The design procedures are based on the concept of maximum permissible tractive force. How to calculate tractive force tractive force is the propulsive force that drive wheels or tracks apply to the ground to move a vehicle along a path, whether it is a road, a railroad track, or soft earth. Material provided by sachin buddhisagar, copyright 2011. Tractive efficiency te is the ratio of drawbar power to axle power and can be estimated when slip is known.
Permanent and parttime four wheel drive and typical. The method is based on depthaveraged velocity rather than shear stress, which was the. Army corps of engineers riprap design guidance for flood channels is presented, and the limitations and basis of sev eral empirical coefficients are discussed. Vehicle forces for driving up slope equations and calculator.
Train resistance and tractive effort are both measurements of force typically in pounds in north america so we can simply overlay the curves how do we relate tractive effort curves to train resistance. There are various tractive effort curves available for different locomotives for different speeds, which enable the computation of. Discussion of tractive force design for sanitary sewer selfcleansing by lavere b. This force, which is simply the pull of water on the wetted area, is known as the tractive force chow, 1959 t. Rr force necessary to overcome rolling resistance lb. Horsepower in automotive terms is the application of a force at a certain speed. In the main line train, tractive effort is caused by the locomotive, and in a suburban train, it is caused by motor coaches.
The tractive effort required to move a train consists of numerous factors, but for most applications only four need to be considered. Methods for determination of hydraulic resistance applied shear stress as well as permissible shear stress for individual linings and lining types are presented. Appendix 7b4 riprap design work sheet for standard vdot riprap sizes only. Pdf discussion of tractive force design for sanitary. Fd5 gravity sanitary sewer design and construction, 2007, section 5. Te and hence tire efficiency of a wheel can be predicted using a series of equations that take into account tire dimensions, soil conditions, slip, etc.
What is difference between tractive force and tractive effort. An ordinary steam locomotive relies upon rotational force or torque developed at the driving wheels produced by the. Apr 15, 2017 calculating traction force friction effects. I have calculate the tractional force required to move the vehicle. Manual transmission calculations 2 tractive forces. Pdf calculation of the traction effort of switching locomotive.
Measurement of tractive force in the creep region and maximum. The tractive force between a car wheel and the surface can be expressed as. Critical tractive forces on channel side slopes hydraulic. So if we look at an ac6000 compared to an ac4400, assuming the weight, traction motors and gear ratio are all the same, they are likely to haul the same load over a given. First, a force of 2 to 5 pounds per ton of train weight is. The maximum permissible traction force that can be applied to the wheels is governed by two things. Tractive force definition of tractive force by the free. This calculator can be used to calculate the maximum acceleration and minimum accelation time for a car on different surfaces.
Analytical study on the performance analysis of power train. We now have the speed rpm and the required tractive effort. A power presizing methodology for electric vehicle. Tractive effort te is the force applied by a locomotive for moving itself and a train. The wheel torque calculated in step five is the total wheel torque. Tire traction force equation and calculator engineers.
The following state equation is obtained if the tractive force f changes as a step function. Maximum tractive effort is defined as the highest tractive force that can be generated under any condition that is not injurious to the vehicle or machine. Merritt article pdf available in journal of environmental engineering 84 may 2012 with 1,254 reads. Tractive force definition and meaning collins english. Tractive efficiency te, usually thought of as percent but used as a ratio in this paper.
If the design has two drive wheels, the force applied per drive wheel for straight travel is half of the calculated tte. Based on the vehicle desired performances, the electric motor optimal power can. Tractive force calculation for a vehicle is important to know the force required to move a car. Maximum rear wheel tractive force before slip, frwmumax n maximum front wheel tractive force before slip, ffwmumax n total tractive force generated by both rear wheels, ftr n total tractive effort required by both front wheels, ftf n total tractive effort of the machine, ftm n. For purposes of design it is desirable to know the ratio of the tractive force per unit area, ts, which will cause impending mo tion on the canal side to tl which will cause impending motion on a level surface. Tractive force when water flows in a channel, a force is developed that acts in the direction of flow on the channel bed. This quantity does not change with the number of drive wheels. The equivalent force is called rolling resistance with a magnitude of where p is the normal load, acting on the center of the rolling wheel when a vehicle is operated on a slope road, the normal load, p, should be replaced by the component, which is perpendicular to. Tire traction force, or tractive force, is the force used to generate motion between a car or truck and the road or tangential surface. Horsepower and tractive effort the idiots guide to. This vehicle dynamics calculation example will show how to. From newtons second law using the equation above you can work out the equivalent accelerations to each tractive effort.
If you double the speed but halve the force, you are producing the same horsepower. Starting tractive effort, found in the locomotive data sheet, is the rated tractive effort starting from a standstill in run8. The total tractive effort tte is the sum of the forces calculated in steps 1, 2, and 3. Pdf discussion of tractive force design for sanitary sewer. A power presizing methodology for electric vehicle traction. Tire traction can also refer to the maximum tractive force between a body and a surface, as limited by available friction. Using equation 1 we calculate the tractive force at wheels for different gears.
Tractor performance is calculated by summing the individual wheel performances. Tractive effort and tractive resistance c12 springerlink. Tractive force steam locomotives calculator fx solver. For a given tractive effort, increased horsepower allows an increased speed with other things remaining the same. Tractive effort determines how much a locomotive can haul. Ld268s roadside and median ditch design form tractive force permissible shear appendix 7b2 water surface profile calculation form. Available tractive effort road vehicle performance. Tractive effort and acceleration ce 322 transportation engineering dr. If the design has two drive wheels, the force applied per drive wheel for. As with power there are different methods of measuring tractive effort. In other words, it is the sum of the tractive force and rolling effort on the road surface. Army corps of engineers riprap design for flood channels. What is the maximum speed possible for this train with this locomotive. Tire traction force equation and calculator engineers edge.
How to calculate traction torque on wheel of automobile. Jun 20, 2018 tractive effort is the force available at the area of contact between the rear wheel tyres and the road for a rear wheel driven car. The calculator can be used for imperial and metric units as long as the use of units are consistent. Jan 07, 20 tractive force calculation for a vehicle is important to know the force required to move a car.
There is a mathematical relationship between body weight and the amount of friction force from the treatment surface. Ahmed abdelrahim available tractive effort tractive effort determined by. To do this we will use the maximum tractive effort calculated in equation 9 which was 100 lbs. The tractive force permissible shear method takes into account the physical factors of bed material, channel geometry, depth, and velocity of flow. Adhesion is the grip or force of attachment, produced by. An amount of torque distributed to the wheel from differential divided by wheel radius is the tractive effort an. Tractive force for hard, smooth surfaces is a proportional function of weigh. Locomotive tractive effort and power calculations tractive effort calculations. The maximum traction force available from one of the two rear wheels on a rear wheel driven car with mass 2000 kg equally distributed on all four wheels on wet asphalt with adhesion coefficient 0.
Permanent and parttime four wheel drive and typical tractive. This vehicle dynamics calculation example will show how to determine tractive effort or traction for a car. Horsepower in automotive terms is the application of a force at a. Tireground adhesion and maximum tractive effort the slip, s, of a tire is usually defined as where v is the translatory speed of the tire center. Or tractive force is nothing but the net force present at wheels. Tractive effort te and tractive resistance tr tractive effort te. The mid range gears provide a balance between tractive effort and speed, whilst at the top. Army corps of engineers riprap design for flood channels stephen t. Identical to find best hydraulic section, if uniform thickness of the lining material is.
The tractive effort of a locomotive should be enough for it to haul a train at the maximum permissible speed. The tractive effort estimation formula, which i found in a paper from virginia tech university. First, a force of 2 to 5 pounds per ton of train weight is required to move on straight level track. Pdf vehicle tractive force prediction with robust and windupstable. Tractive effort or tractive force is measured in kilonewtons kn or pounds force lbf where 1 kn 228.
Total tractive force generated by both rear wheels, ftr n total tractive effort required by both front wheels, ftf n. Total tractive effort is the net horizontal force applied by the drive wheels to the ground. Above is a tractive effort curve typical of a new electric train. The traction parameters involving forces are all normalized by dividing by wd, the dynamic force reaction supporting the wheel or traction device.
The tractive effort of a locomotive is the force that the locomotive can generate for hauling the load. The last step is to calculate the axle torque required to generate this tractive effort. Tractive force calculation for a vehicle tractive force or tractive effort or traction is the force applied between the tire and road surface to move a car or any vehicle for that matter. Design procedures for composite linings, bends, and steep slopes are also provided. Hi there again, i am trying to correctly calculate the tractive effort pf a train, currently i do this.
In future months design parameters for a diesel and steam locomotive. If you double the force but halve the speed again the horsepower is the same. Acceleration is a measure of how quickly you are gaining or losing speed. Force of vehicles engine maximum value transferable maximum tractive effort define the point at which additional enginegenerated tractive effort is not productive. Pdf calculation of the traction effort of switching. Tractive force is the force used for generate the variation between tangential surface and body. What is difference between tractive force and tractive.
On higher speed vehicles friction in drive components may warrant the. Take one example i have one vehicle which has weight of 500kg. A power presizing methodology for electric vehicle traction motors bekheira tabbache1,2, sofiane djebarri2, abdelaziz kheloui1 and mohamed benbouzid2 abstractthis paper proposes a methodology for presizing the power of an electric vehicle traction motor. Tractive effort is defined as the force at the rims or the outer edges of the driving wheels of moving trains. Car vehicle driving up a slope equation and calculator. In railway engineering, the term tractive effort is often used synonymously with tractive force to describe the pulling or pushing capability of a locomotive.
But it doesnt provide realistic values, so i am wondering, what is the correct way of calculating tractive effort of a train. Examine a free body diagram maximum tractive effort l wheelbase h height of the center of gravity l f, l r. Understanding torque and horsepower with tractive force. In order for traction forces to effect spinal segments, traction force has to exceed friction force. W weight or vertical force between wheel and surface n, lb f m mass on the wheel kg, slugs. Eml2322l mae design and manufacturing laboratory drive wheel motor torque calculations. Tractive effort is the force available at the area of contact between the rear wheel tyres and the road for a rear wheel driven car. If the rear wheels of the vehicle in the figure are driven with no slip taking place between the tires and the level road surface, the wheel force or the tractive effort te is equal to the torque at the driven wheels t w divided by the rolling radius or effective radius r w.
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