共查询到20条相似文献,搜索用时 31 毫秒
1.
针对弹体侵彻混凝土环境,提出一种中薄型防护外壳嵌套内壳体,两壳体间填充泡沫铝缓冲材料的记录仪抗冲击防护结构。针对应力波作用下防护外壳的屈曲和泡沫铝缓冲性能不足导致内部电路模块冲击断裂的典型失效模式,通过对记录仪抗冲击防护结构在应力波作用下的结构响应分析,提出一套以壳体厚度h、泡沫铝密度ρ、泡沫铝厚度h_b为主要设计指标的弹载加速度记录仪抗冲击防护结构设计方法。设计出防护外壳半径为29 mm,壁厚3 mm,泡沫铝密度1.1g/cm~3,泡沫铝厚度23 mm的抗冲击防护结构,经计算该结构理论抗冲击能力为63 300 g。在实弹侵彻混凝土试验中,测得冲击加速度峰值为56 300 g,在此冲击下记录仪壳体结构稳定,内部电路工作正常,验证了此抗冲击防护结构具有较高的可靠性。 相似文献
2.
3.
通过LS-DYNA模拟分析泡沫铝填充多棱管的准静态过程。以柱壳比(R)作为比较具有不同截面形状的泡沫铝填多棱管的依据。通过比吸能、比力和能量吸收率,实现泡沫铝填充多棱管吸能性能的定量化比较分析。研究发现在具有相同柱壳比的条件下,泡沫铝填充四棱管的比吸能最高;泡沫铝填充八棱管的能量吸收率最高(约78%);四棱管的吸能量占泡沫铝填充四棱管总吸能量的比例最小(约57%)。不同的几何形状和结构对泡沫铝填充多棱管的吸能性能有着显著的影响。同时,对泡沫铝填充多棱管的变形模式和内在机制也做了初步的分析 相似文献
4.
目的 为了研究静动态加载下泡沫铝填充薄壁金属管结构吸能特性随泡沫铝密度的变化规律。方法利用材料试验机对3种不同密度的泡沫铝填充薄壁金属管结构进行准静态压缩,利用Taylor–Hopkinson实验装置对相同结构进行动态压缩实验,基于电测和光测法获得结构的静动态压缩载荷位移曲线,对载荷位移曲线进行积分得到结构的静动态吸能特性。结果 准静态压缩下,随着泡沫铝密度的增加,泡沫铝填充薄壁管结构能量吸收能力近似成指数增加。动态压缩下,结构能量吸收能力随泡沫铝密度增加先保持不变后增加。结论 准静态压缩下,在薄壁金属管中添加泡沫铝能明显增加泡沫铝填充薄壁金属管结构能量吸收能力,但在动态压缩下,低密度泡沫铝的添加无益于增加结构的能量吸收能力,为增加薄壁金属管的吸能能力需要求泡沫铝的密度超过一定值。 相似文献
5.
6.
7.
填充泡沫铝的多层铝管动态压溃吸能特性研究 总被引:1,自引:0,他引:1
采用数值模拟的方法研究和分析了无填充物的多层铝管结构的吸能特性,结果发现多层铝管相比单层铝管,不但具有较大的吸能量,而且还具有较高的比吸能率;在此基础上,设计了不同层数的多层管泡沫铝填充结构,研究发现泡沫铝不但受轴向压溃变形,同时也受到了铝管层之间的相互作用力使其在径向发生了变形;之后对多层管填充3种不同密度的泡沫铝,采用变参分析的方法研究了多层管层数和泡沫铝密度对整个结构吸能特性的影响;研究结果表明:填充泡沫铝的多层管,随着层数的增加,其比吸能率和吸能量也随之有所增加,随着泡沫铝密度的提高,比吸能率的提高量开始下降,但仍高于填充相同泡沫铝的单层管。 相似文献
8.
为研究泡沫铝填充薄壁铝合金多胞结构与单胞结构的吸能能力,该文基于有限元软件LS-DYNA建立了泡沫铝填充薄壁铝合金多胞结构与单胞结构的数值仿真。对经典薄壁圆管试验及泡沫铝填充薄壁圆管试验进行了数值模拟,分析表明该数值模型能够较好的模拟泡沫铝填充薄壁圆管在轴向冲击过程中的撞击力和变形发展。基于该模型对比研究了不同因素下泡沫铝填充薄壁铝合金多胞结构与单胞结构的轴向吸能特性,分析了其破坏模式、吸能机理和两者吸能效率。结果表明:在轴向冲击荷载作用下,泡沫铝填充薄壁铝合金的破坏模式为轴对称渐进折叠破坏模式,冲击力-位移曲线和变形模态图显示其变形过程分为3个阶段:弹性阶段、平台阶段和强化阶段。当冲击压缩距离为构件高度的80%时,7种不同参数下的泡沫铝填充薄壁铝合金多胞结构的吸能效率明显高于7种单胞结构,吸收的能量E和比吸能SEA都提高了50%以上,是一种优秀的吸能构件,可广泛应用于防护工程中。 相似文献
9.
泡沫铝具有减震和吸收冲击能量的良好特性。但由于泡沫铝自身强度较低,单独作为承载和吸能构件实用意义不大。将泡沫铝作为填充材料能充分发挥泡沫铝的优良性能。采用数值模拟方法研究低密度Duocel泡沫铝填充薄壁方钛管和圆钛管在30m/s的匀速冲击载荷作用下的瞬态吸能特性。提出柱壳比(R)作为比较不同截面形状的泡沫铝填充结构的依据。研究发现泡沫铝填充方钛管的比吸能为ES(F+P)A=0.438J;圆钛管的比吸能为EC(F+P)A=0.344J。泡沫铝填充方钛管的吸能效果好于圆钛管,前者是后者的1.273倍。在相互作用和影响下,泡沫铝柱和管的变形模式和力学性能都发生了较大的改变,被泡沫铝填充的方管的屈曲波长变短,圆管则与之相反。粘合后,泡沫铝柱和管具有类似的力—位移曲线和相似的力学性质。 相似文献
10.
目的 为避免或减小高g值冲击对弹内轻质元器件的破坏,应加强对轻质元器件缓冲防护结构的研究。方法 基于新型复合泡沫和通孔泡沫铝的2种泡沫填充管,通过万能试验机和落锤冲击系统研究了2种泡沫填充管的静动态力学特性,并运用数值模拟方法研究高g值冲击下等质量的泡沫填充管与夹芯管的加速度缓冲效果和吸能机制。结果 数值模拟所得结构变形和落锤加速度与实验结果较为一致,验证了数值模拟方法的可靠性。复合泡沫平台应力具有显著的应变率效应,其填充管压溃载荷平稳且高于泡沫铝填充管,比泡沫铝填充管体现出更优异的高过载防护性能。等质量的泡沫夹芯管的抗冲击性能优于填充管,2种泡沫填充而成的夹芯管具有相似的高过载防护性能,泡沫材料压缩行为对夹芯管压溃载荷特征的影响低于填充管。结论 所得结果对轻质元器件的高g值缓冲防护有较强的指导意义。 相似文献
11.
This work describes an advanced technique for metal welding and composite production, namely laser shock welding. A series of laser shock welding experiments were conducted to verify the welding ability of aluminum/aluminum and aluminum/copper plates. Two kinds of interface morphologies were observed by metallographic investigation on cross-sections of the joint areas, including the linear and wavy interfaces. Besides, micro-hardness testing results show the welded interface has a much greater hardness than the base metals. The lap shearing test was used to characterize the joint. According to the experimental results, it can be imply that this kind of technique shares the same bonding mechanism with explosive welding and magnetic welding. 相似文献
12.
13.
14.
Hwa Young Lee 《Materials Letters》2011,65(17-18):2621-2623
The synthesis of ammonium aluminum oxalate was performed using Bayer aluminum hydroxide as a raw material. For this aim, Bayer aluminum hydroxide of 99.7% purity was dissolved in oxalic acid to produce an aqueous aluminum solution. As a result, it was found that a mixing ratio of ethanol to Al solution exceeding 2:1 and a pH adjusted to greater than 8.0 should be employed in the synthesis of ammonium aluminum oxalate. From the chemical analysis of ammonium aluminum oxalate prepared in this work, the NH4, Al and C content were found to be 14.5, 7.18 and 17.4%, respectively which are very close to the theoretical values of (NH4)3Al(C2O4)33H2O. 相似文献
15.
Bulk and plasma-sprayed aluminum samples were bombarded with 10 keV D3+ to a standard fluence of 1018 atoms cm-2 at implant temperatures of 100–400 °C. Gas re-emission, thermal desorption and D(3He,α)H measurements were conducted. The results indicate that the saturation deuterium trapping level was about 1016-1017 atoms cm-2 and was primarily confined to about the first 0.2 μm depth. Trapping of about 1016 atoms cm-2 was still observed after anneals to 530 °C. 相似文献
16.
采用铁的次灵敏线,分析精密度准确度都较好,操作又十分简捷。建立了快速测定铝及铝合金中含铁量的分析方法。 相似文献
17.
An aluminum borate whisker-reinforced aluminum matrix composite with high plasticity 总被引:3,自引:0,他引:3
A pure aluminum matrix composite reinforced by ZnAl2O4-coated Al18B4O33 whiskers was fabricated by a squeeze casting technique. The effect of ZnAl2O4 coating content on the wettability between whiskers and matrix, the ultimate tensile strength and elongation to fracture of the composite were investigated. The results show that the interface wettability and the ultimate tensile strength increase with increasing the coating content. The coating content remarkably affects the elongation to fracture of composites. When the mass ratio of ZnO and ABOw is 1:30, the elongation to fracture of the composite can reach 7.9% at room temperature. 相似文献
18.
Seung-Joon Yoo Dong-Heui Kwak Se-II Lee Jin-Geol Kim Jai Koo Park Ho Sung Yoon Hee Dong Jang 《Advanced Powder Technology》2011,22(5):617-622
Al sec-butoxide (ASB) has been used as a precursor for activated aluminas but its cost is higher than any other type of precursor. This study was carried out on the dissolution kinetics for synthesis of the ASB from Al dross waste. The reaction was performed under the molar ratio of Al dross and sec-butyl alcohol (SBA) of 3 mol SBA/mol Al with a catalyst of 10?3 mol HgI2/mol Al and three different dissolution temperatures of 80, 90 and 100 °C. The Al reactant was used with Al dross of 3–5 mm size range. As a result of the experiment, the dissolution reaction gave a 65% yield after 24 h. The dissolution mechanism was determined by the shrinking core model assumed by the shape of spherical particles. Especially, the kinetic data were well fitted by a chemical reaction in the model. By the Arrhenius equation, the apparent activation energy was determined to be 40.9 kJ mol?1 at the given reaction temperatures. 相似文献
19.
The partial thermodynamic functions of Al in the Β-bronzes Na2-yAlyV12O30 (0 <y ≤ 0.7), Na2AlyV12O30 (0 <y ≤1.4), and Na1.3AlyV12O30 (0 <y≤ 2.1) were determined as a function of composition in the temperature range 294–348 K. The δG (Al), δ-H (Al), and δS (Al) of the bronzes were found to vary in a complex manner with Al content, passing through extrema neary = 1 as a result of the structural ordering of Al3+ ions. The temperature dependences of δG (Al) show changes in slope between 303 and 318 K, attributable to redistribution
of the Al3+ ions over the possible crystallographic sites in the Β-bronze structure. 相似文献