TASIT TEKNOLOJISI_PASIF
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TASIT TEKNOLOJISI_PASIF
MARMARA ÜNİVERSİTESİ TEKNOLOJİ FAKÜLTESİ TAŞIT TEKNOLOJİSİ PASİF EMNİYET Yrd. Doç. Dr. Abdullah DEMİR Source World Health Organization ALV-General Presentation 2014 v.1.1 – 3; ALV General 2014 Complete Safety System Supplier ALV-General Presentation 2014 v.1.1 – 3; ALV General 2014 Knowledge saves lives Bruno DiGennaro, Volvo & Child Passenger Safety, April 23, 2009 Safety Strategy Bruno DiGennaro, Volvo & Child Passenger Safety, April 23, 2009 “Cars are driven by people. The guiding principle behind everything we make at Volvo, therefore, is – and must remain – safety.” Assar Gabrielsson and Gustaf Larson, founders of Volvo Volvo Cars Gent; PR & Communicatie; mdemey; Issue date: Update 01/2011, Security Class: Public Drive Towards Zero Vision: To develop cars that don’t crash. Zero killed or badly injured in a Volvo car 2020 Johan Konnberg - Volvo Car Electrification Strategy, 2012-10-23 Toyota Toyota Toyota 5 phases of safety 4. Damage reduction •3-point Safety Belt •Deformation zones •PRS •SIPS •WHIPS •ROPS •IC 1. Normal driving •DSTC and CTC •RSC •Collision Warning •Emergency Brake Assist •Lane Departure Warning •Ready Alert Brake 2. Conflict •Driver Alert Control •Adaptive Cruise Control •IDIS •BLIS •Active Bending Lights •Distance Alert Bruno DiGennaro, Volvo & Child Passenger Safety, April 23, 2009 3. Avoidance •Pedestrian Detection 5. After with Full Auto Brake collision •Collision Warning with Full Auto Brake •City Safety 1. Normal driving 2. Conflict 3. Avoidance 4. Damage reduction 5. After collision Okuma Metni: Dinamik Denge ve Çekiş Kontrolü (DSTC) Sistem, aracın ne yönde gittiği, lastiklerin ne kadar hızlı döndüğü ve ne kadar direksiyon hareketi uygulandığı gibi faktörleri hesaba katmaktadır. DSTC tüm bu bilgileri kullanarak, potansiyel bir savrulmayı algılayabiliyor ve bunu önlemek için devreye girerek motor gücünü azaltır ve/veya uygun tekerlekleri frenler. Motor Sürükleme Kontrolünü (EDC) kullanarak, motor freni sırasında tekerleklerin kilitlenmesini de önler. Savrulmayı önlemek için DSTC sisteminin daha da erken ve daha hassas bir biçimde çalışmasına yardım etmek amacıyla Gelişmiş Denge Kontrolü (ASC) sistemi çok eksenli yeni bir sensöre sahiptir. Ancak ASC'nin işi size tatmin edici bir sürüş deneyimi de sunmak; böylece viraj alırken aracın dinamik açıdan çok daha dengeli olduğunu hissedebiliyorsunuz. Bir başka özellik de Viraj Çekiş Kontrolü (CTC). Bu sistem, viraj alırken içteki çekiş tekerleği yol tutuşunu kaybetmeye başladığında bu tekerleği frenleyip, gücü bu tekerlek yerine dıştaki tekerleğe aktararak çalışır. Bazı araçlarda performanslı şekilde otomobil kullanmak istendiğinde, DSTC bir Spor Ayara da sahiptir. Bu ayar, motor gücü azaltma fonksiyonunu devre dışı bırakır ve sürücünün direksiyon simidi ve gaz pedalını dinamik bir şekilde kullandığını ve fazla ileri gitmediğini algıladığı (belli bir sınırı aşarsa o zaman normal DSTC fonksiyonuna geri dönüyor) sürece arka tekerleğin kontrollü bir miktarda kaymasına izin verir. Volvo Boyun Zedelenmesi Koruma Sistemi (WHIPS - Whiplash Protection System): Bir anlık dikkatsizlikle bir sürücünün öndeki araca çarpması. Sonuç da, kafanın aniden geriye doğru atılmasıyla oluşan kırbaç etkisine bağlı uzun dönemde rahatsızlık veren bir yaralanma olabilir. Uzun süreli yaralanma riskini %50'ye varan oranda azaltmaya yardım edecek bir sistem geliştirmiştir. Arkadan bir darbe durumunda, WHIPS sistemi yolcu ya da sürücünün koltuk arkalığının tamamını hareket ettirirken, koltuk başlığı, bir topu nazikçe yakalar gibi sabit kalarak boynu desteklemektedir. • • • • • • • • • Volvo Dinamik Denge ve Çekiş Kontrolü (DSTC) Viraj Çekiş Kontrolü (CTC) Motor Sürükleme Kontrolü (EDC) BLIS (Blind Spot Information System) IDIS (Intelligent Driver Information System) Roll Over Protection System (ROPS) Roll Stability Control (RSC) Structural Insulated Panel (SIP) LDW (Lane Departure Warning) Holistic approach to safety Mitigation: Bruno DiGennaro, Volvo & Child Passenger Safety, April 23, 2009 Azaltma SAFETY Emniyet “tehlike bulunmaması hali” olarak tanımlanmaktadır. Ancak taşıt trafiğinde mutlak bir emniyetten söz edilemez. Emniyet kavramı tehlike oranı yada diğer bir deyişle rizikoyu tamamlayıcı bir emniyet derecesi ile ifade edilebilir. Riziko ise kaza olma olasılığı ve kaza sonucu olabilecek zarar miktarı ile belirlenebilir. Emniyetlilik, kaza olasılığı ile mümkün olan zarar oranının çarpımının az olmasıdır. Active safety: Prevention of accidents Passive safety: Reduction of accident consequences Safety in traffic. Terms and influencing factors • Active safety • Driving safety ACTIVE SAFETY Driving safety is the result of a harmonious chassis and suspension design with regard to wheel suspension, springing, steering and braking, and is reflected in optimum dynamic vehicle behavior. Conditional safety results from keeping the physiological stress that the vehicle occupants are subjected to by vibration, noise, and climatic conditions down to as low a level as possible. It is a significant factor in reducing the possibility of misactions in traffic. Vibrations within a frequency range of 1 to 25 Hz (stuttering, shaking, etc.) induced by wheels and drive components reach the occupants of the vehicle via the body, seats and steering wheel. The effect of these vibrations is more or less pronounced, depending upon their direction, amplitude and duration. Noises as acoustical disturbances in and around the vehicle can come from internal sources (engine, transmission, propshafts, axles) or external sources (tire/road noises, wind noises), and are transmitted through the air or the vehicle body. ACTIVE SAFETY Noise reduction measures are concerned on the one hand with the development of quiet-running components and the insulation of noise sources (e.g., engine encapsulation), and on the other hand with noise damping by means of insulating or anti-noise materials. Climatic conditions inside the vehicle are primarily influenced by air temperature, air humidity, rate of air flow through the passenger compartment and air pressure. Perceptibility safety Measures which increase perceptibility safety are concentrated on • Lighting equipment (Lighting), • Acoustic warning devices (Acoustic signaling devices), • Direct and indirect view (Driver's view: The angle of obscuration caused by the A-pillars for both of the driver's eyes – binocular – must not be more than 6 degrees). Operating safety Low driver stress, and thus a high degree of driving safety, requires optimum design of the driver's surroundings with regard to ease of operation of the vehicle controls. Binocular: İki gözün de kullanılmasını gerektiren Reading Text: Biomechanical Criteria/Approach Several years later it became apparent that this approach is incomplete since it is not linked with the human tolerance limits as a consequence of trauma due to accidents. Thus the need became evident to evaluate the safety of a car with biomechanical criteria requiring the need to verify, in case of accident, that the stress suffered by the occupants are lower than human tolerance limit. This became known as the so-called biomechanical approach. The logical scheme to define the safety standards according to this approach is multi-disciplinary. Fig.: Schematic representation of the biomechanical approach. L. Morello et al.: The Automotive Body, Vol. 2: Structural Design,Springer Science + Business Media B.V. 2011 • • • • • • Pasif emniyet, bir kaza ile karşılaşılması durumunda, kazanın olumsuz sonuçlarını olabildiğince azaltmak amacıyla yapılan bütün yapısal ve tasarım özelliklerini kapsamaktadır. • • • • • • • • • Kapı içi çelik bar sistemleri Enerji sönümleyen direksiyon sistemleri Hava yastığı sistemleri Emniyet kemer sistemleri Ayarlanabilir fren pedal sistemi Baş destekleme veya aktif boyunluk sistemi Çocuk koruma sistemi Aktif diz destekleme sistemi Elektronik kapı kilitleme ve mandallama sistemleri Kaza sonrası yangın önleme sistemi Kaza sonrası acil bilgi sistemi Kaza sonrası kolay çıkış sistemi Kaza sonrası acil aydınlatma sistemi Kaza sonrası elektrik sisteminin kesilmesi Kaza sonrası yakıt sisteminin kesilmesi PASSIVE SAFETY Risk to pedestrians in event of collisions with passenger cars as a function of impact frequency and seriousness of injury (based on 246 collisions) PASSIVE SAFETY Exterior safety: The term "exterior safety" covers all vehicle-related measures which are designed to minimize the severity of injury to pedestrians and bicycle and motorcycle riders struck by the vehicle in an accident. Those factors which determine exterior safety are: • Vehicle-body deformation behavior, • Exterior vehicle-body shape. The primary objective is to design the vehicle such that its exterior design minimizes the consequences of a primary collision (a collision involving persons outside the vehicle and the vehicle itself). The most severe injuries are sustained by passengers who are hit by the front of the vehicle, whereby the course of the accident greatly depends upon body size. The consequences of collisions involving two-wheeled vehicles and passenger cars can only be slightly ameliorated by passenger-car design due to the two-wheeled vehicle's often considerable inherent energy component, its high seat position and the wide dispersion of contact points. Those design features which can be incorporated into the passenger car are, for example: • Movable front lamps, • Recessed windshields wipers, • Recessed drip rails, Recessed: Gönme, girintili Ameliorated: İyileştirmek, düzeltmek • Recessed door handles. PASSIVE SAFETY Interior safety The term "interior safety" covers vehicle measures whose purpose is to minimize the accelerations and forces acting on the vehicle occupants in the event of an accident, to provide sufficient survival space, and to ensure the operability of those vehicle components critical to the removal of passengers from the vehicle after the accident has occurred. The determining factors for passenger safety are: • Deformation behavior (vehicle body), • Passenger-compartment strength, size of the survival space during and after impact, • Restraint systems, • Impact areas (vehicle interior), (FMVSS 201), • Steering system, • Occupant extrication, • Fire protection. PASSIVE SAFETY Laws which regulate interior safety (frontal impact) are: • Protection of vehicle occupants in the event of an accident, in particular restraint systems (FMVSS 208, ECE R94, injury criteria), • Windshield mounting (FMVSS 212), • Penetration of the windshield by vehicle body components (FMVSS 219), • Parcel-shelf and compartment lids (FMVSS 201). Rating-Tests: • New-Car Assessment Program (NCAP, USA, Europe, Japan, Australia), • IIHS (USA, insurance test), • ADAC, ams, AUTO-BILD. Distribution of accidents by type of collision, symbolized by test methods yielding equal results An example crash test requirement profile Bernd Heißing | Metin Ersoy (Eds.), Chassis Handbook Fundamentals, Driving Dynamics, Components, Mechatronics, Perspectives, 2011 Şasi ve Karoseri Sistemleri ve Darbe Emici Sistemler: Baş yaralanma kriterinin (HIC - Head Injury Criterion) belirlenmesinde baş ivme değerleri kullanılmaktadır. Göğüs yaralanma kriteri; göğüs kafesinin müsaade edilebilir maksimum ivmesi ile sınırlandırılmıştır. Diğer genel şartlar şunlardır: • Çarpma sırasında kapılar açılmamalıdır, • Çarpmadan sonra kapılar yeterince açılabilmelidir, • Ön camın koruduğu bölgeye taşıt parçaları girmemelidir, • Direksiyon simidinin yatay kayma miktarı < 10 cm olmalıdır, • Yolcu mahallindeki kapaklar açılmamalıdır, • Hayati hacim boyutları küçülmemelidir. Bu şartların tamamlayıcısı olarak, darbe durumunda enerji absorbe edebilme özelliği bulunan ön yapı, belirli ve olabildiğince düzgün bir yavaşlama ivmesine sebep olmalıdır. Yolcu bölümü ise, mümkün olabildiğince sağlam ve şekil değişimine karşı dirençli olmalıdır. Eskinin ağır gövdeleri yerine, günümüzde uzay kafes (SF-space frame) sistemine göre üretilmekte olan yüksek dayanımlı profillerden yapılan hafif gövdeler ve çarpışma anındaki darbe kuvvetinin yolcu kafesine ulaşmadan sönümlenmesi için eklenen ön deformasyon kuşakları çarpışma anındaki kuvvetleri önemli ölçüde absorbe ederek hayat kurtarıcı bir fonksiyon üstlenmektedir. Darbe Emici Sistemler; gövde yapısı önden, arkadan ve yandan çarpmalardaki darbeyi sönümleyecek şekilde yapılmıştır. Takviye saçları ve elemanları sayesinde kabin deformasyonu minimumda tutularak yolcuların mükemmel korunması düşünülmüştür. Ön/Arka Çarpışmalarda Darbe Sönümleyici Yapı; ön ve arka çarpışmalarda mükemmel darbe sönümleme yapısı sayesinde kabini çevreleyen ön tampon takviyesi, alt gövde elemanları birbirine mükemmel şekilde bağlanmıştır. Önden ve arkadan çarpışma durumlarında alt gövde ve kabin şasisi darbe enerjisinin etkisini azaltmaya ve yaymaya yardımcı olur. Bunun sonucu olarak kabin deformasyonu en aza indirgenir. Şasi kolları üzerindeki çentikler sayesinde ön şasi kolları çarpışma enerjisini azaltmaya yardımcı olur. Bunun sonucu olarak motor da ön çarpışmalarda nispeten korunmuş olur. Yan Çarpışmalarda Darbe Emici Yapı; ön ve arka kapıların alt iç kısmına boru tipli çelik barlar monte edilmiştir. Ön ve arka kapıların iç ve dış kısmına monte edilen takviye saçları kapılara yandan gelen darbe enerjisini sönümler. Yan çarpışmalarda darbe enerjisi direk takviye saçları, çelik barlar, taban traversi yoluyla yolcu kabinine yayılır. Bu yayılmada bu elemanlar vasıtasıyla kabine direk giden enerji seviyesi minimumda tutulur. Bunlara ilave olarak kabin güvenliği açısından gövdede maksimum korunmayı sağlamak için yüksek mukavemetli çelik saçlar birbirine kaynatılmıştır. İlaveten baş bölgesi darbe koruyucu yapıda yapılmıştır. Kapı İçi Çelik Bar Sistemleri; her kapıda çelik bar sistemi bulunur ve yandan gelen darbelerde karşı mukavemet sağladığı gibi çarpışma enerjisinin de gövde üzerinde dağılımını sağlar. Ayrıca sürücü ve yolcuların üzerine gelebilecek olan hasarı minimize eder. Crumple Zones What do crumple Zones help us to do? Crumple Zones are structural area in the front and sometimes the rear of the vehicle designed to absorb energy upon an impact in a predictable way. Ezilme Bölgeleri Araçtaki ezilme bölgeleri kaza esnasında darbenin ortaya çıkardığı enerjiyi emmek üzere sıkışacak şekilde tasarlanmış yapısal bir özelliktir. Ezilme bölgeleri; önden çarpmalarda darbenin şiddetini azaltmak için genellikle aracın önüne yerleştirilir, ancak aracın diğer parçaları üzerinde de bulunabilir. Ezilme bölgeleri, araç tamamen duruncaya kadar geçen süreyi uzatır. Kuvvetlerin ve yavaşlamanın büyüklüğü daha uzun bir zamana yayıldığından yolcular bunu daha az hisseder. Dolayısıyla emniyet kemeri doğru şekilde bağlı olan bir yolcunun bedenine ve organlarına uygulanan kuvvet azalır ve çarpışma sonunda hayatta kalma şansı artar. Bir örnek verelim: 1500 kg ağırlığındaki bir araç, 40 km/h hızla bir duvara çarpıyor. 30 cm gövde deformasyonuna izin veren bir aracın darbe kuvveti yaklaşık 34,5 tondur. 50 cm deformasyona izin veren bir aracın darbe kuvveti yaklaşık 20 tondur. Araç gövde sağlamlığı araç üreticileriş tarafından sürekli geliştirilir. Aracın kabin ön duvarı, tavan köşesi ve C-sütunu gibi bazı bölgelerinde daha dayanıklı malzemelerin kullanılması gövde sağlamlığını artırdığından mükemmel çarpışma derecesi elde edilir. Kia, Hava Yastığı, 2010 Ezilme Bölgeleri Kia, Hava Yastığı, 2010 SASİ VE GÖVDE EMNİYET UYGULAMALARINA ÖRNEKLER Mercedes’ new GL-Class Ensuring a large SUV protects its occupants and other road users presents a significant challenge. Crash Test Technology International, SEPTEMBER 2012 Çarpmalarda Şasi ve Karoserinin İşlevi Kaynak: “Şase ve Karoseri” Sunumu, TÜVTURK, 08/03/2006. Çarpmalarda Şasi ve Karoserinin İşlevi Kaynak: “Şase ve Karoseri” Sunumu, TÜVTURK, 08/03/2006. GÖVDE VE GÜVENLİK Ön ve arka şasi kollarını birleştiren takviye barlar alüminyumdan yapılmıştır. Taşıyıcı bar cıvata ile yüksek dayanımlı çelik (HSS) deformasyon elemanıyla birlikte şasiye cıvata ile bağlanmıştır. Deformasyon elemanına çarpışma kutusu adı verilir ve ön şasiye cıvatalıdır. Opel Vectra, Gövde ve Güvenlik GÖVDE VE GÜVENLİK Opel Vectra, Gövde ve Güvenlik GÖVDE VE GÜVENLİK Opel Vectra, Gövde ve Güvenlik GÖVDE VE GÜVENLİK Opel Vectra, Gövde ve Güvenlik Kaynak: Toyota GÖVDE VE GÜVENLİK Opel Vectra, Gövde ve Güvenlik GÖVDE VE GÜVENLİK Opel Vectra, Gövde ve Güvenlik Kaynak: Toyota Kaynak: Toyota Pop-up Hood (Evolving GOA) Kaynak: Toyota Kaynak: Toyota Kaynak: Toyota EOS 2006 EOS 2006 EOS 2006 EOS 2006 Önden çarpışmada kuvvet akışı: Önden çarpışmada meydana gelen kuvvetler üst ve alt şasi kolları üzerinden taban grubuna ve tavan sütunlarına verilir. 2006 Passat 2006 Passat EOS 2006 EOS 2006 EOS 2006 Audi Q7 Servis Eğitimi READING TEXT Reading text Head acceleration values are used to determine the head injury criterion (HIC). The comparison of measured values supplied by the dummies with the permissible limit values as per FMVSS 208 (HIC: 1000, chest acceleration: 60 g/3 ms, upper leg force: 10 kN) are only limited in their applicability to the human being. The side impact, as the next most frequent type of accident, places a high risk of injury on the vehicle occupants due to the limited energy absorbing capability of trim and structural components, and the resulting high degree of vehicle interior deformation. The risk of injury is largely influenced by the structural strength of the side of the vehicle (pillar/door joints, top/bottom pillar points), load-carrying capacity of floor cross-members and seats, as well as the design of inside door panels (FMVSS 214, ECE R95, Euro-NCAP, US-SINCAP). In the rear impact test, deformation of the vehicle interior must be minor at most. It should still be possible to open the doors, the edge of the trunk lid should not penetrate the rear window and enter the vehicle interior, and fuel-system integrity must be preserved (FMVSS 301). Roof structures are investigated by means of rollover tests and quasi-static car-roof crush tests (FMVSS 216). In addition, at least one manufacturer subjects his vehicles to the inverted vehicle drop test in order to test the dimensional stability of the roof structure (survival space) under extreme conditions (the vehicle falls from a height of 0.5 m onto the left front corner of its roof). Passenger compartment integrity The compartment that houses the driver and passengers should remain intact after an accident. Four measures are necessary: • one is to incorporate crush zones at the each end of the car; • the second is to stiffen the door and its immediate surroundings so that, in the event of a side impact, it will not be penetrated or deflected violently inwards and strike the occupants; • third, the door trim must be soft or side air bags must be installed so that, if the occupants are flung against it by the lateral acceleration, they will not be seriously injured; and • fourth, the door frame and not only its joins but also those between the pillars and cant rail must be strong and stiff enough to react elastically to absorb the shock loading. Basically, the occupants must be housed in what amounts to a strong cage, which will protect them also if the car rolls over. This generally entails the use of substantial fillets, and perhaps the fitting of reinforcement plates, at the joints between the pillars and the cant rails and sills. With the current need to reduce overall weight, the use of thin gauge high strength ductile steel, instead of the traditional thicker gauge high ductility material for structural members and some body panels can help to improve both crushability and integrity of structures. Automotive Engineering - Powertrain, Chassis System and Vehicle Body, Edited by David A. Crolla PASSIVE SAFETY It is important to design so that the loads due to an impact (whether front, rear or side) are, so far as practicable, spread uniformly throughout the whole structure and that the proportions of all the principal members of the cage containing the occupants are adequate to react those loads elastically. Diagonal and transverse members may have to be incorporated under the floor and, possibly, in the roof to transfer some of the loads from one side to the other especially, although not solely, for catering for side or offset frontal impacts. If the shock to the occupants is to be reduced significantly, a considerable proportion of the total kinetic energy of the moving vehicle must be absorbed by the crush zone as it collapses. At the front, the space between the grille and engine is inadequate for absorbing that energy, except in very minor collisions. Consequently, in the more severe accidents the engine will be pushed back, and it is important to prevent it from thrusting the dash and toe board back until they strike the occupants and possibly trap them in their seats. Consequently, the engine is generally mounted in a manner such that it will be deflected downwards and slide under the toe board. In particular, if the engine is on a sub-frame, the attachment of the longitudinal members of that frame to the toe board and front floor can be designed to shear, to enable the whole installation to slide back under the floor. Even so, the dash and toe board structure must still be stiff enough to prevent significant engine intrusion into the saloon. At the rear, there is more space for a crush zone, but the fuel tank must not be ruptured, which is the reason for the modern trend towards installing fuel tanks much further forward than hitherto. Automotive Engineering - Powertrain, Chassis System and Vehicle Body, Edited by David A. Crolla PASSIVE SAFETY Ideally, the structure should collapse progressively at a constant rate, as if it were a sprung buffer, Fig. A. One design method that has been successful is to bow the longitudinal members so that they either spread outwards or collapse progressively inwards when heavily loaded in compression. Another is to incorporate vertical swaged grooves in the side walls of straight members so that they collapse in a controlled fashion. Ideally, the swages would be distributed alternately, along each side, over the length of the longitudinal members of the frame or sub-frame. However, the zig-zag, or concertina type of collapse thus aimed at is extremely difficult to achieve in practice. Once the first kink has formed, usually at the foremost swage, the member is already bowed and therefore is more likely to continue to do so than to concertina. One manufacturer has notched the corners of the rectangular section longitudinal members to initiate progressive collapse. Each notch extends from the corner only a very short distance down one face and a long distance across the other face. However, one should be wary of introducing notches in such structural members subject to fatigue loading, since cracks are liable to be generated by and spread from the stress concentrations thus induced. Automotive Engineering - Powertrain, Chassis System and Vehicle Body, Edited by David A. Crolla PASSIVE SAFETY Fig. A: Diagrammatic representation of front longitudinal frame member carrying the suspension and engine. The lengths of the swages, in each set of four (in the top, bottom and two sides of the frame), become progressively smaller, from the foremost to the rearmost, so that the frame will offer progressively increasing resistance to collapse in a frontal impact. The lower diagram shows it only partially collapsed. Automotive Engineering - Powertrain, Chassis System and Vehicle Body, Edited by David A. Crolla PASSIVE SAFETY It is preferable to encourage simple bowing by siting all the swages along either the outer or the inner face rather than the top and bottom of each member, to cause both to bow respectively either inwards or outwards. If both bow outwards, the restriction imposed by the body panelling attached to them will help considerably in providing a progressive reaction to the crushing force, If they bow inwards, they are similarly restricted, but perhaps by the presence of the engine between them. Inward bowing, however, tends to absorb more energy per unit of length of collapse. This might or might not be what is desired, hence crash testing is essential for proving designs. An aspect that should not be overlooked is that swaging the sides of the longitudinal members will reduce their stiffness for reacting to side loads. This need not be serious if the ends of the vertical swages terminate short of the junction with the top and bottom plates, each of which will then become, in effect, a separate U-section member. The ends of the arms of each U terminate where the swages begin, Fig. B. Incidentally, box section longitudinal members can be welded fabrications. Alternatively, they could be square section tubes, the swages being produced by hydroforming, using internal hydraulic pressure to expand the tube into a mould. Automotive Engineering - Powertrain, Chassis System and Vehicle Body, Edited by David A. Crolla PASSIVE SAFETY Fig. B: Sections through two box section frame side members, one tubular and the other fabricated. Although the swages in their sides weaken them so far as taking side loads is concerned, these loads can be taken mainly in the sections ABCD and EFGH. A useful rule of thumb is that a length equal to 16 multiplied by the thickness of the metal represents the maximum length that is stable on each side of each angle under compression, the measurement being taken from the inner face in each corner or, for the fabricated section, the centres of the bends. Automotive Engineering - Powertrain, Chassis System and Vehicle Body, Edited by David A. Crolla The problem of the small car In an impact with a large car, a small car is inevitably at a disadvantage because the inertia of the former is greater than that of the small car. Moreover, the provision of a crush zone of adequate length at both the front and back of the small vehicle is, of course, much more difficult. For this reason, the principle of designing for the engine so that, when thrust backwards, it slides down beneath the toe board and floor is the only practicable course. Furthermore, maximum use should be made of transverse members to distribute the loads appropriately between all the longitudinal members, including the body panelling, in a manner such that they are all equally stressed, as in Fig. C. Fig. C: Plan view of a Toyota frame designed to spread the loads imposed by front and rear end impacts uniformly throughout the structure. The combination of the front transverse member and the diagonal members, A and B, one on each side, triangulate the front end of the frame to constrain it to collapse concertina fashion, as shown in Fig. A. Scrap view above: elevation of a different frame, showing how the loads are distributed as viewed in a vertical plane. The triangulation struts shown in this example are fitted in the door frames. Automotive Engineering - Powertrain, Chassis System and Vehicle Body, Edited by David A. Crolla PASSIVE SAFETY The problem of the small car (cont.) An interesting feature in this illustration is the pair of gusset struts, one each side, between the front transverse member and each longitudinal side member. If an impact occurs as indicated by either of the two thick arrows, the corner affected by the impact will be pushed back. The gusset strut will stabilise the front end of the side member so that, assuming it is designed to collapse concertina fashion, it will not bow. Moreover, the transverse member will tend to pivot about the opposite corner, which will be stiffened by the gusset strut. It therefore will offer more resistance to the pivoting movement, and therefore a larger share of the impact loading will be transferred to that side than if there were no gusset member there. At the rear, the design is such that the spare wheel will help to take some of the loading from a rear end impact and transfer it to the main structure. Automotive Engineering - Powertrain, Chassis System and Vehicle Body, Edited by David A. Crolla PASSIVE SAFETY At the rear, the main requirement again is to utilise transverse members to the best advantage. Also important is a robust C-pillar and a good supporting structure for the rear axle. Double skinning the rear quarter panels can enormously strengthen that part of the structure, although this does raise problems as regards repair to minor damage. In general, the overall strength and integrity of the occupant cage may need to be higher than that of a car with long crush zones front and rear. Side impacts As regards side impacts, there is not enough space within doors to serve as a crush zone, so the emphasis is on the use of transverse members between the sills and cant rails to share the loading between the structural elements on both sides of the vehicle. Within the doors themselves, horizontal beams the ends of which are securely fixed to the front and rear frame members of each door are widely used. However, it is difficult to make them stiff enough to help much unless the frame and especially its waist and bottom rails are very stiff, so that vertical or diagonal beams can be fixed to them to support the centre of the horizontal ones. The longer the door, the more intractable is the problem. Of particular importance is that the B-pillar be strong enough to prevent it and, with it, both doors from being pushed inwards in a side impact situation. Automotive Engineering - Powertrain, Chassis System and Vehicle Body, Edited by David A. Crolla PASSIVE SAFETY In general, if the central portion of the outer panel of the door is thrust inwards, it will tend to pull not only its front and rear edges, but also the waist and bottom rails towards each other. Consequently, all these members must be adequately stiff. Another measure that has been adopted, for example by Volvo, is to fill the space between the outer and inner panels of the door with a plastics honeycomb. If the hexagonal elements of the honeycomb are fairly thick, the filling as a whole will offer significant resistance to penetration. Moreover, it also transfers some of the loading radially outwards to the door frame members and thus further reduces the tendency towards penetration of the door. It would appear, however, that structural stiffening alone will not be sufficient to satisfy future legislation, so the installation of side air bags to supplement the door stiffening measures will probably be inescapable. Arm rests which could be forced against the vulnerable areas of the lower ribs of the occupants, should not be installed. Automotive Engineering - Powertrain, Chassis System and Vehicle Body, Edited by David A. Crolla PASSIVE SAFETY In general, if the central portion of the outer panel of the door is thrust inwards, it will tend to pull not only its front and rear edges, but also the waist and bottom rails towards each other. Consequently, all these members must be adequately stiff. Another measure that has been adopted, for example by Volvo, is to fill the space between the outer and inner panels of the door with a plastics honeycomb. If the hexagonal elements of the honeycomb are fairly thick, the filling as a whole will offer significant resistance to penetration. Moreover, it also transfers some of the loading radially outwards to the door frame members and thus further reduces the tendency towards penetration of the door. It would appear, however, that structural stiffening alone will not be sufficient to satisfy future legislation, so the installation of side air bags to supplement the door stiffening measures will probably be inescapable. Arm rests which could be forced against the vulnerable areas of the lower ribs of the occupants, should not be installed. Automotive Engineering - Powertrain, Chassis System and Vehicle Body, Edited by David A. Crolla ÇARPIŞMA TESTLERİ NCAP Çarpışma Testi ve Derecelendirme Günümüzde güvenlik bir aracın satışında eskiye oranla daha önemlidir. Müşteriler için satış kararının en belirleyici unsurudur. Müşterilerin özel araç modellerinin performansına bağlı olarak güvenilir ve eksiksiz bir biçimde karşılaştırmalı bilgilere ulaşmaları önemlidir. Kanunen tüm yeni araç modelleri satılmadan önce belirli güvenlik testlerinden geçmelidir. Yine de yönetmelik yeni araçların güvenliği için asgari hukuki bir standart belirler, üreticileri bu asgari gereksinimlerin üzerine çıkma hususunda cesaretlendirme görevi Euro ve Ulusal Otoban Trafik Emniyeti Kurumu (NHTSA) Yeni Araç Değerlendirme Programı'na (NCAP) aittir. Önemli Not: Test prosedürleri açısından Euro ve NHTSA arasında farkların olduğunu unutmayın. Ön darbe testi: Ön darbe testi yönetmelik esasına göre Avrupa Geliştirilmiş Araç Güvenliği Kurulu tarafından geliştirilmiştir, fakat darbe hızı 8 km/h artırılmıştır. Ön darbe 64 km/h'de (40 mil/h) gerçekleştirilir, araç dengelenmiş deforme olabilen bariyere çarpar. Cansız mankenler üzerinden alınan değerler, ön koltuktaki yolcuların güvenliği belirlemek için kullanılır. Yan darbe testi: Darbe 50 km/h'de (30 mph) gerçekleşir Yan darbe testi simülasyonu için aracın sürücü tarafına doğru ön kısmı deforme olabilen bir vagon çekilir. Sürücü güvenliğini belirlemek için manken üzerinden alınan değerler kullanılır. Kia, Hava Yastığı, 2010 NCAP Çarpışma Testi ve Derecelendirme Kia, Hava Yastığı, 2010 Çarpışma Testi Mankenleri Cansız mankenler üzerinde defalarca doğrudan çarpışma gerçekleştirilir. Mankenlerin görevi hayatidir: Kaza simülasyonları, bir kaza esnasında olası yaralanmaların tümünü göstermek için araç içindeki bir sürücü ve yolcu ile gerçekleştirilir. Mankenler normal sürücü ve yolcu değildir: Çelik gövdelidir, duyarlı bir ekipmanla donatılmıştır ve lastikle kaplıdır. Mankenler, çarpışma esnasında ne olduğu hakkında hayati bilgiler sağlar. Uzuvları tek tek açıklayan kılavuz, verinin nasıl sağlandığını açıklar. Baş: Mankenin başı alüminyumdan yapılmıştır ve içi lastikle doldurulmuştur. İçinde çarpışma esnasında beynin maruz kalabileceği kuvvetler ve hızlanma verilerini gösteren her biri dik açıyla yerleştirilmiş üç adet hız ölçer vardır. Boyun: Çarpma esnasında baş ileriye ve geriye doğru hareket ettiğinde, boyun üzerindeki bükülme, kopma ve eğilme kuvvetlerini tespit eden cihazlar vardır. Kollar: Kollarda herhangi bir alet bulunmaz. Çarpışma testinde kollar kontrolsüz olarak sallanır, ciddi yaralanmalar nadir görülmesine karşın kollar için tam bir koruma sağlamak zordur. Kia, Hava Yastığı, 2010 Çarpışma Testi Mankenleri Göğüs (ön darbe): Çelik kaburgaya ön darbe esnasında göğüs kafesinin esnemesini kaydeden bir cihaz takılmıştır. Örneğin emniyet kemerlerinden gelen gibi göğüs üzerindeki kuvvet büyük olduğunda yaralanma meydana gelir. Göğüs (yan darbe):Yan darbe mankeninin göğsü diğerlerinden farklıdır, göğüs basıncını ve bu basıncın hızını kaydetmek için üç kaburga ölçülür. Karın: Mankene, pelvis kemerine yerleştirilen göstergeler kullanılarak karında yaralanmaya neden olabilecek kuvvetleri kaydeden sensörler yerleştirilmiştir. Kırığa veya kalça çıkığına neden olabilen yanal kuvvetleri kaydeder. Üst Bacak: Bu bölüm pelvis, uyluk kemiği (uyluk) ve dizden oluşur. Uyluk kemiğindeki yük hücreleri; kırığın veya kalça çıkığının görülebileceği kalça eklemi dahil tüm bölümlerde yaralanmaya neden olabilecek önden çarpmalar hakkında veri saptar. Özellikle alt panele çarptığında mankenin dizlerinden iletilen kuvveti ölçmek için bir 'dizlik' kullanılır. Alt Bacak: Mankenlerin bacaklarının içerisine takılan göstergeler, kaval kemiğinin (incik kemiği) ve fibulanın (dizi ayak bileğine bağlar) yaralanma riskiyle birlikte bükme, kopartma ve eğilme kuvvetlerini de hesaplar. Ön darbe esnasında ayak ve dizlerin yaralanma riski, sürücünün ayak bölmesindeki esneme ve geriye doğru hareketi ölçüldükten sonra belirlenir. Kia, Hava Yastığı, 2010 Çarpışma Testi Mankenleri Boyun, ön darbe mankeni Göğüs, yan darbe manken Kia, Hava Yastığı, 2010 The most widely used vehicle safety systems worldwide are those modeled after the New Car Assessment Program (NCAP), introduced by the National Highway Traffic Safety Administration (NTHSA) in the U.S in 1979. This program has branched into several regional programs including Australia and New Zealand (ANCAP), Latin America (Latin NCAP), China (C-NCAP) and Europe (Euro NCAP). David Egertz, Sohrab Kazemahvazi, Stefan Hallström, “Novel Safety Requirements and Crash Test Standards for Light-Weight Urban Vehicles”, Stockholm, 2011-01-28 Crash tests on cars in the European market are most often tested according to the Euro NCAP standards. These tests are not mandatory, so vehicles are either tested on initiative by Euro NCAP or by the manufacturers themselves [1]. The tests used are based on the Whole Vehicle Type Approval (ECWVTA) directive by the European Commission [7], which dictates the requirements for making a vehicle legal for sale within the European Union. Euro NCAP’s performance requirements are higher than those described in the directive, and are constantly increasing to inspire safety improvements. Safety ratings are reported by star ratings. David Egertz, Sohrab Kazemahvazi, Stefan Hallström, “Novel Safety Requirements and Crash Test Standards for Light-Weight Urban Vehicles”, The Euro NCAP tests have undergone several evaluations to estimate the effectiveness of the test procedures. These studies show that every added star represents a 12% reduction in collision fatality rates [9]. The crash tests conducted by Euro NCAP are [10]: • Frontal impact into a deformable offset barrier at 64 km/h. • Car to car side impact into the driver’s door at 50 km/h. • Pole side impact into rigid pole at 29 km/h. • Pedestrian impact at 40 km/h. • Rear impact whiplash injury test David Egertz, Sohrab Kazemahvazi, Stefan Hallström, “Novel Safety Requirements and Crash Test Standards for Light-Weight Urban Vehicles”, Stockholm, 2011-01-28 These tests include child protection tests and the implementation of active safety assisting equipment like electronic stability control (ESC), seat belt reminders, speed limitation devices and anti-lock braking systems (ABS) [10]. Crash test scores are then declared with respect to and weighed according to: • 50% - Adult occupant assessment • 20% - Child occupant assessment • 20% - Pedestrian assessment • 10% - Safety assist assessment Figure 1: Euro NCAP’s weighing of test results from each assessment protocol to obtain the final score. David Egertz, Sohrab Kazemahvazi, Stefan Hallström, “Novel Safety Requirements and Crash Test Standards for Light-Weight Urban Vehicles”, Stockholm, 2011-01-28 Safety Assisting Equipment Unlike all other Euro NCAP testing procedures, the safety assist functions do not require any destructive testing. The aim with the protocol is promote standard fitment of safety assisting equipment such as Electronic Stability Control (ESC), Anti-Locking Brakes (ABS), Seat Belt Reminders and Speed Limitation Devices. The scoring of these systems is based on primarily the fitment of such equipment and secondary on the performance of this equipment. David Egertz, Sohrab Kazemahvazi, Stefan Hallström, “Novel Safety Requirements and Crash Test Standards for Light-Weight Urban Vehicles”, Stockholm, 2011-01-28 Frontal Impact Euro NCAP frontal impact tests are performed at an impact velocity of 64 km/h, 8 km/h higher than limits legislated by ECWVTA. The test shall represent two similar cars colliding with each other in a 40% offset impact, which is considered as the most common traffic accident resulting in severe injury or death. 40% meaning that the 40% of the vehicles frontal structure is struck in the impact. Figure A.2 Frontal impact crash test setup David Egertz, Sohrab Kazemahvazi, Stefan Hallström, “Novel Safety Requirements and Crash Test Standards for Light-Weight Urban Vehicles”, Frontal Impact The protection level is assessed using a frontal impact crash test dummy which measure accelerations, forces, deflections and deformations. Çarpışma testlerinde Pelvis: Leğen kemiği kullanılan mankenler Femur: Uyluk kemiği (Dummy) Tibia: Kaval kemiği Yapılan çarpışma testlerinde oluşabilecek yaralanmaları belirleyebilmek için elektronik sensörlerle donatılan son derece gelişmiş mankenler (dummy) kullanılmaktadır. Aynı zamanda üretici firmaların önerdiği çocuk koltukları da araca yerleştirilip çarpışmalarda çocukları koruyup korumadığı Crash test dummy results are presented using a five step scale. belirlenmektedir. David Egertz, Sohrab Kazemahvazi, Stefan Hallström, “Novel Safety Requirements and Crash Test Standards for Light-Weight Urban Vehicles”, Stockholm, 2011-01-28 Reading Text: In a frontal collision, kinetic energy is absorbed through deformation of the bumper, the front of the vehicle, and in severe cases the forward section of the passenger compartment (dash area). Axles, wheels (rims) and the engine limit the deformable length. Adequate deformation lengths and displaceable vehicle aggregates are necessary, however, in order to minimize passenger-compartment acceleration. Damage to the passenger compartment should be minimized. This concerns primarily • dash area (displacement of steering system, instrument panel, pedals, toe-panel intrusion), • underbody (lowering or tilting of seats), • the side structure (ability to open the doors after an accident). Acceleration measurements and evaluations of high-speed films enable deformation behavior to be analyzed precisely. Dummies of various sizes are used to simulate vehicle occupants and provide acceleration figures for head and chest as well as forces acting on thighs. Automotive Handbook Car to Car Side Impact Car side impact tests are performed by using a movable deformable barrier as seen in Figure. The impact is centered at the driver’s door at an impact velocity of 50 km/h. Figure : Car to car side impact test setup. David Egertz, Sohrab Kazemahvazi, Stefan Hallström, “Novel Safety Requirements and Crash Test Standards for Light-Weight Urban Vehicles”, Car to Car Side Impact The aim with the test procedure is to assess any intrusion and occupant protection obtained from the cars side structure, but also to encourage the implementation of side airbags. To assess the occupant protection a side impact test dummy is used. Measures that are recorded are accelerations, forces, moments and deflections. Thoraks: Göğüs kafesi Rib: Kaburga kemiği Figure: Side impact crash test dummy rating. David Egertz, Sohrab Kazemahvazi, Stefan Hallström, “Novel Safety Requirements and Crash Test Standards for Light-Weight Urban Vehicles”, Stockholm, 2011-01-28 Pole Side Impact The pole side impact tests goal is to encourage the fitting of head protection devices such as side impact head or curtain airbags and padding. Since the pole is relatively narrow, 10’’, or 254 mm, major intrusion is a common result. The test is performed by propelling the vehicle into a rigid pole at 29 km/h, representing the vehicle skidding into a pole or a tree, see Figure. Since 2009 this test is mandatory in the assessment process, and focuses on head, chest and abdomen protection. Before 2009 it was an optional test for manufacturers to demonstrate the efficiency of their head protection features. Figure: Pole side impact test setup David Egertz, Sohrab Kazemahvazi, Stefan Hallström, “Novel Safety Requirements and Crash Test Standards for Light-Weight Urban Vehicles”, Pole Side Impact Figure: Pole side impact crash test dummy rating. David Egertz, Sohrab Kazemahvazi, Stefan Hallström, “Novel Safety Requirements and Crash Test Standards for Light-Weight Urban Vehicles”, Pedestrian Protection The pedestrian protection protocol has been a part of Euro NCAP since the start in 1997. Up to 2009 this test had a separate star rating but is now an integral part of the overall rating scheme seen in Figure A.1. Euro NCAP performs a series of tests to evaluate the pedestrian protection for both adult and child pedestrians. During the tests individual vehicle components are assessed to have a better control of the pedestrian impact locations. A legform is used to test the protection of the lower leg towards the front bumper, an upper legform to test the protection towards the leading edge of the bonnet and a child and adult headform to test the protection towards the bonnet top area and windscreen. The tests shall represent an impact velocity of 40 km/h. Figure: Pedestrian impact test setup and rating system. David Egertz, Sohrab Kazemahvazi, Stefan Hallström, “Novel Safety Requirements and Crash Test Standards for Light-Weight Urban Vehicles”, Whiplash Protection The whiplash testing procedure is not a crash test involving the actual vehicle, but instead the seat and head rest assembly. The test is performed with the use of a crash sled on which the vehicle seat with a crash test dummy is fitted. The sled is then subjected to three different crash pulses with varying severity; low, medium and high. The low severity pulse accelerates the sled to approximately Dv=16 km/h in 100ms, and the high severity pulse to approximately Dv=25 km/h in 100ms [23][36]. These pulses are derived from both real world crashes and insurance industry research. The whole concept of whiplash injury is not yet entirely understood, especially the injury causing mechanisms of it, but the high frequency of this injury type has motivated Euro NCAP to include it into its adult occupant protection protocol since January 2009. Figure: Rear impact whiplash rating. David Egertz, Sohrab Kazemahvazi, Stefan Hallström, “Novel Safety Requirements and Crash Test Standards for Light-Weight Urban Vehicles”, Child Protection The child occupant protection is a part of the frontal and car-to-car side impact testing procedures, but also addresses usability of the child restraints (CRS). Since it has shown that many child restraint users fail to secure the restraint safely to the car, Euro NCAP encourage improvements to child restraint design and the installation of standardized mountings such as ISOFIX. In the testing, dummies representing 18 month and 3 year old children are used (Figure 1-2), and the score depends on the child seats dynamic performance in frontal and side impact tests. Additionally, fitting instructions, airbag warning labels and the vehicles ability to accommodate the child restraint safely is also included in the overall scoring. Figure: Child protection testing rating scheme of 18 month old child. Figure: Child protection testing rating scheme of 3 year old child. David Egertz, Sohrab Kazemahvazi, Stefan Hallström, “Novel Safety Requirements and Crash Test Standards for Light-Weight Urban Vehicles”, Child Protection A- Dynamic Assessment B- Frontal Impact C- Side Impact David Egertz, Sohrab Kazemahvazi, Stefan Hallström, “Novel Safety Requirements and Crash Test Standards for Light-Weight Urban Vehicles”, Child Protection D- Child Restraint Based Assessment E- Vehicle Based Assessment David Egertz, Sohrab Kazemahvazi, Stefan Hallström, “Novel Safety Requirements and Crash Test Standards for Light-Weight Urban Vehicles”, ÖZET…. Fig.: Some of the tests done by manufacturers to ensure that the occupants of their vehicles will be, so far as is practicable, safe in the event of an accident. At (a) is the simple basic zero offset frontal impact, at (b) is a 30 offset, at (c) a 40% offset and at (d) a pole impact test. A side impact test for representing an impact between two vehicles moving along lines at right angles to each other is shown at (e) while, at (f ), the vehicle that is struck is stationary. Finally, a rear end impact test is shown at (g). Automotive Engineering - Powertrain, Chassis System and Vehicle Body, Edited by David A. Crolla
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