PSI - Issue 17

Feiyang He et al. / Procedia Structural Integrity 17 (2019) 72–79 Feiyang He/ Structural Integrity Procedia 00 (2019) 000 – 000

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model can also predict the lifetime of other metal structures under high-temperature loads. Arabi and Sadeghi (2017) measured and formulated crack growth rates for Hastelloy X superalloy under induction heating TMF. The paper investigated the TMF behaviour of the superalloy and presented a model to predict the crack propagation based on damage contributions due to pure fatigue and cyclic creep. Spachtholz et al. (2018) simulated the fatigue crack growth of the coated single crystalline nickel-based superalloy PWA 1484 under thermo-mechanical loads with two physical models, which simulated the deformation behaviour and fatigue crack growth respectively. The parameter identification in the model was the empirical approach through experiment. The Young’s Modulus depending on the temperature was measured in the TMF pre-test. Other temperature dependent parameters are measured from isothermal tensile tests. The remaining parameters were determined from cyclic yield curves and creep test through fi tting by regression analysis. Also, the plasticity model relating to the crack closure behaviour was also significant as a crack growth model. Sun and Yuan (2019) developed cyclic plasticity model for high-temperature components with the nickel-based superalloy Inconel 718 material under multi-axial TMF load conditions. The study performed extensive experiments under both isothermal and thermo-mechanical loading conditions. Moreover, the paper modified a constitutive model to simulate the cyclic hardening and softening observed in the tests. Furthermore, the thermal environment also affects the closure of fatigue crack and, then, may affect the crack propagation. So Carroll et al. (2009) investigated the thermal impact to fatigue crack growth and crack closure at elevated temperatures for high-temperature alloy using experimental test. After that, Prasad et al. (2016) also did similar but further research. The paper presented the effect of crack closure on TMF crack growth for Titanium alloy and utilised the conclusion to correct the crack growth rate under either IP or OP loads condition. After the research based on material applied in traditional manufacturing, alot of research, such as Rafael and Sumit (2008), El-Shabasy et al. (2012), Mortazavian and Fatemi (2015), Chandran (2016), Strantza et al. (2016), Tanaka et al. (2016), Syed et al. (2017), Ebrahimi and Mohammadi (2018), Longbiao (2018), Pitti et al. (2018), Chern et al. (2019) and Kita et al. (2019), studied fatigue performance and crack propagation of new materials, which are used in additive manufacturing. Hamdi et al. (2017) investigated the influence of temperature expansion on crack driving forces through an incremental finite element-based approach for thermal cracked wood-based materials. Jones et al. (2018) determined a valid mathematical representation for crack growth in additively manufactured Ti-6Al-4V used in the airframe.

3. Structural Damages under Dynamic Loads for Composites

This section presents the research efforts on the fatigue crack propagation due to thermo-mechanical loads in composites. Even though the delamination is the main fatigue mode for most composites, some research still considers the fatigue crack propagation in composite materials.

Figure 2 Sandwich Structured Composite Beam (Balaban and Tee, 2019)

Balaban and Tee (2019) investigated the fracture behaviour of marine sandwich-structured composite beam with the PVC foam core and different thickness of upper and lower glass fibre reinforced polymer face sheets. They applied analytical, numerical and experimental methods, respectively, to evaluate the effect of different core densities, thickness and loading directions on strain energy release rate. Only static mechanical load condition was considered in their research.