共查询到19条相似文献,搜索用时 125 毫秒
1.
利用常规电炮发射金属飞片的实验技术,将Φ10 mm×0.5 mm、Φ10 mm×0.3 mm铝飞片分别发射到300、500 m/s的速度且具有较好的平面度,有效拓展了电炮在相对较低的飞片发射速度和较低应变率下的加载能力(飞片速度约100 m/s、应变率小于106 s-1),使之可以在更宽的应变率和加载压力下使用。利用二级电炮技术,对Zr51Ti5Ni10Cu25Al9块体非晶合金进行了平面撞击实验,获得了较好的结果,该工作对电炮加载技术的推广应用有着重要的作用。 相似文献
2.
利用激光驱动气库材料形成的等离子体射流对材料进行斜波加载, 可以获得高应变率的准等熵压缩. 在神光III 原型高功率激光装置上开展了激光驱动铝材料的准等熵压缩实验, 成像型速度干涉仪VISAR记录到样品自由面连续、光滑的速度历史, 采用反积分法得到60 GPa以上的峰值压强, 加载上升沿约10 ns,应变率可达108 s -1, 并且观察到了压缩波在样品后表面的反射效应. 相似文献
3.
4.
5.
利用Instron万能试验机与LC4超硬铝合金分离式Hopkinson压杆设备,对3种不同波阻抗的橡胶材料——炭黑母胶(Carbon Black Rubber)、硅橡胶(Silicone Rubber)和泡沫橡胶(Foam Rubber)在较大应变率范围(0.002~15 000s-1)内进行了单轴压缩实验,研究应变率对橡胶材料力学性能的影响。实验结果表明:3种橡胶的准静态与动态应力-应变曲线具有不同的应变硬化形式,且动态加载下随着应变率的增大,硬化效应逐渐增强;在准静态及高应变率(12 000~15 000 s-1)压缩下,泡沫橡胶表现出多孔类材料压缩曲线的弹性、塑性崩塌及致密化3段特征。基于Rivilin应变能模型,构建了一个应变率相关的动态本构模型,模拟结果与实验结果吻合较好,可以用于描述较大应变率范围内3种橡胶的非线性应力-应变关系。 相似文献
6.
7.
8.
9.
10.
11.
12.
某PBX炸药的动态力学性能研究 总被引:1,自引:0,他引:1
PBX炸药作为现代武器的主装药,它的力学行为决定着武器的生存能力。为了研究PBX炸药的动态力学特性,采用分离式霍普金森压杆(Split Hopkinson Pressure Bar,SHPB)作为加载手段,结合半导体应变片测试技术和压电晶体监测技术,保证了实验数据的有效性。利用SHPB加载波整形技术,实现了材料两端应力平衡和常应变率加载,得到了不同应变率(90~410 s-1)下材料的应力-应变曲线。根据材料的模量、破坏强度和破坏应变随应变率的变化规律,采用粘性修正的Sargin模型,得到了该PBX炸药在单轴压缩下的唯象本构模型,模拟结果与实验曲线符合较好。 相似文献
13.
在10~55 GPa的高压范围用化爆装置、采用阻抗匹配法测得了聚四氟乙烯(初始密度ρ0=2.19 g/cm3)的冲击波速度D和波后粒子速度u之关系为:D=2.10+1.62u(mm/μs)。在0.2~3 GPa的低压范围用气炮装置、采用电磁速度计测量了材料内加、卸载过程的拉格朗日粒子速度波形,获得的冲击加载D-u关系为:D=1.24+3.72u-1.94u2(mm/μs)。实测卸载曲线和加载冲击绝热线接近一致,残余应变似乎不存在或者说很小;弹性区段很不明显,聚四氟乙烯本质上呈现出塑性性质。 相似文献
14.
The deformation process in copper and aluminium single crystals under shock loading is investigated using a multiscale model of plasticity that couples discrete dislocation dynamics and finite element analyses. Computer simulations are carried out to mimic loading condition of high strain rates ranging from 105 to 107?s?1, and short pulse durations of few nanoseconds involved in recent laser based experiments. The effects of strain rate, shock pulse duration and the nonlinear elastic properties are investigated. Relaxed configurations using dislocation dynamics show formation of dislocation micro bands and weak dislocation cells. Statistical analyses of the dislocation microstructures are preformed to study the characteristics of the local dislocation densities and the distribution of the instantaneous dislocations velocities. 相似文献
15.
利用MTS材料试验机和分离式Hopkinson压杆(SHPB)实验装置对非退火状态Ta-10W合金进行了准静态和动态压缩实验,给出了材料的静态压缩屈服强度和应变率在700~3 100 s-1范围内的动态压缩应力-应变曲线,并获得了不同应变率下材料的动态屈服强度。通过对实验结果的分析可以发现,非退火状态Ta-10W合金具有较好的韧性,在所进行的实验中试件表面均未出现可见裂纹;试件材料具有较高的静、动态屈服强度,静态屈服强度达到930 MPa,动态屈服强度在1 GPa以上,在所进行的700~3 100 s-1应变率范围内,材料的动态屈服强度随应变率的增加略有提高。 相似文献
16.
介绍了影响激光驱动超高速发射技术的各种因素。分析了激光能量、激光光束空间分布对飞片发射速度及完整性的影响和飞片靶镀膜工艺对飞片速度及完整性的影响。结果表明:空间分布为“平顶型”的激光束有利于发射出完整的飞片。在膜与基底之间增加过渡层Cr可以大大提高膜与基底之间的附着力,从而提高飞片的发射速度。实验上利用波长1 064 nm、脉宽10 ns、能量835 mJ的激光使厚度5 μm、直径1 mm的铝飞片的发射速度达到10.4 km/s。大大提升了对微米级空间碎片速度的发射能力。 相似文献
17.
E.G. Gamaly A.V. Rode B. Luther-Davies 《Applied Physics A: Materials Science & Processing》1999,69(7):S121-S127
The ionization of laser-ablated vapours with lasers producing ns duration pulses at various wavelengths has been studied in order to understand the mechanisms of the vapour-plasma transition. It has been established that there are several regimes characterizing the laser-target interaction which depend on laser intensity, wavelength, and pulse duration. The range of laser intensities for optimal laser evaporation is determined by the condition of transparent vapours. The intensity range is upper-limited by the opaque plasma formation due to vapour optical breakdown. Results are given for laser evaporation of graphite with Nd:YAG laser (1.064 7m), KrF laser (248 nm) and ArF laser (193 nm). For the UV laser wavelength the regime of skin-effect interaction was proposed as the mechanism of ion acceleration, and the range of validity of the skin-effect mode was established. With UV lasers the interaction has a bimodal nature: the interaction may proceed initially in the skin effect regime, resulting in a few high-energy ions, until hydrodynamic expansion begins at a later stage. The skin-effect interaction at the initial stage of the UV laser pulse gives the first, to our knowledge, explanation for the acceleration of ions up to ~100 eV at low laser intensities of 108-109 W/cm2 and ns-range pulse duration. 相似文献
18.
19.
J. Zhang K. Sugioka T. Takahashi K. Toyoda K. Midorikawa 《Applied Physics A: Materials Science & Processing》2000,71(1):23-26
A new technique of dual-beam laser ablation of fused silica by multiwavelength excitation process using a 248-nm KrF excimer laser (ablation beam) coupled with a 157-nm F2 laser (excitation beam) in dry nitrogen atmosphere is reported. The dual-beam laser ablation greatly reduced debris deposition and, thus, significantly improved the ablation quality compared with single-beam ablation of the KrF laser. High-quality ablation can be achieved at the delay times of KrF excimer laser irradiation shorter than 10 ns due to a large excited-state absorption. The ablation rate can reach up to 80 nm/pulse at the fluence of 4.0 J/cm2 for the 248-nm laser and 60 mJ/cm2 for the F2 laser. The ablation threshold and effective absorption coefficient of KrF excimer laser are estimated to be 1.4 J/cm2 and 1.2᎒5 cm-1, respectively. 相似文献