چكيده به لاتين
Due to the significant increase in the use of adhesively bonded joints in various industries such as the aviation industry, marine industry, and automobile industry, it is necessary to predict the mechanical behavior of these joints under fatigue loading, because the phenomenon of fatigue is very common and the highest amount of damage in adhesive joints is caused by fatigue loading. The extended finite element method is one of the most powerful numerical tools to investigate fatigue behavior. Advantages such as no need to have an initial crack in the structure, no need to re-mesh when the crack grows, the high ability of this method to predict fatigue damage behavior, and no need for this method to define the crack path in advance, The application of the extended finite element method has expanded in various fields. In the first part of this research, a method based on the theories of beam and energy, which is known as the compliance-based beam method, is applied on a short beam bend specimen and the relationships required to calculate the strain energy release rate were extracted. Then, failure characterization was done under mode I loading, and in order to validate the obtained results, DCB specimens were made and tested, and a good agreement between the results of both specimens was observed. In the second part, the fatigue life estimation of DCB specimens with epoxy and silicone adhesives under static loading and fatigue conditions was done by the extended finite element method and Paris law. Under static loading conditions, numerical force-displacement curves were obtained for both adhesives with the methods of cohesive zone model and extended finite element method. For the fatigue loading conditions, the parameters of the fatigue model were calibrated according to the experimental fatigue life available in the reference. For both adhesives, the total fatigue life and Paris law parameters obtained from numerical analyses were in good agreement with the experimental results, so the numerical and experimental fatigue life for epoxy adhesive only differed by 2.1% and for silicone adhesive by only 2.7%. which shows the appropriate accuracy of the presented method to estimate the fatigue life of adhesive joints under mode I loading. Keywords: Adhesively bonded joints, Cohesive zone model, Extended finite element method, Compliance-Based Beam Method, strain energy release rate, mode I
