水下接触爆炸作用下船体板架结构渐进损伤破坏机理研究

Underwater contact explosion is an abnormally violent process featured by high-speed, high-pressure, often accompanied by splashing of fluids, tearing of structures, coupling of multi-phase media and so on, which greatly threatens the vitality of the warship. The study focuses on these fundamental problems related to the damage characteristics of underwater contact explosions, based on the previous studies, firstly, the Smoothed Particle Shell (SPS) method for the crack formation and propagation is improved, then the coupling SPH-SPS method for fluid-structure interactions is established by combining with the Smoothed Particle Hydrodynamics (SPH) method for compressible fluid dynamics; On these bases, taking the local cavitation into account, the temporal and spatial distributions of the following loadings are studied, including the shockwave propagation among multiphase media, the asymmetric and short-period pulsations and rapid jets of the high-pressure bubble adsorbed on the wall, etc.; finally, based on the failure mechanics, the combined damage variable is introduced to establish the combined damage model under multiple damage mechanism, with the aid of the model experiments of contact explosions in the explosion tank, the damage mechanism of ship structures subjected to underwater contact explosions are summarized. The main studies are as follows: 1) the coupling SPH-SPS model for the transient fluid-structure interactions of underwater contact explosions; 2) the loadings of underwater contact explosions counting in the local cavitation; 3) the progressive damage characteristics of ship structures subjected to underwater contact explosions.

水下接触爆炸是高速、高压的剧烈物理过程，经常伴随着流体喷溅、结构撕裂、多相介质耦合掺杂等复杂力学现象，极大地威胁着舰船生命力。本研究着眼于水下接触爆炸对船体板架结构损伤破坏的基础问题，首先改进多裂纹形成和扩展的光滑粒子壳单元(SPS)模型，然后与可压缩的光滑粒子流体动力学(SPH)模型结合，建立SPH-SPS的流体-结构耦合数值模型；在此基础上，计及局部空化效应，研究水下接触爆炸冲击波在多相界面间传播、高压气团贴着壁面脉动和射流过程的载荷时空分布特性；最后，基于破坏力学理论，引入复合损伤因子，建立金属材料在多种损伤机制共同作用下的复合损伤破坏模型，结合爆炸水箱实验，探究水下接触爆炸对船体板架结构的损伤破坏机理。研究内容包括：1）建立水下接触爆炸SPH-SPS的瞬态流固耦合模型；2）计及局部空化效应的水下接触爆炸冲击载荷特性研究；3）水下接触爆炸对船体板架结构的渐进损伤破坏特性研究。

水下接触爆炸是高速、高压的剧烈物理过程，经常伴随着流体喷溅、结构撕裂、多相介质耦合掺杂等复杂力学现象，极大地威胁着舰船生命力。本研究着眼于水下接触爆炸对船体板架结构损伤破坏的基础问题，首先建立了能够模拟多裂纹扩展的光滑粒子壳单元(SPS)模型，然后与可压缩的光滑粒子流体动力学(SPH)模型结合，建立SPH-SPS的流体-结构耦合数值模型，并通过模型试验验证其有效性；进而研究了水下接触爆炸冲击波在多相界面间传播、近壁面气泡的脉动和射流过程的载荷时空分布特性，掌握了水下爆炸的局部空化效应；最后，基于破坏力学理论，引入复合损伤因子，建立金属材料在多种损伤机制共同作用下的损伤破坏模型，结合爆炸水箱实验，探究了水下接触爆炸对船体板架结构的渐进损伤破坏机理，为近场水下爆炸舰船结构毁伤特性研究以及舰船结构的防护设计等提供技术支撑。完成的研究内容包括：1）建立水下接触爆炸SPH-SPS的瞬态流固耦合模型；2）计及局部空化效应的水下接触爆炸冲击载荷特性研究；3）水下接触爆炸对船体板架结构的渐进损伤破坏特性研究。