Question

Calculate the Modulus and the specific modulus (modulus/density) for a 82 vol% Kevlar/epoxy aligned fibre composite in the direction of fibre alignment.

I am sure it is only these information for this question.

	Density Mg/m3	Modulus GPa
Epoxy	1.1	5
Kevlar	1.44	131
Ti alloys	4.43	114
Al alloys	2.7	70
steels	7.85	207

Calculate the Modulus and the specific modulus (modulus/density) for a 82 vol% Kevlar/epoxy aligned fi Kevlar/epoxy aligned fibre composite in the direction of fibre alignment Density Moduļus GPa 5 131 114 70 207 Epoxy Kevlar Ti alloys Al alloys steels 1.1 144 4.43 2.7 7.85

Answer 1

The modulus of 82 vol% Kevlar/epoxy = (0.82*131 GPa) + (0.18*5 GPa) = 108.32 GPa (or) 108320 MPa

The density of 82 vol% Kevlar/epoxy = (0.82*1.44 Mg/m³) + (0.18*1.1 Mg/m³) = 1.3788 Mg/m³

Therefore, the specific modulus (modulus/density) for a 82 vol% Kevlar/epoxy = 108320 MPa/1.3788 Mg/m³ = 78561.1 J/g (or) 78.561 kJ/g

Note: The conversion factors involved are 1 GPa = 10⁹ Pa, 1 MPa = 10⁶ Pa, 1 Mg = 10⁶ g, 1 Pa.m³ = 1 J and 1 kJ = 1000 J