The document discusses the design and optimization of a B pillar trim component for automobiles using nonlinear finite element analysis (FEA) and dent testing. It provides background on pillar trims and B pillar trims specifically. The objectives are to computationally design and experimentally test different B pillar trim designs with varying stiffener patterns and materials to improve strength-to-weight ratio. The methodology involves CAD modeling, nonlinear FEA, design iteration, 3D printing fabrication, and dent testing validation. Progress includes understanding rib features, initial CAD modeling, material selection, and reverse engineering of an existing design.

1. Design and Optimization of B Pillar Trim using
Non-Linear FEA and Dent Test
Presentation by
Vaishnavi Ajay Thigale (MITU20MTMD0005)
(M2206007)
Guide
Prof. Ajaykumar Ugale
Date - 9th June 2022
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2. Mechanical Engineering Department 2
CONTENTS
1. Introduction
2. Brief about Pillar Trim
3. Literature Review
4. Research Gap
5. Problem Statement
6. Objectives
7. Proposed Methodology
8. Progress till date
9. Test Methods for B Pillar Trim
10. Expected Results
11. References
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3. Mechanical Engineering Department 3
• Plastics make up almost half of the volume of vehicle but only 10% of its weight. Following are some of its benefits:
 Affordable
 Easily available in market
 Lighter in weight
 Increased safety in comparison with Steel/Aluminium
 More Sustainable
 Fuel efficient
 Weather resistant
 Meet safety standards when mixed with different composites
• Metallic components like steel or aluminium not only increases the weight, but are more costlier in terms of serviceability.
• Optimizing the best plastic component designs to achieve a good strength to weight ratio is the need in automobile market to
reduce overall car weight.
INTRODUCTION
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INTRODUCTION
Following are the Types of Pillars in Automobiles
• A Pillar
• B Pillar
• C Pillar
• D Pillar (in case of SUV, minivan or wagon cars)
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5. Mechanical Engineering Department 5
Trims are the plastic parts installed on the
inside of car, which also hide BIW. The
interior trims are usually used for giving the
aesthetic look to the interior of the car.
Trim application require a variety of essential
plastic material properties:
• High quality aesthetics
• Energy absorption
• Reliable stability
• Long term durability
• Ability to withstand UV light and exposure
to high temperature
PILLAR TRIM
Fig : Exploded view of Pillar trims
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Fig : Inside of B Pillar Trim (BIW)
About B Pillar Trim :
• Interior Cabin Trims component : It is a part
of Pillar Trims which includes A Pillar
Trim, B Pillar Trim, C Pillar Trim and D
Pillar Trim
• Can be classified into B Pillar Upper Trim
and B Pillar Lower Trim, depending on the
location
• Basic function : for good aesthetic, to hide
BIW panels, harnesses, other cables and
supporting brackets
• Guides Airbag to explode during accidental
case
• Must have good strength to weight ratio and
must pose a deformation of 2% during
accident.
Fig : B Pillar Trim with Bezel
and seat belt
B PILLAR TRIM
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7. B SURFACE FEATURES OF B PILLAR TRIM
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• RIB : Different patterns seen on
the B side surface, helps in
strentgthening the part
• Optimizing the B surface features
such as ribs, doghouse, locators,
snaps, bosses helps achieve a
good strength to weight ratio as
well as the required deformation
could be monitored.
Class A Surface
(Style Surface)
Class B Surface
(Inner Surface
with features)
Fig : B Pillar
Trim featuring
B class Surface
features
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8. RIBS AS SUPPORTING STRUCTURE
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Ribs are the most important supporting structure in plastics. Ribs are designed in such a way that they form
patterns. Various rib patterns such as parallel running ribs, X (crossed), boxed shaped, honeycomb could be
designed to achieve below mentioned properties :
• Increase Strength (more strength to weight ratio is required)
• To reduce the warping (failures in plastic)
• Achieve required deformation of 2% in the structure
• To withstand the actual component structure under high temperature
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9. LITERATURE REVIEW
Sr.
No
.
TITLE OF
PAPER
AUTHOR
NAME OF
JOURNAL &
YEAR OF
PUBLICATIO
N
FINDING
1 A Study on
Energy-
Absorbing
Mechanism of
Plastic Ribs
Hideaki Arimoto,
Tsuyoshi Yasuki,
Kouji Kawamura and
Masaaki Kondou
SAE Technical
Paper series, 2018
• HIC (Head injury Criteria) value could be reduced
by optimizing the ribs in any plastic part by iterating
the parameters like thickness, pitch of ribs and
forms.
• It is important to study the deformation as well as
fracture of plastic materials to optimize the best
design
• HIC value becomes small if the deformation
resistance of the impact-energy absorbing material is
constant, and the impact-energy absorbing material
is thick, and unbroken portions are small.
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10. LITERATURE REVIEW
Sr.
No
.
TITLE OF PAPER AUTHOR
NAME OF
JOURNAL &
YEAR OF
PUBLICATIO
N
FINDING
2 Impact of 3D Printing in
Automtive Industries
V.Sreehitha International
Journal of
Mechanical And
Production
Engineering,
ISSN: 2320-2092,
2017
• 3D printing is an emerging technology which has
scopes for new developments and innovations in
automotives which could help reduce component
weight.
• Implementing 3D printing will build competency
and confidence in design for additive process in
automotives that could enable much greater mass
reduction, minimize materials used (sometimes
enabling property of recycling).
• 3D printing and its technology in Automotive
industries is able to create next industrial
revolution.
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11. LITERATURE REVIEW
Sr.
No
.
TITLE OF
PAPER
AUTHOR
NAME OF
JOURNAL &
YEAR OF
PUBLICATIO
N
FINDING
3 Design an
Analysis of a
Typical Wing
Rib for
Passenger
Aircraft
Bindu H.C,
Muhammad
Muhsin Ali.H
International
Journal of
Innovative
Research in
Science,
Engineering and
Technology
Vol. 2, Issue 7,
July 2013
• Ribs maintain the shape of the wing and also support the
bending and compressive loads which acts on the wing.
• Nonlinear buckling analysis is usually the more accurate
approach and is therefore recommended for design or
evaluation of actual structures.
• This technique employs a nonlinear static analysis with
gradually increasing loads to seek the load level at which our
structure becomes unstable. In this type we can include
features such as initial imperfections, plastic behaviour, gaps,
and large-deflection response.
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12. LITERATURE REVIEW
Sr.
No
.
TITLE OF
PAPER
AUTHOR
NAME OF
JOURNAL &
YEAR OF
PUBLICATIO
N
FINDING
4 Influence of
Material
Selection and
Product Design
on Automotive
Vehicle
Recyclability
Xiaohui He,
Dongmei Su,
Wenchao
Cai,
Alexandra
Pehlken,
Guofang
Zhang, Aimin
Wang, and
Jinsheng
Xiao
Influence of
material selection
and product design
on automotive
vehicle
recyclability.
Article of
Sustainability
(Switzerland),
13(6)
2021
• Traditional reinforcement engineering plastics may be
replaced by enhancing product structure design, creating
high-performance PP materials, particularly long-glass or
carbon-fiber-reinforced PP materials, and extending PP
materials dosage and application ratio.
• Using proper material for plastic components can help
achieve estimated weight to the strength ratio, while the
overall car weight could be reduced but just optimizing the
design for different materials.
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13. LITERATURE REVIEW
Sr.
No
.
TITLE OF
PAPER
AUTHOR
NAME OF
JOURNAL &
YEAR OF
PUBLICATION
FINDING
5 On testing of the
stiffness and the
dent resistance of
auto-body panels
Gunnar
Ekstrand,
Nader Asnaf
Journal on Materials
and Design Vol 19
1998
• The thicker is the sheet thickness at the panel centre, the
greater will be the panel stiffness. The greater the panel
radii the more severe the spring Z back, the smaller is
the stiffness.
• The dent resistance test is a process with both elastic
and plastic deformations. Using the elastic portion of the
this deformation to determine the stiffness, it is shown
in this study that the stiffness determined by the denting
punch with ϕ25mm is exactly the same as or almost
equal to that determined by the stiffness measurement
punch with ϕ100 mm
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14. • Linear analysis of plastics often provides poor results when used for in typical injection molded part design. Even
parts that do not yield are often poorly represented by linear analysis tools.
• Study of Pillar trims will improve safety along with which the weight could be optimized, while very less research has
been done for optimizing the features on B surface.
• 3D printing technology or the RPT method is now taking over the manufacturing techniques, which is the future of
automotive market. Hence, new optimized model of B pillar is to be manufatured using RPT technology.
14
RESEARCH GAP
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• To computational design and analysis and experimental testing of specific automotive B Pillar Trim for different
stiffener design, structure and patterns to increase the strength to weight ratio. Hence subsequently reducing the weight
in comparison to the existing component being used while performing tests for different materials like ABS, PP using
Non-linear FEA method and Dent test to achieve the optimized design.
PROBLEM STATEMENT
• To study B pillar trim and its component factors that affecting its functionality.
• To develop a CAD model using CATIA V5 and perform Non-linear FEA analysis using ANSYS Workbench on B-
pillar Trim under static loading.
• To make design iterations on B surface of B-pillar trim to improve the strength of component using different types of
stiffeners.
• To perform experimental dent test and comparative study of optimized design of B pillar trim.
OBJECTIVES
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PROPOSED METHODOLOGY
• Literature Review for B pillar trim plastic component
• Propose problem statement and objectives
• Find research gap and propose project requirements, propose CAD model accordingly
• Material selection and design calculations for B pillar trim
• Optimize design as per requirements and proposed objectives
• Iterate design and perform non-linear analysis using FEA methods at static conditions
• Finalize 3D model and fabricate using 3D printing technology
• Experimental validation of B pillar trim using Dent test
• Comparative study of existing B pillar trim part and optimized B pillar trim
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PROGRESS TILL DATE
• Understanding Rib Feature - Design Rule
• B Pillar Trim tentative CAD model using A surface
• B Pillar Trim for Comparative study
• Material Selection
• Reverse Engineering
• Original CAD Development in CATIA V5 using stl file generated using Reverse Engineering
• Design Itertions for comparative study
• Study of Best Design to go for 3D Printing
• 3D Printing using RPT Method - In progress
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UNDERSTANDING RIB FEATURE - DESIGN RULE
1. Draft: 0.5 deg per side (minimum), but this value should not be high
enough that it will cause failure for other consideration. For
example, more draft will result in less thickness at the top surface.
2. Thickness of ribs: 40% of wall thickness or 0.4*t where t is the wall
thickness.
3. Height: ≤ 5 times the wall thickness i.e. 5*t
4. Spacing (for more than 1 rib): 3:1 - steel height/width ratio
(maximum). h/w =3or2(preferred) where h is the height of the rib
and w is the space between two ribs.
5. Minimum thickness at the tip: 0.75
6. Radius: 0.25mm max
7. Ribs on opposite side of the wall should be offset
8. Ribs should be connected to other structural features where
possible.
9. Rib root thickness should not be more than 30% of the wall
thickness.
Fig : Standard Design of Rib as per DR
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Factors considered for designing the B Pillar Trim :
Trim Panel :
• Thickness
• Geometry
• Connectivity
Rib Structure :
• Thickness
• Depth
• Spacing
• Geometry
• Layout
Materials :
• Yield Strength
• Elastic Modulus
• Plastic Modulus
• Failure Strain
• Thermal Behaviour
CONSIDERATIONS FROM CASE STUDY
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Fig : Rectangular Rib Pattern
TENTATIVE CAD MODEL FOR FEA
B Pillar Trim (Lower)
Rectangular Rib Pattern
Impact Load Ball,
on A Surface
Fig : Input A Style Surface
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Fig : Parallel Run Rib Pattern
B Pillar Trim (Lower)
Parallel Run Rib Pattern
Impact Load Ball,
on A Surface
Fig : Input A Style Surface
TENTATIVE CAD MODEL FOR FEA
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Fig : Sink percentage for different materials
B Pillar Trim (Lower)
Parallel Run Rib Pattern
Impact Load Ball,
on A Surface
PLASTIC DEFECTS WHILE DESIGNING RIBS
Rib Thickness as a Percentage of Wall Thickness
Resin Minimal Sink Slight Sink
PC (Polycarbonate) 50% 66%
ABS (Acrylonitrile Butadine
Styrene)
40% 60%
PC/ABS 50% 66%
Polyamide (Unfilled) 30% 40%
Polyamide (Glass Filled) 33% 50%
PBT Polyester (Unfilled)
Polybutylene Terephthalate
30% 40%
PBT Polyester (Filled) 33% 50%
TPO (Thermoplastic Polyolefin) 25% 35%
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Fig : B Pillar Upper : Ertiga (3 Star Model)
Parallel Run Rib Pattern
Impact Load Ball,
on A Surface
B PILLAR TRIM FOR COMPARATIVE STUDY
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The following relationships (which are expected to be linear in linear FEA) may be
violated in nonlinear FEA:
• When the strain exceeds one or two percent, most metallic materials are no longer
usable. Some materials, such as rubbers, elastomer, and plastics, can be stretched to
hundreds of percent, necessitating finite (large) strain analysis.
• The distorted shape's alterations can no longer be ignored, engineering stress is no
longer acceptable, and real stress or Cauchy stress should be employed instead.
• It's possible that the stress-strain law will become nonlinear even within the materials
effective stress range.
• It's possible that the original equilibrium equations (which relate stress to loads) will
need to be modified.
• Due to geometrical variations in the structure's form, the load in nonlinear FEA is no
longer proportional to the displacement.
NON-LINEAR FINITE ELEMENT ANALYSIS
Fig : Stress stain graph for
different materials
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EXPERIMENTAL TESTING FOR B PILLAR TRIM
Experimental testing is done under static loading conditions, while same results
are validated using ANSYS workbench under static load. Following are few of
the consideration done while performing the dent test.
• Fixture is manufactured according to B pillar trim part designed.
• Single force is applied as per FEA analysis and reanalysis is performed to
determine strain by numerical and experimental testing.
• This experimental setup is governed using pneumatic force/dead weight
drop methods, this setup is also called as Dent test method.
• Non-linear FEA analysis is performed with the readings thus obtained, for
the plastic component under study viz. B pillar trim.
Fig : Dent Test for B Pillar Trim
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• Reverse Engineering was carried out at Jai
Ganesh Industries based in Bhosari MIDC
REVERSE ENGINEERING
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ORIGINAL CAD DESIGN IN CATIA V5
Overall Wall Thickness = 3 mm
Rib Thickness = 1.20 mm (at base)
= 1.00 mm (at top)
Draft angle = 1 Deg
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PROPERTIES
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BOUNDARY CONDITIONS
Note : Same boundary comditions have
been applied on the iterated designs for
comparison purpose as for incremental
loading.
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ORIGINAL B PILLAR TRIM ANALYSIS
Fig (a) Total Deformation = 5mm Fig (b) Equivalent Stress
Fig (c) Equivalent Elastic Strain Fig (d) Reaction Force = 460.44 N
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B PILLAR TRIM (WITH ADDITIONAL RIBS) ANALYSIS
Fig (b) Equivalent Stress
Fig (c) Equivalent Elastic Strain
Fig (a) Total Deformation = 5mm
Fig (d) Reaction Force = 470.42 N
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B PILLAR TRIM (WITH CROSS RIBS) ANALYSIS
Fig (b) Equivalent Stress
Fig (c) Equivalent Elastic Strain
Fig (a) Total Deformation = 5mm
Fig (d) Reaction Force = 784.18 N
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B PILLAR TRIM (WITH HEXAGONAL RIBS) ANALYSIS
Fig (b) Equivalent Stress
Fig (c) Equivalent Elastic Strain
Fig (a) Total Deformation = 5mm
Fig (d) Reaction Force = 571.78 N
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FEA RESULTS OBTAINED
Sr. no. Name of Case
Displacement
applied (mm)
Force Reaction
(N)
Equivalent Stress
(MPa)
Stiffness (k)
(N/mm)
1
Original B Pillar Trim
Component
5 460.44 70.62 92.088
2
B Pillar Trim With
Additional Parallel
Stiffeners
5 470.42 68.95 94.084
3
B Pillar Trim with
Cross Stiffeners
5 784.18 67.028 156.868
4
B Pillar Trim with
Hexagonal Stiffeners
5 571.78 66.006 114.356
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PROBLEMS FACED IN 3D PRINTING
Complex Geometry of Style surface part to be 3D Printed
Original CAD Model
• Part Thickness of 3mm - OK for 3D Printing
• Rib Thickness of 1.2mm - OK for 3D Printing
• Rib Thickness at Top : 1mm - OK for 3D Printing
Scaled down model (if reduced to half)
• Part Thickness of 1.5mm - OK for 3D Printing
• Rib Thickness of 0.6mm - NOK for 3D Printing
• Rib Thickness at Top : 0.5mm - NOK for 3D Printing
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36. REFERENCES
[1] Xiaohui He, Dongmei Su, Wenchao Cai, Alexandra Pehlken, Guofang Zhang, Aimin Wang, and Jinsheng Xiao (2021).
Influence of material selection and product design on automotive vehicle recyclability. Article of Sustainability (Switzerland),
13(6).
[2] P, C. T., Dinesh Kumar, S., S, H. K., & Harti, J. I. (2021). FMVSS Head Crash Target Point Bp2 FEA Simulation Using B
Pillar Trim, IRE Journals.
[3] Zhang, M., Zhu, Z., Zeng, Y., Liu, J., & Hu, Z. (2020). Analytical Method for Evaluating the Impact Response of Stiffeners
in a Ship Side Shell Subjected to Bulbous Bow Collision. Mathematical Problems in Engineering, 2020.
[4] Sabah, F., Wahid, A., Kartouni, A., Chakir, H., & ELghorba, M. (2019). Failure analysis of acrylonitrile butadiene styrene
(ABS) materials and damage modeling by fracture. International Journal of Performability Engineering, 15(9), 2285–2293.
[5] Hideaki Arimoto, Tsuyoshi Yasuki, Kouji Kawamura and Masaaki Kondou (2018). A Study on Energy-Absorbing
Mechanism of Plastic Ribs, SAE Technical paper series.
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37. REFERENCES
[6] Arimoto, H., Yasuki, T., Kawamura, K., & Kondou, M. (2018). A Study on Energy-Absorbing Mechanism of Plastic Rib.
SAE International.
[7] Chen, D., Lu, G., He, L., Li, W., & Yuan, J. (2015). Warpage of injection-molded automotive B pillar trim fabricated with
ramie fiber-reinforced polypropylene composites. Journal of Reinforced Plastics and Composites, 34(14), 1144–1152.
[8] Ahmad Rosli Abdul Manaf, Mohd Zairulnizam Mohd Zawawi and Nik Zuraida Imran Adly (2014). Thin walled part
warping overcoming by honeycomb ribs design. Advanced Materials Research, 903, 181–186.
[9] Kim, D. Y., Kim, Y., & Kim, H. Y. (2014). Material modelling considering the pressure dependence and the volume change
for plastics with applications to the interior parts of a vehicle. Proceedings of the Institution of Mechanical Engineers, Part D:
Journal of Automobile Engineering, 228(5), 535–548.
[10] Bindu H.C1, Muhammad Muhsin Ali.H (2013). DESIGN AND ANALYSIS OF A TYPICAL WING RIB FOR
PASSENGER AIRCRAFT. International Journal of Innovative Research in Science, Engineering and Technology (Vol. 2).
Mechanical Engineering Department 37
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38. REFERENCES
[11] V.Shreehita, (2017). Impact of 3D Printing in Automtive Industries. International Journal of Mechanical And Production
Engineering, ISSN: 2320-2092, Volume- 5, Issue-2.
[12] Balaji Thiyagarajan, P. (2008). Non-linear finite element analysis and optimization for light weight design of an automotive
seat backrest, Tiger-prints.
[13] Santiago, J. (2005). Comparing Material Impact Strength of Three High Impact Plastic Resins Used In Automotive Grille
Using Nonlinear Finite Element Analysis Tools.
[14] Deng, N., & Chen, Z. (1998). A new nonlinear ABS-type algorithm and its efficiency analysis. Optimization Methods and
Software, 10(1), 71–85.
[15] Ekstrand, G., & Asnafi, N. (1998). On testing of the stiffness and the dent resistance of autobody panels. In Materials and
Design (Vol. 19).
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39. Question & Answers
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