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Cold formed carbon steel C sections are often employed as load carrying structural members in heavy commercial trucks. The cold forming operations employed during the making of these members generate certain amount of residual stresses throughout the sections. As the residual stresses play a significant role in determining the structural behavior of truck frame rail members, a careful assessment of residual stresses resulting from cold forming operation is needed. In the present investigation, residual stresses in frame rail corner sections were numerically predicted with the help of non-linear Finite Element (FE) analysis in ABAQUS and compared with the experimentally measured residual stress values using X-ray diffraction technique. It has been observed that the numerically predicted residual stresses are in agreement with the experimentally measured residual stresses in forming direction.

Camber angle of steered wheels varies with steering angle as a function of the kingpin inclination angle (KPIA) and caster angle. Thus, the aim of the study herein was to understand the possibility of control of KPIA and caster angle and thus also control camber angle during turn. Hence a detailed study has been done to evaluate the effects of KPIA and caster angle on kinematics and lateral dynamics of the school bus. TruckSim® simulation tool has been used to carry out a simulation study on an 8.5 tonne 6.45 m wheelbase bus model. This open loop study was done to evaluate individual and combined effects of the aforementioned input variables on camber angle which directly influences the kinematic and dynamic response of the bus. Thus, for both KPIA and caster angle variation, handling response metrics were studied for three different manoeuvres, namely straight path driving, steady-state circles and double lane change.

Heavy commercial road vehicles are less stable in terms of rollover because of their elevated center of gravity (CG). Rollover is a type of accident in which the vehicle rotates excessively about its longitudinal axis. An untripped rollover happens when the centrifugal force acting at the CG is stronger than the cornering force acting at the tires and the vehicle rolls outwards of the turn. The accurate detection of the onset of untripped rollover is a critical step towards its prevention. This study presents a model based rollover index using the lateral Load Transfer Ratio (LTR) for detection of untripped rollover of heavy commercial road vehicles. The corroboration of any rollover detection and prevention strategy with a full-sized vehicle would be costly and potentially dangerous.

The pressure gain characteristics of jet pipe servovalve is required as an input to the designer for improving performance of the servovalve. An attempt has been made to design the first stage jet pipe servovalve parameters to get maximum pressure recovery. The static recovery pressure in receiving holes is a function of jet pipe nozzle displacement relative to receiver plate. The recovery pressure depends on web thickness, jet pipe nozzle diameter, receivers hole diameter, nozzle offset and nozzle stand-of distance. A detailed static recovery pressure analysis of a two stage, four-way, closed ports electrohydraulic flow control valve considering the effect of web thickness, nozzle diameter, receiver hole diameter and offset parameters are presented in the paper. Also the effect of supply pressure on recovery pressure is presented.