Chassis and suspension design of Baja SAE vehicle

Tema ovog rada je konstrukcija šasije i ovjesa Baja SAE vozila. Razvoj vozila prikazan je kroz nekoliko koraka, od definiranja samih zahtjeva na šasiju i ovjes, koncipiranja šasije i ovjesa, analize kinematike ovjesa i dinamike vozila, konstrukcijske razrade šasije i elemenata ovjesa te analize naprezanja pojedinih elemenata. Pri tome su se pratili zahtjevi prvenstveno Baja SAE pravilnika, dok su pojedini koraci konstrukcijske razrade koji nisu propisani pravilnikom razrađeni na temelju literature i iskustva. U uvodu diplomskog rada ukratko je opisano Baja SAE natjecanje koje se organizira pod okriljem SAE organizacije. Navedene su ispitne procedure koje se provode na natjecanju te način bodovanja na svakoj od njih. Iz navedenog je vidljivo kako Baja vozilo mora biti sposobno za vožnju u velikom broju različitih i zahtjevnih situacija. Osim toga, u uvodnom dijelu, objašnjeni su osnovni pojmovi dinamike i kinematike vozila te zahtjevi koji se postavljaju na njih i kako oni utječu na ponašanje vozila. Nakon toga, na temelju prethodnog teorijskog uvoda, prikazana je praktična konstrukcijska razrada vozila. Kao polazna točka za daljnju analizu uzima se simulacija dinamike Baja SAE vozila u programskom paketu CarSim. Vozilo je provedeno kroz proceduru u kojoj je promatran utjecaj osnovnih parametara vozila i ovjesa na ponašanje vozila. Rezultati analize korišteni su u idućim koracima razvoja vozila. Da bi se moglo nastaviti, najprije je koncipirano vozilo i odabrana konfiguracija ovjesa s gledišta konstrukcije i komponenti koje su na raspolaganju. U sljedećem koraku napravljen je kinematički model ovjesa i upravljanja te je analizirana kinematika u programskom paketu Lotus Suspension Analyser. Nakon definiranih pozicija karakterističnih točaka i postignute željene promjene kinematskih veličina, izrađena je konstrukcija u programskom paketu Solidworks 2015. Prikazana su konstrukcijska rješenja ovjesa, šasije, upravljanja i sklopa kotača. Bitno je napomenuti da analiza kinematike i konstrukcijska razrada obuhvaća veći broj iteracija zbog potrebe usklađivanja kinematike i mogućih konstrukcijskih rješenja. Na kraju rada proveden je kontrolni proračun čvrstoće šasije i ramena ovjesa na temelju opterećenja preuzetih iz analize dinamike vozila u CarSim-u i literature.The topic of this work is chassis and suspension design of Baja SAE vehicles. The work demonstrates steps in development of vehicle, from definition of chassis and suspension demands, conceiving of chassis and suspension, suspension kinematics and vehicle dynamics analysis, design development of chassis and suspension components to tension analysis of certain components. Thereby it is necessary to follow demands of Baja SAE rulebook while other guidelines and demands which are not regulated by the rulebook have been elaborated based on literature and experience. Introduction of the graduation work shortly describes Baja SAE competition organized under protection of SAE organisation. This part of the work also lists test procedures on the competition as well as their weighting method. Hereby it is apparent that Baja vehicle has to be equipped for various demanding situations. Besides, in the introduction part, the work gives clarification for basic terms of dynamics and kinematics of the vehicle as well as demands being posted upon them with their influence on the performance of the vehicle. This theoretical introduction is followed by practical design development of the vehicle. Simulation of dynamics of the Baja SAE vehicle in programme package CarSim has been taken as the starting point for further analysis. The vehicle has been run through the procedure in which influence of basic vehicle and suspension parameters on vehicle behaviour was observed. Next phase of the development was based according to the obtained results. In order to continue, first the vehicle was conceived and suspension configuration was chosen from the point of design and available components. The following step was creating kinematic model of suspension and steering whereupon kinematics was analysed in the programme package Lotus Suspension Analyser. After defining the position of characteristic points and achieving required changes of kinematic measures, a design was made in the programme package Solidworks 2015. Design solutions for suspension, chassis, steering and wheel assembly have been suggested. It is important to note that the analysis of kinematics and design development includes a large number of iteration which therefore need to be balanced. At the end of this work there is the control testing of chassis and suspension links strength which was based on load taken from analysis of vehicle dynamics in CarSim and literature