【摘要】：復合多層結構在爆炸荷載作用下的抗爆、抗沖擊性能研究是當前重大、重要土木工程結構防護設計中的熱點課題。常見的復合多層結構一般采用面板-泡沫材料芯層-背板的三明治夾層板結構形式。以泡沫鋁為代表的多孔輕質材料由于在外荷載作用下的應力-應變曲線表現(xiàn)出具有較長的塑性屈服平臺,具有較高的塑性吸能能力,可以抵御爆炸沖擊產(chǎn)生的塑性大變形,特別適用于承受爆炸沖擊作用的服役環(huán)境,工程上常將其作為夾層板結構的芯層使用。近年來,國內(nèi)外研究者還利用粉煤灰空心球殼和純鋁基體制備出力學性能更為優(yōu)異的鋁基復合材料-空心微球/Al復合泡沫材料,這種多孔復合材料不僅具有相比普通泡沫鋁更高的壓縮屈服強度,還具有更高的吸能能力和其他獨特的物理化學性能,在國防、航天、艦船等多種領域內(nèi)具有巨大的應用潛力,針對鋁基復合材料及其夾層板結構在爆炸沖擊作用下的相關力學性能和吸能特性研究目前還處于起步階段。本文圍繞泡沫鋁及鋁基復合泡沫材料制備而成的夾層板結構在可燃預混氣體爆炸荷載作用下的動態(tài)力學響應和吸能特性開展系列研究,試驗和數(shù)值模擬技術相結合,主要開展了以下研究工作:(1)利用動力非線性有限元軟件LS-DYNA,對鋁基復合泡沫材料進行了細觀尺度上的模型建立和壓縮力學特性分析,研究了不同應變率加載條件下鋁基復合泡沫材料內(nèi)部空心微球的動態(tài)損傷演化與破碎全過程、單胞模型損傷破壞過程以及單胞模型的動態(tài)壓縮應力應變曲線的三階段特征,得到不同材料參數(shù)對鋁基復合泡沫細觀力學性能的影響規(guī)律;(2)利用大型可燃預混氣體爆轟試驗加載系統(tǒng)(GBS)進行氣體爆炸試驗,利用PCB高頻動態(tài)壓力傳感器測量模爆器內(nèi)部爆炸沖擊波在不同位置的超壓-時程關系曲線,探索乙炔氣體濃度、充氣時間等因素對可燃預混氣體爆炸沖擊荷載強度的影響規(guī)律;(3)基于GBS爆炸試驗裝置對泡沫鋁夾層板和實心鋁板進行爆炸沖擊性能試驗,得到所考察試件的動態(tài)應變、結構變形失效模式以及結構最大塑性位移,并比較不同夾層板結構的吸能性差異;利用非線性動力有限元軟件LS-DYNA建立GBS系統(tǒng)和所考察試件的有限元仿真模型,對爆炸試驗結果進行數(shù)值模擬重現(xiàn),得到可燃預混氣體爆炸沖擊波在模爆器內(nèi)的傳播規(guī)律,并與試驗實測超壓值進行比較,驗證了有限元模型的正確性。
[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.
【學位授予單位】：哈爾濱工業(yè)大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TU352.1;TB383.4

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本文編號：2453647