What is elastic fatigue?

Explanation

### Step-by-Step Solution:

1. **Definition of Elastic Fatigue**: Elastic fatigue refers to the phenomenon where a material loses its elasticity after being subjected to repeated or frequent deforming forces.

2. **Understanding Deforming Forces**: Deforming forces are external forces applied to a material that cause it to change shape or size. These forces can be tensile (stretching), compressive (squeezing), or shear (sliding).

3. **Frequency of Application**: When these deforming forces are applied and removed repeatedly over time, the material undergoes cycles of deformation.

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