Search

One of the most important criteria that vehicle customers take into consideration when buying vehicles is ride comfort. Ride comfort is determined in two different ways, called objective and subjective methods. This research presents an approach for subjective and objective evaluations of vehicle ride comfort through road tests. In this study, first, reliable driver evaluation for subjective tests is made and tests are performed with these reliable drivers. Correlation between objective and subjective test results is achieved for different vehicle types and road groups and software is developed to evaluate subjective ride comfort by using objective test data acquired from the vehicle. This software is intended to be used instead of subjective tests in future vehicle development studies.

Çarpışma kutuları, olası bir kaza esnasında sürücü ve araç içi yolcularda oluşabilecek yaralanmaları en aza indirmek için kullanılan pasif güvenlik sistemi elemanlarındandır. Araştırmacılar çarpışma kutularının çarpışma performansını iyileştirmek için farklı yapılar ve malzemeler kullanmaktadır. Bu çalışmada alüminyum alaşım AA6061-O, magnezyum alaşım AZ31B ve DP600 çeliğinden tasarlanan kare, altıgen ve dairesel dış duvara sahip tek hücreli ve çok hücreli olmak üzere dokuz farklı çarpışma kutusu sonlu elemanlar analizi ile incelenmiştir. Çalışmada kullanılan sonlu elemanlar modelleri literatürden elde edilen deneysel veriler ile doğrulanmıştır. Farklı malzemelerden tasarlanmış çarpışma kutuları en büyük çarpışma kuvveti, çarpışma kuvveti verimi ve özgül enerji sönümleme kapasiteleri açısından incelenmiştir. İnceleme sonucunda aynı kesite sahip çarpışma kutuları içinde yırtılmalara maruz kalmasına rağmen AZ31B malzemeli modellerin daha yüksek özgül enerji sönümleme kapasitesine sahip olduğu görülmüştür. Ayrıca çok hücreli yapılar tek hücreli yapılara daha iyi çarpışma performansı sergilemiştir.

Structural performance and lightweight design are a significant challenge in the automotive industry. Optimization methods are essential tools to overcome this challenge. Recently, nature-inspired optimization methods have been widely used to find optimum design variables for the weight reduction process. The objective of this study is to investigate the best differential mount design using nature-based optimum design techniques for weight reduction. The performances of the nature-based algorithms are tested using convergence speed, solution quality, and robustness to find the best design outlines. In order to examine the structural performance of the differential mount, static analyses are performed using the finite element method. In the first step of the optimization study, a sampling space is generated by the Latin hypercube sampling method. Then the radial basis function metamodeling technique is used to create the surrogate models. Finally, differential mount optimization is performed by using genetic algorithms (GA), particle swarm optimization (PSO), grey wolf optimizer (GWO), moth-flame optimization (MFO), ant lion optimizer (ALO) and dragonfly algorithm (DA), and the results are compared. All methods except PSO gave good and close results. Considering solution quality, robustness and convergence speed data, the best optimization methods were found to be MFO and ALO. As a result of the optimization, the differential mount weight is reduced by 14.6 wt.-% compared to the initial design.

Çarpışma kutuları araçlarda darbe emici yapılar olarak araçların tampon kısımlarında bulunur. Çarpışma kutularının şekli, çarpışma performansını önemli oranda etkilemektedir. Çarpışma kutuları üzerine yapılan çalışmalarda çok hücreli çarpışma kutularının tek duvardan oluşan çarpışma kutularına göre daha iyi performansa sahip oldukları ortaya koyulmuştur. Çok hücreli çarpışma kutularında dış duvar içerisindeki yapıların geometrisi çarpışma performansını arttırmada önemli rol oynamaktadır. Bu çalışmada her birinin dış duvarı silindirik olan ve içi kare, altıgen, sekizgen ve dairesel kesitler ile eklenmiş dört farklı çarpışma kutusunun performansları incelenmiştir. En iyi performansa sahip olan içerisine dairesel kesit eklenmiş dairesel çok hücreli çarpışma kutusuna çoklu arama stratejileri kullanan çok amaçlı parçacık sürü optimizasyonu (MMOPSO) yöntemiyle optimizasyon çalışması yapılmıştır. Optimizasyon çalışması, radyal temelli fonksiyonlar yöntemi ile elde edilen metamodel kullanılarak gerçekleştirilmiştir. Metamodel, latin hiperküp yöntemi ile belirlenen otuz adet örnekleme noktası kullanılarak oluşturulmuştur. The crash boxes are located in vehicles in the part of the bumper as energy-absorbing structures. The shape of the thin-walled tubes significantly influences the crashworthiness performance. In the studies on thin-walled tubes, it has been shown that multi-cell tubes have better crashworthiness performance than mono-cell tubes. In multi-cell tubes, the cross-section of the structures within the outer wall plays an important role in improving the crashworthiness performance. In this study, the crashworthiness performance of circular multi-cell tubes filled with square, hexagonal, octagonal and circular cross-sections are examined. The circular multi-cell tube filled with a circular cross-section, which has the best values within four multi-cell tubes, has been selected to optimize the crashworthiness performance using the multi-objective particle swarm optimization using multiple search strategies (MMOPSO). The optimization study is performed using the surrogate model. A surrogate model is created by using the radial basis function with thirty sampling points which are created using the Latin hypercube method.

Twist beam rear suspension systems are frequently used in front wheel drive cars owing to their compactness, lightweight and cost-efficiency. Since the kinematic behavior of twist beam rear suspension systems are determined by the elastic properties of the twist beam, the twist beam is the most critical component of this suspension system. In the study, a simplified optimization model is presented to offer designers the most suitable beam structure in the early stage of the vehicle system development. With the optimization model, designers will be able to obtain the most suitable twist beam structure in a very short time. Opposite wheel travel analysis based on finite element modeling of twist beam is conducted to examine the kinematic performance of the twist beam rear suspension. The cross-section, position and direction of the twist beam are the most important parameters affecting the performance of the twist beam rear suspension system. In this study, optimization studies with 25 design variables including variable cross-sections, twist beam position and twist beam orientation are performed. Nine different optimization studies are carried out to investigate the effects of design variables better. In optimization studies carried out with the genetic algorithm, the objective and constraint functions are obtained with the moving least squares meta-modeling method. In the study, toe angle, camber angle and roll steer are decided as constraints, and mass as the objective function. With the optimization models, lightweight designs up to 25% have been obtained according to the initial design. It is validated that the proposed simplified model and analysis of twist beam rear suspension with connecting bushing is a quite efficient approach in terms of accuracy and to speed up the optimum design process.

Twist beam suspension systems are usually used in middle segment vehicles due to certain advantages. Researchers have presented many studies on both lightweight and functional twist beam design. In this paper, an optimization study is presented for enhancing the conceptual design of the twist beam by defining design variables along the twist beam as subject to vehicle handling conditions.Toe and camber angles are essential parameters that determine vehicle behavior during maneuvering. In this study, opposite wheel travel analysis is performed to represent maneuvering behavior. Therefore, while the optimization study is presented in the form of weight reduction, it is aimed to keep the toe and camber angles at certain intervals. Ant lion optimizer and mothflame optimization methods, which are population-based optimization methods, are used in the optimization phase to evaluate the performance of the new algorithms as compared with genetic algorithm in terms of robustness and correctness in the case of twist beam design. A two stage approach is introduced for presenting the optimization model and analysis. In the first stage, design space is created via the Latin hypercube method; the mathematical model is obtained via the least squares regression method. Finally, the mathematical model is solved to enhance twist beam conceptual design using recently developed population based optimization algorithms.

In this study, the effects of sections added to multi-cell square tubes on crash performance are examined. Square, hexagonal and circular sections are added to multi-cell square tubes and their results are examined. Finite element analyses under axial loading are performed to examine the crash performance of the multi-cell tubes. Analyses show that by adding a section to the multi-cell square tubes. the crash behavior of the tubes is improved. According to the results, S5H multi-cell square tube reveals the best crash performance. The optimization of S5H is carried out by using genetic algorithms and radial basis functions. The S5H tube presents a good crashworthiness performance and could be used as an energy absorber.

This article presents an implementation of one of the latest optimization methods of obtaining light vehicle designs. First, the problem of coupling with a bolted rim is optimized using the butterfly optimization algorithm (BOA). Finally, the BOA is used to solve the shape optimization of a vehicle suspension arm. It is utilized from the Kriging metamodeling method to obtain equations of objective and constraint functions in shape optimization. At the end of the research effort in this paper, the weight reduction of the suspension arm by using the BOA is 32.9%. The results show the BOA's ability to design better optimum components in the automotive industry. King Fahd University of Petroleum and Minerals Khon Kaen University

Thin-walled tubes are extensively used in the automotive industry because of their high energy absorption capacity and lightweight advantages. These structures are expected to have high energy abso...

Approaches such as changing the cell number, changing the rib direction, and adding internal structure are utilized to acquire a multi-cell thin-walled structure, and these approaches have meaningful effects on the crashworthiness performance of multi-cell thin-walled tubes. In this study, a comprehensive review is done by using and comparing these approaches together under quasi-static three-point bending conditions. A different crashworthiness indicator is better for each of the produced multi-cell thin-walled structures. The overall best tubes are determined by the complex proportion assessment (COPRAS), a multi-criteria decision-making technique. The weights used in the COPRAS technique are calculated by the entropy method. Thus, two different tubes are chosen as the best ones. Then, multi-objective optimization is performed on these tubes with the multi-objective genetic algorithm (MOGA). The surrogate models of PCF and SEA, which are defined as the objectives in multi-objective optimization studies, are obtained by the (radial basis functions) RBF. Multi-objective optimized multi-cell thin-walled W1L1 and W1L1S1 tubes achieved the same SEA values as the W0L0 square tube at 13.1% and 15.4% lower PCF values, respectively.

This study focuses on the use of lightweight design and optimization methodology as a computer aided approach to enhancing the conceptual design of an impact attenuator for a Formula SAE race car. The most important question answered here is how to improve conceptual design outlines to assist a designer with respect to an impact attenuator design. In this study, different tools for lightweight design and optimization are compared to find the most suitable procedures and optimization techniques for an impact attenuator design. The geometrical features used as design variables and constraints are defined according to Formula SAE rules. The optimization problem is solved using a genetic algorithm and sequential quadratic programming methods by means of meta-modeling techniques. It is found that lightweight design and optimization can be used to enhance the conceptual design outlines of an impact attenuator through EPP foam, kriging meta-modeling and genetic algorithm optimization techniques.

Nature is an important source of inspiration for researchers to create better designs. In this study, graphene type multi-cell tubes is inspired by graphene due to its strong and lightweight mechanical properties. Peak crushing force (PCF), energy absorption (EA) and crushing force efficiency crashworthiness indicators have been taken into consideration under different loading angles, and the complex proportion assessment (COPRAS) which is a multicriteria decision-making method has been used to determine the best model. The best model is found to be GTMT5 (second-order and third-order hollow cylinders in the graphene type multi-cell tube) by the COPRAS selection method. The multiobjective optimization, whose objective is to minimize PCF and maximize EA, is applied on the GTMT5 using the multiobjective particle swarm optimization and non-dominated sorting genetic algorithm II methods, and the techniques are compared. The optimization study is carried out on the radial basis function metamodels. This study shows that circular structures placed in multi-cell tubes have a significant effect on the crashworthiness performance.

Bu makalede, LS-DYNA sonlu elemanlar çözücüsü kullanılarak gerçekleştirilen dinamik simülasyonlarda, ağ örgüsü geometrik şeklinin, basıncın havadaki ilerleyişine ve büyüklüğüne etkisi incelenmiştir. İncelenen geometrik şekiller kübik, silindirik ve küresel olarak seçilmiştir. Dinamik simülasyonu modellemek için ALE metodu kullanılmıştır. Hedef bir noktadaki pik basınç değerleri, test sahasındaki dinamik testten elde edilen değer ile kıyaslanmıştır. Son olarak çalışmada belirtilen koşullarda hangi ağ örgüsü geometrik şeklinin daha doğru sonuçlar verebileceği değerlendirilmiştir.

Bu calismada Formula SAE araci icin komponent agirliklarinin azaltilmasi dogrultusunda, kompanse edilebilir maliyetler de olacak sekilde fren pedali yapisal optimizasyonu calismasi yapilmistir. Fren pedallari Formula SAE komitesinin belirledigi kurallara uygun olarak tasarlanmaktadir. Fren pedali tasariminda ilk olarak hafifligi, teknik ozellikleri ve maliyeti avantaji nedeniyle aluminyum 7075-T6 malzeme secimi yapilmistir. Fren pedalinda en iyi tasarimi ortaya koyabilmek icin topoloji optimizasyonu yapilmistir. Topoloji optimizasyonunda malzeme dagilim metodu secilmistir. Topoloji optimizasyonu ilk adimi olarak ilk tasarim uzerinden tasarim hacmi olusturulmus ve tanimlamalar yapilmistir. Topoloji optimizasyonu icin tasarim degiskeni olarak bosalma istenilen bolgeler, kisit olarak gerilme ve optimizasyon amaci olarak ise agirlik belirlenmistir. Yapilan topoloji optimizasyonu ve uretim kisitlari dahilinde yeni fren pedali tasarimi olusturulmustur. Olusturulan fren pedali tasarimi ilk tasarima gore % 11 daha hafiftir. Arac agirliginin azaltilmasi amacina yonelik yapilan calismada, hafifletme oncelikli kriter oldugu icin maliyet artis yuzdesi kompanse edilebilir olarak kabul edilmistir. Mukavemet acisindan istenilen degerler icinde kalinmistir, stress degerinde %6 oraninda artis olsa da bu deger kisit degerlerinin cok altinda kalmaktadir. Ayni zamanda yer degistirme degeri de %5 oraninda azalmistir.

Multi-cell, multi-corner and adding edge-junctions structures are widely used approaches to enhance the crash characteristic of the thin-walled structures. In this study, the crashworthiness of twenty-one structures combining these three structures is examined under axial and oblique loading angles. The finite element models under axial loading are validated by experimental data from the literature and theoretical approach. In the theoretical approach, removing the corner elements in the inner structure from the theoretical calculation in multi-cell tubes has increased the accuracy. With the validations performed in axial loadings, it is predicted that the finite element model will be accurate also in oblique loadings. On the other hand, rupture strain has not been used in finite element models, which may cause some errors. Crashworthiness performance has improved as the cell number increases under all loading conditions except the C2 tube under 20-degree oblique loading. Also, the sub-sections added to the inner wall corners of the tubes significantly increase the energy absorption capacity. The complex proportion assessment (COPRAS) method and the technique for order of preference by similarity to ideal solution (TOPSIS) are utilized to get the tube with the best crashworthiness performance. The entropy method is used for weighting to avoid human intervention. The best tube varies depending on the weighting and selection method. Finally, the radial basis function (RBF) approximation approach and four multiobjective optimization methods are used to obtain optimum sizes of the C4O tube. The results of the optimizations show that the optimum structure does not differ depending on the optimization method, and the results are very close to each other.

The impact attenuator is a safety component which is used to reduce the effects of frontal crash on driver, which can cause injuries. This article describes the design process of the impact attenuator with lightweight materials to satisfy the required weight reduction targets for Formula SAE racing car. This study is carried out as part of weight reduction studies on Formula SAE racing car. First step in design process is about literature survey and benchmarking about impact absorbing components and their specifications. In this step, it is decided to use EPP foam material with a density of 100 g/l as basic material to design a lightweight impact attenuator. Also, the design outlines of shape and analysis techniques for impact attenuator is defined in this step. Then, verification process is carried out for virtual model of 100 g/l EPP foam material. The results of the physical drop test at the initial speed of 2.2 m/s to the 50 mm cubic are taken as reference points to verify the material model. After model verification, a 10% lighter impact attenuator compared to the standard model is designed according to Formula SAE rules. The results show that selected EPP foam material can be used to design a lightweight impact attenuator for formula SAE race car to satisfy weight reduction requirements successfully.