PSI - Issue 19

Sara Eliasson et al. / Procedia Structural Integrity 19 (2019) 81–89 Sara Eliasson / Structural Integrity Procedia 116 (2019) 000 – 000

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Figure 1: Specimen type used in this study; parallel-side-coupon specimen. L spec = 250 mm, t spec = 2 mm, w spec = 15 mm. L tab = 50 mm, t tab = 1.5 – 3 mm, w tab = 10 – 20 mm,  ≤ 

2.2. Fatigue testing specimen parameters

The goal was to achieve failure within the gauge length of the specimen, although it is common that failure occurs in the tab area of a specimen. The tab configuration and tab material are crucial parameters. Figure 2 shows an example of the stress distribution for different tab configurations, illustrating the high stress concentration in the interface between tab and CFRP. These results are not always consistent with choice of specimen configuration. More factors sometimes need to be considered when defining the parameters e.g. manufacturing. For this study that is the case and straight-end tabs have been used even though it goes against the numerical theory.

Figure 2: Principal stress, σ 11 , along surface of specimen for different tab materials and configurations, reproduced (Pagano, et al., 2018).

In the current study several parameters were evaluated and investigated. Specimens were manufactured differently dependent on these parameters. The different parameters are presented in Table 1.

Table 1: Specimen parameters investigated in this study.

Tab material

Tab dimensions

Adhesive

Clamping force

Temperature

Aluminum

Thickness

Araldite 420 A/B

Min allowed Max allowed

Hysteric heating

GFRP

Width Angle

Araldite 2015

Heating in tab region

3M DP420