A double cantilever beam incorporating cohesive crack modeling for superconductors

Abstract

In this paper, a double cantilever beam (DCB) specimen incorporating cohesive crack is developed for superconductors which have potential applications in high temperature superconducting cables in space solar power station. The cohesive interface is introduced along the crack front of the DCB model under electromagnetic force. The load-separation relation (i.e. the crack opening displacement) is used as the fracture mechanics parameter and the corresponding curves during fracture process are obtained and verified by the finite element numerical method. Results show that the presence of tensile electromagnetic force makes crack propagate easily. Superconductors with small cracks have good adaptability to the oscillation of magnetic fields while that with large cracks are easier to fracture during the descent of the magnetic field. In addition, the ductility ratio of the cohesive interface can significantly increase the fracture strength. The length of fracture zone decreases as the crack length increases.

Low‐Temperature Bending Fatigue of MXene/PDMS Flexible Pressure Sensor

“…As shown in Figure 5c, due to different thermal expansion coefficient, the delamination occurs when the temperature changes, leading to crack propagation. Thus, the energy release rate is a strong function of temperature T , which can be expressed as: [ 31 ] $$\[ \begin{array}{*{20}{c}}{{G_T} = \frac{1}{{2b}}\left[ {4\frac{{EI}}{{{a^2}}}\Delta T\Delta \alpha + EA{{\left( {\Delta T\Delta \alpha } \right)}^2}} \right]}\end{array} \]$$where $$\[ \begin{array}{*{20}{c}}{\Delta \alpha = \left( {1 + {v_1}} \right){\alpha _1} - \left( {1 + {v_2}} \right){\alpha _2}}\end{array} \]$$ $$\[ \begin{array}{*{20}{c}}{EI = \frac{{{E_1}h_1^3b}}{{12\left( {1 - v_1^2} \right)}}}\end{array} \]$$ $$\[ \begin{array}{*{20}{c}}{EA = \frac{{{E_1}A}}{{\left( {1 - v_1^2} \right)}}}\end{array} \]$$ $$\[ \begin{array}{*{20}{c}}{A = {h_1}b}\end{array} \]$$where A is the area of across section of MXene film, b is the width of the MXene layer, α is half length of the crack, α i is the th...…”