No description available.

No description available.

No description available.

The aim of suspension systems in vehicles is to provide the best balance between ride and handling depending on the operating conditions of a vehicle. Active suspensions are far more effective over a variety of different road conditions compared to passive suspension systems. This is because of their ability to store and dissipate energy at different rates. Additionally, they can even provide energy of their own into the rest of the system. This makes active suspension systems an important topic of research in suspension systems. The biggest benefit of having an active suspension system is to be able to provide energy into the system that can minimize the response of the sprung mass. This is done using actuators. Actuator design in vehicle suspension system is an important research topic and a lot of work has been done in the field but little work has been done to estimate the peak control force and bandwidth required to minimize the response of the sprung mass. These two are very important requirements for actuator design in active suspensions. The aim of this study is estimate the peak control force and bandwidth to minimize the acceleration of the sprung mass of a vehicle while it is moving on a compliant surface. This makes the road surface a bi-lateral boundary and hence, the total system is a combination of the vehicle and the compliant road. Generalized vehicle and compliant road models are created so that parameters can be easily changed for different types of vehicles and different road conditions. The peak control force is estimated using adaptive filtering. A least mean squares (LMS) algorithm is used in the process. A case study with fixed parameters is used to show the results of the estimation process. The results show the effectiveness of an adaptive LMS algorithm for such an application. The peak control force and the bandwidth that are obtained from this process can then be used in actuator design. / Master of Science

This research project was conducted to fulfill a Master of design specialising in Transport Design, at Massey University’s Auckland School of Design. It was aimed to create a new visual identity for Hyundai Motors by designing a car model forecasting and utilising methods pertinent to Hyundai Motors. Simultaneously the designed car model focuses on specifically accommodating the needs of surfers. The whole philosophy behind this particular model involves three important elements of Visual Identity as pointed out by Warell; recognition, comprehension and association. As a result, in each stage of the design process, the model was designed and amended continuously to incorporate these three issues to create a design for Hyundai that targeted the surfing market. This research sets out a departure point for designing differentiated vehicle concepts for Hyundai by targeting a niche market. The Exodus was designed for a particular demographic and a subculture. The targeted market began with participants of Extreme Sports such as snowboarding, windsurfing, and surfing, but was narrowed down to surfers, because they had specific requirements that were not well catered via by existing vehicles. These requirements also translated into specific design features that allowed the development of a strongly differentiate of vehicle concept. In this way the Exodus represents an example of how specific and user needs can drive differentiated design in both a practical and visually expressive way. This process was facilitated by way of three major research stages. Firstly, a field trip to Piha, one of Auckland’s most popular surfing beaches was conducted in order to find out more about surfing culture and as a general means of vehicle observation. Secondly, informed interviews were conducted in order to gather qualitative information to generate specific user requirements and inform design development that would meet the needs of surfers. Existing car designs types were analysed to extract any design features and attributes suitable for surfers. Thirdly, a comparative analysis of two established vehicle brands, alongside Hyundai was undertaken in order to reveal the weaknesses of Hyundai’s visual identity. This phase then culminated in a research model specifically aimed at creating a new design image for them. Based on requirements developed using the above methods, the design were developed through an interactive process of sketching, modeling and critique. The aim was to create a car with an advanced design that met the functional needs of the surfing market. The main focus was to create a specific, differentiated brand image based on association, comprehension and recognition for the Hyundai.

Leaf springs are a part of the suspension system attached between the axle and the chassis of the vehicle to support weight and provide shock absorbing capacity of the vehicle. For more than half a century the leaf springs are being made of steel which increases the weight of the vehicle and is prone to rusting and failure. The current study explores the feasibility of composite leaf spring to reduce weight by designing, manufacturing and testing the leaf spring for the required load cases. An off the shelf leaf spring of Ford F-150 is chosen for making of composite hybrid spring prototype. The composite hybrid prototype was made by replacing all the leaves with glass fiber unidirectional laminate except the first leaf. Fatigue tests are then done on steel and composite hybrid leaf spring to observe the failure locations and mechanism if any. High frequency fatigue tests were then done on composite beams with varying aspect ratio in a displacement-controlled mode to observe fatigue location and mechanism of just glass fiber composite laminate. It was observed that specimens with low aspect ratio failed from crack propagation initiated from stress concentrations at the loading tip in 3-point cyclic flexure test and shear forces played a dominant role in propagation of crack. Specimens with high aspect ratio under the same loading did not fail in cyclic loading and preserved the same stiffness as before the cyclic loading. The preliminary fatigue results for high aspect ratio composite beams predict a promising future for multi-leaf composite springs.

<p>Composite materials have become widely used for high-performance applications, particularly in the aerospace industry where annual production volumes are low and a higher part cost can be supported. During the last decades composite materials are beginning to see use in a broader range of applications, including the automotive and sports equipment industries. Simultaneously, there is increasing demand from consumers and regulatory bodies to make cars more fuel efficient and in the case of EV’s longer drive range, which can be accomplished by reducing vehicle weight. Composite materials have high specific stiffnesses and strengths, resulting in weight savings when they are used to replace traditionally metal components. However, in order for widespread adoption of composite parts to be viable for the automotive industry, high-rate manufacturing must be realized to reach the required production volumes and part costs.</p> <p>Toward this goal, advanced composite manufacturing techniques have been developed. These techniques typically combine high automation with careful material selection, which can include fast-curing resins and thermoplastics with adapted melt viscosities and thermomechanical properties. They also allow for complex part geometries to be produced in a single step, reducing the need for additional assembly time. Further, they can be used to easily create multi-material components, which can result in parts that benefit from the desirable mechanical properties of the constituent materials without sacrificing performance.</p> <p>This thesis develops a framework for the design and high-rate manufacture of multi-material components. First, a critical literature review is conducted to develop a clear understanding of existing research into combinations of dissimilar materials, including epoxy/polyamide, thermoplastic elastomer/polyamide, and aluminum/thermoplastic. It is shown that, for all material combinations studied, interfacial delamination and subsequent deformation are the primary energy absorption mechanisms and that manufacturing conditions may affect interfacial bond strength. Based on this foundation, adhesion testing is performed on devoted sample configurations fabricated under controlled molding conditions. For these material combinations, interfacial adhesion can be significantly improved with carefully selected processing temperatures, even to the extent that adhesive bond between dissimilar materials can be stronger than the cohesive bond in the constituent materials. Next, impact and quasi-static indentation testing were performed to determine the effects of interfacial adhesion and part design on crash performance. The materials tested all benefit from the placement of a more ductile material on the impacted side of the sample (top surface), indicating a more favorable dissipation of the contact stresses from the impactor, and a higher strength material on the bottom surface where it can withstand tensile stresses imposed by impact-induced bending. </p> <p> Finally, a complex part consisting of a unidirectional polyamide/carbon fiber preform and a thermoplastic overmold is manufactured via a hybrid overmolding process. Interfacial temperature during overmolding is varied to confirm if the same improvements in interfacial bond strength seen in the compression molding test samples are attainable under realistic high-rate manufacture conditions. Additionally, the preform volume is varied to examine the effect of the preform reinforcement on a part’s bending performance. For this system, varying the preform temperature had no effect on interfacial bond strength. A predictive technical cost model is also used to determine the effect of manufacturing changes on part costs. Increasing the tow volume three-fold increased the absorbed energy by more than 30% and requires an increased cost of only 3.8%. </p> <p>This thesis proves that a tough, multi-material part can be rapidly produced via hybrid overmolding. It was demonstrated that a complex shaped part could be produced at a complete line cycle time of approximately 90 secondsmaking it a viable method to produce high-performance, low-cost components. </p>

Platelets made of slit and chopped unidirectional, carbon-fiber prepreg are becoming a popular option for use as a high performance molding compound because of their high fiber volume fraction and increased ability to flow compared to continuous fiber systems. As this molding compound is newly introduced to industry, increasing amounts of research have gone into understanding how platelets flow during molding and how components perform mechanically based on the final orientation state of platelets. This work investigates the performance of prepreg platelet molding compound (PPMC) as a viable alternative to continuous fiber systems for use with geometrically complex structural members on vehicles subjected to collisions. In doing so, the crash performance, energy absorption, and failure morphology of crush tubes made with PPMC are investigated and quantified. Then, a simulation methodology is developed to obtain manufacturing-informed performance models to predict the effect of platelet orientation state on mechanical behavior of PPMC components. This methodology uses a building block approach where each block in modeling is verified against closed-form solution (when available) and validated against experimental results. Once confidence is developed in a modeling block, the complexity of the simulation is increased until a component with full platelet orientation distribution is captured. The result is PPMC component models that are capable of predicting mechanical performance in orientation regimes that are not investigated experimentally.

Esse estudo procura integrar as áreas de termodinâmica, transferência de calor e aerodinâmica no desenvolvimento de veículos de alto desempenho. É proposta uma ferramenta computacional que auxilie a análise de alternativas de trocadores de calor compactos, parte integrante do sistema de arrefecimento veicular. O aplicativo desenvolvido, denominado TROCALC, tem dois modos de uso: para colaborar no projeto de um trocador de calor ou para avaliar o desempenho de um trocador existente. Estruturado por um conjunto de equações e parâmetros com base na metodologia de Kays e London (1984), no primeiro modo esse aplicativo fornece alternativas de trocadores a partir dos dados de rejeição de calor por parte do motor e dos valores de vazão e temperatura dos fluidos envolvidos. Para o modo de avaliação de desempenho, além dos dados de entrada já mencionados, é necessário o detalhamento da geometria de superfície do trocador para calcular a quantidade de calor que o radiador é capaz de remover do sistema e comparar com o valor de fluxo de calor rejeitado pelo motor. É adotado um estudo de caso que considerou um veículo de competição da Fórmula SAE para investigar a eficácia do aplicativo TROCALC na análise de desempenho e na definição de novas alternativas para o trocador de calor dedicado àquele automóvel. Foram realizados ensaios em laboratório com a medição de valores para a rejeição de calor, vazão em massa de ar e perda de pressão no trocador existente. Os resultados validaram a ferramenta computacional e oferecem uma redução de 37% nas dimensões do trocador. Por fim é feita uma análise aerodinâmica para o conjunto duto-trocador de calor, que é uma solução típica utilizada em veículos de competição, integrando este conjunto à geometria da carenagem do veículo. Quatro alternativas, incluindo nova geometria para a carenagem do duto-trocador são investigadas do ponto de vista aerodinâmico com o auxílio de programa de dinâmica dos fluidos computacional (CFD). Nesta investigação, o objetivo é melhorar o comportamento de parâmetros relacionados ao escoamento de ar junto do sistema duto-trocador de calor, mantendo um bom comportamento para o arrasto total do veículo. / This study looks for the integration of thermodynamics, heat transfer and aerodynamics in the high-performance vehicles development. A computational tool that facilitates the compact heat exchanges analysis, part of the vehicle cooling system, is proposed. The application denominated TROCALC has two different modes of use: one for compact heat exchanger design and another one to evaluate existent heat exchangers performance. This program, which is structured by a set of equations and parameters based on the Kays and London (1984) methodology, provides heat exchangers alternatives through the input of the engine heat rejection, fluids temperature and mass flow (air and coolant). The tool is also capable of providing a performance analysis of an existent compact heat exchanger. In this case, besides of the inputs already mentioned, it is necessary to inform the surface geometry data of the actual heat exchanger to calculate the heat rejection capacity and compare to the established value of the engine. The case study of the Formula SAE is proposed in order to investigate the efficiency of TROCALC in performance analysis and definition of new alternatives for the Formula SAEs dedicated heat exchanger. Laboratory tests were performed in order to achieve experimentally the heat rejection, mass flow (air side) and pressure drop values in the current heat exchanger. The results validated the computational tool and offered a reduction of 37% in the heat exchangers dimensions. At last, aerodynamic analyses are performed for the duct-compact heat exchanger system, a typical solution adopted in race cars that is the integration of this set to the vehicles bodywork. Four alternatives are researched from the aerodynamic perspective with the computational fluid dynamics program support (CFD), including a new geometry for the duct. In this research, the aim is the improvement of parameters behavior related to the air flow around the duct-compact heat exchanger system, keeping a good behavior to the total drag of the vehicle.

O CAN possui diversas características intrínsecas que o fazem mais apropriado para aplicações automotivas. Neste trabalho serão destacadas algumas dessas características aplicadas a sistemas que exigem um nível muito alto de confiabilidade, através de dois estudos de casos, um para analisar as características gerais do funcionamento da rede CAN, numa arquitetura eletrônica distribuída de um veículo em diversas configurações, cuja taxa de ocupação do barramento é alterado através da modificação do tempo de transmissão de algumas mensagens, e outro estudo para verificar o comportamento de um sistema de controle em malha fechada sobre a rede, focando no impacto do atraso temporal da rede. / The CAN has several inherent characteristics that are more appropriate for automotive applications. In this work will be highlighted some of those characteristics applied to systems that require a very high level of reliability. It is presented two case studies, one to analyze the general characteristics of operation of the CAN network in a electronic distributed architecture of a vehicle for various configurations, whose busload is amended by modifying the time of transmission of some messages, and another study to verify the behavior of a control system in closed loop on the network, focusing on the impact of the delay time in the network.