Mechanics of Composite, Hybrid and Multifunctional Materials, Fracture, Fatigue, Failure and Damage Evolution, Volume 3

Progressive failure process of adhesive joint under cyclic loading is of particular interest in this study. Such fatigue failure is described using damage mechanics with the assumed cohesive behaviour of the adhesive joint. Available cohesive zone model for monotonic loading is re-examined for extension to capture cyclic damage process of adhesive joints. Damage evolution in the adhesive joint is expressed in terms of cyclic degradation of interface strength and stiffness. Mixed-mode fatigue fracture of the joint is formulated based on relative displacements and strain energy release rate of the interface. A power-law type variation for each of these cohesive zone model parameters with accumulated load cycles is assumed in the presence of limited experimental data on cyclic interface fracture process. The cyclic cohesive zone model (CCZM) is implemented in commercial finite element analysis code and the model is validated using adhesively bonded 2024-T3 aluminium substrates with epoxy-based adhesive film (FM73M OST). The CCZM model is then examined for cyclic damage evolution characteristics of the adhesive lap joint subjected to cyclic displacement of Δδ = 0.1 mm, R=0 so as to induce shear-dominant fatigue failure. Results show that the cyclic interface damage started to initiate and propagate symmetrically from the both overlap edges and degradation of interface strength and stiffness started to accumulate after 0.5 cycles of displacement elapsed. The predicted results are consistent with the mechanics of relatively brittle interface failure process.

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Challenges in Mechanics of Time Dependent Materials, Fracture, Fatigue, Failure and Damage Evolution, Volume 2

10.1007/978-3-030-29986-6 ◽

2020 ◽

Keyword(s):

Fatigue Failure ◽

Damage Evolution ◽

Time Dependent

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Fracture, Fatigue, Failure and Damage Evolution , Volume 3

10.1007/978-3-030-60959-7 ◽

2021 ◽

Keyword(s):

Fatigue Failure ◽

Damage Evolution

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A new damage-coupled cyclic plastic model for whole-life ratchetting of heat-treated U75V steel

International Journal of Damage Mechanics ◽

10.1177/1056789520930408 ◽

2020 ◽

Vol 29 (9) ◽

pp. 1397-1415

Author(s):

Ziyi Wang ◽

Xiang Xu ◽

Li Ding ◽

Guozheng Kang ◽

Ping Wang ◽

...

Keyword(s):

Fatigue Failure ◽

Damage Evolution ◽

Damage Mechanics ◽

Hysteresis Loops ◽

Continuum Damage Mechanics ◽

Damage Evolution Equation ◽

Plastic Model ◽

Cyclic Plastic ◽

Heat Treated ◽

Proposed Model

In the framework of continuum damage mechanics, a new damage-coupled cyclic plastic model is proposed to describe the nonlinear evolution of whole-life ratchetting and its dependence on the stress level. The characteristic that the damage evolution rate of U75V heat-treated steel decays in the initial load cycles is considered by introducing a modified term into classic damage evolution equation. A hybrid fatigue failure criterion considering both the fatigue and ratchetting strain-induced failures is established based on the fatigue failure rule concluded from experiments. Comparisons between simulated and experimental stress–strain hysteresis loops, ratchetting strains, damage evolutions, and fatigue lives are performed to validate the proposed model.

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