PSI - Issue 14

Abhijit Kulkarni et al. / Procedia Structural Integrity 14 (2019) 158–167 Abhijit Kulkarni a , Rushikesh Nanaware b , Akhilesh Kulkarni c , Vikrant Garud d / Structural Integrity Procedia 00 (2018) 000–000 3

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these objectives, principle of steering must be followed i.e. to achieve true rolling of a four-wheeled vehicle moving on a curved track. Actually, the lines drawn through each of the four-wheel axes must intersect at the instantaneous center ‘P’ which is also called as center of rotation as shown in Fig. 1. While tractor is turning about this point with a constant steering angle, the semi-trailer turns the fifth wheel inwards until the centerline of its center axle also passes through point P. But it was an experienced that this line does not coincide exactly with the centerline of the axle but lies a little to the rear which gives rise to a scrubbing rather than a rolling action and results in a very high level of tire wear.

Fig. 2. Ideal angles for articulated vehicle.

2. Synthesis of Mechanism To optimize the objective parameters along with synthesizing the dimensions of the mechanism of articulated vehicle, genetic algorithm method has been used. To synthesize the dimensions of mechanism following constraints, which were set as per requirement, were taken into consideration:  Distance between fifth wheel and first axle = 11939mm.  Distance between fifth wheel and IC line = 6804mm.  Distance between IC line and first axle = 5368mm.  Distance between Trailer rear axles = 1600mm.  Track width = 1464mm.  Cylinder initial length = 832mm.  100< � <400.  M = 220mm. Ideal angles for articulated vehicle is the angles that should be turned by individual stub axles such that pure rolling exists. For given articulation angle, position of Theoretical Instantaneous Centre IC line of the trailer from fifth wheel and axles is given by following equations.  Outer angle of tractor: � = �� � � � (1)  Inner angle of tractor: � = tan �� �� � � � (2)  Articulation angle: � ��n �� � � � (3)