“…Therefore, since the composite tubes used in this study have a D/h of 32, it is reasonable to say that the failure of these tubes will be due to instability that occurs in the elastic region. Knowing that the initial stiffness is proportional to the collapse pressure of the structure, 33,34 the same tube stiffness shown in Figure 3 guarantees the structural collapse initiation behavior to be the same.Figure 3.Test data for ASTM D2412 compression tests on composite stocks of length L = 86.36 mm (3.4 in).…”
An experimental study was performed to analyze the dynamic buckling behavior of stiffened composite tubes. The structures analyzed were filament-wound carbon-fiber/epoxy composite tubes with press-fitted compliant and rigid aluminum ring stiffeners. The ring thicknesses were chosen for a consistent buckling pressure for equally spaced one, two, and three compliant stiffener configurations. The composite structures were submerged inside a pressure vessel and then subjected to increasing hydrostatic pressure until buckle initiation. High-speed photography and Digital Image Correlation were used to acquire full-field displacements and velocities of the collapse event. In addition, piezoelectric transducers were used to concurrently record the local dynamic pressure histories along the length of the tube. The results show that increasing the number of stiffeners for the same collapse pressure decreases the overall energy emission from the implosion event by more than 16%. However, the energy mitigation effects are also influenced by the location of the stiffeners in relation to the buckling initiation point.
“…Therefore, since the composite tubes used in this study have a D/h of 32, it is reasonable to say that the failure of these tubes will be due to instability that occurs in the elastic region. Knowing that the initial stiffness is proportional to the collapse pressure of the structure, 33,34 the same tube stiffness shown in Figure 3 guarantees the structural collapse initiation behavior to be the same.Figure 3.Test data for ASTM D2412 compression tests on composite stocks of length L = 86.36 mm (3.4 in).…”
An experimental study was performed to analyze the dynamic buckling behavior of stiffened composite tubes. The structures analyzed were filament-wound carbon-fiber/epoxy composite tubes with press-fitted compliant and rigid aluminum ring stiffeners. The ring thicknesses were chosen for a consistent buckling pressure for equally spaced one, two, and three compliant stiffener configurations. The composite structures were submerged inside a pressure vessel and then subjected to increasing hydrostatic pressure until buckle initiation. High-speed photography and Digital Image Correlation were used to acquire full-field displacements and velocities of the collapse event. In addition, piezoelectric transducers were used to concurrently record the local dynamic pressure histories along the length of the tube. The results show that increasing the number of stiffeners for the same collapse pressure decreases the overall energy emission from the implosion event by more than 16%. However, the energy mitigation effects are also influenced by the location of the stiffeners in relation to the buckling initiation point.
“…Plates immersed in saline water and tested under different hydrostatic pressures showed that at 0 MPa, saline-exposed plates experienced increased displacement, but at 3.45 MPa, displacement changes were negligible, indicating that at certain pressures, the UNDEX response may align with unexposed plates, as illustrated in figure 13. Additionally, the response of composite cylinders to saline water exposure under UNDEX blast loads was examined (Javier et al 2018). Cylinders immersed in saline water and subjected to blasts in a pressure vessel showed significant damage, particularly for those immersed for 35 days compared with 70 days.…”
Section: Shock Response After Prolonged Environmental Exposurementioning
Underwater explosions are inherently complex and unique physical phenomena markedly distinct from those occurring above the surface. This distinctiveness is primarily attributed to the relatively incompressible nature of water, which fundamentally alters the propagation and impact of shock waves. The study of underwater explosions is paramount in applications such as underwater demolitions for construction and salvage operations. These applications require a comprehensive understanding in order to mitigate the disturbances’ impact on marine structures and ecosystems. Studying underwater explosions and their mitigation encompasses various disciplines, including fluid mechanics, materials science and structural engineering. The work reviewed in this study contributes significantly to enhancing safety measures in marine structures by providing critical insights into the behaviour of structures under extreme conditions. This includes understanding the behaviour of gas bubbles formed by explosions, the transmission of shock waves through different media and the resultant forces exerted on structures submerged in water. Consequently, this review is meant to aid in designing robust and resilient marine systems capable of withstanding severe loading conditions caused by underwater explosions by providing key engineering considerations. The continuous evolution of this research area is essential for advancing maritime technology, ensuring the safety of undersea operations and protecting marine environments from the adverse effects of extreme subaqueous loadings.
“…The former can be difficult to apply in predictive methods as they involve a complex loading state, while the latter are limited to investigations of simple geometries. An exception is the recent studies by Le Blanc, Shukla and colleagues, who have investigated the influence of environmental degradation on tubular composite structures [19][20][21]. They applied an accelerated aging procedure and used the Arrhenius equation to predict lifetime under static and dynamic external pressure loading for underwater applications.…”
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