Explain the concept of ‘stability of vehicle on turn and slopes’ with sketch.
1 Answer
Answer :
Stability of vehicle on Slope: Let the vehicle rest on a slope of inclination Q to the horizontal. This alters the distribution of the weight between the front and back axle and gives rise to reaction which can have com-ponents along the perpendicular to the inclined plane as shown in Fig.
If the angle θL is increased gradually, a situation arises when, 1. The vehicle about to overturn, or 2. The vehicle is about to slide down the slope, The limiting angle θL for overturning is given by,
Stability of vehicle on turn: When vehicle is taking a turn along a curved path three conditions arises - 1) Centrifugal force acts at centre of gravity in radially outward direction and normal reaction due to centrifugal force acts at wheel contact. The reactions (PIF, PIR) will be in inward direction at inner wheels and the reactions (POF, POR) outward directions at outer wheels. The centrifugal force and reactions forms overturning couple. 2) At the wheels reaction due to weight (RIF, RIR, ROF, ROR) acts at a wheel in radially outward direction. 3) Reaction at a wheel due to gyroscopic couple. These three conditions causes the over turning couple leads to sliding (skidding) and overturning of the vehicle. To avoid this height of center of gravity of the vehicle should be lower; speed during turning should be lower.