As part of the development process for new stamping dies, in the automotive sheet metal forming (SMF) industry, the majority of all forming operations are simulated with the Finite Element Method (FEM) before the dies are manufactured. Today, these simulations are conducted with rigid tools under the assumption that there are no tool deformations. However, research shows that tool deformations have an influence on the finished product. In real production these deformations are compensated by manual rework during the try-out. Additional reason for simulating with rigid dies is that there are non-existing simulation methods elaborated for elastic stamping dies. Also, simulation of elastic tools requires high computational power.     Since simulations today are performed with rigid stamping dies the purpose of this work is to investigate the conditions of how to conduct SMF-simulations with elastic stamping dies. The object that will be studied is a stamping die for a Volvo XC90 inner door used in a single-action press. This work is part of the development to minimize the manual rework, with the goal to compensate for tool deformations in a virtual environment.    Results for rigid stamping dies in LS-Dyna was compared to currently used AutoForm as a pre-study. A simple model was then created to find a suitable method while using elastic stamping dies. The developed method was used for an industrial size stamping die.     Since there are little amount of research performed on simulations using elastic stamping dies, elasticity and complexity were gradually introduced into the FE-model. As a first step, only the punch was included as an elastic solid. Secondly, the die was added. Finally, the entire die was simulated as elastic together with the hydraulic cushion of the press. When the FE-model worked as expected a suitable method for minimizing the simulation time with acceptable results was studied.     Comparisons of measured- and simulation results show a high correlation. To improve the results from the FE-model factors such as press deformations, advanced friction models, etc. should be included.    Conclusions from this work shows that it is possible to perform SMF-simulations with elastic stamping dies. As the computational time normally is high this work also presents a method first step to reduce the computational time with acceptable results. Comparisons between simulations with rigid and elastic stamping dies proves that there are significant differences in the outcome of the two methods. / Reduced Lead Time through Advanced Die Structure Analysis - Vinnova

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Les machines à double excitation (aimants permanents et bobines d’excitation) sont depuis quelques années étudiées par de nombreuses équipes de recherche dans le monde pour leur souplesse de fonctionnement et leur puissance volumique importante. Dans cette thèse, nous présentons une nouvelle structure de machine à double excitation. C’est une machine à commutation de flux, donc qui possède un rotor passif, et dont la partie de double excitation située au stator est maintenue par une culasse à griffes. Dans une première partie, les caractéristiques importantes de cette structure sont exposées à partir de mesures sur un prototype et de modèles par éléments finis. Les différents trajets de flux ainsi que l’excursion du flux à vide en fonction du courant de double excitation ou encore les FEM à vide et le courant de court-circuit sont présentés. L’objectif est de caractériser de façon précise le fonctionnement de cette machine. Outre le fonctionnement à vide, les fonctionnements en mode moteur et en mode générateur sont présentés pour évaluer les performances. Le second chapitre de cette thèse présente différents modèles de la machine à double excitation. Tout d’abord à partir de modélisations par éléments finis nous montrons les impacts des caractéristiques magnétiques telles que la courbe BH et l’induction rémanente des aimants permanents sur le flux à vide de différentes machines à commutation de flux et double excitation. Puis nous présentons deux méthodes basées sur la modélisation par éléments finis qui permettent le calcul du courant de court-circuit. Enfin, afin de s’affranchir d’un modèle magnéto-transitoire trop gourmand en temps de calcul, nous présentons un modèle analytique. Ce modèle permet à partir de la valeur du flux à vide et de l’inductance cyclique d’une machine synchrone à aimants permanents de calculer la puissance en générateur débitant sur un pont de diodes et une source de tension fixe en fonction du courant d’excitation et de la vitesse de rotation. Dans le dernier chapitre de la thèse, nous avons développé un modèle de la machine à double excitation à bobinage global basé sur les schémas réluctants. A partir de ce modèle, nous calculons le flux à vide et l’inductance cyclique de la structure de façon plus rapide que par des simulations par éléments finis et sensiblement aussi précise afin de les utiliser dans le calcul de la puissance. Dans un dernier temps, nous avons utilisé ce modèle dans une procédure d’optimisation pour différents cahiers des charges. / In this thesis, a new hybrid excitation, flux-switching machine is being presented. The main feature of this device is its global winding hybrid excitation with claw poles. This solution has been explored in order to reduce the copper mass and increase excitation winding efficiency. One of the most widely used alternators in automotive applications is a claw pole alternator whose claws are located on the rotor. The prototype introduced in this study is based on the same principle yet with claws located on the stator, which allows its rotor to be passive in rotating at higher speeds without slip-rings or brushes. Furthermore, the advantages of the double excitation are cumulative.The thesis will first describe the structure and operating principles of this new hybrid excitation, flux-switching machine, For example, the no-load flux linkage and the back-electromotive force on a no-load are measured and calculated;. Moreover, the load testing of this machine will be displayed. Short-circuit currents will be calculated and measured in order to determine the output power capability while operating in generator mode. The second chapter presents finite element and analytical models which allows to determine the output power capability while operating in generator mode. And with the FEA, the no-load flux linkage is investigated, This investigation serves to highlight: the influence of the stacking factor, the B-H curve definition, and the permanent magnet residual induction value, Finally, a lumped-parameter magnetic circuit model is developed and validated by 3-D finite element analysis, The model allows estimating output power of the structure when running in generator mode (with a DBR) faster than with 3D-FEA. In addition, thanks to the model the geometry is optimized for several specifications,

Indiana University-Purdue University Indianapolis (IUPUI) / Traumatic Brain Injuries (TBI) are one of the most apprehensive issues today. In recent years a lot of research has been done for reducing the risk of TBI, but no concrete solution exists yet. Helmets are one of the protective devices that are used to prevent human beings from mild TBI. For many years some kind of foam has been used in helmets for energy absorption. But, in recent years non-traditional solutions other than foam are being explored by different groups. Focus of this thesis is to develop a completely new concept of energy absorption for helmet liner by diverting the impact forces in radial directions normal to the direction of impact. This work presents a new design of an advanced layered composite (ALC) for energy dissipation through action of a 3D array of compliant mechanisms. The ALC works by diverting incoming forces in multiple radial directions and also has design provisions for reducing rotational forces. Design of compliant mechanism is optimized using multi-material topology optimization algorithm considering rigid and flexible material phases together with void. The design proposed here needs to be manufactured using the advanced polyjet printing additive manufacturing process. A general and parametric design procedure is explained which can be used to produce variants of the designs for different impact conditions and different applications. Performance of the designed ALC is examined through a benchmark example in which a comparison is made between the ALC and the traditional liner foam. An impact test is carried out in this benchmark example using dynamic Finite Element Analysis in LS DYNA. The comparison parameters under consideration are gradualness of energy absorption and peak linear force transmitted from the ALC to the body in contact with it. The design in this article is done particularly for the use in sports helmets. However, the ALC may find applications in other energy absorbing structures such as vehicle crashworthy components and protective gears. The ultimate goal of this research is to provide a novel design of energy absorbing structure which reduces the risk of head injury when the helmet is worn.

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Det här arbetet handlar om komplettering av transmission och stabilisering av en pedagogisk anordning som bygger på en begagnad cykelram. Anordningens syfte är att demonstrera omvandlingen av mekaniskt arbete till elström, vilket görs genom att användaren vevar runt cykelpedalerna för hand för att driva i gång en generator. I dagsläget saknar anordningen en koppling mellan bakhjulet och generatorn, vilket behövs för att överföra användarkraften från pedalerna till generatoraxeln. Dessutom vilar anordningen på en smal pakethållare som är ostabil och orsakar stora svängningar under användning. Utifrån uppdragsgivarens krav och önskemål har en lämplig utväxling tagits fram genom konstruktion av en remskiva av lämpliga mått som kopplas till en kilrem mellan bakhjulet och generatoraxeln. Utöver det utvecklades en stabiliseringsmekanism som förstyvar anordningen och motverkar oscillationer vid användning samt bidrar till ökad driftsäkerhet. Stabiliseringsmekanismen bygger på teorin om tvåkraftselement, där elementen endast är belastade med krafter i sin längdriktning, vilket möjliggör för mindre materialåtgång och lättviktskonstruktion. Fästen har också konstruerats för att koppla förstyvningsstöden till både cykelramen och plattformen som anordningen vilar på. Avslutningsvis genomfördes en brottsriskanalys i syfte att kartlägga möjliga risker vid användning. Arbetet har delats mellan tre studenter, där var och en hade sitt specialiseringsområde, och en färdig prototyp har utvecklats och testats med goda resultat. / This report considers a case of stabilizing and complementing a transmission mechanism for a pedagogical device which is built around a used bicycle frame. The purpose of the device is to demonstrate the conversion of mechanical work to electrical current, which is done by cranking the bicycle pedals manually to drive an alternator. Currently, the device lacks a connection between the rear wheel and the alternator, which is needed to transfer user force from the pedals to the alternator shaft. In addition to that, the device rests on a thin pannier rack that is unstable and causes a considerable swaying movement under usage. In compliance with the given requirements, a suitable transmission mechanism was designed using a belt pulley with specified dimensions that connects the rear wheel to the alternator shaft using a v-belt. Also, a stabilization mechanism was developed to strengthen the device, counteract the oscillations while operated and increase its reliability. The stabilizers are designed according to the theory on two-force members, which are members that are exclusively loaded with forces along their length direction, which allows for lower material usage and lightweight construction. Holders have also been designed to connect the stabilizers to both the bicycle frame and the platform on which the device is built. Lastly, a failure analysis has been conducted in order to identify the possible risks while  the device is used. The project was divided between three students based on individual specialization fields, and a finished prototype was developed and tested with good results.

This report covers a bachelor’s degree in mechanical engineering program at School of Engineering at Jönköping University. The work in the report is carried out by Diako Ahmadi and Rickard Surtevall where the assignment is originally performed by Mattr Collective AB. Mattr has been commissioned by the Swedish Motorsport Federation (Svemo) to follow through with this project. The background to this project is to develop an add-on kit which makes it possible to electrify the 2023 model Yamaha R3 motorcycle. The final goal for the client (Svemo) is to start a cost and climate-effective racing class for electrified motorcycles 2024. Through-out the report, calculations and simulations are presented to evaluate the stiffness of the motorcycle and the technical solution. The mission taker, Mattr, have developed a prototype built on a smaller motorcycle, a Yamaha R125. The outcome of the prototype had some issues such as deficit in its performance and carrying capacity. Thus, this project has covered those points that Mattr had problems with on their prototype. At first, a study has been performed on the motorcycle’s frame where a representative model has been recreated. The recreated frame together with different test methods will act as a benchmark for comparison between the add-on kit and the original frame. This because the manufacturer doesn’t hand out files and technical specifications. During the course of the work, the product development method Double Diamond have been used to make several iterations through FEA (Finite Element Analysis), this to obtain a result by evaluating and simulating. The result of this work is an add-on kit which is compatible with a Yamaha R3, this without affecting the motorcycle’s appearance and stiffness. Through the simulations, the add-on kit performs better together with the electrical components than with the combustion engine in some of the studies. Through the simulations, conclusions can be made that the different electrical components aren’t affected negatively on their performance through high displacements. The world is currently trying to transition to a more fossil-free society, this where electrical solutions are a major contributing factor. Several industries are trying to electrify their products to contribute to a less climate impact, hence the reason for this project.