2.2 Force Analysis On Vehicle

803 Words4 Pages

2.2 Force analysis on vehicle
Determing the axle loadings on a vehicle under arbitrary conditions is a simple application of Newton’s Second Law. It is a vital step because the axle loads determine the tractive effort, which infulence the acceleration, gradeability, maximum speed and drawbar effort [5].
The important forces that act on the vehicle are shown in fig: 2.2 Fig 2.2: arbitrary forces acting on a vehicle
 W is the weight of the vehicle acting at its CG with a magnitude equal to its mass times the acceleration of gravity. On a slope vehicle will have, a cosine component which is perpendicular to the road surface and a sine component parallel to the road.

 If the vehicle is moving along the road, it is convenient to represent the effect by an equivalent inertial force …show more content…

...2.7
Thus when the vehicle accelerates, load is transferred from the front axle to the rear axle in proportion to the acceleration and the ratio of the CG height to the wheelbase.

Loads on Grades.
The influence of grade on axle loads is also worth considering. Grade is defined as the “rise” over the “run.” That ratio is the tangent of the grade angle, θ. The common grades on interstate highways are limited to 4 percent whenever possible. On primary and secondary roads they occasionally reach 10 to 12 percent. The cosine of angles this small are very close to one, and the sine is very close to the angle itself. That is: Cos θ = 0.99+ ≈ 1 Sin θ ≈ θ
Thus the axle loads as influenced by grade will be: Wf = W (c / L – h / L θ) = Wfs – W * h / L * θ …………………………………………….2.8 Wr = W (b / L + h / L θ) = Wrs + W * h / L * θ

More about 2.2 Force Analysis On Vehicle

Open Document