Lightweight Design of Vehicle Side Door

Tipo di pubblicazione: Tesi di dottorato
Tipologia MIUR: Tesi di dottorato > Tesi di dottorato - Polito
Titolo: Lightweight Design of Vehicle Side Door
Autori: Jindong Ji
Autori di ateneo:
Tutor: Prof. Giovanni Belingardi
Dottorato di ricerca: XXVII Ciclo > MECCANICA
Istituzione: Politecnico di Torino
Abstract: Due to increasing environmental concern about emission of Green House Gas and government regulations on vehicle safety, vehicle manufacturers, and their suppliers, must turn to new technologies. This is the main way to help them to achieve the goals of making vehicles lighter and safer. These two targets seem to be in deep contrast one with the other as increasing expectations from car consumers and the crashworthiness requirements. Nowadays a lot of innovative vehicle technologies are being considered in order to reduce emissions of GHG, such as engine with increased efficiency, less drag losses, regenerative braking systems, lower weight and so on. Lightweight design is becoming an effective way to get higher fuel efficiency and less vehicle emissions in recent years. Some vehicle weight reduction techniques such as vehicle redesign and vehicle downsizing are playing a negative role on both customer comfort and vehicle safety, since vehicle size and safety are linked together. Consequently, research work and car makers design departments are willing to find advanced materials with excellent performances to substitute traditional materials, such as high strength steel, aluminum, magnesium, composite and so on. Composite have many advantages comparing to traditional materials, such as their relatively higher strength and lower weight, better corrosion resistance, better energy absorption in case of impact and so on. But many difficulties are encountered on the way of successful incorporation of huge quantities of composites, which could be divided into some categories: production cost, production volume, design methodologies, joining technology, repair and recycling issues. Also vehicle safety should be discussed when lighter materials are adopted into automobiles. The research activity in this PhD thesis is motivated and drawn from the above stated problems. Vehicle lateral door substructure is the focus point of this study. Vehicle side door is not a simple panel but rather a substructure system which satisfies many different functions. This structure is traditionally built with steel material traditionally. Basically, the door is composed by an outer panel supported by an inner panel where different additional components are placed. Furthermore, nowadays car doors usually have a reinforcing element (side impact beam) placed longitudinally between outer and inner panels which protects the driver and passengers in case of a side impact event. This thesis has developed several composite side door structures for vehicle model Toyota Yaris 2010, considering static design requirements, NVH design criteria and crashworthiness. All the composite models are simulated with numerical tools ABAQUS and LS-DYNA. The original Yaris steel door structure is considered as reference solution in this study and its performance compared with all composite solutions. The first chapter is dedicated to vehicle fuel consumption and emissions in Europe during recent years. Then the chapter discusses the CO_2 emission limitations from Euro 1 to Euro 6 for gasoline and diesel passenger cars. The second chapter covers technological strategies adopted by car manufacturers in order to reach vehicle noxious gas emissions and fuel consumption reduction. Lightweight design is the main way considered in this thesis and then advanced materials used to substitute traditional material are summarized. Both advantages and disadvantages of composite materials are discussed in detail; also safety of lighter vehicles is covered briefly in the end. The third chapter introduces the particular application of the vehicle lateral door in the past. In this activity, the differences between finite element model of Yaris and real car are investigated. Active safety and passive safety of vehicle is discussed, usually the passive safety includes frontal crash, side crash and rear crash. Every vehicle fleet must pass not only legislation safety tests before they are permitted to be sold in market but also "New car Assessment Program", all the NCAP established in different countries are summarized. The Federal Motor Vehicle Safety Standard 214 is the reference normative in the study, which is discussed in deepth. Biomechanical response of instrumented dummy is used to assess injury risk of body part, including Head Injury Criteria (HIC), thorax, abdomen and pelvis. At the end, three composite door solutions developed in this study are briefly described. The fourth chapter covers composite characterization; types of fiber and matrix common in use are summarized at first. The selection of composite for vehicle side door should consider bending stiffness, strength and capacity to absorb energy. As a response, several composite materials are considered because of their own advantages, they are carbon fiber reinforced plastic (CFRP), E-Glass/epoxy composite (GFRP), glass mat thermoplastic (GMT), GMT-UD, GMT-TEX and semi impregnated micro sandwich material (SIMS). The fifth chapter introduces composite door solutions in detail, such as sizes of models, types of element and so on. The first composite door solution is framed by composite thin-walled beams based on the size of Yaris door. The composite beams are connected by aluminum joint through epoxy adhesives. In this case, outer panel and inner panel of door structure are not considered, so it is not possible to integrate this solution into Yaris vehicle directly. The second solution is to substitute traditional materials using composite, interesting parts are outer panel, inner panel and impact beam. In third solution, one innovative side door reinforcing structure is presented, the proposal is that traditional impact beam and some particular reinforcements are replaced by an innovative composite reinforcing panel, and this innovative panel could be bonded with outer surface panel and inner surface panel together. The sixth chapter is covering numerical simulation results for first and second solutions under static loading cases, including vertical, horizontal, lateral stiffness, sagging and quasi static intrusion simulation test. At the end the modal analysis is done for second solution. All the numerical results of composite solutions are compared with Yaris reference solution. The crashworthiness evaluation is in chapter seven, including intrusion displacements of compartment and biomechanical response of instrumented dummy which is placed at driver's seat. Acceleration of head, rib deflection, abdominal force and pubic symphysis force are used to assess the injury risk of body parts. All the biomechanical response of composite solutions are compared with steel reference solution and limitation value required in regulation FMVSS214. Finally in chapter eight the main conclusions of this research activity are briefly summarized
Data: 2015
Status: Pubblicato
Lingua della pubblicazione: Inglese
Parole chiave:
Dipartimenti (originale): DIMEAS - Dipartimento di Ingegneria Meccanica e Aerospaziale
URL correlate:
    Area disciplinare: Area 09 - Ingegneria industriale e dell'informazione > MECCANICA APPLICATA ALLE MACCHINE
    Data di deposito: 01 Apr 2015 16:43
    Data ultima modifica (IRIS): 01 Apr 2015 16:11:09
    Data inserimento (PORTO): 22 Mag 2016 13:52
    Numero Identificativo (DOI): 10.6092/polito/porto/2598565


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