【作者】 肖锋；

【导师】 华宏星；

【作者基本信息】 上海交通大学 ， 机械设计及理论， 2014， 博士

【摘要】 舰艇的水下爆炸抗冲击性能与它的战斗力、生命力密切有关,具有重要的战略地位。根据当今我国舰艇设计新的发展需求,强化和提高舰艇整体抗冲击水平,达到保护主船体结构和改善设备冲击环境的目的,本文重点开展艇体湿表面抗冲防护覆盖层水下抗爆机理及实验的基础研究。研究成果对不同覆盖层的水下爆炸动响应特性、抗冲击性能和机理认识做出深刻的阐释,为新型结构形式的设计和进一步优化提供方法,同时也为在实船上的应用打下良好的理论基础。论文主要完成了以下几个方面的工作：(1)覆盖层压缩行为和力学特性的参数化分析：根据橡胶材料实验数据,选择合适的超弹性本构模型,确定材料模型参数,对不同周期性蜂窝覆盖层(手性、六角凹孔、圆孔)的压缩行为和动力学特性进行细致分析。探讨压缩速度、覆盖层胞元拓扑形式、高度及镂空率对压缩性能的影响。研究覆盖层的变形机制、能量吸收特性及缓冲机理,寻找给定基体材料和重量下承压性能优良的覆盖层结构。(2)水下爆炸冲击载荷和覆盖层的相互作用机制：研究冲击载荷下波在不同介质中的传播规律、水下非接触性爆炸下流体和覆盖层之间的流固耦合效应、覆盖层的动态响应过程、冲击波能量的耗散机制。比较相同材料和重量的实芯橡胶与蜂窝覆盖层在抗冲击性能上的差异。从覆盖层胞元拓扑结构、高度、镂空率、面板材料对防护性能的影响,探讨基于阻抗失配、变形吸能原理的覆盖层隔冲、耗能机理。(3)分层圆孔蜂窝覆盖层的优化设计：利用流固耦合效应和结构的分段能量吸收特性,将功能梯度材料引入到覆盖层的水下爆炸抗冲击设计中,主要探讨不同压力幅值入射冲击波载荷作用下梯度半径圆孔覆盖层的压缩性能和水下冲击防护效果之间的内在关系。并从频域的角度,分析空爆和水下爆炸下不同覆盖层对板冲击环境的影响。(4)潜艇覆盖层在高静水压及冲击作用下变形吸能特性的探讨：为解决覆盖层承压与抗冲之间存在的矛盾,借鉴“高的静刚度、低的动刚度”的思想,对六边形蜂窝覆盖层做进一步改进,即在空腔中放置两薄弯曲钢片,开展覆盖层在高静水压及冲击作用下的变形吸能特性研究。重点讨论钢片厚度和偏距对压缩特性和抗冲击性能的影响。(5)抗冲覆盖层的试验研究：针对覆盖层的实际抗冲效果,分别开展不同覆盖层-气背壳板结构的水下抗爆性能对比试验和敷设不同覆盖层圆板结构的水下爆炸响应特性研究。通过比较敷设覆盖层前后的爆炸压力、壁压、加速度及应变时域响应,分析覆盖层的抗爆作用机理及对实际效果进行评估,并与仿真结果做对比。同时,结合耦合面附近空化及射流的形成过程及溃灭的影像资料进一步考察水下冲击波、气泡对柔性覆盖层的作用过程,解释有无柔性覆盖层的抗冲击防护机理。更多还原

【Abstract】 The fighting capacity and vitality of a warship depend on its underwater explosion shock resistance. In order to meet the developments of modern warship, strengthen the blast resistance technology, protect the hull, and improve the overall shock environment, a research on the shock resistance and experimental study of the coatings on the hull wet surface subjected to underwater explosion was carried out in this paper. The results explain the dynamic characteristics, shock resistance, and mechanism of different coatings subjected to underwater explosion, and give a resolution to new coating and further optimization, and lay a good theoretical foundation for practical application. Main researches completed are as follows:(1) Parametric analysis of coatings’compression behavior and mechanical performance:According to rubber test data, an appropriate hyperelastic constitutive model was selected to define the model parameters; The dynamic compressive behavior and characteristic of different periodic coatings, including hexachiral honeycomb, re-entrant honeycomb and circular honeycomb, were analyzed; The effects of compression speed, cellular topology, height, and relative density on compression performance were explored; The mechanisms of deformation, energy absorption, and buffering of the coatings of the same material and weight were studied to find the reasonable structure with the best crush performance.(2) The interaction mechanism of underwater blast shock loading and coatings:The wave transmission law through an air bounded system or a water bounded system subjected to shock pressure wave, under non-contact underwater explosion, fluid-structure interaction (FSI) effect, coating’s dynamic response, and the dissipation of shock wave energy were studied; The shock resistance between solid rubber and honeycomb coatings of the same weight was compared; The isolation and dissipation mechanisms of shock energy based on the impedance mismatch and deformation and energy absorption were explored from the protective effects of cell topology, height, relative density, and panel materials.(3) The optimization design of layered circular gradient coatings:On the background of fluid-structure interaction (FSI) effect and graded energy absorption of functionally graded materials, the intrinsic relationship between compression performance and shock protective effect of layered circular coatings was discussed under different underwater shock wave pressure amplitudes; By comparing the shock response spectrum of metal plates with these coatings under air and underwater explosions, the influence of the coatings on the transient responses can be revealed.(4) Performance on the deformation and energy absorption of the coating on submarine’s wet surface:In order to solve the existing contradiction between high hydrostatic pressure and shock resistance, a hexagonal honeycomb coating was improved that two steels were placed in the honeycomb, referring to the thought of " high static stiffness and low dynamic stiffness"; The characteristics on deformation and energy absorption of the coating subjected to high hydrostatic pressure and shock were studied; The influences of steel sheet thickness and eccentricity on compression performance and shock resistance were discussed.(5) Experimental research:Two kinds of live UNDEX tests were carried out, including the response characteristics of the air-backed structures and circular plates with various coatings; Actual effects of the coatings and simulation results were assessed through the comparison of free field pressure, wall pressure, acceleration, and strain. Combined with the image data about the cavitations near the coupling surface and the jet formation and collapse, the shock resistance mechanism of the coatings were studied, which is very helpful in understanding the process of shock wave and bubble acting on the flexible coatings.更多还原