Figure 1: The forces acting on the vehicle during lifting.
If we consider the model problem (see Figure 1) when
lifting a load on an inclined plane, then it is easy to
conclude that an additional force is required for
lifting, proportional to the sine of the lifting angle
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It is known from the school mathematics course
that at small angles (expressed in radians), the sine
behaves almost like a linear function. But, as we must
quantitatively assess the lifted load effect on the force
required to move, we will propose a graph of the
fraction of the gravity force that needs to be overcome
depending on the ascending angle.
Figure 2: Weight proportion when moving uphill.
Although at first glance, the dependence is very
similar to a linear one, it is not. From a practical point
of view, the most important conclusion is that the
force, required for movement, can be tens of percent
of the body weight. For example, with an ascending
angle of just over 10%, about 17% of the weight
should be lifted. And thus the additional force can be
higher than the rolling friction force, which, as can be
seen from the section above, is a percentage of the
body weight, even by an order of magnitude. The
gravity effect becomes commensurate with rolling
forces already at a few degrees.
This result is qualitative. It shows how
unfavorable the rough terrain is in terms of transport
as compared to a plain. For a similar movement in the
mountains, it is required to apply the force, which is
higher by an order of magnitude.
It is for this reason that road engineers are forced
to build bridges and tunnels, so that there are no
sections with a steep rise, although these are very
expensive facilities to build and maintain
(Biondini
and Frangopol, 2012).
3 RESEARCH RESULTS
3.1 Accessibility Areas
One of the main quantitative approaches to assessing
the efficiency of a particular mode of transport or
their combinations is the approach based on the
concept of accessibility areas (Bobrik, 2018).
In the most general case, the accessibility area is
taken as the territory that can be reached from a
specific point, after spending a certain amount of a
particular resource. These resources may include
time, travel costs, fuel costs, comfort levels, and
many others. That is, this is precisely a general
approach that can generate different definitions,
depending on the problem.
For example, for megalopolises, transport
accessibility is often calculated within an hour, which
is largely explained by the physiological reasons of
the human psyche, since after an hour the trip for
passengers begins to seem tiresome. For international
and intercity trips, as well as in geopolitics, the
accessibility area per day is becoming more
significant. For railway freight transport, it is not time
that is of great importance, but the cost of
transportation. Therefore, it is relevant to consider the
accessibility area, for example, for a $ 1,000 tariff.
As it is obvious from the examples above, the
accessibility area is a point characteristic. There are
various methods of how to match this area with a
certain numerical characteristic so that quantitative
comparisons can be made in the future. The most
common way is to estimate an accessibility area using
its square area. But it is not the only one.
At the same time, quite significant fluctuations of
this numerical indicator for different points can be
observed for the territory. In this case, the average
value of the accessibility area, averaged over the
territory of districts or other small territories, gives a
general idea of the transport of the territory. The
ISSDRI 2021 - International Scientific and Practical Conference on Sustainable Development of Regional Infrastructure