1.2 Load Determination: The Invisible Dance of Forces
Have you ever wondered why things fall, fly, or just lie around? Of course, forces are responsible for that! But did you know that there are different types of forces?
Let's illustrate this with an example:
Engineers are like builders – they create bridges, buildings, machines, and other marvels of engineering. But before the first stone can be laid or the first steel beam can be set, we need to understand what forces are acting on our work. This is where load determination comes into play – an invisible dance of forces that decides success or failure.
Imagine you are building a gigantic skyscraper. Wind gusts whip against the facade, snow piles up on the roof, people stream through the floors. All these factors create loads that stress the building.
There are different types of dancers, er, loads:
In engineering mechanics, we often use point forces to simplify complex force systems. They are idealized representations of forces that do not actually exist in reality. These forces are considered point-shaped forces because their entire effect is concentrated at a single point on the body.
Distributed loads are also idealized representations of forces that do not actually exist in reality.
Distributed loads are a special type of load that act continuously over a distance. In contrast to point loads, which act at a single point, distributed loads act over the entire length.
- Imagine a long line of people standing on a bridge. The load is distributed evenly over the length of the bridge.
- Consider a beam that is much longer than it is wide. If, for example, there is snow on this beam, we can ignore the width of the beam and have a practical distributed load.
Imagine you are pressing your finger on a tabletop. Do you feel the resistance? This very force that you exert on the surface is a surface force. It acts distributed over the entire surface and is, so to speak, the pressure times the area.
- Air pressure inflating your balloon
- Water pressure holding back a dam
- Snow load heating up your roof
Volume loads, unlike surface loads, are not limited to the surface, but act throughout the volume of a body.
- Gravity! It pulls every body with mass towards the center of the earth. The more mass a body has, the greater the gravitational force.
In the real world, loads are often complicated and irregular. But engineers are clever: They use the power of idealization.
Idealization means that the real loads are simplified in order to be able to calculate them better. This way, an irregular snowdrift becomes a uniform surface load and a stormy wind becomes a constant point load.
Idealization is useful, but it should not be confused with reality. It is important to know the limits of simplification and always keep an eye on the actual conditions.
Point loads, line loads, surface loads, and volume loads – the world of engineering mechanics is full of exciting force actors. With the knowledge of their properties and their interaction, we can better understand the world around us and even design it ourselves.
Knowing the spatial distribution of forces is important to understand the effects on a body or structure and to be able to apply the appropriate mechanisms for analysis and calculation in engineering mechanics.
Load determination is an important step in engineering. It allows us to calculate the load-bearing capacity of engineering marvels and ensure that they stand and function safely – for invisible dances of forces that last a lifetime.
P.S.: This text is just a small glimpse into the world of forces. In engineering mechanics, there are many more types of forces and exciting application areas. So, dive deeper and discover the fascination of engineering mechanics!