[en] The efforts in this project have been focused on the force analysis of a motorbike´s fork structure (mainly in the triple trees). This analysis has been used for a 4T 250cc competition motorbike triple trees design state. This design needs to meet the current standards imposed by "MotoStudent" association. The MotoStudent contest organizers impose some technical requirements and the elements must be designed in such a way that they can be included in the motorbike without breaking the rules given. In this project it has been achieved a viable model which meets the "MotoStudent" current standards and is different from the previous models which have been used. The triple trees attach the fork tubes to the frame. This way, the triple trees connect the fork with the main part of the motorcycle. The most important part of the porject has been the force analysis on the triple trees considering the most stressfull working situation for these. The results obtained in this process have been used to study the stress analysis. Once the triple trees requirements for the correct motorbike functioning are stablished, it has been designed an initial CAD model which is tested by the use of EFM to ensure it works properly. The initial model has been modified following an iterative porcess whose purpose is to improve the design reducing the component´s weith taking into account the stress analysis results. An excessive weight is the principal issue for the motorcycles designed for competition. This is the reason why the triple tree model should be as lighter as possible. At last, in this project it has been decided the safety factor of the model for its fatigue study. There are also considered different materials just in case the model was manufactured.

[eu] Lanaren helburua motoaren aurreko urkilan sortzen diren indarrak aztertzea izan da, bereziki zela-tutuetan ematen direnei dagokionez. Analisi hori 250 cc eta 4 T dituen lehiaketa-moto baten aurreko urkilako zela-tutuak diseinatzeko erabili da. Diseinua "MotoStudent" txapelketan ezarritako arauen arabera burutu behar izan da. "MotoStudent"norgehiagokaren antolatzaileek erabakitzen dute lehiaketa bakoitzean erabiltzen diren zela-tutuen diseinu zehatza, eta osagai horrek berdina behar du izan moto guztietan. Hala ere, lan honetan bestelako diseinu bideragarri bat lortu da, aipatutako lehiaketako ezaugarriak betetzen dituen moto batentzako. Zela-tutuak diraaurrealdeko indargetzaileko barrak xasisaren goialdean estu elkartuta dagoen norabide-ardatzera lotzen dituzten piezak. Beraz, osagai horiek aurrealdeko urkilaren eta motoaren gorputzaren arteko lotura dira. Zela-tutuentzako baldintza okerrenetan aurrealdeko urkilan eragiten duten indarrak aztertzea izan da proiektuaren atal erabakigarria. Indarren ikerketa hori zela-tutuen esfortzu analisi baterako erabili da. Goiko nahiz beheko zela-tutuek funtzionamendu egoera zailena jasateko bete beharreko eskakizunak kalkulatu ostean, CAD bidez hasierako diseinu bat gauzatu da, eta horren baliozkotasuna ikertu daelementu finituen metodoaz. Piezaren diseinua optimizatzeko hasierako diseinua aldatu egin da prozesu iteratibo batez baliatuz, elementu finituen analisiaz lortutako emaitzen arabera. Jomuga lehiaketa-moto bat denez, osagai guztiek pisuari dagokionez ere optimizatuta egon behar dute. Moto arinek maniobratzeko ahalmen handiagoa eta, oro har, jokabide hobea dute. Azkenik, benetako zela-tutuek akidura jokaeran izango luketen segurtasun koefizientea zenbatetsi da, eta aluminio mota ezberdinak hartu dira kontuan.