#BRIGHTER 3D 2015 PLUGIN CRACK CRACK#
Using marble specimens coasted with brittle polyester, Daniel and Rowlands 24 observed isochromatic fringe patterns during crack propagation loaded by a steel wedge in a notch, however, the results obtained were only qualitative. For instance, Bieniawski 1 obtained a photographic record of propagating rock fracture using birefringent coating technique combined with a high-speed camera and explored the stability of the fracture propagation, terminal fracture-velocity and dynamic stresses generated by the propagating crack. In pioneering studies that aimed to experimentally probe the mechanical properties and fracture behaviour of solids, photoelastic tests combined with a high-speed camera were used to observe the isochromatic fringe patterns during fracturing 1, 24, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39.
The direct capture and experimental visualization of the dynamic stress evolution during fracture rapid propagation remains challenging 26, 27. However, because of the simplification of models’ geometries and boundary conditions, the analytical results of the complex fractures have sparked significant debate owing to the lack of direct experimental validation 24, 25, 26. Over the past decades, a large number of theoretical models 1, 14, 15, 16, 17, 18 and numerical methods 19, 20, 21, 22, 23 have been proposed to characterise the rapid evolution of stress-field in solid materials. Underground engineering, roadway excavation 8, surrounding rock stability 9, 10, stress-controlled fluid flow in geological disposal of nuclear waste 11 and hydraulic-driven oil and gas exploitation 12, 13 all involve, to varying degrees, the dynamic stress redistribution in rock masses induced by rock fracture. In medical science, the mechanical resistance of fractured bone fixations in surgery acts as an input for clinical decision-making related to fixation methods 7. In machinery manufacturing, the strength and fatigue-life prediction of a component depends on its geometry and stress state 4, 5, 6. In geoscience, for instance, laboratory observations of stress wave and crack propagation provide valuable information on the rupturing process of earthquake faults 2, 3. Knowledge of how those stress fields evolve yields valuable information that is used in a wide variety of practical applications 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13.
Load-induced stress fields govern the deformation and fracture behaviour of solids. It is proved that the crack propagation velocity is strongly governed by the stress field around the crack tips. The results show that the proposed method is suitable to directly visualize and quantitatively characterize the stress-field evolution during crack rapid propagation.
#BRIGHTER 3D 2015 PLUGIN CRACK FULL#
A photoelastic testing system that synchronized a high-speed digital camera and a pulsed laser with a nanosecond full width at half maximum (FWHM) was used to capture the rapid evolution of the stress field in the vicinity of crack tips.
Three-dimensional (3D) printing technology and a stress-sensitive photopolymer resin were adopted to produce the disc model and to alleviate the residual processing stress that usually blurs the dynamic stress field due to overlap.
We report an experimental method to quantitatively visualize and characterize rapid evolution of the stress-field during crack propagation in a transparent disc model containing a penetrating fusiform crack. However, the direct capture and accurate characterization of a rapidly-changing stress field during crack propagation remains a challenge. Quantitative visualization and characterization of stress-field evolution during fracture rapid growth is critical for understanding the mechanisms that govern the deformation and failure of solids in various engineering applications.
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