China
Africa
Explore chapters and articles related to this topic
Design of Series Hybrid Drivetrain for Off-Road Vehicles
Published in Mehrdad Ehsani, Yimin Gao, Stefano Longo, Kambiz M. Ebrahimi, Modern Electric, Hybrid Electric, and Fuel Cell Vehicles, 2018
Mehrdad Ehsani, Yimin Gao, Stefano Longo, Kambiz M. Ebrahimi
Off-road vehicles (military, agricultural, and construction) usually operate on unprepared ground and need to overcome very complex and difficult ground obstacles, such as a steep grade and very soft ground. Depending on the functional requirements, different criteria are used to evaluate the performance of various types of off-road vehicles. For tractors, their main function is to provide adequate draft to pull various types of implements and machinery. Drawbar performance is of primary interest; this may be characterized by the ratio of drawbar pull to vehicle weight, drawbar power, and drawbar efficiency. For off-road transport vehicles, the transport productivity and efficiency are often used as basic criteria for evaluating their performance. For military vehicles, the maximum feasible operating speed at two specific points in a given area may be employed as a criterion for the evaluation of their agility.1
Transportation - haulage and hoisting
Published in Ratan Raj Tatiya, Surface and Underground Excavations, 2013
Drawbar pull: This is the force exerted on the coupled load by a locomotive through its drawbar, or coupling, and is the sum of the tractive resistance of the coupled load. The drawbar pull that a locomotive is capable of developing is determined by subtracting the tractive effort, from the sum of the tractive resistance of the locomotive. This resistance is offered by several sources: rolling resistance, which the entire train offers is equal to weight of the train in tons. (i.e. weight of locomotive + weight of mine cars with pay load) multiplied by a frictional coefficient ^, which could be 10-15 kg/ton (20-30 lb/ton); Curve resistance which can be ignored, gradient resistance and the force required to provide acceleration to the motion (as given in the formulae specified below). Drawbar pull=R0WTRunning resistance/tR0=μ+/-{(1/n)×1000)+/-(a/g)
Terramechanics-based investigation of grouser shape for rigid wheels: Comparison between rectangular and trapezoidal grousers
Published in Cogent Engineering, 2020
Hirotaka Suzuki, Yutaro Watanabe, Taizo Kobayashi, Karl Iagnemma, Shingo Ozaki
The method of applying the RFT to wheel traveling analysis can be summarized as follows: ) The wheel surface is discretized into small sections and the values of and for each part during forced-slip traveling are calculated. Specifically, each part has an angular velocity, and a translational velocity, , as shown in Figure 11. Thus, is obtained from these combined velocity vectors, and can be obtained considering the inclination of each section.) By substituting and into Equation (7), the resistive force of each section on the wheel surface can be calculated.) The drawbar-pull and wheel load corresponding to the horizontal and vertical forces are calculated by performing area integration of the resistive force of small piece-wise sections. Meanwhile, the sinkage can be evaluated from the balance between the prescribed wheel load and the vertical force calculated from the RFT.