Konstruktionsanalys av lastbilsbotten : En jämförelse av stålbotten och sandwichbotten

Sammanfattning: The structure and design of truck body work can look in several different ways. SpecialKarosser AB is one of the leading companies in Scandinavia when it comes to specially adapted truck body work. The body works are designed to carry different types of loads. When in use, the structure is affected by various types of forces and repeated dynamic loads. The body works have several constituent parts which includes bottom structure and support frame. SKAB manufactures two types of bottom structures, one fully made of steel and one with sandwich technology.  The purpose of this project was to analyze and compare the two bottom structures based on von Mises stress, weight and deflection at a load of 80 000 N. The project was divided into five different phases that consisted of literature studies, 3D modeling, calculation, evaluation and verification and validation. Surface and solid modeling was performed in Catia V6. FE-analysis was executed in Abaqus and verified with a meshless structural analysis in SIMSOLID. The result was further verified with simplified manual calculations. Lastly a comparative evaluation of the bottom structures was performed. The following conclusions could be drawn from the analysis: the von Mises stress was generally lower in the sandwich bottom structure compared to the steel bottom structure. The cross beams in the steel bottom structure were exposed to von Mises stress of 18.9 MPa. In the sandwich bottom structure, the front end cross beams in the were exposed to a stress of 15.4 MPa and the back end 9.76 MPa. The deflection of the steel structure was 0.34 mm greater compared to the sandwich bottom, this corresponded to approx. 29%. The steel bottom has a 6% lower mass of 849.7 kg compared to 901.6 kg. The results from this study could be used by SKAB for further analysis and environmental-, weight- or cost optimization of the structure.