Iranian Society of Acoustics and Vibration and Avecina Journal of Theoretical and Applied Vibration and Acoustics 2423-4761 12 2 2026 07 01 Stress estimation in fifth wheel coupling system using finite element model validated by experimental modal test 735807 10.22064/tava.2026.2066958.1271 EN Reza Ebrahimi Mechanical Engineering, Faculty of Engineering, Yasouj University, Yasouj, Iran 0000-0002-0118-437X Alireza Shafiei Research and Development Department, Espahan Koosha Company, Isfahan 81611-98371, Iran Seyed Masoud Fatemi Research and Development Department, Espahan Koosha Company, Isfahan 81611-98371, Iran Journal Article 2025 08 03 In the heavy vehicle transport industry, the fifth wheel coupling system is used as important component for connecting the semi-trailer with the tractor. Misfunction, corrosion or fracture of the fifth wheel can affect the stability and consequently the safety of the heavy vehicles. During operation, the fifth wheel experiences different loading conditions. So, a reliable model which represents stresses due to acting forces on the fifth wheel coupling system plays a significant role. For this purpose, first, controlled vibration experiments are conducted on a JOST’s fifth wheel coupling system and modal parameters of the system is obtained. Moreover, a finite element model (FEM) is constructed in ABAQUS software and successfully validated by the results of the experimental modal analysis (EMA). Then, the validated FEM is used to achieve the stress distribution in the system for accelerating and breaking conditions. Also, it is found that stresses in the JOST’s fifth wheel coupling system remain below the mechanical strength limit of the material. https://tava.isav.ir/article_735807_9340113410887504dbba05a37f589592.pdf