چكيده به لاتين
Mixed-adhesively bonded joints are used in the automotive industry, since it leads to stress concentration reduction, higher fatigue life, and reduction in the weight of the joints. A combination of flexibility and stiffness can be found in mixed-adhesive joints. Through this work, an extensive experimental and numerical study is carried out to clarify the behavior and failure in the mono-adhesive joints and mixed-adhesive joints in different humidity ratio condition (dry, 75.3%, 84.2% and immerged in tape water at 25ºC) and different strain rates (1 mm/min and 100 mm/min). However, the experimental results show that the static strength of SLJs are reduced with higher humidity ratios and higher exposure time. Mixed-adhesive joints show a continual reduction in static failure load. Meanwhile, the flexibility behavior of all types of the joints increases and mixed-adhesive joints have the maximum increase. Experimental investigations are compared to the numerical analysis which is carried out by bilinear cohesive zone model (CZM) in ABAQUS6.14.1. Through this work, the degradation of cohesive parameters of adhesives is calculated by using open face DCB and ENF specimens. It is found that cohesive parameters are degraded with higher moisture content condition for mode I and mode II of failure. Then through Gravimetric, bulk specimens for both adhesives are examined and diffusion parameters are extracted. The mass diffusion equation is solved for SLJ’s adhesive interface. By the way, the SLJ which has non-uniform moisture content distribution is modelled by engaging specific CZM parameters related to the specific moisture content. There is a good agreement between experimental and numerical data.
