Silicon carbide composites (SiC/SiC) are promising candidate materials for fusion reactors. For the practical application of this class of materials, a design basis for SiC/SiC composites needs to be developed because of inherent brittle-like fracture, i.e., quasi-ductility, which is totally different from ductility of metals. For this purpose, the failure behavior, i.e., matrix cracking behavi...

Fatigue crack initiation and early short crack propagation behaviour in two microstructural variants of a recently developed Low Solvus, High Refractory (LSHR) disc superalloy at room temperature has been investigated by three-point bending with replication procedure. The results shows that fine gained (FG) LSHR possesses higher fatigue life due to its better crack initiation resistance, limite...

Impact tests were carried out on composite laminates and composite scarf repairs, while both were subjected to in-plane loading with tensile pre-strain levels up to 5000 microstrain. The results show that pre-straining of the composite laminates has no noticeable influence on the size of the delamination area for the given impact energy of 8 J, which represents a typical barely-visible impact o...

Normally closed (NC) micro check-valve is used to stop liquid flow when liquid pressure difference across the membrane is lower than the designed cracking pressure. As shown in Figure 2-1, when the applied pressure P is lower than the designed cracking pressure, P c , the NC check-valve is closed, and vice versa. Generally the cracking pressure can be introduced electrically such as electromagn...

The initiating explosive devices are prohibited in rock breaking near the goaf of the highly gassy mine. It is effective and applicable to cracking the hard roof with static cracking agent. By testing the static cracking of cubic limestone (size: 200 × 200 × 200 mm) with true triaxial rock mechanics testing machine under the effect of bidirectional stress and by monitoring the evolution process...

It is broadly accepted that so-called 'thermal' gas is the product of thermal cracking, 'primary' thermal gas from kerogen cracking, and 'secondary' thermal gas from oil cracking. Since thermal cracking of hydrocarbons does not generate products at equilibrium and thermal stress should not bring them to equilibrium over geologic time, we would not expect methane, ethane, and propane to be at eq...

Cracking is a major concern in welding aluminum alloys. Although weld solidification cracks can be eliminated through addition of filler alloy, the additives modify the alloy or base-metal constituents and may not always be desirable. High-energy beam processes, such as electron-beam welding, that result in minimal heat input reduce crack sensitivity, but their high cost limits their applicatio...

Crack surveys of bridge decks, performed over a 10-year period in northeast Kansas as part of three studies, provide strong guidance in identifying the parameters that control cracking in these structures. The surveys involve steel girder bridges—bridges that are generally agreed to exhibit the greatest amount of cracking in the concrete decks. The surveys include monolithic decks and decks wit...

A novel, two-scale computational model has been developed to predict the progressive damage and failure responses of fiber-reinforced composite laminates using the material properties at the constituent (fiber and matrix) level. These properties were measured from coupon level tests on a unidirectional lamina of the same material system. In the proposed computational scheme, the macroscale fini...

Final failure of laminated composite structures is preceded by different damage mechanisms involving fracture initiation and propagation. Fracture in a composite laminate can appear either between two plies or within a lamina. In the first case, interlaminar fracture or delamination, the crack causes separation of two adjacent plies and will mainly involve matrix failure or matrix-to-fibre debo...