PSI - Issue 52

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

185

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Fig. 12 shows the parabolic criterion and the experimental and analytical values of interfacial strength in compression shear test and flatwise test. Strength in shear test are average values.

Fig. 12. Parabolic Criterion.

We were able to develop a parabolic criterion for the strength of the adhesive interface in ultrasonic welding for CFRTP. As can be seen from Fig. 12, the apparent strength obtained from the experiments differs significantly from the analytical results (FEM and parabolic criterion). As described in Sections 2.2 and 3.2, in strength tests, failure occurs in a mixed mode of shear and tensile stress. Therefore, it is possible to accurately evaluate the adhesive strength of the interface by considering the combined shear and tensile stresses. 5. Conclusions In this study, two types of fracture tests, ‘ compressive shear test ’ and ‘ flatwise test ’ , were conducted on ultrasonic welded CFRTP. Finite element analysis of the tests revealed that both tests fail in a mixed mode of shear and tensile stress. Furthermore, a parabolic criterion fracture envelope was developed from the experiments and analysis, and a quantitative and comprehensive evaluation method for the adhesive strength of the interface was proposed. As a future prospect, we would like to optimize the welding conditions for actual ultrasonic welding of CFRTP using the evaluation method proposed in this paper. In addition, in this paper, we assumed that the failure of the adhesive part is interface failure, but in the future, we will explore an evaluation method that also takes resin failure into account.

References

JP, Reis., M de Moura,., S, Samborski., 2020, Thermoplastic composites and their promising applications in joining and repair composites structures: A review, Materials 2020 , 13(24).