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Mechanics of Materials

Stress State: Dive into the World of Forces and Stresses!

Are you ready for an exciting journey into the world of physics? Then buckle up and discover the secrets of the stress state with us!

What is stress? Imagine you are building a giant Lego structure. The individual blocks push and pull against each other - that's exactly what stress is! In this course, you will learn how to calculate and understand these forces.

Stress components: Break down stress into its individual parts and discover how they interact. Just as a puzzle consists of many pieces, stress is also made up of different components.

Calculation: Crack the code of stress calculation! With a few clever formulas and tools, you can determine the forces in any component.

Transformation: Stresses change depending on the perspective. Learn how to transform them into different cutting planes and thus make the whole story of the load in the component visible.

Maximum stresses: Where does the greatest danger lurk? Find out where the stresses are highest in the component and how you can minimize them.

Mohr's circle of stress: This ingenious tool helps you to visualize stresses and to grasp important information at a glance.

Discover the fascination of the stress state! In this course you will not only learn dry knowledge, but also immerse yourself in the world of engineering. With good explanations and exciting application examples, the stress state becomes child's play.

Together we are strong! We will accompany you on your journey and help you to understand the complex concepts of the stress state. With our support you will master every challenge and become an expert for stable constructions.

So what are you waiting for? Start your journey into the world of stress now!

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1.5 Indexing and Sign Convention of (Shear) Stresses

Okay, enough with the boring stuff! Now things are getting exciting – we're talking about indexing stresses.

But before we dive into the world of stresses, we need to get a little organized.

That's why: Indexing of stresses!

Just remember the following:

  • 1st index: Shows you the direction of the normal, i.e. perpendicular to the cutting plane.
  • 2nd index: Tells you the direction of the stress.
This Figure 1.1.4 illustrates how normal and shear stresses are indexed.
Fig. 1.1.4: Indexing of Stresses

For normal stresses, you can usually save yourself the second index. Since the direction of the normal and the direction of the stress are the same anyway.

Speaking of stress: What about the sign convention?

  • It's simple: Positive stresses are on the positive (or negative) cut edge and point in the direction of a positive (or negative) axis direction.
  • Take a look at Figure 1.1.4: All stresses are positive there. Cool, right?
Now, enough talking. Let's get down to business!