F2008-04-029
Preliminary Optimization of General-Arrangement Decisions of Multilink Trucks for Virtual Design
An actual challenge is the creation of new generations of heavy-duty trucks for transportation of cargoes on long and ultralong distances. They are able to reduce the amount of transport on roads and drivers borrowed in cargo transportations, to increase an economic efficiency and a safety of transportations and to reduce harmful emissions in an environment.
Multilink trucks with three and more active trailers are most suitable to achieve the indicated purposes. Every trailer includes cargo and traction modules, steering system, etc. The traction module includes a power unit and elements of transmission.
We note an absence of well-known methods in scientific and technical papers that describe how to design such type of vehicles. Consequently there is a necessity to work out design fundamentals for the following use in a virtual vehicle creation process. This helps to prove an operate opportunity of ultralong trucks with several active trailers without an infringement of different regulations. First of all it concerns parameters of general length and full weight of the truck.
At the initial stage of an offered method (we named it as the preliminary optimization) it is grounded and optimized: the general-arrangement scheme with finding the best values of the longitudinal and high-altitude coordinates, defining positions of gravity centres for units and axes in the base of a trailer; the quantity of freedom degrees of trailers for realization of maneuvers. In other words it is defined such mass and geometric parameters of multilink trucks when normal wheels loadings to a road do not exceed the admissible normative values, but provide necessary traction for the truck, and overall dimensions are kept within maneuverability requirements.
For mention stage parameters are optimized for a motionless and making maneuver with infinitesimal speed multilink truck. As initial data and to restrictions for optimization we refer a full weight of the truck, overall dimensions, traction (a grade climbing is not less than 18%, an ascent for start is not less than 12%) and maneuverability (minimal external and internal radiuses of turn) requirements.
In the given paper the authors offer computation method and algorithm of the preliminary optimization of general-arrangement schemes, the mathematical model of the multilink trucks in MSC.ADAMS and results of computation researches. Mass and geometrical parameters, which are found, have a transient state and should be finally determined and substantiated during the further optimization in accorder with estimated running characteristics using dynamic models and carrying out of virtual tests in a full cycle of virtual designing.
Session: Design Process