For this project, our group was assigned to create a 3D model of a new version of a helmet, designed by us. This meant we had research helmets, find out why they are designed the way they are, and how we can improve them, all whilst adhering to the strict safety guidelines that exist for them. Then we had to use this info to design a helmet on paper, using what we had just learned about rapid ideation sketching in class. Then these sketches would be used to create the final 3D model in fusion 360.
Our Project:
For our project, my group decided to redesign the hard hat, a safety staple in industry that hasn't really been improved in a while. Below, you will find the design process we went through, the resulting helmet we created, and the research that led to this design.
Hard hats are very important safety devices used in industry. Generally, these hats are meant to protect workers for the thousands of uncontrollable safety hazards that they are subjected to each day. They are used in a variety of industries, from factory jobs, to construction, to naval and aircraft maintenance, as well as countless other places that would be impossible to list here. Helmets may appear basic (a hard shell to protect from oncoming objects), but they actually utilize numerous scientific and engineering concepts.
My group decided to focus on the current structural weaknesses of hardhats. Hard hats are designed on a broader scope than other products so are just decent for a variety of applications. Use of hardhats in industry is generally just a standard practice; if you want to walk onto a construction site, you must be wearing a hard hat. Because of this, we need to design a helmet that satisfies the various needs of these companies perfectly, or else they won’t see a reason to choose our product.
Hard Hats are simplistic designs and have been modified greatly over time leaving little room for pragmatic improvements. As such we used much of our ingenuity and creativity to find a good solution to meet safety, aesthetic, and advantageous requirements. Aside from the various safety improvements we made, we decided to incorporate a work light and radio to improve functionality. The work light was included because workers who need hardhats often work in dimly lit areas. When a light is included on the hat, the worker does not need to search all over for a light just to do some work in a duct or under a car or in an attic. It makes their job easier and safer. The radio was included because this is the medium that most construction workers communicate by. By including it as part of the helmet, workers can quickly and easily communicate with fellow workers hands free and without needing to remember to carry their radio with them. This speeds up the workflow and increases worker safety, because they always have a communication device with them, and they can talk hands free.
We also wanted our helmet to be cool and unique, so we borrowed design cues from our favorite hats and bicycle helmets, through many orthographic sketches, developed a more curved front brim that is far more organic and in our opinions, tasteful than the current options on the market today.
The Research:
A lot of research went into helmet design, to allow us to get the best possible final product. We used various internet sources, as well as our pre-existing physics knowledge we came into the class with. Here is the path we took in our research:
In researching the physics behind helmet design, we learned the numerous aspects that go into the design of a helmet, in order to protect the user. What we found was surprising; construction helmets are very simplistic and lack the modern impact protection mechanisms that bike, skateboard, and motorcycle helmets contain. This is due to a lack of interest in the industry because large construction firms must purchase these safety devices, not individuals who put their own safety paramount, even if it costs them. But these workers safety is still vital. So we researched how the aforementioned helmets with impact protection actually achieve this goal. Most share a similar principle; a hard shell encases a layer of hard foam that will crush on impact. What this does is extend the impact time between your head and whatever surface or oncoming object is heading your way. We can easily see why this works by looking to the equation F=MA with force being F, M being mass, and A being acceleration. In order to minimize the impact, it would be logical that we would want to minimize F (force). To do this then, we would need to minimize either mass or acceleration. Since the mass of you or the object hitting you is constant, then it would only make sense that we would want to reduce acceleration. Once again, we can go to the old physic textbook to find the formula for acceleration: A=ΔV/TΔ. The two variables on the right side of the equation stand for change in velocity and change in time respectively. Once again, we find ourselves with one variable we can’t change (change in velocity), and one that we can (time). If we can increase the duration the head is impacted by the object, we can decrease the acceleration, thereby decreasing the force. This is the simple principle that helmets use to protect their users. Helmets normally do this by implementing hard foam that will crumple on impact. Ideally, this foam will be softer for a light impact and harder for a hard impact. Hard hats specifically have a couple of differences from other types of helmets. Firstly, they are less protective against impact, normally opting for an isolated headband that holds up a hard plastic shell. This is primarily because these hats are made to protect workers from any falling debris, not impact. But what we also found is this is also due to a simple lack of initiative from the companies that make these helmets. Ultimately, without these impact protection features, the workers wellbeing is compromised. The sturdy outer shell we found was also very important. Unlike a motorcycle or bike helmet, hard hats must protect from sharp objects that may fall (think rebar, concrete, wood) so a sturdy shell is essential to make sure these objects do not pierce or indent the skull of the worker. Instead, the impact is distributed, lessening the pressure experienced on any one part of the skull. Given this, the material the shell is made of is vital to the design. What we found is that the material of choice in this application is a material known as high density polyethylene (HDPE). We found that this material is actually the most common plastic used in the united states, and for good reason. The material is strong, lightweight, moldable, impact resistant, long lasting, and resistant to wear. Because of this, we decided to stick to the industry standard in this case, simply because there is nothing to improve.
The preceding research was helped by the following definitions given to us by our teacher, as things to keep in mind while designing our helmet. Many proved quite useful, while we found others simply weren't applicable to our unique choice; a hardhat.
Definitions we used:
ACCELERATION is a change in speed over a period of time; the higher the acceleration, the faster the change in speed. For example, if a car goes from 0 miles per hour (mph) to 60 mph in 2 seconds, it is a higher acceleration than if the car goes from 0 mph to 40 mph in 2 seconds. Acceleration is a rate of change of speed; NO change means NO acceleration. If something is moving at constant speed, it is NOT accelerating. COEFFICIENT OF FRICTION is the measurement of the level of friction embodied in a particular material. The formula is μ = f/N, where μ is the coefficient of friction, f, is the amount of force that resists motion, and N is the normal force. Normal force is the force at which one surface is being pushed into another. CRUMPLE ZONES are areas of an object designed to deform and crumple in an impact, as a means to absorb the energy of a collision. The fronts of most automobiles are designed as crumple zones to protect the passengers from frontal collisions. DRAG is a term used in fluid dynamics that is sometimes referred to as air resistance or fluid resistance. Friction is one of multiple factors that influence the amount of drag encountered by a body moving through a fluid such as air or water. INERTIA: when an object remains still or moves in a constant direction at a constant speed. G FORCE: a force acting on a body as a result of acceleration or gravity, informally described in units of acceleration equal to one g. FRICTION is a force that resists motion when two objects or surfaces come in contact. FORCE causes masses to accelerate; they are influences that cause a change of movement, direction, or shape. When you press on an object, you are exerting a force on it. When a robot is accelerating, it does so because of the force its wheels exert on the floor. Force is measured in units such as pounds or newtons. For instance, the weight of an object is the force on the object due to gravity (accelerating the object towards the center of the earth). KINETIC FRICTION (or dynamic friction) occurs when two objects are moving relative to each other and rub together (like a sled on the ground).