The material used in this study consists of 2400 Tex E-glass fibres impregnated with an epoxy matrix. The resin is an EPOLAM pre-polymer, EPOLAM 2020 hardener and 2020 accelerator from Axson. Glass fibres are commonly used for naval applications because of their high strength/mass ratio and their low cost compared to other reinforcements. The reinforcement consists of a plain weave fabric with 90% warp yarns and 10% weft yarns. Panels are made by an infusion process and seven orientations are studied: 0°, ±20°, ±30°, ±45°, ±60°, ±70° and 90°. The square panels, 500×500 mm, were cut into cubic samples of the geometry dimensions as shown in Table 1. The standard deviations are indicated in brackets.
|
Panel |
Thickness, (mm) |
Surface (mm2) |
Void fraction (%) |
Stacking sequence |
Fibre volume Fraction (%) |
|
A |
13.00 (0.1) |
13×13 (0.2) |
2.26 |
[0]40 |
53.5 (0.5) |
|
B |
12.52 (0.3) |
13×13 (0.2) |
2.00 |
[±20]20 |
54.0 (0.5) |
|
C |
13.00 (0.1) |
13×13 (0.2) |
1.78 |
[±30]20 |
55.0 (0.5) |
|
D |
12.78 (0.2) |
13×13 (0.2) |
1.69 |
[±45]20 |
54.3 (0.5) |
|
Table 1. Geometry and fibre mass fraction of the samples, standard deviation in brackets |
Two types of static compression tests are used to obtain the elastic properties of the lamina. In-plane loading (IP), parallel to the plies plane; plane (1,2), and out-of-plane loading (OP), according to the thickness; direction 3 (Figure 1). Table 2 compares the elastic values of the characteristics drawn from relations of micromechanics (Chamis, 1984) with those resulting from experimental work.
|
Characteristics |
E1 (MPa) |
E2 (MPa) |
E3 (MPa) |
V12 |
V13 |
V 23 |
G12 (MPa) |
G13 (MPa) |
G23 (MPa) |
|
Experimental |
46217 |
16086 |
9062 |
0.28 |
0.41 |
0.097 |
2224 |
3500 |
4540 |
|
Rules law |
42030 |
14524 |
9130 |
0.31 |
– |
0.01 |
3441 |
3273 |
4508 |
|
Table 2. Elastic properties of E-glass/epoxy lamina |
|
1} mm
|
Fig. 1. Sample loadings and coordinates of axis
