PSI - Issue 50

Danila D. Vlasov et al. / Procedia Structural Integrity 50 (2023) 299–306 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

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During the experiment, the data presented in Table 2 were obtained. Simultaneously with loading, registration of displacements was carried out using the method of digital image correlation (DIC) (Fig. 8), which made it possible to obtain a picture of strain in the adhesive joint zone.

Fig. 8. Strain patterns in the adhesive joint zone.

4. Results and discussion The experiments conducted have fully confirmed the theoretical studies (10), saying that the joint strength decreases with increasing length, despite the data on specimen 9 falling out of the general picture. According to the simplest Volkersen`s solution used in this work, if the joint length is unchanged, its strength should be the same, but actually there should also be a dependence on the width - when the area of the joint increases, its bearing capacity should increase. This is evident from the test results obtained. The correlation of digital images confirmed that the edge areas of the glued surfaces experience more strain than the parts in the center of the glue, which confirms the rule about the most stressed edge parts of the joints. An interesting result was obtained when testing specimens with the same joint area, but with different proportions - specimens 3 and 4. The specimen with the wide adhesive area endured a larger load and, correspondingly, larger shear stresses occurred in it than in the specimen with the narrow area. 5. Conclusion The overlapping joint is not the most effective joint in terms of load-bearing capacity, but it is the easiest to make. And the possibility to modify it with double overlaps or tabs allows to get away from such a significant disadvantage as an arising bending moment. As the length of the joint increases, its load-carrying capacity decreases due to inhomogeneous stress distribution. At the same time, an increase in the bearing capacity is also observed in the experiment with an increase in the width of the joint. The use of the DIC method made it possible to clearly see an increase in strain (and hence stresses) at the edges of the joint. This method showed its effectiveness in the estimation of the stress-strain state of specimens with adhesive joints.