PSI - Issue 40

S.A. Bochkareva et al. / Procedia Structural Integrity 40 (2022) 61–69 Bochkareva S. A., Panin S. V. / Structural Integrity Procedia 00 (2019) 000 – 000

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either via the neck or (at a low adhesion level) via the interface towards the neck through the plates then. In this case, it had initiated as a result of delamination or fracture of the interlayer at the edges of its contact with the plates. Figure 8, a shows the computational domain of the ‘PEEK -PEEK film-PEEK prepreg/USW-PEEK film- PEEK’ US-welded joint under tension. In this case, the interlayer thickness increased up to 600 μ m.

Fig. 8 – The computational domain of the ‘PEEK -PEEK film-PEEK prepreg/USW-PEEK film- PEEK’ welded lap joint after tension (a) and the elastic modulus surface (b)

Therefore, micro-bending of the weld regions (presented in Figures 5, a and 7, a) was absent but macro-bending enhanced (Figures 8, a and 9, c) due to an increase in the interlayer thickness (a longer shoulder formed, as a result). Respectively, shear stresses and strains rose that caused a more rapid achievement of their limit values and failure (Figure 9).

Fig. 9 – The intensity distribution surfaces for strains (a) and stresses (b) in the ‘PEEK -PEEK film-PEEK prepreg/USW-PEEK film- PEEK’ welded lap joint after tension, as well as the corresponding relief images (c)