Before discussing what is really wrong with speed bumps, it is essential to know about their importance. The speed bumps are a great way to control the speed limit of vehicles passing through the road. It is essential as it ensures the safety of both the driver and other pedestrians. So far speed bumps have proven to be the most efficient way to control traffic on roads and prevented many accidents which may have occurred due to overspeeding.

    WHAT ARE THE DISADVANTAGES OF THESE SPEED BUMPS

    Here are some disadvantages of conventional speed bumps ➭

    • They cause damage to the "shocks"&(Shocks are basically the shock absorbers which absorb sudden energy release due to abrupt change which we encounter on-road) of your vehicle.
    • When the "shocks" are out of order, the whole vehicle pays the price. The wheel alignment, the steering, the control on the vehicle, all get heavily affected.
    • The frame of the vehicle gets bent and the hydraulic fluid also gets leaked.


    WHAT CAN BE DONE ABOUT THEM

    Reading the above facts it can be concluded that conventional speed bumps though necessary, pose a lot of problems. The solution for this lies in the LIQUID SPEED BUMP.

    WHAT ARE LIQUID SPEED BUMPS

    These speed bumps are smart bumps that can allow the vehicle to pass smoothly when they are in the correct speed limit and harden for those vehicles which violate the speed limit. They have a simple working principle and are filled with shear-thickening non-newtonian fluid.

    This kind of fluid act as fluid with low viscosity when shear stress is applied to them slowly and act as fluid with high viscosity(similar to solid) when shear stress is applied suddenly. This property helps in targeting the overspeeding vehicles while does not affect the vehicles within the specified speed limit.

    NEWTON'S LAW OF VISCOSITY

    The fluids which do not follow "Newton's law of viscosity" are known as non-newtonian fluids.


    THE NEWTON'S LAW OF VISCOSITY


    Here 𝝻 is the viscosity of the fluid, du is the velocity difference between two layers separated by distance dy caused by the shear stress applied. According to Newton's law of viscosity, the rate of shear deformation is directly proportional to shear stress applied.

    The fluids that we encounter in our daily life are Newtonian fluid or we can say that they follow newton's law of viscosity. 

    WHAT ARE NON NEWTONIAN FLUIDS

    The fluids which do not follow "Newton's law of viscosity" are known as non-newtonian fluids.

    There are different kinds of non-newtonian fluids :

    1. Bingham plastic fluid: They show their fluid behaviour only after the yield stress is applied, eg. Toothpaste in the tube.
    2. Pseudoplastic fluid(shear-thinning fluid): These fluids show solid-like behaviour or have high viscosity when shear stress is applied slowly and behave as fluid with low viscosity when shear stress is applied suddenly, eg. Paints, Tomato ketchup.
    3. Dilatant fluid(shear-thickening fluid): These fluids show solid-like behaviour when sudden shear stress is applied and act as a fluid when shear stress is applied slowly, eg. mixture of corn starch and water .

    GRAPH OF SHEAR RATE VS SHEAR STRESS 

    DILATENT FLUID(Shear-thickening fluid)

    Due to it's remarkable property to harden on application of sudden shear stresswhile remain in liquid state makes it an ideal fluid for use in "liquid speed breaker".

    In non-newtonian fluid shear stress (𝝉)is not directly proportional to(du/dy), instead it may not be a linear relation.


    Here the '𝛍 effective' is not constant and can change with shear stress applied.The'𝛍 effective' increases with as we increase the velocity gradient.

    WORKING PRINCIPLE OF LIQUID(NON NEWTONIAN) SPEED BREAKER

    The Non Newtonian fluid speed breaker can be either permanently or temporarily placed at a desired location, such as in street or roadway. The material in the reinforced rubber layer tubes can be selected based on a desired shear rate. The shear rate selected will correspond to predetermined vehicle speed. The non- Newtonian fluid acts as controlling the resistance by the strip to its deformation. It depends on the speed of the wheels of the vehicle on it. Thus, if the vehicle travels at a low speed (within speed limit) the fluid has a low viscosity and the strip is easily deformed, whereas if the speed of the vehicle is high (Beyond the speed limit) the viscosity of the fluid is high and as a result has great resistance to deformation, thus forming a rigid obstacle to the passage of the vehicle.



    CONCLUSION

    We have thus learned to remove the shortcomings of conventional speed breaker by replacing them with non newtonian fluid speed breakers and have learned their working principle. These speed breakers are comparatively cheap and easy to install.