炸药量对爆炸焊接界面波影响的数值模拟

为了保证金属复合材料的爆炸焊接质量,对爆炸焊接过程中的爆轰荷载大小起着决定性作用的炸药量及布药方式进行了探索。应用AUTODYN非线性显式动力学分析软件,模拟了基、复板爆炸焊接复合过程,得到了不同炸药量下爆炸焊接过程中的压力时程,结合理论公式,分析炸药量、爆轰荷载、碰撞速度和界面波状之间的关系,及炸药量对爆炸焊接界面波的影响。并在复板上、下表面等间距各设置了8个关键点,比较了炸药厚度均匀布药方式和厚度递减布药方式产生的波状形态。结果表明,在可焊性窗口内,炸药量多的会产生较大波状结合界面;厚度递减布药方式能够消除均匀布药方式下界面波的不均匀现象,其中方案2的速度波动效果最好。并且已经结合的界面受到后续压力的振动破坏明显降低。     

Scaling aspects of quadrangular plates subjected to localised blast loads—experiments and predictions

A series of experimental results on clamped mild steel quadrangular plates of different thicknesses (1.6, 2.0, 3.0 and 4.0 mm) and varying length-to-width ratios (1.0–2.4) subjected to localised blast loads of varying sizes is reported. Disc shaped explosive charges of varying charge diameter-to-plate width ratios (0.2–0.37) and charge heights (1.8–14 mm) are centrally positioned on quadrangular plates to provide impulses resulting in mid-point deflections in the range from two plate thicknesses to central plate tearing. The effects of varying both the loading conditions and the plate geometries on the deformation are described. A modified dimensionless number is presented for the quadrangular plate response when subjected to localised circular blast loading. In addition, numerical predictions are carried out and compared with experiments for a limited selection of plate geometries.     

钛/钢多层爆炸焊接界面的实验研究

为探究膨化硝铵炸药作用下,厚度均为2 mm的钛(Ti)、钢板的最优爆炸焊接参数以及验证一种新的爆炸焊接试验方案,实验采取阶梯型多层基板的爆炸焊接试验方案,以控制药量和间距为变量,并将Ti板作为复板,同时对多层阶梯型钢基板进行爆炸焊接试验;利用金相显微镜对焊接复合板进行观察,并分析多层基板同时焊接的方案可行性以及不同实验参数对界面波形的影响。试验结果和分析表明:通过观察Ti/钢复合板界面波形呈正弦微波状且无明显过渡层,验证了新方案的可行性,同时突出了阶梯型多层基板的同时爆炸焊接方案,能够在单次试验下对比分析不同基复板间距情况下的焊接效果的能力;并经分析得出在单位面积装药为1.048 g/cm~2及装药间距范围为(9~11)mm时,能得到质量较佳的Ti/钢爆炸复合板。     

Behaviour of sandwich panels subject to intense air blasts – Part 2: Numerical simulation

Finite element simulation is employed to analyse the behaviour of clamped sandwich panels comprising equal thicknesses mild steel plates sandwiching an aluminium honeycomb core when subject to blast loadings. Pressure-time histories representative of blast loadings are applied to the front plate of the sandwich panel. The FE model is verified using the experimental test results for uniform and localised blast loading in the presence of a honeycomb core and with only an air gap between the sandwich plates. It is observed that for the particular core material, the load transfer to the back plate of the panel depends on the load intensity, core thickness and flexibility of the sandwich panels.     

Fatigue strength of mash seam welded joints

Reversed bending fatigue tests have been conducted using four series of mash seam welded joints obtained from the coupling of two different steels and plate thicknesses. Fatigue strength was evaluated and the effects of material property changes resulting from welding were studied. Fatigue strength of all series of the welded joints decreased slightly compared with that of the base steel. Type of steel and plate thickness in the welded samples exerted very little influence on fatigue strength. In the welded joints between steels with the same plate thickness, fatigue failure took place at a location away from the weld zone in the plate with the lower strength, while in the welded joints between plates of different thickness, failure occurred at the shoulder between the thin and thick plate, i.e. at the weld zone. Regardless of the type of steel and the plate thicknesses joined, fatigue strengths of the mash seam welded joints were slightly higher than those of the laser welded butt joints.     

Performance of mild steel perforated plates as a blast wave mitigation technique: Experimental and numerical investigation

This article presents the results of an experimental and numerical investigation into the influence of hole size and thickness on the performance of mild steel perforated plates as a blast wave mitigation technique. Results of the blast tests showed that the perforated plates with small hole sizes reduced the damage imparted to the target plate by reducing the target plate mid-point deflection and increasing the tearing threshold impulse. Ansys Autodyn was used to model the experiments and the perforated plate hole diameter was varied during the simulations. The impulse imparted to the pendulum, target plate and perforated plate deflections compared favourably to the experimental results. The modelling simulations also gave further insight into the interaction between the blast wave and the plates. The simulations showed that the impulse imparted to the target plate was higher than the impulse measured from the experimental pendulum swing and that the difference increased with increasing blockage ratio. The simulations also showed that the total load duration was much longer than the response time of the plate, indicating that a proportion of the impulse does not contribute to the deformation of the target plate. The response time was shown to increase with increasing blockage ratio and decrease with increasing impulse.     

AN INVESTIGATION INTO THE EXPLOSIVE PERFORATION OF MILD STEEL SHEET

Experiments are described in which mild steel plates of 1/10; in. thickness were set on hardened and ground flat steel dies having central square-shouldered round holes, of diameter ranging from 1/10; to 1£ in., and subjected to the shock wave resulting from the detonation of an underwater high explosive charge. Graphical results are presented showing the variation of the deformation of the plates due to cupping and to shear, with increasing charge size, and with varying hole diameter.

Results from records of the pressure wave arising from the detonation of the charge are provided, and attempts are made to correlate these with the predictions of established empirical formulae.     

Research on honeycomb structure explosives and double sided explosive cladding

In order to resolve the current issues about the backward method of charge and low energy efficiency of explosives, honeycomb structure explosives and double sided explosive cladding were used in the present study. Honeycomb structure explosives are used to ensure the quality of charge. Double sided explosive cladding can clad two composite plates simultaneously. Honeycomb structure explosives and double sided explosive cladding, which significantly reduce the critical thickness of stable detonation of explosives, are used to increase the energy efficiency of explosives and save the amount of explosives. Emulsion explosives with the thickness of 5 mm can be stable detonation. In this paper, the experiment of double sided explosive cladding for two groups of steel of No. 45 with the thickness of 2 mm to steel of Q235 with the thickness of 16 mm and two groups of stainless steel with the thickness of 3 mm to steel of Q235 with the thickness of 16 mm were successfully investigated. Without constraints, the critical diameter of emulsion explosives is 14–16 mm. Compared to the existing explosive cladding method, the consumption of explosives for steel of No. 45 to steel of Q235 and stainless steel to steel of Q235 are reduced by 83% and 77% in the case of cladding the same number of composite plates. The explosive cladding windows and collision velocity of flyer plate were calculated before experiment. It shows that the calculation prefigures exactly the explosive cladding for steel of No. 45 to steel of Q235 and stainless steel to steel of Q235.     

The influence of core height and face plate thickness on the response of honeycomb sandwich panels subjected to blast loading

This paper reports on an investigation into the behaviour of circular sandwich panels with aluminium honeycomb cores subjected to air blast loading. Explosive tests were performed on sandwich panels consisting of mild steel face plates and aluminium honeycomb cores. The loading was generated by detonating plastic explosives at a pre-determined stand-off distance. Core height and face plate thickness were varied and the results are compared with previous experiments. It was observed that the panels exhibited permanent face plate deflection and tearing, and the honeycomb core exhibited crushing and densification. It was found that increasing the core thickness delayed the onset of core densification and decreased back plate deflection. Increasing the plate thickness was also found to decrease back plate deflection, although the panels then had a substantially higher overall mass.     

Examination of copper/stainless steel joints formed by explosive welding

In this study, bonding ability of copper and steel with explosion welding was investigated using different ratios of explosive and different stand-off distance. Experimental studies showed out that, copper and stainless steel could be bonded with a good quality of bonding properties with explosion welding. In the bonding interface, intermetallics were not formed. It was observed that, when explosive ratio and stand-off distance were increased smooth bonding interface was transformed to a wavy bonding interface. As the ratio of explosive and stand-off distance increase, the amplitude and wavelength of wave were increased. It was found that, hardness of bonding interface and outer face of plates were increased because of deformation that was originating from impact the effect. Total interface area increased as a result of wavy interface, which was caused by increased explosive ratio and stand-off distance. In addition, wavy interfaces did not separate after tensile-shearing test. Bending tests applied on bonded samples had different diameters indicated that interfaces of the bonded samples have not any defect. EDS analyses in SEM showed that diffusion did not take place between bonding plates, however, diffusion was observed after annealing of the bonded samples for different times.     

高锰钢-碳钢复合板的制造和应用

介绍了一种高锰钢与结构钢的爆炸焊接工艺，包括表面处理方法、表面处理参数及条件、所采用的炸药和复合板的性能、爆炸焊用材料的准备。进行了成品复板（复合板）的质量检验，给出了该技术的应用实例。     

Optical techniques for the investigation of the ballistic impact of thin plates

The normal impact of chrome steel spheres upon mild steel and copper plates of various thicknesses was investigated. The bulging of their rear surfaces was monitored during the first 30 μs after impact using stereo digital speckle photography. The experimental data for copper was compared with two path-dependent models, one optimised for annealed and the other for pre-stressed (work-hardened) copper. It was not possible to differentiate between the two copper models using single-point displacement data. However, full-field data revealed clear differences in the shapes of the bulges, with greater global deformation and closer agreement with experiment for the model that included pre-stress. For both mild steel and copper, thin plates resulted in localised bulging whilst thicker plates produced global dishing. The bulge peak also grew earlier and more quickly in thinner specimens. The greater ductility of copper resulted in narrower, faster-growing bulges compared with mild steel of comparable thickness.     

Simultaneous measurement of refractive index and thickness of birefringent wave plates

A nondestructive measurement system based on a position sensing detector (PSD) and a laser interferometer for determining the thickness and refractive indices of birefringent optical wave plates has been developed. Unlike previous methods presented in the literature, the proposed metrology system allows the refractive index and thickness properties of the optical plate to be measured simultaneously. The experimental results obtained for the e-light and o-light refractive indices of a commercially available birefringent optical wave plate with refractive indices of n(o)=1.542972 and n(e)=1.552033 are found to be accurate to within 0.004132 and 0.000229, respectively. Furthermore, the experimentally derived value of the wave plate thickness deviates by no more than 0.9 microm from the analytically derived value of 453.95 microm. Overall, the experimental results confirm that the proposed metrology system provides a simple yet highly accurate means of obtaining simultaneous measurements of the refractive indices and thickness of birefringent optical wave plates.     

超级双相钢SAF2507+16MnR复合钢板爆炸复合工艺研究

本文说明了用进口超级双相钢SAF2507和国产16MnR钢板,运用爆炸焊接方法生产的复合钢板各项性能指标满足标准要求;重点阐述了爆炸焊接技术措施的制定及爆炸工艺参数的选取,合理的热处理工艺规范,对不同工艺规范下的试验数据进行了分析和研究。为今后SAF2507+16MnR复合钢板大批量生产及大量投入工业工程应用提供了科学依据。     

SUS304不锈钢/Q345R碳钢爆炸焊接工艺参数研究

针对实际生产中在爆炸焊接窗口内取值时因为所取参数不同而导致生产的复合板结合强度差异较大这一现状,通过对SUS304不锈钢／Q345R碳钢爆炸焊接窗口内不同工艺条件得到的复合板进行剪切强度测试及金相分析,得到界面结合强度与界面波形的关系以及两者随工艺参数的变化规律,找到窗口内最佳的工艺参数,以提高爆炸焊接复合板质量以及生产效益。研究表明：界面波形的波长和振幅随着装药量的增加而增大,随基复板间距的增加先增大后减小。爆炸焊接窗口内最佳工艺参数取值范围与复板厚度有关。复板为薄板（3mm）时,取得最佳结合强度时界面波形波长为1250μm左右,振幅为200μm左右,对应的最佳装药质量比为1．02,基复板间距为8mm,取值比理论最佳值偏高;复板为厚板（6mm）时,取得最佳结合强度时界面波形波长为900岫,左右,振幅为100μm左右,对应的最佳装药质量比为0．45,基复板间距为14mm,取值靠近下限。当界面波长与振幅相同时,复板为薄板的结合强度要高于厚板。     

Explosive scarf welding of aluminum to copper plates and their interface properties

Explosive welding was used to produce scarf joint between aluminum and copper plates. This process is known as explosive scarf welding (ESW). In a scarf joint, the final bond interface is oblique. In this study, chamfered end of aluminum and copper plates were joined explosively and named scarf joint, employing changes in chamfered angle at different stand‐off distance and explosive loading. The geometry of scarf joint enables consideration of both flyer and base plate thickness and explosive loading and the effects on mechanical properties of interface such as bond shear strength and micro‐hardness can be investigated. Mathematical models developed on the interface properties of scarf joint to make relationship between the bond shear strength and explosive loading ratio. To check the adequacy of developed models, mechanical properties of interface, such as bond shear strength was predicted and compared with actual values in explosive cladding process. The results show reasonable agreement with theoretical predictions. Consequently, mathematical model which is based on scarf joints, can predict bond shear strength of cladding metals under desired explosive loading and flyer plate thickness.     

厚板爆炸焊接窗口理论的应用

厚板爆炸焊接的焊接质量，焊接与否都比薄板更加强烈地依赖于爆速，复板加速间抛掷角，打击速度等焊接参数，该文根据可焊窗口理论，对厚板爆炸焊接参数选择时应注意的总理２进行了分析，尤其对焊接上限问题进行了较深入地讨论。     

钛/钢双立式爆炸焊接参数优化

为解决大面积钛/钢爆炸焊接窗口窄,在结合区易出现"过熔"和"射流堆积"等微观缺陷的问题,开展了双立爆炸+轧制综合制造技术,进行了低爆速爆炸焊接用炸药试验优化,发明了一种最低临界爆速爆炸焊接用炸药,设计确定了刚性防护板和柔性防护墙构成的双立综合防护结构及参数,研究了钛/钢爆炸焊接装药厚度窗口.结果表明,双立钛/钢复合板结合界面成波状结合,几乎不存在金属熔化、漩涡等微观缺陷.     

聚能射流前驱波起爆靶板屏蔽炸药的数值模拟

为系统地研究聚能射流前驱波对靶板屏蔽炸药冲击起爆的影响,从前驱波的形成机理出发,结合前驱波在靶板中传递时能量的衰减、作用面积的增大和在靶板-炸药界面能量的转化,对炸药冲击起爆的窄脉冲准则进行改进,构建了聚能射流前驱波冲击起爆靶板屏蔽炸药的数学模型,并对模型进行了详细地分析和研究,得到如下结论:对于直径3mm的聚能射流,其前驱波最大可起爆约4.2mm钢板屏蔽的A4炸药,符合试验结论;前驱波起爆能力的降低主要是由于作用面积的增大和不同材料交界面的能量转化,说明可以通过靶板厚度与靶板层数之间的最优组合,以最小的代价达到最大的前驱波防护能力,为复合靶板的研究、野战弹药生存能力的提高和废旧弹药的处理提供了理论依据。     

多次水下爆炸钢制圆板应变与挠度增长规律分析

在海上战争中,水面舰艇以及潜艇可能会受到多枚水中兵器的攻击,产生的累计损伤问题影响着水面舰艇以及潜艇的持续作战能力和生命力。对膨胀直径为390 mm,厚度为5 mm空气背衬钢制圆板,在50 g药量下,进行持续多次水下爆炸加载试验,对板中心应变、挠度以及厚度减薄率进行测量,试验结果分析表明:第一次爆炸加载时,局部空化使钢板产生的应变是冲击波加载的1倍,当钢板被炸弯后,再次爆炸加载局部空化的二次加载现象不明显。此外,气泡脉动及气泡射流会使钢板发生明显的弹性应变,应变值是初始冲击波作用的10%。对中心挠度和厚度减薄率的数据分析发现,钢板厚度减薄率是随着中心挠度呈线性增加的。该研究对舰船持续作战能力及生命力的评估提供了一定的试验支撑。