A rod of length L and diameter D is subjected to a tensile load P. whi...
For longitudinal strain we need Youngs modulus and for calculating transverse strain we need Poisson’s ratio. We may calculate Poissons ratio from E = 2G(1 + μ) for that we need shear modulus.
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A rod of length L and diameter D is subjected to a tensile load P. whi...
Understanding the Relationship Between Load and Diameter Change
When a rod is subjected to a tensile load, both its length and diameter change. To calculate the change in diameter specifically, we need to consider certain material properties.
Key Concepts Involved
- Young's Modulus (E):
- It measures the stiffness of a material and indicates how much it will deform under a given load.
- It is directly related to the axial strain in the rod when subjected to tensile stress.
- Poisson's Ratio (ν):
- This is the ratio of lateral strain to axial strain.
- While it does provide insight into how much the diameter will change in relation to the length change, it cannot be used alone to determine the absolute change in diameter.
- Shear Modulus (G):
- This property relates to the material's response to shear stress, which is not directly involved in calculating changes in diameter resulting from tensile loads.
Why Young's Modulus is Sufficient
- When calculating the change in diameter due to a tensile load, Young's modulus provides the necessary information about how the material will stretch, which is the primary factor affecting both length and diameter.
- Although Poisson's ratio is important for understanding the relationship between axial and lateral strains, it cannot provide the absolute values needed without knowing the Young’s modulus.
- Therefore, the combination of Young's modulus and Poisson's ratio would give a complete understanding, but since the question is about sufficiency, Young's modulus alone is enough to initiate the calculation.
Conclusion
In summary, for calculating the change in diameter of a rod under tensile stress, Young's modulus is indeed sufficient since it directly relates to how the material deforms under load.