scholarly journals A Fuzzy Simulation Model for Military Vehicle Mobility Assessment

2017 ◽  
Vol 2017 ◽  
pp. 1-12 ◽  
Author(s):  
Aby K. George ◽  
Harpreet Singh ◽  
Macam S. Dattathreya ◽  
Thomas J. Meitzler
Keyword(s):  
Simulation Model ◽  
Fuzzy Rules ◽  
Fuzzy Simulation ◽  
Ground Vehicles ◽  
Military Vehicles ◽  
Mobility Assessment ◽  
Military Vehicle ◽  
Vehicle Mobility ◽  
Definition Of

There has been increasing interest in improving the mobility of ground vehicles. The interest is greater in predicting the mobility for military vehicles. In this paper, authors review various definitions of mobility. Based on this review, a new definition of mobility called fuzzy mobility is given. An algorithm for fuzzy mobility assessment is described with the help of fuzzy rules. The simulation is carried out and its implementation, testing, and validation strategies are discussed.

DETERMINATION OF PERFORMANCE INDICATORS OF THE TRUCK KrAZ-6510TE

2020 ◽  
pp. 19-26
Author(s):  
Olexandr Pavlenko ◽  
Serhii Dun ◽  
Maksym Skliar
Keyword(s):  
Mathematical Model ◽  
Surface Friction ◽  
Building Structures ◽  
Maximum Torque ◽  
Military Equipment ◽  
Military Vehicles ◽  
Force Magnitude ◽  
Vehicle Mobility ◽  
The Mathematical Model

In any economy there is a need for the bulky goods transportation which cannot be divided into smaller parts. Such cargoes include building structures, elements of industrial equipment, tracked or wheeled construction and agricultural machinery, heavy armored military vehicles. In any case, tractor-semitrailer should provide fast delivery of goods with minimal fuel consumption. In order to guarantee the goods delivery, tractor-semitrailers must be able to overcome the existing roads broken grade and be capable to tow a semi-trailer in off-road conditions. These properties are especially important for military equipment transportation. The important factor that determines a tractor-semitrailer mobility is its gradeability. The purpose of this work is to improve a tractor-semitrailer mobility with tractor units manufactured at PJSC “AutoKrAZ” by increasing the tractor-semitrailer gradeability. The customer requirements for a new tractor are determined by the maximizing the grade to 18°. The analysis of the characteristics of modern tractor-semitrailers for heavy haulage has shown that the highest rate of this grade is 16.7°. The factors determining the limiting gradeability value were analyzed, based on the tractor-semitrailer with a KrAZ-6510TE tractor and a semi-trailer with a full weight of 80 t. It has been developed a mathematical model to investigate the tractor and semi-trailer axles vertical reactions distribution on the tractor-semitrailer friction performances. The mathematical model has allowed to calculate the gradeability value that the tractor-semitrailer can overcome in case of wheels and road surface friction value and the tractive force magnitude from the engine. The mathematical model adequacy was confirmed by comparing the calculations results with the data of factory tests. The analysis showed that on a dry road the KrAZ-6510TE tractor with a 80 t gross weight semitrailer is capable to climb a gradient of 14,35 ° with its coupling mass full use condition. The engine's maximum torque allows the tractor-semitrailer to overcome a gradient of 10.45° It has been determined the ways to improve the design of the KrAZ-6510TE tractor to increase its gradeability. Keywords: tractor, tractor-semitrailer vehicle mobility, tractor-semitrailer vehicle gradeability.

scholarly journals THEORETICAL-EXPERIMENTAL ASSESMENT OF BRAKING SISTEMS FOR INCLINED LIFTS ACCORDING TO EN 81:22-2014.

2016 ◽  
Author(s):  
Enrique Alcalá ◽  
Beatriz Valles Fernandez ◽  
Angel Luis Martin López
Keyword(s):  
Simulation Model ◽  
Relative Displacement ◽  
Dynamical Behaviour ◽  
Emergency Braking ◽  
Braking System ◽  
Calculation Methodology ◽  
Norm Series ◽  
Definition Of ◽  
Optimal Behaviour

The inclined lifts, in case of emergency braking, can experience high longitudinal decelerations that can lead to passengers’ collisions with lift walls and interior elements. In 2014 the CEN/TC10 WG1 published the part 22 of the norm series 81 with regard to the construction elements and installation of electrical lifts with inclined trajectory. This norm stablishes, amongst other requirements, the maximum and minimum deceleration levels in both longitudinal and vertical directions. Both requirements, in opposite senses and the definition of the braking system, do not cause design difficulties in case of high slopes, but in case of lifts with the slope under a certain level they can be needed, to guarantee the fulfilment of the norm, elements that allow and additional relative displacement between the braking system and the cabin. To define the performances and the optimal behaviour of these systems it has been defined a simulation model of the dynamical behaviour of the lift under the conditions of the norm tests. Additionally, in this work it is presented a calculation methodology to define the cabin allowable weight corridor, for each braking effort made by each safety gear model, and the simulations have been validated with the results of tests with different braking efforts, weights and lift slopes. The present work has been performed in cooperation with Thyssen Krupp Elevadores with the aim of improving the knowledge of the brake dynamics of inclined lifts.DOI: http://dx.doi.org/10.4995/CIT2016.2016.2173

Vehicle Mobility Assessment for Project Wheels Study Group

1972 ◽  
Author(s):  
Adam A. Rula ◽  
Clifford J. Nuttall ◽  
Dugoff Jr. ◽  
Howard J.
Keyword(s):  
Study Group ◽  
Mobility Assessment ◽  
Vehicle Mobility

Finite Element Model for Prediction of Ground Vehicle Mobility Over Vegetation Covered Terrains

2020 ◽  
Author(s):  
Tamer Wasfy ◽  
Hatem Wasfy ◽  
Paramsothy Jayakumar ◽  
Srinivas Sanikommu
Keyword(s):  
Finite Element ◽  
Beam Model ◽  
Ground Vehicles ◽  
Body Type ◽  
Vegetation Model ◽  
Normal Contact ◽  
Ground Vehicle ◽  
Large Trees ◽  
Vehicle Mobility ◽  
Thick Beam

Abstract A finite element vegetation model is presented for predicting the dynamic interaction of ground vehicles with vegetation. The purpose of the model is to predict ground vehicle mobility over vegetation covered terrains. The types of vegetation can range from small diameter highly compliant stems to large stiff trees. Those include various types of vegetation such as grass, crops, shrubs/bushes, small trees, and large trees. Mobility measures which can be predicted include maximum safe vehicle speed along a specified path, tire slip, and fuel consumption. The ground vehicles are modeled using high-fidelity multibody dynamics models. The vegetation stems are modeled using an arrangement of thin and/or thick beam finite elements. The thin beam model uses the torsional spring beam formulation for small flexible vegetation and only includes the axial and bending beam responses. The thick beam model includes axial, bending, torsional, and shear beam responses and uses a lumped parameter beam element which connects two rigid body type nodes. The vegetation model includes the effects of normal contact and friction with the vehicle and between stems, stem breaking, and stem aerodynamic forces.

scholarly journals An Overview of Indicators and Indices Used for Urban Mobility Assessment

2019 ◽  
Vol 31 (6) ◽  
pp. 703-714 ◽  
Author(s):  
Krešimir Vidović ◽  
Marko Šoštarić ◽  
Damir Budimir
Keyword(s):  
Urban Areas ◽  
Assessment Process ◽  
Urban Mobility ◽  
Dimensional Approach ◽  
Global Trends ◽  
Mobility Data ◽  
Mobility Assessment ◽  
Local Specifications ◽  
Layered Approach ◽  
Definition Of

The urban mobility is affected by global trends resulting in a growing passenger and freight transport demand. In order to improve the understanding of urban mobility in general, to evaluate mobility services and to quantify the overall transport system performance, it is necessary to assess urban mobility. Urban mobility assessment requires the application of methodology integrating different metrics and explicitly applying a multi-dimensional approach. Since scientific community does not define urban mobility in an unambiguous way, part of this paper is devoted to the analysis of the definition of urban mobility. This step enables better understanding of urban mobility in general, as well as understanding of the urban mobility assessment process. Usually, a three-layered approach that includes urban mobility data, indicators and indices is used for the assessment. Therefore, the aim of this paper was to perform extensive research in order to synthesize, define and organize the elements of those layers. The existing urban mobility indicators and indices have been developed for specific urban areas, taking into account local specifications, and they are not applicable in other cities. Also, the choice of urban mobility indicators is mainly related to the existence of data sources, which limits the objective and comparable assessment of the mobility of cities where such data do not exist.

Understanding the Effects of a Discrete Element Soil Model's Parameters on Ground Vehicle Mobility

2019 ◽  
Vol 14 (7) ◽  
Author(s):  
Tamer M. Wasfy ◽  
Dave Mechergui ◽  
Paramsothy Jayakumar
Keyword(s):  
Particle Size ◽  
Nonlinear Behavior ◽  
Discrete Element ◽  
Model Parameters ◽  
Vehicle Speed ◽  
Ground Vehicles ◽  
Tractive Force ◽  
Wheel Slip ◽  
Soil Model ◽  
Vehicle Mobility

The Army's mission is to develop, integrate, and sustain the right technology solution for all manned and unmanned ground vehicles, and mobility is a key requirement for all ground vehicles. Mobility focuses on ground vehicles' capabilities that enable them to be deployable worldwide, operationally mobile in all environments, and protected from symmetrical and asymmetrical threats. In order for military ground vehicles to operate in any combat zone, mobility on off-road terrains should be extensively investigated. Mobility on off-road terrains is poorly understood because of the empirical and semi-empirical height-field based methods which are often used for predicting vehicle mobility, such as Bekker–Wong type models. Those methods do not capture the three-dimensional soil deformation/flow as well as the soil's nonlinear behavior. The discrete element method (DEM) in which soil is modeled using discrete particles was identified as a high-fidelity method that can capture the deformation of the soil and its nonlinear behavior. In this paper, a simulation study is undertaken to understand the influence of DEM soil model parameters on vehicle mobility. A typical wheeled vehicle model was built in ivress/dis software and simulated over different cohesive and noncohesive soils modeled using DEM, with a particular emphasis on weak soils (with both low friction angle and low cohesion). Some characteristics of these soils were varied, namely, the interparticle cohesion, the interparticle friction, the particle size, and the particle mass. The mobility measures, including vehicle speed, wheel sinkage, wheel slip, and tractive force were evaluated using the model and correlated to the DEM soil model parameters. This study shows that the vehicle speed increases with cohesion, friction, soil density, and particle size while wheel sinkage, wheel slip, and tractive force decrease with those parameters. The combined influence of those parameters is more complex. Extensive studies of those and other soil parameters need to be carried out in the future to understand their effect on vehicle mobility.

Gauging Military Vehicle Mobility Through Many-Body Dynamics Simulation

2014 ◽  
Author(s):  
Daniel Melanz ◽  
Hammad Mazhar ◽  
Dan Negrut
Keyword(s):  
Programming Languages ◽  
Dynamics Simulation ◽  
Design Decision ◽  
Soil Behavior ◽  
Many Body ◽  
Simulation Tools ◽  
Military Vehicle ◽  
Two Factors ◽  
Vehicle Mobility ◽  
Tire Models

This paper describes a modeling, simulation, and visualization framework aimed at enabling physics-based analysis of ground vehicle mobility. This framework, called Chrono, has been built to leverage parallel computing both on distributed and shared memory architectures. Chrono is both modular and extensible. Modularity stems from the design decision to build vertical applications whose goal is to reduce the end-to-end time from vision-to-model-to-solution-to-visualization for a targeted application field. The extensibility is a consequence of the design of the foundation modules, which can be enhanced with new features that benefit all the vertical applications. Two factors motivated the development of Chrono. First, there is a manifest need of modeling approaches and simulation tools to support mobility analysis on deformable terrain. Second, the hardware available today has improved to a point where the amount of sheer computer power, the memory size, and the available software stack (productivity tools and programming languages) support computing on a scale that allows integrating highly accurate vehicle dynamics and physics-based terramechanics models. Although commercial software is available nowadays for simulating vehicle and tire models that operate on paved roads; deformable terrain models that complement the fidelity of present day vehicle and tire models have been lacking due to the complexity of soil behavior. This paper demonstrates Chrono’s ability to handle these difficult mobility situations through several simulations, including: (i) urban operations, (ii) muddy terrain operations, (iii) gravel slope operations, and (iv) river fording.

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