Mekanika Kekuatan Material | Diagram Momen & Shear Part 2

Introduction

This tutorial focuses on drawing bending moment and shear force diagrams, essential skills in the study of mechanics of materials. Understanding how to create these diagrams helps in analyzing the internal forces and moments acting on structural elements.

Step 1: Create a Free Body Diagram

• Begin by sketching the structure you are analyzing.

Identify all forces acting on the structure, including

• Applied loads (point loads and distributed loads)
• Support reactions
• Clearly label all forces and moments. This diagram serves as the foundation for further calculations.

Step 2: Determine Mathematical Equations

• Set up equilibrium equations based on the free body diagram.

Use the following equations

• Sum of vertical forces (ΣFy = 0)
• Sum of horizontal forces (ΣFx = 0)
• Sum of moments about a point (ΣM = 0)
• Solve these equations to find unknown forces and reactions.

Step 3: Draw the Shear Force Diagram

• Start from one end of the beam and move to the other.

At each point of interest

• Calculate the shear force using the cumulative effect of loads and reactions.

Use the following rules

• Shear force increases by the magnitude of upward forces.
• Shear force decreases by the magnitude of downward forces.
• Plot the shear force values on the diagram, connecting them with straight lines.

Step 4: Draw the Bending Moment Diagram

• Use the shear force diagram to aid in calculating moments.

At each section along the beam

Calculate the bending moment by integrating the shear force

• Bending moment increases in the direction of the shear force.
• Bending moment decreases in the opposite direction.
• Plot the bending moment values on the diagram.
• For distributed loads, consider the area under the shear force diagram to find moments.

Practical Tips

• Ensure all units are consistent throughout your calculations.
• Pay close attention to support types (simple, fixed, etc.) as they affect the reactions.
• Double-check your calculations for accuracy, especially when integrating forces for moments.

Conclusion

In this tutorial, we covered how to create bending moment and shear force diagrams by starting with a free body diagram and determining the necessary mathematical equations. Mastery of these steps is vital for analyzing structures effectively. For further learning, consider practicing with different loading scenarios and support conditions to enhance your skills.