The elastic modulus for hydroxyapatite [Ca5 (PO4) 3 (OH) ] is 98.3 GPa, which possesses a 10 vol% porosity. Calculate the following:

a. Elastic modulus E0 for the nonporous ceramic material.

b. The elastic modulus for the same sample with 50 vol% porosity. With a larger porosity, will you expect Young's modulus to increase or decrease? Why?

Eo = 120.02 GPa

Eo = 357.454 GPa

Explanation:

given data

elastic modulus E = 98.3 GPa

porosity P = 10 % = 0.1

solution

we know that young modulus of porous material that is express as

young modulus of porous material = Eo (1 - 1.9 P + 0.9 P²) ... 1

here Eo is young modulus of non porous material and P is porosity so we get here Eo

98.3 = Eo (1 - 1.9 * (0.1) + 0.9 * (0.1) ²)

Eo = 120.02 GPa

and

now for P is 0.5 for the this same material

put value in equation 1

98.3 = Eo (1 - 1.9 * (0.5) + 0.9 * (0.5) ²)

Eo = 357.454 GPa

so here young modulus increase will porosity.

but in generally elastic modulus of material will decrease

so here P is 0.1 an P is 0.5 consider same classic modulus 98.3 GPa

so value will increase