Mehmet Murat Topaç

Dokuz Eylul University | DEÜ · Department of Mechanical Engineering

Failure analysis and optimal redesign study of the connecting rod prototype to be used in the multi-axle steering linkage of an 8x8 Aircraft Rescue and Fire Fighting (ARFF) vehicle is reported. At the prototyping stage, the field tests showed that the connecting rod experiences a plastic deformation during a zero-speed steering manoeuvre. In order...

The effect of damping rate on the failure tendency of a truck cab suspension swing arm was numerically investigated. Firstly, the mechanical design of the swing arm was carried out using topology optimisation by taking the standard load cases into account. Displacement differences which occurred in the front cab suspension springs, as a result of t...

Design and experimental validation stages of an independent front suspension (IFS) that is designed for truck tractors of articulated commercial vehicles are summarised. Firstly, the suspension geometry, which satisfies the required conditions of minimum deviation of camber angle and track width during wheel travel, is obtained within the given des...

The origin of fatigue failure that occurs on the air ventilation holes of a newly designed heavy commercial vehicle steel wheel in dynamic radial fatigue tests is studied. In these tests, all of the test samples failed in the same regions. The cause of this damage was studied via finite element analysis. In order to determine the reason of the fati...

A premature failure that occurs prior to the expected load cycles during the vertical fatigue tests of a rear axle housing prototype is studied. In these tests, crack mainly originated from the same region on test samples. To determine the reason of the failure, a detailed CAD model of the housing was developed. Mechanical properties of the housing...

The design and optimisation stages of the connecting arm, which distributes the steering torque from the pitman arm to the front axle wheels of a 6x6 heavy-duty vehicle steering system, are summarised. For this purpose, firstly, the steering mechanism was modelled in MATLAB® environment as two four-arm mechanisms acting simultaneously. The idealise...

In this study, the effects of the cross member structural parameters on the torsional stiffness of the ladder chassis of a 4x4 special purpose truck were examined and the mass reduction of the frame was carried out. In the first stage, a simplified sub-model of the chassis, consisting of U-section longitudinal beams and closed circular cross-sectio...

In this study, the design and optimisation processes of the link used in the steel track undercarriage system of a tracked vehicle are summarised. In the first stage, a preliminary model was created by considering the applied design examples and design constraints. Two different Finite Element (FE) models were established with the help of the maxim...

Due to the increasing number of internal combustion engine vehicles, fossil fuel sources have decreased drastically in the last century. In addition, the concerns about global warming caused by vehicle emissions have led automotive manufacturers to search for new alternatives to transport. Quadricycles have started to be seen as future transport ve...

Günümüzde ulaşım, genellikle sabit güzergâhla toplu taşıma ve bireysel taşıtlar arasında bir seçim sunmaktadır. Özellikle konvansiyonel içten yanmalı motorla donatılmış bireysel taşıtların kullanımı, şehir trafiğinde yoğunluğa bağlı tıkanıklıklara, sera gazı emisyonuna ve çevre kirliliğine neden olmaktadır. Artan nüfusa karşın enerji kaynaklarının...

Çok amaçlı yürür askeri platformlar, aynı şasi tasarımı üzerine monte edilebilen farklı üstyapılar yardımıyla çok çeşitli tiplerde özel maksatlı taşıtların pratik şekilde üretimine imkân sağlamaktadır. Bu sistemler, söz konusu özelliklerinden dolayı, savunma sanayiinde giderek daha geniş bir uygulama sahası bulmaktadır. Modern tekerlekli yürür aske...

İnsansız Kara Taşıtları / Araçları (İKT ya da İKA), askeri ve sivil sektörlerde giderek artan bir kullanım alanına sahiptir. Bu sistemler, askeri alanda gözetleme, keşif, mayın tarama, belirli bir hedefe atış yapma gibi görevleri yerine getirirken, sivil sektörde de tarım ve inşaat gibi endüstrilere katkı sağlamaktadır. İKT’ler, zorlu arazi koşulla...

Sabit akslar, basit yapı, yüksek yük taşıma kapasitesi ve kolay imal edilebilirlik gibi özellikleri sebebiyle, ağır ticari taşıtlarda özellikle tahrik aksı olarak halen geniş bir kullanım alanı bulmaktadır. Tahrikli sabit aks uygulamalarında diferansiyel, bir aks kovanı içine yataklanmakta ve vites kutusu ya da transfer kutusundan diferansiyel piny...

The effect of the eccentric tie rod to be used in the steerable rigid front axle of a military purpose 4x4 chassis platform, on the structural behaviour of the steering system was investigated with the help of Finite Element Analysis (FEA). For this purpose, firstly, a detailed solid model of the solid axle including the Ackermann trapezoid was bui...

The structural investigation of the independent suspension system used in a prototype tracked unmanned weapon platform was carried out with the help of Finite Element Analysis (FEA). For this purpose, firstly, the vertical force acting on the track rollers on flat ground and fully loaded is calculated with the help of an idealized track-ground cont...

Special-purpose mobile robots are increasingly in demand due to their ability to perform dangerous tasks such as firefighting and demining without risking human life. Crawler track undercarriage systems are mostly preferred especially in off-road types of these systems because of their advantages in terms of traction and handling. In this study, a...

The variation of the stresses under the operating loads on the link designed for a steel track crawler platform, according to the link-pulley contact position was investigated. For this purpose, a subsystem model was created that includes three links of the track chain. A simplified load model was established for the structural analyses, considerin...

Crawler track undercarriage systems have a wide range of applications in many different disciplines such as defence, construction, mining, agriculture and mobile robotics. One of the widely used types of these structures, which can operate with high performance in off-road conditions such as soil, mud and snow, is the steel track system. In these s...

Havaalanlarında yolcu taşıma amacıyla kullanılacak bir apron otobüsünün, yanal ivme altındaki yalpa eğiliminin azaltılması için gerçekleştirilmiş tasarım iyileştirme ve saha testi çalışmaları özetlenmiştir. İlk olarak, seçilen referans taşıta uygulanan testler sonucunda, hedef yalpa karakteristiği belirlenmiştir. İkinci aşamada, oluşturulan ön prot...

The effects of cross member section and connection type on the torsional stiffness of the bus structure are discussed. In the first stage of the study, a detailed virtual model of the vehicle body including the superstructure and the chassis frame is built. Pure torsion simulations are carried out on this model by using finite element (FE) analysis...

Torsiyon milleri, çeşitli taşıt süspansiyon uygulamalarında yay görevini üstlenen yapısal elemanlardır. Yol konforuna verilen önemin gün geçtikçe artmasıyla daha geniş alanlarda kullanılmaya başlanan kabin süspansiyonlarında, torsiyon milleri sıklıkla kullanılmaktadır. Bunun önemli bir sebebi olarak, torsiyon millerinin diğer süspansiyon sistemi ya...

Modüler üst yapıya sahip özel amaçlı 8x8 Havalimanı Kurtarma ve Yangınla Mücadele (ARFF) taşıtında kullanılan burulmaya dayanıklı merdiven şasinin, simetrik olmayan tekerlek yükleri altındaki yapısal davranışı sayısal olarak incelenmiştir. Bu amaçla, şasinin basitleştirilmiş bir alt modeli oluşturulmuştur. Aynı aksa bağlı tekerlerde, yol düzgünsüzl...

Structural analysis and design evaluation of a torsion resistant ladder chassis used in a special purpose 8x8 Airport Rescue and Firefighting (ARFF) vehicle with modular superstructure are carried out. For this purpose, firstly, a method for the structural analysis of multi-axle vehicle frames is suggested. The finite element (FE) model of the fram...

Conceptual development stages of a newly designed L6e class quadricycle structure are reported. In the first part, general design requirements and limitations for the urban microcars, such as design volume, structural dimensions, weight and motor power are reviewed. Subsequently, design concept of the microcar body is presented. Some possible load...

Considered as a safety sub-system, steering linkages should work under variable loads that arise in any extreme conditions during operation of the vehicle. Therefore, they should resist failure during service conditions, which require sufficient mechanical strength against different stress values. During the mechanical design stages of a steering l...

8x8 zırhlı askeri taşıtlarda uygulanabilecek bir bağımsız süspansiyonun kavramsal tasarımı özetlenmiştir. İlk aşamada, süspansiyon bağlantı noktalarının, tasarım hacmi içerisindeki uygun konumları belirlenmiştir. Daha sonra, çeşitli sürüş koşullarını temsil eden tasarım yükü değerleri, Çoklu Cisim Dinamiği simülasyonları yardımıyla elde edilmiştir....

Yüksek manevra kabiliyetine sahip, üç akstan dümenlemeli 8x8 zırhlı askeri bir personel taşıyıcına ait direksiyon mekanizmasının kinematik tasarımı yapılmış ve bu tasarımı etkileyen mafsal konumları optimize edilmiştir. Bu amaçla, taşıta ait süspansiyon ve direksiyon mekanizmalarının ayrıntılı Çoklu Cisim Sistemleri Adams/View™ programında tam taşı...

In this paper, within the scope of a competitive product development process in accordance with customer demands and ISO comfort standards, development of the cab suspension system for a 4 × 2 semi-truck is presented. In the first part of the study, benchmark vehicles were selected due to the customer demands. Cab comfort evaluation tests were appl...

An important design challenge of modern vehicles is mass reduction. Hence in many cases, mechanical design of vehicle components covers different optimization processes. One important structural optimization technique which is highly utilised in weight reduction applications is the topology optimization. This paper contains a multi-stage optimizati...

In the scope of this work, design steps of an L6e-class vehicle which is one of the most suitable alternatives for future urban transportation was introduced. Firstly, technical requirements have determined. Design features such as the vehicle mass, motor power and maximum speed were indicated, and the limitations that are determinative on them wer...

Vehicle steering mechanisms are generally considered as safety subsystems due to their control and stability functions. Therefore, structural elements of a steering linkage should strictly resist the service loads without any overload failure. This paper reports an exemplary buckling evaluation case study of the multi-axle steering linkage tie rods...

The driving capabilities and the ability to reach desired combat areas immediately in rough road conditions are highly requested in military vehicle applications. Besides, a safe and comfortable cruise of military personnel is also accounted among the tasks of such vehicles. Thus, the suspension systems of these types of vehicles should be designed...

The reserves of fossil fuels in the world are decreasing day by day. On the other hand, the problems of global warming and climate change caused by greenhouse gas emissions accumulated in the atmosphere through the use of fossil fuels have necessitated the development of renewable energy systems for a sustainable and clean environment. It is forese...

As one of the most crucial problems that the World experiences, the population increase has reached a point where transportation becomes more challenging each day. As a result, vehicle manufacturers started to search for alternative ways for daily transportation. Developed for the urban transportation requirements only, vehicles categorised under t...

Motorlu kara taşıtlarının seyir dinamiği karakteristiklerinin sanal ortamda değerlendirilebilmesi amacıyla geliştirilmiş MATLAB® tabanlı bir taşıt simülasyonu uygulaması tanıtılmıştır. Uygulama, taşıt gövdesinin ve tekerleklerin uzaysal hareketlerinden türetilen ikinci mertebe diferansiyel denklem ifadelerini temel alan, beş kütleli ve on beş genel...

Increasing traffic congestion in major cities yields to a growing demand to microcars in global automotive market. Due to their easy-to-use characteristics, microcars are seen as convenient transport vehicles for urban districts. Furthermore, more environment-friendly mobility can be achieved with more frequent utilisation of microcars, due to the...

Military vehicles are frequently operated on rough terrains which may cause comfort issues and driver fatigue. Road irregularities also affect the driving safety negatively. According to Test Operations Procedure (TOP), ride dynamics and ride quality parameters for wheeled vehicles are investigated under 3 main titles, namely, ISO, absorbed power a...

An exemplary mechanical design optimization study of the multi-axle steering mechanism of an 8×8 vehicle is summarized. Firstly, joint forces of the mechanism were determined for the critical service conditions by using the multibody dynamics (MBD) model of the vehicle. Reaction forces obtained for the worst load case scenario were used for the fin...

Majority of the modern land vehicles utilize internal combustion engines for main propulsion requirements. However, environmental needs and reality of exhaustibility of fossil fuel resources push the automotive industry for alternative solutions. Electromobility is a consolidating alternative for both on-road and off-road vehicles. Each passing day...

Conceptual design steps of a 4.5 metric tonnes capacity, trailing arm-type independent suspension system, which will be applied to special type semi-trailers suitable for the transport of glass and other sensitive loads, are summarized. In the first phase of the work, the design volume of the suspension system is determined, by taking the total wor...

The load-deflection characteristic of the parabolic leaf springs used in the solid front suspension of a four-wheel-drive multipurpose service vehicle is determined by using nonlinear finite element analysis. For this purpose, a detailed finite element model of the parabolic leaf springs of the vehicle was created and the non-linear finite element...

As the world is running out of fossil fuels and the environment is being seriously damaged by the combustion residuals of the internal combustion engines, the world countries have begun to search alternative ways for mobility. Lightweight electric vehicles with low energy consumption values are seen as one of the strongest candidates of future mobi...

Weight reduction has a crucial role in the design philosophy of the modern vehicles. Topology optimization is one of the key techniques to obtain lightweight and robust designs. In this paper, a topology optimization-based numerical lightweight design study of the rear axle-chassis connection bracket for an articulated heavy commercial truck is rep...

Steering linkage is a vital subsystem of a land vehicle since it determines the manoeuvrability capacity and handling characteristics. Therefore a steering mechanism should provide sufficient wheel turning angle range with an acceptable Ackermann error. Moreover, during an operation, it must be able to function without lock-up effect for the requir...

Structural elements of a tactical wheeled vehicle (TWV) suspension have to resist extreme time-dependent service loads caused by the uneven road surfaces. Therefore, durability is one the main requirements for these subsystems. In the scope of this work, durability analysis case study of a double wishbone-type independent suspension that can be use...

Lightweight urban electric microcars: an overview

An exemplary mechanical design optimization study of the multi-axle steering mechanism of an 8x8 vehicle is summarized. Firstly, joint forces of the mechanism were determined for the critical service conditions by using the multibody dynamics (MBD) model of the vehicle. Reaction forces obtained for the worst load case scenario were used for the fin...

ÖZET: Yüksek hareket kabiliyetine sahip bir taktik tekerlekli taşıtın bağımsız ön süspansiyonunda (BÖS), küresel mafsal konumunun, mafsallara etkiyen dinamik kuvvetlere etkisi incelenmiştir. Bu amaçla, taşıtın ayrıntılı Çoklu Cisim Sistemleri (ÇCS) modeli oluşturulmuştur. Bu model kullanılarak, farklı sürüş manevraları simüle edilmiştir. Küresel ma...

Computer-aided design phases of the steering linkage of a passenger bus are presented. In the first part of the study, proper joint positions of the mechanism which satisfy the kinematic requirements such as, acceptable toe deviation and steering error ranges, were determined. For this purpose, a rigid multibody model of the mechanism was built by...

Because of their advantages, double wishbone independent suspension systems are increasingly used in modern defence industry. In this scope, adaptation of the independent suspension systems to domestic tactical wheeled vehicles which are originally equipped with solid axles is gaining importance. In this study, multi-body dynamics (MBD) analyses of...

Lightweight design study of the air spring carrier body that will be applied on a passenger bus rear axle was investigated by using finite element method. For this purpose, 3D model of the body was created in CATIA® V5R20 commercial software. The alterations of the mechanical properties of the carrier material due to manufacturing conditions were e...

Conceptual kinematic design and optimization stages of the multi-axle steering mechanism of an 8x8 special purpose vehicle are summarized. In the first part of the work, pre-kinematic design of the steering mechanism was composed. In the second part, the kinematic model of this mechanism was created by using Adams ® /View multibody systems software...

In the scope of this work, mechanical design stages and the structural optimisation process of a relay lever that will be used as one of the main load carrying members of a passenger bus multi-link steering system are summarised. In the first stage of the study, design load of the steering mechanism was determined. For this reason, two different me...

Structural design of the lower wishbone which will be used in the independent front suspension of a four-wheel drive, two-axle military vehicle was carried out by using topology optimisation. For this purpose firstly, the primary design of the lower wishbone was developed, by taking the positions of the wheel drive shaft, suspension spring and brak...

Mechanical design and optimisation processes of an axle beam which is the main load carrying part of the heavy commercial vehicle solid front suspensions are summarised. Firstly, basic dimensions of the beam was determined by taking the design limitations such as chassis height, ground clearance and the load capacity into account. Finite element (F...

Ekli ağır ticari taşıt çekicilerinin ön aksları için tasarlanmış bir çift salıncaklı bağımsız süspansiyon sisteminin tasarım, prototip üretimi ve yorulma testi süreçleri özetlenmiştir. Çalışma kapsamında önce, yaylanma sırasında minimum kamber açısı ve iz genişliği değişimi hedeflerini sağlayan optimum süspansiyon geometrisi, model taşıtın ön aksın...

Stress and mass optimisation of a differential housing that will be used in the front axle of a 4WD vehicle was carried out. In order to do that, firstly, a parametric solid model of the axle was composed. By using this model, finite element (FE) analyses of the axle were carried out by taking the effects of the various driving conditions into acco...

Optimal kinematic design and stress analysis of the steering system of a 4WD multi-purpose vehicle were performed. In the first part of the study, the multibody (MB) model of the front axle including the Ackermann steering trapezoid was built by Adams/Car™ software. With the help of the Adams/Insight™ optimisation module, the trapezoid geometry whi...

Conceptual kinematic design study of a double wishbone suspension that will be used as the front axle of a 40 metric tonnes capacity articulated heavy commercial vehicle is summarised. Design problem is basically established on two main goals namely, minimum deviations of the wheel track and the camber angle under all drive and load conditions. In...

A response surface-based design application to obtain an optimum multi-link steering mechanism is presented. Design problem is essentially established on two main goals: minimum deviation of toe angle (βV) during the wheel travel and optimum steering error during the steering angle (βL) range of the wheel. In the first stage, a complete multibody m...

Yol taşıtlarının kritik alt sistemlerinden biri olan bağımsız süspansiyon sistemleri, binek taşıtların yanında, yurtdışında üretilen ağır ticari ve askeri taşıtlarda da yarım asırdan uzun bir süredir uygulama sahası bulmaktadır. Bu sistemler sabit akslara göre daha pahalı ve karmaşık olmalarına karşın, yaylandırılmamış kütlenin ve ihtiyaç duyulan y...

In recent decades, the application of fuel cells in vehicles has been the focus of increased attention. In contrast to a chemical battery, the fuel cell generates electric energy rather than storing it and continues to do so as long as a fuel supply is maintained. Compared with the ICE (Internal Combustion Engine) vehicles, it has the advantages of...

Mekanik traktör uygulamalarında traktörün ileri geri hareketini yapması için operatörün debriyaj pedalına basmak suretiyle ileri-geri vites kolunu istediği pozisyona getirerek traktörü kullanması sağlanmaktadır. Powershuttle projesi kapsamında, debriyaj pedalına basmaksızın traktörün ileri geri hareketini tamamlaması amaçlanmaktadır. Böylece operat...

Bu çalışmada özellikle, ağır ticari araçlarda yüksek yük taşıma kapasiteleri için tercih edilen döküm diferansiyel kovanı incelenip; fabrikasyon saç diferansiyel kovanına dönüştürülmüştür. Dönüşüm işlemi sırasında, döküm kovanda kullanılan diferansiyel, aks milleri poyra grubu, fren sistemi ve braketlerin saç kovanda da kullanımına izin verilecek ş...

Stress concentration at the corner bends of an anti-roll bar that is designed for an intercity passenger bus is reduced by optimising the shape of the critical regions. In order to do this, parameters which constitute the geometry of the stress concentrated regions are determined. The effect of these parameters on stress concentration is evaluated...

An air spring suspension system for a tractor truck is designed. To reduce the unsprung mass, it is decided to manufacture the front axle beam which is the main load carrying part, by using cold forming and welding procedures. In this study, static and fatigue strength investigations and the design enhancement studies which were carried out by usin...

In this study, conceptual design of a test device that provides laboratory test of brake systems of heavy commercial vehicles was performed. Initially, inertia must be overcome while braking of translating and rotating masses of vehicle were calculated. Then, design of inertial-equivalent rotating mass system was carried out.

Position analysis of an independent suspension that will be used in an inter-city passenger bus is carried out. For this purpose, a vector algebra-based computer application that calculates the kinematic properties of the suspension system depending on the relative motion of the wheels according to vehicle body was developed. In this way, changes i...

One of the desired goals in vehicle suspension system design is to minimize the unsprung mass. In order to achieve this, sheet thickness of an axle housing which is used in a 45 metric tonnes capacity five axle truck, has been reduced to a certain extent. However, during the vertical fatigue tests applied to the new prototypes, fatigue failure occu...

A practical method to determine the diameter of the anti-roll bars used to limit the body's tendency to roll of heavy commercial vehicles is described. In order to do this, a roll analysis was performed by using equivalent roll stiffness approach in the light of the prior known technical data of a 17 tonnes capacity passenger bus. Roll angle values...

A structural analysis of a clutch cover that will be used in a truck clutch is performed.For this reason, the elastic deformation of the diaphragm spring occuring during disengagement of the clutch was simulated and forces acting on the clutch cover were determined by finite element method. The results of the analysis were compared with the force c...

Trapez geometrili yönlendirme mekanizmaları, tasarım ve üretim kolaylığı, maliyet düşüklüğü gibi faktörler dolayısıyla, ağır vasıta tasarımında halen yoğunlukla tercih edilen sistemlerden biridir. Bu çalısmada, sabit akslı ağır vasıtalarda kullanılan bu yönlendirme mekanizmalarının yapısını etkileyen unsurlar incelenmis, bu inceleme ışığında hazırl...

1980’li Yılların ikinci yarısından bu yana, özellikle yüksek performans taleplerine yanıt vermesi beklenen tek ya da birden fazla akstan çekişli taşıtlarda kullanılmakta olan Torsen diferansiyeli, alışılandan oldukça farklı tasarımı sayesinde klasik otomobil diferansiyelinin bilinen olumsuzluklarını büyük ölçüde bertaraf etmekte ve çekiş performans...

Bu çalışmada; bir motorlu aracın frenlenmesi olayı sırasında açığa çıkan enerji miktarı, bu enerjinin yutulması sırasında fren elemanlarında, özellikle de balata malzemesinde meydana gelen sıcaklık artışı ve bu artışa bağlı olarak sürtünme katsayısının hızla azalması sonucunda frenin tutmaması açıklanmıştır. Bunun çözümü olarak yurt dışında zorunlu...

Günümüzde kullanılan motorlu taşıtların her geçen gün artan tüketici ihtiyaçlarına cevap verebilmeleri için, daha yüksek hız ve yükleme kapasitesine sahip olmaları gerekmektedir. Bu da, modern fren sistemlerinin taşıtı kontrol edebilmek amacıyla daha çok zorlanması anlamına gelir. Özelikle belediye otobüslerinin sık sık duraklarda durmasına bağlı o...

Motorlu taşıtlarda faydalı motor gücünün tekerleklere aktarılması fonksiyonunu, farklı hız kademelerine ihtiyaç duymadan, dolayısıyla herhangi bir kayba yol açmaksızın gerçekleştirebilen sürekli değişken çevirim oranlı güç aktarıcılar (CVT), ekonomik düşünce tarzının her alanda egemen olduğu günümüzde giderek önem kazanmaktadır. Malzeme, tasarım ve...