Experimental and numerical investigation of water aging effects on traction–separation and failure mechanisms in CFRP-aluminum adhesive joints

• Aditya Anand ^[1] ; Vivek Kumar ^[1] ; Akhilendra Singh ^[1] ; Rajendra Kumar Gupta ^[2]
  1. [1] Indian Institute of Technology Patna

     Indian Institute of Technology Patna

     India

     
  2. [2] R&DE, DRDO, Pune, India
• Localización: Mechanics based design of structures and machines, ISSN 1539-7734, Vol. 53, Nº. 8, 2025, págs. 5534-5562
• Idioma: inglés
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• Resumen

  • This study examines the effects of water aging over 7, 14, 21, 28, and 35 days on the mode I fracture energy of CFRP-aluminum double cantilever beam (DCB) adhesive joints. The longitudinal strain-based criterion was used to determine the optimal thickness of composite and aluminum adherends in dissimilar bonded DCB joints for mode-I fracture, with finite element analysis via the virtual crack closure technique (VCCT) approach validating the specimen design. Gravimetric tests and numerical simulations were used to evaluate moisture uptake in the CFRP and adhesive layer. Digital image correlation (DIC) was employed to measure the crack length and crack tip opening displacement, enabling the calculation of strain energy release rate (SERR) via the extended global method (EGM). The finite element model, utilizing cohesive zone modeling (CZM) with a trapezoidal traction-separation law, effectively simulated the mode I fracture process, showing strong alignment between the predicted finite element analysis (FEA) and the experimental load response of the joints. The study is anticipated to provide insights into water aging effects on CFRP-Aluminum adhesive joints and their degradation mechanisms, critical for enhancing the durability of aerospace and marine structures.