9.1. Introduction

Try these first

1. 1.

   What does the first law of thermodynamics state?

   Hint

   Think about energy conservation.

2. 2.

   Define strain energy.

   Hint

   Connect it with deformation processes.

3. 3.

   What is the essence of the first law of thermodynamics in structural analysis?

   • Energy can be created.
   • Energy is conserved.
   • Energy cannot be destroyed.

   Hint

   It deals with energy changes.

4. 4.

   Virtual work can be defined as what?

   • True
   • False

   Hint

   Think about the definitions of virtual forces.

5. 5.

   A structural beam supports a load of 10 kN. Calculate the strain energy stored in the beam if its length is 3 m, area is 40 cm², and E is 200 GPa.

   Hint

   Use U = (P^2 L) / (2AE) directly in your calculations.

6. 6.

   Explain how you would apply the Virtual Work method to assess bending in a simply supported beam with a central load.

   Hint

   Ensure that you maintain equilibrium for both real and virtual loads.