An Energy Frame of Reference to Assess Vehicle´s Physical Externalities
Different rheological models can be considered for simulating the behavior of materials, as a function of its nature. Such different models have been represented by configurations of mechanical elements, encompassing combinations of pure elastic springs with different types of damping effects, whether viscous or dry. For example, the Kelvin-Voigt model has been used individually or in generalized forms to characterize the behavior of viscoelastic materials such as asphalt pavements. Plasticity of the materials is represented through dry friction components in the model of Miller. These different principles have been even used to model the failure of the materials on the basis of the energies involve. In particular, it has been assumed that the stored energy in the material, splits into the relaxing energy and the creeping energy. Considering the different energies involved in the deformation process of a viscoelastic material, the stored deviatory strain energy has been associated to the failure of the material. However, the energy linked to the normal strain has also been considered as a failure-criteria by some authors, as a function of the amplitude of the stress / deformation, which is expressed in terms of the stress/strain variables. In the case of asphalt pavements, the relationship between the level of force and the level of damage (rutting) has been linked on the basis of the instantaneously stored normal energy within discrete and uncoupled asphalt elements, where the viscoelastic properties of the pavement´s material in such a case, are represented by a dynamic elastic modulus whose value depends on both the properties of the binder and the granular materials, according to validated methodologies. Such an approach has been validated through experimental data reported in the literature, on the basis of a calibrated model that took into account the rate at which the strain hardening of the material takes place. That is, the calibration of the model was carried out for a certain level of cargo, and the pavement damage for another force level was successfully predicted by such methodology. Regarding the failure of viscoelastic materials, there are thus available tools to assess the material damage potentials of the dynamic loading, which involve the consideration of the strain energies, in particular, the shearing and the normal strain energies. The selection of the appropriate energy approach to assess the vehicle damage´s potentials of the vehicle forces, should be thus based upon the availability of verification data, and on the similarities of the validation data and the problem stated herein. Consequently, the normal strain energy will be used in this paper to assess the vehicle and infrastructure damage potentials of the dynamic forces developed in the vehicle due to vehicle-pavement-cargo interaction. Such dynamic loading exerted on the vehicle components and on the infrastructure, will be simulated as a function of the following: i) type of cargo (liquid and solid); ii) the infrastructure characteristics, including its geometric design (horizontal and vertical alignment), and pavement roughness (smooth, medium and rough); and iii) vehicle`s operational conditions (speed and cargo level); and iv) the environment temperature. While the infrastructure is being simulated as a viscoelastic beam supported on elastic elements, the vehicle components will be simulated as viscoelastic elements, to include the tires and the suspension as well as the rubber dampers between the chassis and the suspension.
A comparison is made of the above described methodology with existing road and vehicle pricing approaches, highlighting the benefits of having a deterministic and parametric comprehensive analysis to include as transport pricing criteria some additional cargo-vehicle-infrastructure and environmental parameters.
An Energy Frame of Reference to Assess Vehicle´s Physical Externalities
Category
Poster Paper Publication
Description
Session: 17-01-01 Research Posters - On Demand
ASME Paper Number: IMECE2020-23745
Session Start Time: ,
Presenting Author: Jose A. Romero-Navarrete
Presenting Author Bio:
Authors: Frank Otremba Federal Institute for Materials Research and Testing (BAM)
Alejandro A. Lozano Guzmán Instituto Politécnico Nacional Centro de Ciencia Aplicada y Tecnología Avanzada-Qro
Jose A. Romero Navarrete Federal Institute for Materials Research and Testing (BAM)