PSI - Issue 52

Minori Isozaki et al. / Procedia Structural Integrity 52 (2024) 176–186 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

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2014, Koyanagi et al. 2010, Ogihara et al. 2010), it can be concluded that the failure of the weld interface in the compression shear test is due to normal and shear stresses. The stresses listed in Table 5 are the interfacial stresses at the initiation point of rupture. Thus, from Fig. 6 and Table 5, the failure in the compression shear test which force applied only in the shear direction is due to the mixed mode of tensile and shear stresses. In addition, it can be said that the effect of tensile stress not in the test direction is rather significant in the failure of the interface.

Fig. 6. Stress Distribution (a) Normal Stress (b) Shear Stress (Compression Shear Test, Specimen No. 1).

Table 5. Normal Stress and Shear Stress (When the load in FEM is the same as failure load of the experiment). Specimen No. Experiment FEM Normal stress ( MPa ) Shear stress ( MPa ) Normal stress ( MPa ) Shear stress ( MPa ) 1 0 28.4 48.3 29.5 2 0 22.9 38.2 28.5 3 0 45.1 58.9 34.4 4 0 44.6 64.8 34.2 Ave. 0 35.3 52.5 31.6

3. Flatwise Test

3.1. Experiment The CFRTP laminates were bonded by ultrasonic welding in the same manner as the specimens prepared for the compression shear test (2.1). However, the thickness of the CF/PEEK prepreg was 2 mm, unlike 2.1. For this test, one specimen was prepared (Specimen No. 5). This adhesion was successful. Flatwise test was performed on ultrasonic welded CFRTP (Specimen No. 5). First, an aluminum block jig was bonded to the welded CFRTP as shown in Fig. 7 using adhesive (two-component epoxy adhesive DP410 (3M)). Then, a tensile test was performed on the specimen (Fig. 8 (a)). Displacement was applied to the load cell of an