Physics of Caterpillar Tracks :: physics tank tracks

Every time you see one of the CATs clearing the hill at university of the snow, you probably don't see anything amazing about it. However, caterpillar tracks used on it are just ingenious and its invention is comparable to the invention of the wheel. History First vehicles powered by the steam engine started to appear in the early 1800s. Various machines started slowly replace horses. It was especially true for the jobs that required a lot of power. Transportation, of course, was the first and the most beneficial adopter. Goods could be carried across large distances with relative ease. No wonder that farmers were also eager to adopt engines. By that time most of the work was done using horses and basic tools. Problems Steam powered harvesters and tractors were introduced by the end of 19th century. It started to gradually replace horses. However in some regions they created new problems as well. Vehicles proved to be too heavy for soft soils and often stuck and even sunk. Experiments with various sizes of wheels didn't produce good results. Increasing size of wheels just made vehicles heavier and more difficult to operate. Benjamin Holt of Holt Manufacturing figured that using an old trick of pouting planks before the wheel would improve cross-country ability. By doing so, it provides solid plane for better traction and lower pressure on the ground since size of the plank is larger then of the wheel. Basics The main advantage of the track over the wheels is that it can distribute a very large force over a large area. That means that instead of applying all the force on little area where wheels touch the ground, it applies it over the whole area of the track. In physics terms it can be expressed as P = F / A where P is pressure, F is force and A is area. Less force applied to every square meter means that it's harder for the heavy vehicle to sink into the ground. Another benefit of the tracks is that large area of contact allows to have a very good traction with the ground. That is why tracks are used for mission critical jobs, including military use and high cost operations, such as excavations and space rocket movements. Drawbacks Even though caterpillar tracks provide very good cross-country ability, they have its drawbacks. Because of the weight and the construction of tracks speed of the vehicle is limited in comparison to the wheeled machines.