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A B S T R A C T The present paper examines crack growth in a range of aerospace and automotive structural adhesive joints under cyclic-fatigue loadings. It is shown that cyclic-fatigue crack growth in such materials can be represented by a form of the Hartman-Schijve crackgrowth equation, which aims to give a unique and linear 'master' representation for the fatigue data points that have been experimentally obtained, as well as enabling the basic fatigue relationship to be readily computed. This relationship is shown to capture the experimental data representing the effects of test conditions, such as R-ratio and test temperature. It also captures the typical scatter often seen in the fatigue crack-growth tests, especially at low values of the fatigue crack-growth rate. The methodology is also shown to be applicable to both Mode I (opening tensile), Mode II (in-plane shear) and MixedMode I/II fatigue loadings. Indeed, it has been demonstrated that the fatigue behaviour of structural adhesives under both Mode I and Mode II loadings may be described by one unique 'master' linear relationship via the Hartman-Schijve approach.Keywords adhesives; fatigue crack growth; Hartman-Schijve equation; joints; mode mix; safe life. N O M E N C L A T U R E a ¼ crack lengthA ¼ a constant in the Hartman-Schijve equation da/dN ¼ rate of crack growth per cycle D ¼ a constant in the Hartman-Schijve crack-growth equation G ¼ strain-energy release rate G c ¼ quasi-static value of the fracture energy G max ¼ maximum value of the applied strain-energy release rate in the fatigue cycle G min ¼ minimum value of the applied strain-energy release rate in the fatigue cycle ΔG ¼ range of the applied strain-energy release rate in the fatigue cycle, as defined later

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A broad-band perfect absorber composing a two-dimensional periodic metal-dielectric-metal sandwiches array on dielectric/metal substrate is designed and numerically investigated. It is shown that the nearly-perfect absorption with a bandwidth of about 50 nm in visible region can be achieved by overlapping of two plasmon resonances: one originating from the coupling of electric dipoles between adjacent unit cells and another arising from magnetic dipole plasmon resonances. A capacitor-inductor circuit description is introduced to explain the dependence of resonance frequencies and band-width on geometrical parameters.

Low-cost and environment-friendly dual-ion batteries (DIBs) with fast-charging characteristics facilitate the development of high-power energy storage devices. However, the incompatibility between the cathode and electrolyte at high voltage results in low Coulombic efficiency (CE) and short lifespan. Here, the addition of ≈0.5 wt% lithium difluoro(oxalate) borate salt into the electrolyte forms a robust and durable cathode-electrolyte interface (CEI) in situ on the graphite surface, which enables remarkable cycling of the graphite||Li battery with 87.5% capacity retention after 4000 cycles at 5 C and ultrafast rate capability with 88.8% capacity retention under 40 C (4 A g −1 ), delivering high-power of 0.4-18.8 kW kg −1 at energy densities of 422.7-318.8 Wh kg −1 . Taking advantage of this robust CEI, a graphite||graphite full battery demonstrates high reversible capacities of 97.6, 92.8, 88.7, and 85.4 mAh (g cathode) −1 at current rates of 10, 20, 30, and 40 C, respectively. The full battery also shows a long cycling life of over 6500 cycles with 92.4% capacity retention and an average CE of ≈99.4% at 1 A g −1 , which is superior to other dual-graphite (carbon) batteries in the literature. This work offers an effective interface-stabilizing strategy on protecting graphite cathodes and a promising approach for developing DIBs with high-power capability.