PSI - Issue 14

Robert Brandt et al. / Procedia Structural Integrity 14 (2019) 891–899 Robert Brandt/ Structural Integrity Procedia 00 (2018) 000 – 000

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the test at prevent for an analysis. Ambient temperature and ageing severely affects the fracture toughness of the here considered hybrid laminates. The here depicted findings indicate a drastic weakening of the interface by temperature and ageing. In contrast to that, the reference type of specimen #GFRP exhibit an inverse behaviour.

0.00 0.10 0.20 0.30 0.40 0.50 0.60 0.70 0.80

reference

T = 80 ° C

T = RT

aged

Fracture Toughness G I,50mm [N/mm] +46% +96%

-80%

-78% -53%

w/ o an aly sis

w/ o an aly sis

-84%

#GFRP

#Si

#Ti

#GB

Fig. 3. Fracture toughness in terms of the extrapolated energy release rate

4.2. Shear Strength

The force of failure and the effective shear area of the specimen define the nominal shear strength by

(3) Fig. 4 shows the corresponding results of the EST. Each group, labeled as #GFRP, #Si, #Ti, and #GB, respectively, contains the results for the tests of the as manufactured specimens at both temperatures as well as the aged variant. In contrast to the case of fracture toughness, ageing or an elevated temperature diminishes the shear strength of the #GFRP reference. However, the drop of the shear strength for the hybrid specimens is not as severe as observed for the fracture toughness. A maximum reduction of 62 % only occurs for the aged variant of #Ti. The test comprises as before the lowest shear strengths for the grid blasted specimens.

0 10 20 30 40 50 60 70

reference

T = RT T = 80 ° C aged

-15%

-16%

-17%

-15%

-19%

-13%

Shear Strength s [MPa]

-32%

-62%

#GFRP

#Si

#Ti

#GB

Fig. 4. Static shear strength s for the specimens