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The fatigue crack propagation of CFRP (carbon fiber reinforced composite material) laminates is of current interest, particularly with regard to their durability under fatigue loading. Recently, carbon fiber reinforced composite materials (Woven fabric) are widely used in various fields of engineering because of its advanced properties. Then, many researchers have studied woven fabric CFRP materials but fatigue crack propagation behaviors for composites have not been still standardized . It shows the different crack propagation behavior according to load and fiber direction. Therefore, there is a need to consider fatigue crack propagation behavior in conformity with fiber arraying direction to load direction at designing structure using woven CFRP materials. In this study, therefore, the fatigue crack propagation for plain woven CFRP composite materials was investigated under two different fiber array direction (fiber arraying direction to load : 0°, 45°). Fatigue crack propagation tests of the woven CFRP composite were conducted under sinusoidal wave-form with stress ratios of 0.3 at a frequency of 10Hz, respectively. As a result of test, fatigue crack propagation rates (da/dN) were plotted against the stress-intensity factor amplitude (ΔK) and other factor. Also we compared ΔK with other factor that considering in-plain anisotropy. All of tests of fatigue crack propagation were carried out under mode I opening loading by using compact tension specimens.

Silicon carbide (SiC) exhibits good strength at high temperatures and resistance to radioactivity. However, it has poor fracture toughness. The ability to heal cracks represents a very desirable means of overcoming this weakness. This study focuses on the crack-healing behavior and bending strength of SiC ceramics to which sintering additives have been added. Optimized crack-healing condition was found to be 1hr at an atmospheric level of 1100 °C. The maximum crack size that can be healed at the optimized condition was a semi-elliptical surface crack of 450 µm in diameter. Si oxide was revealed to be the principle material involved in crack-healing.

To solve the problem of rail crack propagation, inadequate studies mainly use a two-dimensional (2D) model for macroscopic crack analysis owing to the failure of accurately reflecting the contact status between the wheel and rail. In this work, we use ANSYS software to establish a three-dimensional (3D) wheel–rail contact model to clarify the microcracks on the rail tread. The influence of the number of horizontal and vertical cyclic loads during the rail’s fatigue crack growth is analyzed. The results suggest that as the number of vertical and tangential cyclic loads increases, the length of the rail crack increases. Using experiments to verify the law between the number of cyclic loads and rail crack growth length, the experimental findings proved that the law of crack growth is basically consistent with the aforementioned simulation results and the outcome of the Paris expansion curve, verifying the validity of the simulation results.