气体爆炸作用下泡沫铝夹层板结构动态力学响应研究
发布时间：2019-04-04 08:34
【摘要】：复合多层结构在爆炸荷载作用下的抗爆、抗冲击性能研究是当前重大、重要土木工程结构防护设计中的热点课题。常见的复合多层结构一般采用面板-泡沫材料芯层-背板的三明治夹层板结构形式。以泡沫铝为代表的多孔轻质材料由于在外荷载作用下的应力-应变曲线表现出具有较长的塑性屈服平台,具有较高的塑性吸能能力,可以抵御爆炸冲击产生的塑性大变形,特别适用于承受爆炸冲击作用的服役环境,工程上常将其作为夹层板结构的芯层使用。近年来,国内外研究者还利用粉煤灰空心球壳和纯铝基体制备出力学性能更为优异的铝基复合材料-空心微球/Al复合泡沫材料,这种多孔复合材料不仅具有相比普通泡沫铝更高的压缩屈服强度,还具有更高的吸能能力和其他独特的物理化学性能,在国防、航天、舰船等多种领域内具有巨大的应用潜力,针对铝基复合材料及其夹层板结构在爆炸冲击作用下的相关力学性能和吸能特性研究目前还处于起步阶段。本文围绕泡沫铝及铝基复合泡沫材料制备而成的夹层板结构在可燃预混气体爆炸荷载作用下的动态力学响应和吸能特性开展系列研究,试验和数值模拟技术相结合,主要开展了以下研究工作:(1)利用动力非线性有限元软件LS-DYNA,对铝基复合泡沫材料进行了细观尺度上的模型建立和压缩力学特性分析,研究了不同应变率加载条件下铝基复合泡沫材料内部空心微球的动态损伤演化与破碎全过程、单胞模型损伤破坏过程以及单胞模型的动态压缩应力应变曲线的三阶段特征,得到不同材料参数对铝基复合泡沫细观力学性能的影响规律;(2)利用大型可燃预混气体爆轰试验加载系统(GBS)进行气体爆炸试验,利用PCB高频动态压力传感器测量模爆器内部爆炸冲击波在不同位置的超压-时程关系曲线,探索乙炔气体浓度、充气时间等因素对可燃预混气体爆炸冲击荷载强度的影响规律;(3)基于GBS爆炸试验装置对泡沫铝夹层板和实心铝板进行爆炸冲击性能试验,得到所考察试件的动态应变、结构变形失效模式以及结构最大塑性位移,并比较不同夹层板结构的吸能性差异;利用非线性动力有限元软件LS-DYNA建立GBS系统和所考察试件的有限元仿真模型,对爆炸试验结果进行数值模拟重现,得到可燃预混气体爆炸冲击波在模爆器内的传播规律,并与试验实测超压值进行比较,验证了有限元模型的正确性。
[Abstract]:The research on explosion resistance and impact resistance of composite multi-storey structures under explosive loads is a hot topic in the protection design of civil engineering structures. The common composite multi-layer structure usually adopts the sandwich board structure of panel-foam core-back plate. The porous light materials represented by aluminum foam exhibit long plastic yield platform and high plastic energy absorption capacity because of the stress-strain curve under external load, which can resist the large plastic deformation caused by explosive shock. It is especially suitable for the service environment subjected to explosive impact, which is often used as the core layer of sandwich plate structure in engineering. In recent years, researchers at home and abroad have also made use of fly ash hollow spherical shell and pure aluminum matrix to prepare aluminum matrix composites-hollow microspheres / Al composite foams with better mechanical properties. This porous composite not only has higher compression yield strength than ordinary aluminum foam, but also has higher energy absorption ability and other unique physical and chemical properties. It has great application potential in many fields such as national defense, aerospace, ship and so on. The research on mechanical properties and energy absorption characteristics of aluminum matrix composite and its sandwich plate structure under explosive impact is still in its infancy at present. In this paper, a series of studies on dynamic mechanical response and energy absorption characteristics of sandwich plate structure made of aluminum foam and aluminum-based composite foam under explosion load of combustible premixed gas are carried out, and the combination of experiment and numerical simulation technology is carried out. The main research work is as follows: (1) the meso-scale model establishment and compression mechanical characteristics analysis of aluminum-based composite foams were carried out by using the dynamic nonlinear finite element software LS-DYNA,. The dynamic damage evolution and fragmentation process of hollow microspheres in aluminum-based composite foam under different strain rates, the damage and failure process of single cell model and the three-stage characteristics of dynamic compression stress-strain curves of single cell model were studied. The effects of different material parameters on the meso-mechanical properties of aluminum-based composite foam were obtained. (2) the large-scale premixed gas detonation test system (GBS) is used to carry out the gas explosion test, and the PCB high frequency dynamic pressure sensor is used to measure the overpressure-time history curve of the explosion shock wave in different positions. The effects of acetylene gas concentration, gas filling time and other factors on the explosive impact load strength of combustible premixed gas were investigated. (3) the dynamic strain, deformation failure mode and maximum plastic displacement of aluminum foam sandwich plate and solid aluminum plate were obtained by explosive impact test based on GBS explosion test device, and the dynamic strain, deformation failure mode and maximum plastic displacement of the specimen were obtained. At the same time, the difference of energy absorption of different sandwich plate structures is compared. The nonlinear dynamic finite element software LS-DYNA is used to establish the GBS system and the finite element simulation model of the examined specimen. The explosion test results are numerically simulated and reproduced, and the propagation law of the explosion shock wave of the combustible premixed gas in the mold detonator is obtained. The validity of the finite element model is verified by comparing with the measured overpressure.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU352.1;TB383.4
本文编号：2453647
[Abstract]:The research on explosion resistance and impact resistance of composite multi-storey structures under explosive loads is a hot topic in the protection design of civil engineering structures. The common composite multi-layer structure usually adopts the sandwich board structure of panel-foam core-back plate. The porous light materials represented by aluminum foam exhibit long plastic yield platform and high plastic energy absorption capacity because of the stress-strain curve under external load, which can resist the large plastic deformation caused by explosive shock. It is especially suitable for the service environment subjected to explosive impact, which is often used as the core layer of sandwich plate structure in engineering. In recent years, researchers at home and abroad have also made use of fly ash hollow spherical shell and pure aluminum matrix to prepare aluminum matrix composites-hollow microspheres / Al composite foams with better mechanical properties. This porous composite not only has higher compression yield strength than ordinary aluminum foam, but also has higher energy absorption ability and other unique physical and chemical properties. It has great application potential in many fields such as national defense, aerospace, ship and so on. The research on mechanical properties and energy absorption characteristics of aluminum matrix composite and its sandwich plate structure under explosive impact is still in its infancy at present. In this paper, a series of studies on dynamic mechanical response and energy absorption characteristics of sandwich plate structure made of aluminum foam and aluminum-based composite foam under explosion load of combustible premixed gas are carried out, and the combination of experiment and numerical simulation technology is carried out. The main research work is as follows: (1) the meso-scale model establishment and compression mechanical characteristics analysis of aluminum-based composite foams were carried out by using the dynamic nonlinear finite element software LS-DYNA,. The dynamic damage evolution and fragmentation process of hollow microspheres in aluminum-based composite foam under different strain rates, the damage and failure process of single cell model and the three-stage characteristics of dynamic compression stress-strain curves of single cell model were studied. The effects of different material parameters on the meso-mechanical properties of aluminum-based composite foam were obtained. (2) the large-scale premixed gas detonation test system (GBS) is used to carry out the gas explosion test, and the PCB high frequency dynamic pressure sensor is used to measure the overpressure-time history curve of the explosion shock wave in different positions. The effects of acetylene gas concentration, gas filling time and other factors on the explosive impact load strength of combustible premixed gas were investigated. (3) the dynamic strain, deformation failure mode and maximum plastic displacement of aluminum foam sandwich plate and solid aluminum plate were obtained by explosive impact test based on GBS explosion test device, and the dynamic strain, deformation failure mode and maximum plastic displacement of the specimen were obtained. At the same time, the difference of energy absorption of different sandwich plate structures is compared. The nonlinear dynamic finite element software LS-DYNA is used to establish the GBS system and the finite element simulation model of the examined specimen. The explosion test results are numerically simulated and reproduced, and the propagation law of the explosion shock wave of the combustible premixed gas in the mold detonator is obtained. The validity of the finite element model is verified by comparing with the measured overpressure.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU352.1;TB383.4
【参考文献】
相关期刊论文 前2条
1 潘艺,胡时胜,魏志刚;泡沫铝动态力学性能的实验研究[J];材料科学与工程;2002年03期
2 Junjie Huang;Mingxiang Chen;Jian Sun;;Mesoscopic characterization and modeling of microcracking in cementitious materials by the extended finite element method[J];Theoretical & Applied Mechanics Letters;2014年04期
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