The strength of plastic is one of the most important concepts in engineering. If we can not break a product with our hands, it is good for us. But if the material is too weak, it will be broken by outside forces or does not survive transport and storage after manufacture. It turns out that different plastics have very different characteristics.
Can plastic be as strong as steel?
Plastics can be as strong as steel depending on what plastic and the type of steel it is being compared against. Plastics are generally stronger than metals like aluminum. But they are not as strong as steel. Steel, like other metals, is much stronger than plastics.
Plastic can be as strong as steel if it is made of tough high-density polyethylene (HDPE). But even HDPE has 7 times less strength than steel. Steel has a tensile strength of 700 – 2000 MPa (mega Pascal). While the tensile strength of high-density polyethylene is only 70 MPa.
If you are looking for a material that combines the lightness of aluminum with high tensile strength, steel will always be more suitable, although it may have drawbacks in terms of environmental impact.
Why are motorcycle helmets made off the plastic, not with a steel shell?
Steel helmets are very heavy. A metal helmet weighs about 1 kg. Metal is only 3 times stronger than plastics, but it weighs 7 times more. The manufacturers usually take the plastic part of the motorcycle helmets to save weight for riders. Therefore if you ask a question does dropping a motorcycle helmet ruin it, the answer is no.
In addition, the plastic parts can be made with a 3D printer, which is cheaper than injection molding.
Plastic is a common material that has many benefits for manufacturing, but it does come with some limitations. While this may seem like an obvious drawback, plastics are lightweight so they save weight on heavy items such as motorcycle helmets where the rider’s head needs protection from falls at high speeds while also needing to maintain optimal aerodynamics in order to increase speed without losing too much energy due to drag.