Experimental Methods for Road Tankers: A Critical Review
Road transport negative environmental externalities occur during both the normal and the extraordinary, accidental/ incidental, operation of the vehicles, as a function of the type of transport and nature of the payload. Road tankers signify special situations under such circumstances, as a result of the interaction of the payload and the vehicle, which involves different vibrating masses, one of which can be the cargo itself. When compared with situations involving solid cargoes, the physical condition of the liquid cargo demands for a non-rectangular container, in order to resist the hydrostatic and dynamic pressures developed inside the cargo´s containers. Consequently, as a result of the curved containers, some usable space is left empty at the bottom part of the vehicle´s cross section, causing that road tankers tend to have a higher center of gravity when compared with solid cargo´s vehicles. This situation is further complicated due to the mobility of the liquid cargo within its container, as such condition causes additional dynamic forces associated to the sloshing of the liquid, together with an unfavorable shifting of the center of gravity of the cargo. The probability of a road tanker to suffer a rollover crash is thus higher than its solid cargo counterpart. In this respect, a higher center of gravity also induces larger roll inertial forces on both the cargo supporting components (chassis, suspension, tires), and the transport infrastructure. This would lead to the relatively premature failure of the suspension components, and an accelerated wearing of the tires. The infrastructure would also be subjected to higher stresses as a result of such condition. The negativities from liquid cargo transportation thus involve both normal and extraordinary, crashing conditions, especially when dealing with hazardous materials.
While the gross effects regarding the safe transportation of liquid cargo could be theoretically modelled through even simplified models, the need for more environmentally friendly transportation demands comprehensive, experimentally validated theoretical models. In this respect, for example, one key issue involving a big spectrum of engineering issues concerns the shape of the tanks. That is, the optimum tank shape should be defined in the light of many needs, covering from the drag resistance of the vehicle and the thickness/weight of the tank´s shell, to the lateral stability and braking efficiency of the vehicles. In this respect, assessment of the effect of the tank shape on the lateral stability of the vehicle should consider a multitude of influential factors that involve, necessarily, quasistatic and dynamic approaches, but also involve the performance of vehicle´s other components such as the suspension and tires. The resultant experimental approach should assess the developed stresses and the expected useful life of such different components. In this regard, while the use of longitudinal baffles should bring a better safety performance of the vehicle regarding its roll stability, the incorporation of such sloshing mitigating components could involve, for example, an increase in the number of load repetitions, which could be linked to vehicle components´ fatigue, while would affect the cargo-vehicle coupled dynamics. These significant aspects that involve other vehicle´s components, including the suspension and the tires, have not been addressed from the experimental perspective.
In this paper a critical review is presented of the experimental approaches reported in the literature, from which specific needs for running experimental tests are described. Specifically, to focus in potentially innovative road tankers components, including the tank shape.
Experimental Methods for Road Tankers: A Critical Review
Category
Poster Paper Publication
Description
Session: 17-01-01 Research Posters - On Demand
ASME Paper Number: IMECE2020-23069
Session Start Time: ,
Presenting Author: Jose A. Romero-Navarrete
Presenting Author Bio:
Authors: Jose Antonio Romero Navarrete Federal Institute for Materials Research and Testing – BAM, Berlin
Frank Otremba Federal Institute for Materials Research and Testing – BAM
Alejandro Alfredo Lozano Guzman Instituto Politécnico Nacional Centro de Ciencia Aplicada y Tecnología Avanzada-Qro