PSI - Issue 23

Zdeněk Chlup et al. / Procedia Structural Integrity 23 (2019) 505 – 510 Zdenek Chlup/ Structural Integrity Procedia 00 (2019) 000 – 000

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Table 2 Basic characteristics of fibres and composites.

D f,avg [um]

v f [-]

Fibre density [g.cm -3 ]

Composite density [g.cm -3 ]

Reinforcement

Basalt

11.8  2.11 0.69 15.1  1.00 0.70

2.6 2.6

2.17 2.13 1.73 1.49

E-Glass R-Glass Carbon

9.4  0.9 6.7  0.25

0.68 0.70

2.53 1.76

The fibre volume fraction in all composites is on a similar level reaching 70 %, therefore, mechanical properties of composites can be directly compared. The bulk geometrical density of composites varies in accordance with the respective density of fibres. The density of the matrix should remain unchanged on the level of 1.35 g.cm -3 as measured recently (Černý et al., 2015) .

Fig. 2 Dependence of the flexural strength and the fracture toughness values on used reinforcement.

The strong effect of the fibres type used is observed on the flexural strength values where basalt fibres are used in the composite reaching the level of 800 MPa, the composites reinforced by carbon and R-Glass reached 200 MPa and E-Glass 125 MPa only (see Fig. 2). The fracture toughness values correspond well with the flexural strength results which are in a good agreement with the expectations when the defect size is on the comparable level except for R-glass fibre reinforcement.

a)

b)