Bulk (Volume) Modulus of Elasticity
Mechanics of Materials · FE Reference Handbook section
Core formulas for this FE topic
Definitions, applicability, units, assumptions and worked examples for each relation.
Worked exam-style examples
The four ways this section is written on the real exam — thoughts first, then equations, then substitution.
A metal specimen has E = 10.4×10⁶ psi and Poisson's ratio ν = 0.26. Compute the bulk (volume) modulus of elasticity, the shear modulus, and the volumetric strain produced by a hydrostatic pressure of 14,000 psi.
Given
Find
K, G and the volumetric strain
Start with the thinking
- The bulk modulus links hydrostatic pressure to volume change; it blows up as ν approaches 0.5 (incompressible).
- E, G, K and ν are not independent — any two fix the others.
Step-by-step solution
Formula
Substituting
Formula
Substituting
Formula — ΔV/V = −p/K
Substituting — ΔV/V = −14000/7,222,222 = -1.9385 × 10⁻³
K = 7.22×10⁶ psi, G = 4.13×10⁶ psi, ΔV/V = -0.1938%
Why the other options are there
- K = 2.28×10⁶ psi (sign in the bracket flipped)
- K = G (moduli confused)
Reference: FE Reference Handbook — Mechanics of Materials → Bulk (Volume) Modulus of Elasticity
A metal specimen has E = 29.0×10⁶ psi and Poisson's ratio ν = 0.32. Compute the bulk (volume) modulus of elasticity, the shear modulus, and the volumetric strain produced by a hydrostatic pressure of 27,000 psi.
Given
Find
K, G and the volumetric strain
Start with the thinking
- The bulk modulus links hydrostatic pressure to volume change; it blows up as ν approaches 0.5 (incompressible).
- E, G, K and ν are not independent — any two fix the others.
Step-by-step solution
Formula
Substituting
Formula
Substituting
Formula — ΔV/V = −p/K
Substituting — ΔV/V = −27000/26,851,852 = -1.0055 × 10⁻³
K = 26.85×10⁶ psi, G = 10.98×10⁶ psi, ΔV/V = -0.1006%
Why the other options are there
- K = 5.89×10⁶ psi (sign in the bracket flipped)
- K = G (moduli confused)
Reference: FE Reference Handbook — Mechanics of Materials → Bulk (Volume) Modulus of Elasticity
A metal specimen has E = 16.0×10⁶ psi and Poisson's ratio ν = 0.32. Compute the bulk (volume) modulus of elasticity, the shear modulus, and the volumetric strain produced by a hydrostatic pressure of 8,000 psi.
Given
Find
K, G and the volumetric strain
Start with the thinking
- The bulk modulus links hydrostatic pressure to volume change; it blows up as ν approaches 0.5 (incompressible).
- E, G, K and ν are not independent — any two fix the others.
Step-by-step solution
Formula
Substituting
Formula
Substituting
Formula — ΔV/V = −p/K
Substituting — ΔV/V = −8000/14,814,815 = -0.5400 × 10⁻³
K = 14.81×10⁶ psi, G = 6.06×10⁶ psi, ΔV/V = -0.0540%
Why the other options are there
- K = 3.25×10⁶ psi (sign in the bracket flipped)
- K = G (moduli confused)
Reference: FE Reference Handbook — Mechanics of Materials → Bulk (Volume) Modulus of Elasticity
A metal specimen has E = 30.0×10⁶ psi and Poisson's ratio ν = 0.31. Compute the bulk (volume) modulus of elasticity, the shear modulus, and the volumetric strain produced by a hydrostatic pressure of 23,000 psi.
Given
Find
K, G and the volumetric strain
Start with the thinking
- The bulk modulus links hydrostatic pressure to volume change; it blows up as ν approaches 0.5 (incompressible).
- E, G, K and ν are not independent — any two fix the others.
Step-by-step solution
Formula
Substituting
Formula
Substituting
Formula — ΔV/V = −p/K
Substituting — ΔV/V = −23000/26,315,789 = -0.8740 × 10⁻³
K = 26.32×10⁶ psi, G = 11.45×10⁶ psi, ΔV/V = -0.0874%
Why the other options are there
- K = 6.17×10⁶ psi (sign in the bracket flipped)
- K = G (moduli confused)
Reference: FE Reference Handbook — Mechanics of Materials → Bulk (Volume) Modulus of Elasticity
A metal specimen has E = 29.0×10⁶ psi and Poisson's ratio ν = 0.30. Compute the bulk (volume) modulus of elasticity, the shear modulus, and the volumetric strain produced by a hydrostatic pressure of 19,000 psi.
Given
Find
K, G and the volumetric strain
Start with the thinking
- The bulk modulus links hydrostatic pressure to volume change; it blows up as ν approaches 0.5 (incompressible).
- E, G, K and ν are not independent — any two fix the others.
Step-by-step solution
Formula
Substituting
Formula
Substituting
Formula — ΔV/V = −p/K
Substituting — ΔV/V = −19000/24,166,667 = -0.7862 × 10⁻³
K = 24.17×10⁶ psi, G = 11.15×10⁶ psi, ΔV/V = -0.0786%
Why the other options are there
- K = 6.04×10⁶ psi (sign in the bracket flipped)
- K = G (moduli confused)
Reference: FE Reference Handbook — Mechanics of Materials → Bulk (Volume) Modulus of Elasticity
A metal specimen has E = 10.4×10⁶ psi and Poisson's ratio ν = 0.33. Compute the bulk (volume) modulus of elasticity, the shear modulus, and the volumetric strain produced by a hydrostatic pressure of 34,000 psi.
Given
Find
K, G and the volumetric strain
Start with the thinking
- The bulk modulus links hydrostatic pressure to volume change; it blows up as ν approaches 0.5 (incompressible).
- E, G, K and ν are not independent — any two fix the others.
Step-by-step solution
Formula
Substituting
Formula
Substituting
Formula — ΔV/V = −p/K
Substituting — ΔV/V = −34000/10,196,078 = -3.3346 × 10⁻³
K = 10.20×10⁶ psi, G = 3.91×10⁶ psi, ΔV/V = -0.3335%
Why the other options are there
- K = 2.09×10⁶ psi (sign in the bracket flipped)
- K = G (moduli confused)
Reference: FE Reference Handbook — Mechanics of Materials → Bulk (Volume) Modulus of Elasticity
A metal specimen has E = 29.0×10⁶ psi and Poisson's ratio ν = 0.31. Compute the bulk (volume) modulus of elasticity, the shear modulus, and the volumetric strain produced by a hydrostatic pressure of 9,000 psi.
Given
Find
K, G and the volumetric strain
Start with the thinking
- The bulk modulus links hydrostatic pressure to volume change; it blows up as ν approaches 0.5 (incompressible).
- E, G, K and ν are not independent — any two fix the others.
Step-by-step solution
Formula
Substituting
Formula
Substituting
Formula — ΔV/V = −p/K
Substituting — ΔV/V = −9000/25,438,596 = -0.3538 × 10⁻³
K = 25.44×10⁶ psi, G = 11.07×10⁶ psi, ΔV/V = -0.0354%
Why the other options are there
- K = 5.97×10⁶ psi (sign in the bracket flipped)
- K = G (moduli confused)
Reference: FE Reference Handbook — Mechanics of Materials → Bulk (Volume) Modulus of Elasticity
A metal specimen has E = 30.0×10⁶ psi and Poisson's ratio ν = 0.27. Compute the bulk (volume) modulus of elasticity, the shear modulus, and the volumetric strain produced by a hydrostatic pressure of 40,000 psi.
Given
Find
K, G and the volumetric strain
Start with the thinking
- The bulk modulus links hydrostatic pressure to volume change; it blows up as ν approaches 0.5 (incompressible).
- E, G, K and ν are not independent — any two fix the others.
Step-by-step solution
Formula
Substituting
Formula
Substituting
Formula — ΔV/V = −p/K
Substituting — ΔV/V = −40000/21,739,130 = -1.8400 × 10⁻³
K = 21.74×10⁶ psi, G = 11.81×10⁶ psi, ΔV/V = -0.1840%
Why the other options are there
- K = 6.49×10⁶ psi (sign in the bracket flipped)
- K = G (moduli confused)
Reference: FE Reference Handbook — Mechanics of Materials → Bulk (Volume) Modulus of Elasticity
A metal specimen has E = 10.4×10⁶ psi and Poisson's ratio ν = 0.31. Compute the bulk (volume) modulus of elasticity, the shear modulus, and the volumetric strain produced by a hydrostatic pressure of 40,000 psi.
Given
Find
K, G and the volumetric strain
Start with the thinking
- The bulk modulus links hydrostatic pressure to volume change; it blows up as ν approaches 0.5 (incompressible).
- E, G, K and ν are not independent — any two fix the others.
Step-by-step solution
Formula
Substituting
Formula
Substituting
Formula — ΔV/V = −p/K
Substituting — ΔV/V = −40000/9,122,807 = -4.3846 × 10⁻³
K = 9.12×10⁶ psi, G = 3.97×10⁶ psi, ΔV/V = -0.4385%
Why the other options are there
- K = 2.14×10⁶ psi (sign in the bracket flipped)
- K = G (moduli confused)
Reference: FE Reference Handbook — Mechanics of Materials → Bulk (Volume) Modulus of Elasticity
A metal specimen has E = 16.0×10⁶ psi and Poisson's ratio ν = 0.31. Compute the bulk (volume) modulus of elasticity, the shear modulus, and the volumetric strain produced by a hydrostatic pressure of 19,000 psi.
Given
Find
K, G and the volumetric strain
Start with the thinking
- The bulk modulus links hydrostatic pressure to volume change; it blows up as ν approaches 0.5 (incompressible).
- E, G, K and ν are not independent — any two fix the others.
Step-by-step solution
Formula
Substituting
Formula
Substituting
Formula — ΔV/V = −p/K
Substituting — ΔV/V = −19000/14,035,088 = -1.3538 × 10⁻³
K = 14.04×10⁶ psi, G = 6.11×10⁶ psi, ΔV/V = -0.1354%
Why the other options are there
- K = 3.29×10⁶ psi (sign in the bracket flipped)
- K = G (moduli confused)
Reference: FE Reference Handbook — Mechanics of Materials → Bulk (Volume) Modulus of Elasticity