The acid digestion test left 2.595 g of fiber from a composite specimen weighing 3.697 g. The composite specimen weighs 1.636 g in water. If the specific gravity of the fiber and matrix is 2.5 and 1.2, respectively, find the 1. Theoretical volume fraction of fiber and matrix 2. Theoretical density of composite

0.4323 ; 1.5394

Explanation:

Given that :

Specific gravity of Fibre (Sf) = 2.5

Specific gravity of Matrix (Sm) = 1.2

Mass of Fibre, Mf = 2.595g

Weight of composite specimen in water , Wc = 1.636g

Composite weight, Ww = 3.697 g

Weight of Fibre and matrix

Volume fraction of Fibre and matrix :

[(Mf/Sf) ÷ (Mf/Sf + Wc/Sm)] * 100

[(2.595/2.5) ÷ (2.595/2.5 + 1.636/1.2)]

(1.038 ÷ 2.4013333)

= 0.43225986

= 0.4323

2.)

Theoretical density of composite :

Weight of composite / (Mf/Sf + Wc/Sm)

3.697 / (2.595/2.5 + 1.636/1.2)

3.697 / 2.4013333

= 1.5395613

= 1.5394