrates and move towards finding the characteristics of the mode shapes, damping factors and frequencies of car door. FEA analysis and experimental analysis are the two methods which is choosed for analyzing and results of these were compared.
Basanth Kumar et.al. / Materials Today: Proceedings 5 (2018) 22237–22244
22239
3.2. Method followed
The step by step process of modifying and analyzing the components are as below Generally, the 3D model of the car door using software CATIA V5 R20. Importing Catia model to Hypermesh software and meshing the model. Analyzing the model. Post processing and collecting results. Procedure followed in EMA Cleaning the car door for removal of dust. Marking the required number of points. Required necessary connections are made and hanging the door. Hitting on the points marked before, using Dytran hammer. Collecting the data such as mode shapes, frequency and damping factor. Finally validating the both the results. FEM method
4. Modelling and Meshing 4.1. CATIA Model The modelling of car door is created using CATIA V5 R20. Since the friendly tools of the software helps to create the 3D modal of the car door. CATIA is multiplatform for CAD/CAM/CAE software developed by a French company Dassault system. After finishing of the modal, it is being imported to meshing software for next step i.e., for meshing.
Fig. 1. 3 – D model of car door
4.2. Meshing Mesh generation is defined as approximation of geometry domain in the form of polygon. FEA contains tetrahedron, pyramids, prisms or hexahedron in 3D meshing. Altair HYPERMESH tool is used to mesh the door.
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Basanth Kumar et.al. / Materials Today: Proceedings 5 (2018) 22237–22244
Fig. 2. Meshed model of car door
4.3. Meshed parameter The meshed parameters considered while meshing automotive car door is listed in the below table Table 1. Material properties Quality check parameters
Values
Minimum size
<1
Maximum size
> 10
Aspect ratio
>5
War page
> 15
Maximum angle quad
> 140
Minimum angle quad
< 40
Maximum angle tria
> 120
Minimum angle tria
< 30
Skew
> 40
Jacobian
< 0.6
Quality index
>1 Table 2. Material properties
Item
Unit
D – 300 N
Thickness
Mm
1.50
Density
gm/cm3
1.50
90º peeling adhesion
N/25 mm
102.37
4.4. Material and its properties Material and its properties play a vital role for the analysis of any component. Material properties are the specification of the material. Viscoelastic damper is the material which is selected for present work.
Basanth Kumar et.al. / Materials Today: Proceedings 5 (2018) 22237–22244
22241
Table 2.1 Properties of Steel Young’s Modulus
210GPa
Poisson’s Ratio
0.3
Density
7800 Kg/m3
4.5. Solver Present work analyses the car door by two condition and the conditions are with and without viscoelastic damping material. The solver known ABAQUS 6.13 software to get the solution. This ABAQUS software contains 3 main products they are as follows ABAQUS/Standard ABAQUS/Explicit ABAQUA/Implicit ABAQUS solves the implicit problems of FEA. Step by step procedures for the analysis of problem are Pre processing Analyzing Post processing 4.6. Modal analysis The external vibrations which are exerted on the structure, deforms the structure and it can be studied by a method called modal analysis. The deformation of structure is in the form of mode shapes, natural frequencies, damping factors. Whereas dynamic characteristics are obtained by experimental method. 4.7. Numerical analysis of Conventional automotive car door for free – free condition The natural frequencies of the conventional car door are listed in the below table for free – free condition without any modification such no dampers were added in this condition. The first six modes are the local modes and the next modes are the global modes. Table 3. Natural frequency of the Conventional car door for free – free condition
Mode shape
Frequency in Hz
7
30.843
8
50.657
9
67.245
10
77.276
11
96.687
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Basanth Kumar et.al. / Materials Today: Proceedings 5 (2018) 22237–22244
Fig. 3. 8th mode shape
4.8. Numerical analysis of car door with visco elastic damping for free – free condition The natural frequencies of the conventional car door are listed in the below table for free – free condition with visco elastic damping material using FE analysis Table. 4. Natural frequency of car door with visco elastic damping for free – free condition Mode shape
Frequency in Hz
7
41.129
8
57.076
9
67.203
Fig. 4. 8th mode shape
5. Experimental modal analysis Frequency response testing or Frequency response analysis is defined as method of finding the modal parameters of machine component. Present work, focuses on identifying the structural response of car door by considering structural vibrational problems. Whereas, structural vibration is a combination of resonant and forced vibration.
Basanth Kumar et.al. / Materials Today: Proceedings 5 (2018) 22237–22244
22243
EMA is used for describing the modal factors of the component. Internal, unbalanced, outside, atmospheric etc., forces or excitation are the primary causes for forced vibration. Thunderous vibration modes are defined as individual or combined reverberation due to excitation of structure or machine. Model elements are the dynamic conduct of structure or machine. Ex. Modular recurrence, modular damping, modular shape Linearity response is directly proportional to the force. Properties of a time invariant should not be dependent upon time. Before excitation, vibration should be independent of causal structure. Above are the assumption made in modal Analysis. 5.1. Experimental modal analysis results of Conventional car door for free – free condition The natural frequencies of the conventional car door are listed in the below table for free – free condition without any damper using experimental modal analysis. Table 5. Natural frequency of the conventional car door for free – free condition Mode Shape
Frequency (in Hz)
Damping (%)
7
53.7
0.398
8
62
.37
9
92.3
0.89
10
102
1
11
142
1.08
Fig. 5. 8th Mode shape
5.2. Experimental results of car door with visco elastic damper for free – free condition The natural frequencies of the conventional car door are listed in the below table for free – free condition with viscoelastic damping as a material.
22244
Basanth Kumar et.al. / Materials Today: Proceedings 5 (2018) 22237–22244 Table 6. Natural frequency of a car door with visco elastic damper for free – free condition Mode shape
Frequency (in Hz)
Damping (%)
7
41.8
0.261
8
53.9
0.429
9
61.5
0.501
Fig. 6. 8th mode shape
6. Conclusion The experimental and numerical analysis carried out for free – free condition of car door with and without viscoelastic damper. When the car door was tested under free – free condition without viscoelastic damper five mode shapes were obtained which caused high noise and vibration. Later on a damper known as viscoelastic damper is inserted; only three mode shapes obtained rest of the mode shapes were destroyed by damping layer and also frequency had decreased considerably intern reducing noise and vibration. All the experimental and numerical done, matched approximately. Hence it can be conclude that the damping material introduced to car door at free – free condition, the noise and vibration considerably decreases. References [1] “Modal analysis of conventional and sandwich constructed Passanger car Door” – Suresh PM, CS Venkatesha. International conference on convergence of science and Engineering (ICSE) in education and research 21-23, April 2010 at Dayanand sagar college of Engineering, Bangalore. [2] “A strategy for standardization and automation of door durability CAE analysis using ANSA task manager”, Daniel J2ames, Santosh Patil Chrysler Group LLC, USA, 2Beta CAE, USA, 4th ANSA & μETA International Conference. [3] “Dynamic modelling of car door weather seals: A first outline”, A. Stenti, D. Moens, W. Desmet, K. U. Leuven, Department of Mechanical Engineering, division PMA Celestijnenlaan 300 B, B-3001 Leuven, Belgium.
ScienceDirect Materials Today: Proceedings 5 (2018) 22237–22244
www.materialstoday.com/proceedings
ICASE_2017
Numerical and Experimental Modal Analysis of Car Door with and without Incorporating Visco-elastic Damping Basanth Kumar Ba, Chandru B. Ta*, Suresh.P. Mb, Maruthi.B.Hc b
a EWIT, Visvesvaraya Technological University, Bengaluru, India ACS college of Engg., Visvesvaraya Technological University, Bengaluru, India c EWIT, Visvesvaraya Technological University, Bengaluru, India
Abstract Analysis of Noise, vibration and Harshness (NVH) of the car door was carried out, the door component is a very vital body in the passenger car, it not only provides safety against the outside obstacles which are disturbing driver and occupants and it also protects from wind and also offers aerodynamic effects while in motion, door will vibrate due to wind force and by the less strong weak reinforcement, this can be overcome by adding some Vibration Dampers. Initially numerical analysis is conducted for conventional car door for without and with viscoelastic damping material at free – free condition. In the next step, Experimental modal analysis is carried out for automotive car door for without and with viscoelastic damping at same condition. Natural frequencies and mode shapes were collected at both methods and compared together; Hence, it proved that component with viscoelastic damping material one was better than conventional one. © 2018 Elsevier Ltd. All rights reserved. Selection and/or Peer-review under responsibility of International Conference on Advances in Science & Engineering ICASE - 2017. Keywords: Noise vibration harshness, Aerodynamic, Reinforcement, ME scope, FE analysis, stiffeners
1. Introduction The superior function of the door is to decrease the hazard caused during the side impact and also to prevent the passenger being ejected while vehicle collision.
* Corresponding author: Tel: +91 9448170148 E-mail address: [email protected] 2214-7853 © 2018 Elsevier Ltd. All rights reserved. Selection and/or Peer-review under responsibility of International Conference on Advances in Science & Engineering ICASE - 2017.
22238
Basanth Kumar et.al. / Materials Today: Proceedings 5 (2018) 22237–22244
As well as with these important parameters of the door opening, comfortable entry into the passenger compartment includes. Generally, doors are expensive but many manufacturers simplify them and reduced to lower number of cost. Doors are designed with bore type cross section. Stiffness is an important parameter for any kind of door because the concentrated force from hinge and door locks must be equally distributing throughout the complete door, such that there must be any chance to local distribution. In addition to this stiffness ensures the tightness with the surrounding frame. Globalization and liberalization made a drastic change in an industrialized nation. In turn caused number of business start working towards automobile vehicle and took off number of variations in it and postured difficulties, which leads to the achievement of bigger populace at greater part of nation. In the meantime, greater nation opened up themselves, welcomed other nations to contribute them in order to fulfil their financial structure enhancing per capita wage. The virtue of the above situation got changed the nation and opened up substantial road. Thus the per capita impiety of the nation expanded and turned into an aid for the makes and commercial ventures of the customer durables. The above reflected in expanded vitality requests and prompted the issue global energy crisis. The government gathered intending to the vitality issue by defining control and arrangements; one such is fuel productive vehicle. Now a day’s car business is growing very well in any nation, per the customer requirements. Thus vibration plays a vital role in automobile industry. In particular, carefully examining the vibration related an issue is enhanced to decide the vibration delivered on the segment because of different reason. For example, transmission of power from one segment to another segment or running state motor. In general examining vibration issues found its application in automobile industry. Automobile industry considered these vibrational issues and investigated seriously sort to accomplish the object of fuel effective vehicle. These serious ileostomies increased the quality of the vehicle, in turn achieved the wellbeing and solace of the customer. 2. Literature review Suresh PM et al [1] carried out the modal analysis of conventional and sandwich constructed passenger car door. Their results showed that the sandwich car roof properties were better than the conventional car roof. Daniel James et al [2] the paper described, to compete in the modern automotive industry the CAE analysis must be one of the important tool and it has been increasingly in effective manner and it has to be performed using standard method. Chrysler group LLC and Beta CAE worked together to developed a template for performing door durability using ANSA task manager. These templates were developed to automate routine tasks, reduce duplication of effort, increase quality, and facilitate standardization of the processes. Stenti. A et al [3] the paper showed, generally complex structure will be connected via different types joints such as joints, seals, gaskets etc. In their paper their concern the structure – borne vibrations transmission of a highly nonlinear joint, mainly they were concerned about car door weather seal. In order to investigate the seal, they developed a nonlinear FE model and it is being analysed. Thus they mainly focused on the seal stiffness contribution. 3. Objectives and Methodology 3.1. Objectives Today we come across with many of new modified structures, components, machines or machine elements etc., when these things are affected by vibration or vibration related problems results in fracture, fatigue and failure in the component or structure. The components of structure may be beams, body, frame etc., Because of this it is necessary that every component or structure has to be analyzed in order to avoid resonance. There are several ways and several methods to analyze, such as Finite Element Analysis (FEA), Experimental analysis and by harmonically. Present work concentrates and move towards finding the characteristics of the mode shapes, damping factors and frequencies of car door. FEA analysis and experimental analysis are the two methods which is choosed for analyzing and results of these were compared.
Basanth Kumar et.al. / Materials Today: Proceedings 5 (2018) 22237–22244
22239
3.2. Method followed
The step by step process of modifying and analyzing the components are as below Generally, the 3D model of the car door using software CATIA V5 R20. Importing Catia model to Hypermesh software and meshing the model. Analyzing the model. Post processing and collecting results. Procedure followed in EMA Cleaning the car door for removal of dust. Marking the required number of points. Required necessary connections are made and hanging the door. Hitting on the points marked before, using Dytran hammer. Collecting the data such as mode shapes, frequency and damping factor. Finally validating the both the results. FEM method
4. Modelling and Meshing 4.1. CATIA Model The modelling of car door is created using CATIA V5 R20. Since the friendly tools of the software helps to create the 3D modal of the car door. CATIA is multiplatform for CAD/CAM/CAE software developed by a French company Dassault system. After finishing of the modal, it is being imported to meshing software for next step i.e., for meshing.
Fig. 1. 3 – D model of car door
4.2. Meshing Mesh generation is defined as approximation of geometry domain in the form of polygon. FEA contains tetrahedron, pyramids, prisms or hexahedron in 3D meshing. Altair HYPERMESH tool is used to mesh the door.
22240
Basanth Kumar et.al. / Materials Today: Proceedings 5 (2018) 22237–22244
Fig. 2. Meshed model of car door
4.3. Meshed parameter The meshed parameters considered while meshing automotive car door is listed in the below table Table 1. Material properties Quality check parameters
Values
Minimum size
<1
Maximum size
> 10
Aspect ratio
>5
War page
> 15
Maximum angle quad
> 140
Minimum angle quad
< 40
Maximum angle tria
> 120
Minimum angle tria
< 30
Skew
> 40
Jacobian
< 0.6
Quality index
>1 Table 2. Material properties
Item
Unit
D – 300 N
Thickness
Mm
1.50
Density
gm/cm3
1.50
90º peeling adhesion
N/25 mm
102.37
4.4. Material and its properties Material and its properties play a vital role for the analysis of any component. Material properties are the specification of the material. Viscoelastic damper is the material which is selected for present work.
Basanth Kumar et.al. / Materials Today: Proceedings 5 (2018) 22237–22244
22241
Table 2.1 Properties of Steel Young’s Modulus
210GPa
Poisson’s Ratio
0.3
Density
7800 Kg/m3
4.5. Solver Present work analyses the car door by two condition and the conditions are with and without viscoelastic damping material. The solver known ABAQUS 6.13 software to get the solution. This ABAQUS software contains 3 main products they are as follows ABAQUS/Standard ABAQUS/Explicit ABAQUA/Implicit ABAQUS solves the implicit problems of FEA. Step by step procedures for the analysis of problem are Pre processing Analyzing Post processing 4.6. Modal analysis The external vibrations which are exerted on the structure, deforms the structure and it can be studied by a method called modal analysis. The deformation of structure is in the form of mode shapes, natural frequencies, damping factors. Whereas dynamic characteristics are obtained by experimental method. 4.7. Numerical analysis of Conventional automotive car door for free – free condition The natural frequencies of the conventional car door are listed in the below table for free – free condition without any modification such no dampers were added in this condition. The first six modes are the local modes and the next modes are the global modes. Table 3. Natural frequency of the Conventional car door for free – free condition
Mode shape
Frequency in Hz
7
30.843
8
50.657
9
67.245
10
77.276
11
96.687
22242
Basanth Kumar et.al. / Materials Today: Proceedings 5 (2018) 22237–22244
Fig. 3. 8th mode shape
4.8. Numerical analysis of car door with visco elastic damping for free – free condition The natural frequencies of the conventional car door are listed in the below table for free – free condition with visco elastic damping material using FE analysis Table. 4. Natural frequency of car door with visco elastic damping for free – free condition Mode shape
Frequency in Hz
7
41.129
8
57.076
9
67.203
Fig. 4. 8th mode shape
5. Experimental modal analysis Frequency response testing or Frequency response analysis is defined as method of finding the modal parameters of machine component. Present work, focuses on identifying the structural response of car door by considering structural vibrational problems. Whereas, structural vibration is a combination of resonant and forced vibration.
Basanth Kumar et.al. / Materials Today: Proceedings 5 (2018) 22237–22244
22243
EMA is used for describing the modal factors of the component. Internal, unbalanced, outside, atmospheric etc., forces or excitation are the primary causes for forced vibration. Thunderous vibration modes are defined as individual or combined reverberation due to excitation of structure or machine. Model elements are the dynamic conduct of structure or machine. Ex. Modular recurrence, modular damping, modular shape Linearity response is directly proportional to the force. Properties of a time invariant should not be dependent upon time. Before excitation, vibration should be independent of causal structure. Above are the assumption made in modal Analysis. 5.1. Experimental modal analysis results of Conventional car door for free – free condition The natural frequencies of the conventional car door are listed in the below table for free – free condition without any damper using experimental modal analysis. Table 5. Natural frequency of the conventional car door for free – free condition Mode Shape
Frequency (in Hz)
Damping (%)
7
53.7
0.398
8
62
.37
9
92.3
0.89
10
102
1
11
142
1.08
Fig. 5. 8th Mode shape
5.2. Experimental results of car door with visco elastic damper for free – free condition The natural frequencies of the conventional car door are listed in the below table for free – free condition with viscoelastic damping as a material.
22244
Basanth Kumar et.al. / Materials Today: Proceedings 5 (2018) 22237–22244 Table 6. Natural frequency of a car door with visco elastic damper for free – free condition Mode shape
Frequency (in Hz)
Damping (%)
7
41.8
0.261
8
53.9
0.429
9
61.5
0.501
Fig. 6. 8th mode shape
6. Conclusion The experimental and numerical analysis carried out for free – free condition of car door with and without viscoelastic damper. When the car door was tested under free – free condition without viscoelastic damper five mode shapes were obtained which caused high noise and vibration. Later on a damper known as viscoelastic damper is inserted; only three mode shapes obtained rest of the mode shapes were destroyed by damping layer and also frequency had decreased considerably intern reducing noise and vibration. All the experimental and numerical done, matched approximately. Hence it can be conclude that the damping material introduced to car door at free – free condition, the noise and vibration considerably decreases. References [1] “Modal analysis of conventional and sandwich constructed Passanger car Door” – Suresh PM, CS Venkatesha. International conference on convergence of science and Engineering (ICSE) in education and research 21-23, April 2010 at Dayanand sagar college of Engineering, Bangalore. [2] “A strategy for standardization and automation of door durability CAE analysis using ANSA task manager”, Daniel J2ames, Santosh Patil Chrysler Group LLC, USA, 2Beta CAE, USA, 4th ANSA & μETA International Conference. [3] “Dynamic modelling of car door weather seals: A first outline”, A. Stenti, D. Moens, W. Desmet, K. U. Leuven, Department of Mechanical Engineering, division PMA Celestijnenlaan 300 B, B-3001 Leuven, Belgium.