Effect of Deadweight on Frame and Correlation with Human Passenger in a Two Wheeler

Deadweight as payload is an important parameter, which affects the vehicle dynamics and durability of the vehicle. This paper presents a study performed to evaluate the effect of deadweight on dynamic input load, suspension operation, and fatigue life of frame in a two wheeler. Also, an optimization exercise was undertaken to correlate and optimize deadweight with a human payload in terms of equivalent damage to the frame. Strain, wheel acceleration, and suspension displacement data were acquired with pillion and multiple deadweights and compared. Relative damage spectrum (RDS) characterization and best-fit optimization methods were used for deadweight correlation. It was observed that with deadweight addition dynamic loads decreases on the front wheel while increases on the rear. Strain damage wise increasing deadweights have marginal effects on the front zone of the frame while on the middle and rear side, deadweights are detrimental. Human payload behaves like deadweight for dynamic loading as observed with higher acceleration and suspension stroke level given its magnitude, but in terms of strain damage it has very low damaging effect as compared to deadweights. Deadweight optimization exercise suggested an optimum weight to have an equivalent damage for the same durability cycle as human pillion. The study aimed to help in understanding the design load considerations taking deadweight into account as well as in the development of proving ground test cycle with deadweight as a human substitute. The latter could be applied in case of manpower planning or pandemic scenario such as COVID-19.