Introduction · Methods · Results · Discussion. There are situations all around us in which people, products and equipment are being impacted. It's important that you understand shocks and know effective shock protection. The impact force is a force that produces a shock or a large impact in a relatively short period of time.
It happens when two bodies, of any type, collide. This collision is the result of a body falling or crashing into another body. This collision produces a shock wave, in the form of energy, that is transferred to the impacted bodies. This energy is what actually causes damage and injury.
Injuries can occur when a carpenter hits a nail or when a runner's foot hits the pavement. Damage can occur when metal parts of the machine collide with each other or when the covers of sensitive electronic devices are pushed back and forth during shipping. For companies, this unwanted energy is causing injuries and damage to their workers, equipment and products. In an explosion surrounded by air, the atmosphere will compress and absorb some of the explosive energy.
This reduces the lethal range of the explosion. However, water is often described as incompressible. Technically, it can be compressed, but it takes an enormous amount of pressure to apply a small amount of compression. This means that in an underwater explosion, the surrounding water doesn't absorb pressure like air does, but moves with it.
An underwater explosion doesn't propel objects through the water as far as a surface explosion throws shrapnel because of the drag that water exerts on objects. However, an underwater explosion transmits pressure with greater intensity at a greater distance. In addition, the model of the multilayer structures composed of two hemispherical layers and the fluid filled between the layers subjected to an underwater explosion is established, and the pressure characteristics of the shock wave that propagates through the multilayer structures are analyzed with respect to the reflection and transmission of the wave. The pressure sensor mounted on the actuated section (at the end of the shock tube) was used to verify the pressure that could be applied to the test sample for each exposure.
They are considered to be the boxes in the middle between the two shells filled with water, and the boxes with air backup are absent because they are too small. The importance of offshore oil exploration and exploitation as a source of environmental noise is increasing, as these activities are more frequently carried out in the shallow water parts of the continental shelf, which can provide optimal conditions for the propagation of sound to distant receivers. In Figure 16, the pressure histories of the transmitted shock wave for different shell thicknesses are presented. In this article, AUTODYN's coupled Eulerian-Lagrangian (CEL) method is used to simulate the process of shock wave propagation and solve FSI problems.
To address these problems, the present paper adopts the CEL method in AUTODYN to study the characteristics of shock wave propagation in multilayer structures during an underwater explosion. Ewing and Worzel's research also served as the basis for a series of seabed geological structure studies conducted mainly in shallow waters off the east coast of the United States. UU. An example of the lower limit, or microcavitation, is the irradiation of biological tissue with femtosecond laser pulses, which produces ultra-short shock pulses (photodisruption effect).
The ratio of pressure across the shock wave versus the non-dimensional distance from the center of load for a spherical load PBX. An example of the upper limit is the gas sphere from an underwater explosion, which can be thought of as a huge single bubble. Such an innovative overall design will ensure that liquid effectively exits the plastic tubes through the openings, while the plastic tubes interact both with the impact force (action) created by the shock wave and with the reaction force exerted by the hard plates (light metal alloy plate and Kevlar panel) and is then increased by springs. When the wave is transmitted over the outer layer, a maximum pressure is produced, called a transmitted peak, regardless of whether the medium behind the outer layer is water or air.
The maximum pressure of the reflected shock wave is the difference between the pressure measured near the surface of the outer layer and the incident pressure in the free field. Xiao, “Analytical models for the response of the double-bottom structure to an underwater explosion based on wave motion theory,” Shock and Vibration, vol. In addition, the pressure of the waves reflected and transmitted in the inner housing of the water-backed housing is obviously greater than in the air-backed housing. .