چكيده به لاتين
The adhesive joints have many applications in many industries due to their mechanical performance. The disadvantage of joints made of polymer-based adhesive is creep behavior at different temperatures and stress levels. The aim of this study is improving the creep behavior of single lap adhesive joints by using carbon nanotubes. In this study, single lap joint made of neat adhesive, adhesive reinforced with 7,2 wt% carbon nanotube and adhesive reinforced with 7,9wt% carbon nanotubes were tested under tensile loading in order to achieve the ultimate strength of the joints at temperatures of 47, 17 and 67 ° C. The ultimate strengths of the joints reinforced with 7,2 wt% of carbon nanotubes compared to the joints with neat adhesive at temperatures of 47, 17
and 67 degrees, were changed by, 97,1% , 17,28% and -23,88% respectively while The ultimate strengths of the joints reinforced with 7,9 wt% of carbon nanotubes compared to the joints with neat adhesive at temperatures of 47, 17 and 67 degrees, were changed by, 6,74% , -3,18% and -28,71% respectively
Then the joints were tested under creep loading with stress levels of 11% and 91% of the ultimate strengths at two temperatures of 47 and 175C. At 47 ° C and stress level of 11% of the ultimate strength, the values of Elastic displacement and creep displacement in joints reinforced with 7,2 wt% of carbon nanotubes compared to the joints made of neat adhesive, were changed by -12,8% and 99,9% respectively.
The best improvement of the creep behavior and lowest level of creep and elastic displacement due to adding carbon nanotubes was obtained for the joints reinforced with 7,2 wt% of carbon nanotubes on the 11% of the ultimate strength. Reinforcement of joints with 7,2 wt% of carbon nanotubes also reduced the slope of the second phase of the creep curve.
This study shows that in joints reinforced with nanotubes, creep displacement is more affected by changes in surface stress, and less affected by temperature changes.
Key words: creep, adhesive joints, carbon nanotubes, single lap joint, temperature