Title: An investigation on friction coefficients between multi-body bell-end circular thin-walled tubes Pouya Azarandaz Affiliation: Shahid Bahonar University of Kerman Email: Pouyaazarandaz@gmail.com Amirhosein Mozafari Affiliation: Shahid Bahonar University of Kerman Email: Amiirmozafari@gmail.com Hossein Raiszade Affiliation: Shahid Bahonar University of Kerman Email: Hraiszade@gmail.com Abstract In this paper, the effects of different friction coefficients used as general contact in ABAQUS/Explicit for novel multi-body circular tubes, which are called bell- end circular tubes, is investigated. For this purpose, a Python script was written to apply the friction coefficients from 0.09 to 0.6 in the finite element simulation of double and triple bell-end tubes. The force-displacement results are then transferred to MATLAB in order to calculate the Absorbed Energy, Peak Crush Force, Average Crush Force, Crush Force Efficiency, and Specific Absorbed Energy. The results depict a decrease in Crush Force Efficiency and an increase in the mentioned calculated crashworthiness characteristics by increasing the friction coefficient value. Furthermore, two deformed shapes of double and triple bell-end tubes were observed. The first deformation happens with lower values of friction coefficient in which the tubes enter and expand one another and then crushing happens, and the second one happens with the higher values in which crushing of the lower and upper part of the tubes happens between the entering and expanding mode of deformation. Keywords: Thin-walled Tubes, Crashworthiness, Friction Coefficient, Energy Absorber, Finite-element Method