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Technical Paper

Thermoplastic Roof Crush Countermeasure Design for Improved Roof Crush Resistant to Meet FMVSS-216

2011-04-12
2011-01-1119
An automobile is designed to meet numerous impact events, including frontal impact, side impact, rear impact, and roll over. Roof crush resistance is a test defined by Federal Motor Vehicle Safety Standard (FMVSS) 216. The intent of this test is to evaluate the strength of the roof and supporting body structure during a vehicle rollover. Steel countermeasures are typically used as structural-reinforcing elements to the body structure to improve the crush strength of a vehicle roof. This paper presents a thermoplastic countermeasure (CM) design as a light-weight solution to replace traditional steel countermeasures. Two concepts are discussed in the paper: an all-plastic countermeasure and a plastic/metal hybrid countermeasure consisting of stamped steel with a thermoplastic reinforcing rib structure. Finite Element (FE) methods using LS-DYNA are used to evaluate the performance of these countermeasure concepts.
Technical Paper

Diagnosing Vehicle Aggressiveness for Pedestrian Leg Impact and Development of Efficient Front End Energy Management Systems

2010-04-12
2010-01-1168
Worldwide involvement in Global Technical Regulation (GTR) discussion shows the increasing importance of pedestrian safety as a global concern. Vehicle front styling plays an important role in vehicle to pedestrian impact. Front styling can change the pedestrian kinematics and injury levels during an impact. Key elements of bumper front are Fascia, Upper & Lower Grille, Hood, spoiler or undertray, bumper beam and height of these components from ground level, determine the vehicle aggressiveness for pedestrian safety. This paper presents an approach to diagnose the vehicle front aggressiveness for pedestrian leg impact. Eight different vehicle bumper front configurations from ‘minis’ to ‘sedans’ are studied for lower leg impact cases, to understand the bumper stiffness profile (stiffness in upper, middle and lower load path).
Technical Paper

Prediction of Thermoplastic Fender Behavior During E-coat Bake Cycle - Part 1: FEA Methodology and Problem Formulation

2010-04-12
2010-01-0232
This paper presents a Finite element analysis (FEA) methodology to predict the behavior of an automotive thermoplastic fender subjected to the e-coat paint bake cycle. Such a methodology, essential for an optimum fender design involves solution of a thermo-viscoelastic problem whose solution is not yet reported in literature. This FEA methodology employed in the early design phase would help in the development of an optimum thermoplastic fender and support strategy. It is shown with help of a case study that the efficacy of different support combinations and their effect on final fender deformations can be predicted virtually very early in the design phase. While this paper presents the methodology and its application using the example of a large body panel (BP) like fender, it can easily be applied for predicting the response of other thermoplastic parts like tailgate and tank flap during the paint cycle.
Technical Paper

Prediction of Thermoplastic Fender Behavior During E-coat Bake Cycle - Part 2: Influence of Temperature Distribution

2010-04-12
2010-01-0231
This paper is motivated by the need to predict deformation behavior of an automotive thermoplastic fender during its residence in e-coat paint bake oven where it is heated by convective currents from blowers. Part - 1 [ 1 ] of this paper, presented a FEA methodology to model the behavior of thermoplastic fender during ecoat bake. Additionally a multiphysics computational procedure to include effect of temperature and stress history was also proposed to enhance the accuracy of the solution. In this paper, we focus on the prediction of temperature history and its influence on fender deformation. Towards this, we present a two-stage thermo-mechanical simulation procedure utilizing CFD and FEA to model the ecoat bake process. While the procedure can model the heating of the fender by convective currents from blowers using CFD, the required flow field data of the ecoat oven is highly confidential.
Technical Paper

Pedestrian Safe and Impact Resistant Headlamp Design Through a Novel Energy Absorber Ring Concept

2010-04-12
2010-01-0293
As the pedestrian impact regulations are continuing to evolve, there is a growing emphasis on each and every component of a vehicle front to be pedestrian friendly. Traditionally pedestrian safety during an automotive impact is ensured through bumper, grill, fender and hood. However, the headlamp design was not under the same level of consideration as compared to other frontal components. To make pedestrian safety complete, the headlamp also needs to adhere to the pedestrian safety regulations. A novel energy absorber ring (EAR) concept was developed to make the headlamps pedestrian friendly. The proposed EAR concept was found to improve the pedestrian safety and low speed vehicle damageability performance. It was also observed that the proposed concept reduces the replacement and insurance cost.
Technical Paper

Life Cycle Assessment of Lightweight Noryl* GTX* Resin Fender and Its Comparison with Steel Fender

2012-04-16
2012-01-0650
Global warming and climate change are among the top subjects of growing global concern. According to International Energy Agency (IEA), about 19% of the greenhouse gas emissions from fuel combustion are generated by the transportation sector, and its share is likely to grow. A forecast by US Census Bureau predicts that there will be 3.5 billion cars by 2050 for a population of 9 billion. In this context, numbers in the industrialized world are expected to double from around half a billion to over one billion. An increase in fleet volume will have a direct and major impact on increase of CO₂ emissions. Therefore, reducing vehicle fuel consumption is one of the most critical steps for reducing greenhouse gas emissions, and reduction of vehicle weight is one of the best solutions for improving fuel efficiency.
Technical Paper

Effect of Glazing Thermal Conductivity on Cabin Soak Temperature

2012-04-16
2012-01-1207
Previous papers by the present authors described use of computational fluid dynamics (CFD) to quantify the effect of glazing thermal conductivity on steady-state heating, ventilation and air-conditioning (HVAC) load under wide-ranging climate and state of motion scenarios, and to estimate the significance of this effect for electric battery performance. The CFD simulations yielded the total heat transfer between the ambient and the cabin of a model car, including radiative and convective heat transfer. The five-fold lower inherent thermal conductivity of polycarbonate relative to glass was found to reduce steady-state HVAC load by several percent in all scenarios, leading to reduced greenhouse gas emission or increased electric range, according to the type of vehicle.
Technical Paper

A Novel Energy Absorber Design Technique for an Idealized Force-Deformation performance

2008-04-14
2008-01-0184
This paper presents a novel approach to design an efficient energy absorber using thermoplastic (PC/PBT - Polycarbonate/ Polybutylene Terephthalate) material. Automotive industry always demands minimum package space between bumper beam and fascia from styling perspective. This requires an efficient energy absorber, which can meet the energy absorption target through an idealized force-intrusion performance. In the present study, thermoplastic energy absorber with sequential failure is designed through geometrical configuration to achieve the idealized Force-Deformation (FD) curve. CAE techniques are used extensively for optimizing the design parameters of energy absorber to achieve the desired performance level. The results in the form of FD curve are compared with the idealized curve and the efficiency is calculated. Comparative studies are also performed with foam energy absorber solution.
Journal Article

Thermoplastic Reflector Design for Robust Optical Performance

2012-04-16
2012-01-0266
A headlamp reflector has many performance requirements. Principal among these is the need to deliver a compliant beam pattern while withstanding a severe heat environment. In serving this requirement, the reflector must reliably secure the light source (bulb filament) relative to the optical prescription (facets) of the reflector. Traditionally, achieving this performance requirement has been challenging since the reflector elements which are designed to deliver stable and reliable optical performance, are the same elements which must also withstand thermal stresses and adjustment-related static stresses within the reflector. The integrity of these optical elements may also be limited by surface sink, especially in the bulb fastening and attachment locations. The current work describes the design of a reflector bracket through which these forces can be minimized and accommodated while delivering robust optical performance.
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