Why do we need to know this stuff?
Look around you today as you go to school, work, or while at home. Notice the walls and ceilings that surround you in daily life. What engineering concepts are at play in these structures? When you drive over a bridge, how often do you worry about the bridge failing? When bridges and buildings are engineered properly, we usually don’t stop to think about the science behind their construction.
This unit uses ideas about building structure to develop concepts in science. The central concept in the mechanics and materials science curriculum is force. The National Science Education Standards present force as a fundamental concept of physics. We observe the structure of buildings, homes, bridges, stores, schools, shops and businesses every day. Our perspective will be concerned mainly with “static” forces, meaning that a building or bridge is not moving; therefore the forces acting on them are called “static.”
What is the big picture?
We use three main ideas from construction to show examples of how force works in the structures around us. Learning these main ideas helps students to see the world differently, with more meaning. Knowing that bridges are designed to distribute forces from one side to the other can create curiosity about how different designs accomplish this. To help understand these concepts, try one of the activities in Tension and Compression. Next time you look at a bridge or a ceiling in a building, ask yourself what forces are acting on the different parts of that structure.
Bending is a force caused by an external load, which tends to deform a body about an axis lying within the plane of the area.
Torque is a force caused by an external load, which tends to twist one segment of the body with respect to the other about an axis perpendicular to the area.
Tension is a force which acts on a member, such as a truss component, which tends to cause the member to elongate, or be pulled.
Compression is a force which acts on a member, such as a truss component, which tends to cause the member to shorten, or be pushed.
Watch the Tension & Compression video to help understand how these forces work inside structures in our daily lives. Then try the bridge building activity in Tension & Compression to see if better understanding these ideas helps you to build a better bridge!
Shear is a force caused by an external load which causes two segments of a body to slide over each other.
Where is Materials and Mechanics in your life?
The study of Mechanics and Materials is the study of the world in which we live. This study is the underlying foundation of the architecture and infrastructure that we use on a daily basis. As we learn more about science and engineering, we begin to see evidence of their uses all around us.