共查询到18条相似文献,搜索用时 218 毫秒
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利用动力分析软件ANSYS/LS-DYNA模拟研究水下爆破破冰过程中爆炸冲击波压力的作用特征和传播规律,对比分析在冰体覆盖的相对封闭条件和常规水下爆炸时水中压力变化的差异性。研究表明:爆炸冲击波产生的水压力以炸药为中心向四周传播,对冰面破碎起主要作用,被扰动冰体主要发生振动折裂。炸药周围近区压力初始峰值大体上相同,爆源远区相差较大,冰盖的存在减弱了爆破能量的耗散。对于相同集中药包,入水深度直接影响爆破破冰效果。和常规水下爆炸相比,在冰体覆盖的相对封闭条件下水中峰值压力较小,衰减速度较慢。 相似文献
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Two-dimensional linear flexural gravity wave scattering by a nearly vertical porous wall is analyzed through a simplified perturbational analysis. A continuous semi-infinite ice sheet of uniform thickness is assumed to be floating over water of infinite depth. The ice sheet, with inclusion or exclusion of compressive stress, has either a free edge or a clamped edge at the porous wall. The first-order correction to the reflected flexural gravity wave amplitude is obtained by two different methods. The first method involves an application of Green’s theorem, and the second method involves a first kind integral equation. The integral equation method proves to be robust as it provides a complete solution in all cases of the problem, whereas the first method fails to produce the same when the ice sheet with a free edge is under compressive stress. The strain in the ice sheet and shear force along the ice sheet are computed and explained graphically for suitable parameters and a particular wall shape function. 相似文献
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The behavior of flexural gravity waves propagating over a semi-infinite floating ice sheet is studied under the assumptions of small amplitude linear wave theory. The vertical wall is assumed to be either fixed or harmonically oscillating with constant horizontal displacement, in which case the problem is analogous with a harmonically oscillating plane vertical wavemaker. The potential flow approach is adhered to and the higher-order mode–coupling relations are applied to determine the unknown coefficients present in the Fourier expansion formula of the potential functions. The ice sheet is modeled as a thin semi-infinite elastic beam. Three different edge conditions are applied at the finite edge of the floating ice sheet. The effects of different edge conditions, the thickness of the ice sheet and the water depth on the surface strain, the shear force along the ice sheet, the horizontal force on the vertical wall, and the flexural gravity wave profile are analyzed in detail. 相似文献
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The linear two-dimensional problem of hydroelastic waves reflected by a vertical wall is analysed. The fluid is of finite depth and is covered by an ice sheet. The fluid is assumed incompressible and inviscid. The ice sheet is assumed thin compared with both the water depth and wavelength of the incident wave. The deflection of the ice sheet is described by linear elastic plate theory, and the fluid flow by using the potential-flow model. The ice sheet extends infinitely and is clamped to the vertical-walled structure. The incident hydroelastic wave is regular. An analytic solution is found by integral-transform methods. The ice deflection, the vertical and horizontal forces acting on the wall and the bending stresses in the ice caused by the incident wave are determined. The forces on the wall are analysed in detail, and relevant physical parameters are varied for comparison. The phase shift between the incident and reflected wave amplitudes is found as part of the complete solution. It is shown that the ice clamping condition leads to a specific effect on the ice deflection. 相似文献
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基于欧拉-拉格朗日流体与固体耦合算法,针对移动载荷激励冰层响应问题开展了数值模拟。对均匀水深条件下的冰层位移响应进行了数值计算并与实验结果进行对比分析,发现二者获得的临界速度值、冰层位移响应波形特征以及最大下陷值都吻合较好,说明所采用的数值计算方法是可靠、有效的。针对限制水域不同航道边界形状条件下移动荷载激励冰层位移响应和载荷临界速度进行了数值模拟,得到了航道边界形状对位移响应和临界速度的影响规律,结果表明:不同截面形状直航道条件下,当矩形截面变化到梯形截面时,临界速度变小,且各速度下冰层最大下陷位移也相应变小;矩形截面形状弯曲航道条件下,临界速度仍存在,且该临界速度对应的冰层最大下陷位移幅值比直航道条件下大。 相似文献