Strength to Weight & Modulus to Weight

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SUMMARY

The discussion focuses on calculating the strength-to-weight ratio and modulus-to-weight ratio for a material with a tensile strength (σ) of 230 MPa, a modulus (E) of 15 GPa, and a density (ρ) of 1.85 g/cm³. The calculations yield a strength-to-weight ratio of 124,324.32 N/m²/kg and a modulus-to-weight ratio of 8,108,108.108 N/m²/kg. The participants clarify that the resulting units are indeed not dimensionless, as they depend on the chosen density units, either mass density or weight density.

PREREQUISITES
  • Understanding of tensile strength (σ) and modulus of elasticity (E)
  • Knowledge of density (ρ) and its units
  • Familiarity with ratio calculations in material science
  • Basic grasp of unit conversions in physics
NEXT STEPS
  • Research the implications of strength-to-weight ratios in material selection
  • Explore the significance of modulus-to-weight ratios in engineering applications
  • Learn about unit conversions between mass density and weight density
  • Investigate the role of tensile strength and modulus in composite materials
USEFUL FOR

Material scientists, mechanical engineers, and students studying material properties and structural analysis will benefit from this discussion.

CRich
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Homework Statement


σ=230MPa (tensile strength)
E=15GPa (modulus)
ρ=1.85 g/cm^3 (density)



Homework Equations



Strength/Weight = σ/ρ
Modulus/Weight = E/ρ

The Attempt at a Solution



Strength/Weight = σ/ρ = 230x106 N/m2 / 1850 kg/m2
= 124324.32 (Units?) ___Shouldn't this be unit less?

Modulus/Weight = E/ρ = 1.5x10 10 N/m2 / 1850 kg/m2
= 8108108.108 (Units?) ___Shouldn't this be unit less?

____Any help is appreciated, thank you__
 
Physics news on Phys.org
Units are Nm/kg using mass density. Or if you use weight density,
the
units are length units (meters or feet or inches, etc)
 

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