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A testing fAcility to Assess rAilwAy cAr infrAstructure dAmAge. A conceptuAl design jose A. romero nAvArrete And frAnk otrembA federal institute for materials research and testing (bAm), germany AbstrAct wheel forces generate stresses in the rail as a function of several vehicle and infrastructure characteristics and operating conditions. the different components of the wheel forces develop strains in the rail which contain an elastic and hysteretic (irreversible) components. the irreversible deformations of the rail would be associated with locomotive energy losses. in this paper, a testing facility is proposed to indirectly characterize the level of stresses in the rail, in terms of the energy that is lost during turning manoeuvres. different potentially influential factors are considered, including the friction at the centre plate, the wheelbase length, the distance between bogies and the radius of the curved track. the change in the potential energy during a u-turn displacement is measured. in this respect, an experimental model under this operating principles, aimed at validating such a principle of operation, reveals a significant effect of the friction at the centre plate on the energy lost during turning manoeuvres, and consequently, on the level of stresses in the rail.

Taking into account a multitude of experimental and theoretical studies reported in the literature, the braking efficiency of road tankers can be affected by the sloshing forces developed by the carried liquid during such maneuvers, as a result of the dynamic pressures exerted by the sloshing liquid on the vehicle containers walls, and of the shifting of the liquid center of gravity. However, such studies have not involved a full scale experiment. In this paper, a simplified model is proposed to study the effect of the sloshing dynamics on a road tanker braking efficiency. Results from this simplified approach, are compared with data from full scale testing, revealing that the simplified model is good to predict the maximum pressure that the sloshing liquid exerts on one of the vehicle chambers. The simplified model considers a straight truck and a pendulum analogy for the sloshing liquid, whose parameters are derived from a validated methodology to predict the sloshing frequency of the fluid within its container. Simulation of non-sloshing cargo further suggests that the stopping time can be increased by 7 % due to the sloshing cargo.