Distribution and Dissipation of Braking Power of Wet Multidisc Brake

To study the distribution and dissipation of braking power of wet multidisc brake and determine thermal load and thermal flux distribution between mated discs, the concept of distributing brake power four times was put forward. The third and the fourth distribution of brake power were calculated by using finite element(FE) software ANSYS. The third and the fourth distribution of wet multidisc brake are mainly related to material characteristics of discs during emergency braking, while most of the braking power is carried off during continuous braking. Basis is provided for further analysis of disc failure and applicability of different friction materials.

Full Power Hydraulic Brake System Based on Double Pipelines for Heavy Vehicles

The hydraulic caliper disc brake system with air-over-oil is widely adopted at present for heavy vehicles,which makes use of air pressure system propelling the hydraulic pressure system acting on friction plates divided and combined for braking.There are some disadvantages such as pneumatic components failure,dust polluted and produce lots of heat in hydraulic caliper disc brake system.Moreover,considering the demands of the high speed,heavy weight,heavy load and fast brake of heavy vehicles,the full power hydraulic brake system based on double pipelines for heavy vehicles is designed and analyzed in this paper.The scheme of the full power hydraulic brake system,in which the triloculare cylinder is controlled by dual brake valve,is adopted in the brake system.The full power hydraulic brake system can accomplish steering brake,parking brake and emergent brake for heavy vehicles.Furthermore,electronic control system that is responsible for coordinating the work of hydraulic decelerator and hydraulic brake system is developed for different speed brakes.Based on the analysis of the influence of composed unit and connecting pipeline on braking performance,the nonlinear mathematic model is established for the full power hydraulic brake system.The braking completion time and braking pressure in braking performance of the double-pipeline steering brake and parking brake are discussed by means of simulation experiments based on Matlab/Simulink,and the simulation results prove that the braking performance of steering brake and parking brake meets the designing requirement of the full power hydraulic brake system.Moreover,the test-bed experiments of the brake system for heavy vehicles are carried out.The experimental data prove that the braking performance achieves the goal of the design,and that the full power hydraulic brake system based on double pipelines can effectively enhance braking performance,ensure braking reliability and security for heavy vehicles.

A Comprehensive Analysis of the Stability and Powering Performances of a Hard Sail-Assisted Bulk Carrier

The wind-assisted propulsion system is becoming one of the most popular and efficient ways to reduce both fuel consumption and carbon dioxide emission from the ships.In this study,several analyses have been carried out on a model of bulk carrier fitted with five rigid sails with a 180°rotating mechanism for maximum usage of wind power and a telescopic reefing mechanism for folding it during berthing.The stability of the ship has been verified through the calculations of initial stability,static stability,and dynamic stability through the fulfillment of the weather criterion using MAXSURF software.The structural analysis of the sail was carried out in ANSYS static structural module.Several flow simulations were carried out in ANSYS fluent module to predict the thrusts produced by the sails at different apparent wind angles,which would in turn reduce the thrust required from the propeller.In this way,the brake horse powers required for different sail arrangements were analyzed to find out a guideline for this wind propulsion system to generate better powering performances.To consider drift and yaw effect on propulsion system,an MMG mathematical model–based simulation was carried out for different drift angles of motion of the ship considering hard sail–based wind loads.Through these analyses,it has been found out that the hard sail–based wind-assisted propulsion system in some cases have produced a reduction of more than 30%brake power in straight ahead motion and around 20%reduction in case of drifting ships compared to the model having no sails.

Assessment of the curving performance of heavy haul trains under braking conditions

To study the curving performance of trains, 1D and 3D dynamic models of trains were built using nu- merical methods. The 1D model was composed of 210 simple wagons, each allowed only longitudinal motion; whereas the 3D model included three complicated wagons for which longitudinal, lateral, and vertical degrees of freedom were considered. Combined with the calculated results from the 1D model under braking conditions, the behavior of draft gears and brake shoes were added to the 3D model. The assessment of the curving performance of trains was focused on making comparisons between idling and braking conditions. The results indicated the following： when a train brakes on a curved track, the wheel-rail lateral force and derailment factor are greater than under idling conditions. Because the yawing movement of the wheelset is limited by brake shoes, the zone of wheel contact along the wheel tread is wider than under idling conditions. Furthermore, as the curvature becomes tighter, the traction ratio shows a nonlinear increasing trend, whether under idling or braking conditions. By increasing the brake shoe pressure, train steering becomes more difficult.

Development of database and mathematical models for predicting engine performance parameters using biodiesel

A database for complete and quick knowledge of biodiesel was developed in Microsoft access linked with interactive interfaced of Visual Basic which contains various information such as biodiesel properties,engine performance parameters and emission characteristics.The comparisons of fuel properties among the biodiesel,its blends and engine performance parameters are one of the most attractive features of the developed database.Based on the data collected from the developed database,the analysis of variance(ANOVA)was carried out to know the effect of fuel properties on engine performance parameters.The fuel properties such as a change in calorific value and viscosity with respect to diesel were found to be significant at 5%level with brake power(BP)and brake specific fuel consumption(BSFC).However,flash point and density were found to be insignificant.Therefore,mathematical models were developed for(i)change in BP and(ii)BSFC based on the significant fuel properties.The model efficiency for BP and BSFC were found to be 92%and 91%respectively.The RMSE values were also calculated from the predicted value and found to be 1.85 and 5.45 for BP and BSFC respectively.From the above statistical facts,it is revealed that the developed mathematical models can be used to predict the change in BP and BSFC.Further,it is also expected that the developed database shall be expedient for researchers and engineers to locate various information related to biodiesel.