Development of a new concept for a v-stay in a heavy vehicle using dynamic analyses

Sammanfattning: Society of today is struggling with both large amounts of emissions as well as congestion on the roads. For this reason, AFRY in collaboration with Volvo GTT is working on develop and implement longer and heavier transports in traffic network. These combinations are called high capacity transport and have high performance-based demands. Dynamic stability is one demand that can be improved for the DUOCAT, which is a high capacity transport combination. The hypothesis is that a displacement backward in the direction of travel of the v-stay can improve the dynamic stability. The v-stay is a component of the rear wheel suspension and has an important function regarding dynamic stability by absorbing lateral forces. To achieve better dynamic stability, the goal is to create counter steering on the rear axle of the DUO-CAT through small design changes on the v-stay. The suggestion from Volvo is to move the v-stay backward in the direction of travel, which in this thesis has become the focus in both concept generation and design work. The thesis includes development of new concepts of the v-stay. An extensive evaluation process consisting of dynamic analysis was carried out in PTC Creo Parametric, which made it possible to compare the new concepts with the current v-stay. An important part of the thesis is to obtain a simplified model that simulate the physical conditions. The delimitations are to examine lateral acceleration with load on the axle and friction between asphalt and wheels. The maneuver in the analyses emulates a quick lane change at 80 km/h. This has resulted in a new concept that includes the current v-stay where only the position on the frame and axle is changed with the help of new fastening components. The new concept provides an increased counter steering of 6%. The conclusion is that a displacement backwards in the direction of travel of the vehicle gives an increased counter steering. Future work is required to achieve the desired improved steering and safety requirements.