This article explains the main branches of mechanics in mechanical engineering: thermodynamics, solid mechanics, dynamics, and fluid mechanics, and how these principles are applied through real-life examples such as automobiles.
“You sound like you know” and “you look like you know” are two phrases that we have all heard around us and experienced in our lives. I have also experienced these situations while studying my major, and learning my major has taught me more about one way of looking at the world. In this article, I’ll try to explain in simple terms how my major has helped me in this way.
If I had to describe mechanical engineering in one word, I think the most appropriate word would be mechanics. The dictionary definition of “mechanics” is the study of the relationship between forces and motion between objects. If you pay attention to the dictionary definition of force and motion, you can see that mechanical engineering is concerned with the relationship between moving objects and the forces that cause them to move. To better understand mechanics, its foundations are tied to Newton, who is often associated with the anecdote about dozing off under an apple tree and realizing the universal law of gravity when an apple fell on his head. There’s a mechanics behind this anecdote. The apple is the object in motion, and Newton wondered why it was moving, and concluded that the cause was a force called universal gravitation. There is a force that attracts all objects in the universe, and it’s called universal gravity. In this example, you can easily think of it as gravity. The apple tree made Newton realize the force acting on objects, and he established fundamental laws about objects and forces. Mechanics is also called Newtonian mechanics because it started with these laws. Mechanical engineering is rooted in this mechanics and is divided into four main branches: thermodynamics, solid mechanics, dynamics, and fluid mechanics. To make it easier to understand, let’s take the example of the car we drive.
Let’s start with thermodynamics, which is the study of thermal phenomena and thermal motion. If we look at this in the context of a car, we can see thermodynamics in the air conditioner and heater. These may seem like simple devices that blow cold air out and warm heat in, but it takes knowledge of thermodynamics to make them work. In this era of high gas prices, people are also concerned with the fuel efficiency of their cars, which is also related to thermodynamics as it is about how the energy from the fuel, or heat, is utilized within the engine.
Next is solid mechanics. Solid mechanics is easy to understand when you think about the body of a car. In modern times, we’re aiming for more fuel-efficient vehicles that can travel farther using less oil. This requires a lightweight body because the lighter the vehicle, the less energy it consumes. However, a lighter body makes it harder for the vehicle to support the load it carries, and in the event of an accident, the driver and passengers are subjected to a large impact, which can cause loss of life. Therefore, it is necessary to try to reduce the risk in the event of an accident while still being lightweight and able to support the load. Solid mechanics plays an important role here, calculating the loads that the body can support and calculating the impact forces and deformation of the body in the event of an accident.
Third is fluid dynamics. Fluid dynamics is the study of the motion of fluids such as gases and liquids, which can be understood through the body of a car. If you look at the cars around us, you won’t find many that have an angled connection between the driver’s seat and the bonnet when viewed from the side. Most of them have a streamlined shape. This is to reduce the amount of air resistance the vehicle experiences when moving. Increased air resistance can cause problems with fuel economy and speed because it can cause the vehicle to roll over, and it also makes it harder for the vehicle to move forward, requiring more energy to move the vehicle. Fluid dynamics is used to calculate this airflow between the air and the vehicle, and the forces that the air exerts on the vehicle, and it plays a big role in producing a car that performs well.
Finally, there’s dynamics. Kinematics is the study of the motion and forces of objects, but unlike the objects of thermodynamics and hydrodynamics mentioned earlier, which are shapeless like heat and fluids, kinematics is the study of objects in motion, that is, objects that are visible. To understand this, let’s take the example of a car: some cars corner well, and some cars don’t corner well. The reason for this is that the designer of the former car has a good understanding of the characteristics of the car’s behavior in corners and controls it, while the designer of the latter car has a poor understanding of the car’s behavior and fails to control it. In other words, it is the difference between how well or poorly the designer understands the dynamics of the object’s behavior, which is a characteristic of dynamics. In this way, dynamics helps us understand the behavior of objects.
In this way, I was able to divide mechanical engineering into four types of mechanics: thermodynamics, solid mechanics, dynamics, and fluid mechanics. Since we’ve looked at it from four different perspectives, you might think that mechanical engineering consists of only these four mechanics. However, mechanical engineering is not only about studying and utilizing mechanical properties. Mechanical engineering is an incredibly important discipline that affects most of the objects and technologies around us, including bio-robotics in conjunction with biological systems, biomechanical engineering in relation to medical technology, and acoustical engineering that utilizes dynamical properties.
Mechanical engineering is also a major contributor to today’s high-tech advances. For example, mechanical engineering plays a key role in cutting-edge fields such as the design and manufacture of artificial intelligence robots, the development of green technologies utilizing renewable energy, and space exploration. These examples show that mechanical engineering is not just theoretical, but plays an important role in real life and across industries. As such, mechanical engineering is constantly evolving to make our daily lives easier and safer, and its importance will only grow in the future.
Studying mechanical engineering has broadened my perspective on the world and given me the ability to solve a variety of problems. I hope this article has helped you understand the importance and fascination of mechanical engineering.
