Jet formation and penetration performance of a double-layer charge liner with chemically-deposited tungsten as the inner liner

This paper proposes a type of double-layer charge liner fabricated using chemical vapor deposition(CVD)that has tungsten as its inner liner.The feasibility of this design was evaluated through penetration tests.Double-layer charge liners were fabricated by using CVD to deposit tungsten layers on the inner surfaces of pure T2 copper liners.The microstructures of the tungsten layers were analyzed using a scanning electron microscope(SEM).The feasibility analysis was carried out by pulsed X-rays,slug-retrieval test and static penetration tests.The shaped charge jet forming and penetration law of inner tungsten-coated double-layer liner were studied by numerical simulation method.The results showed that the double-layer liners could form well-shaped jets.The errors between the X-ray test results and the numerical results were within 11.07%.A slug-retrieval test was found that the retrieved slug was similar to a numerically simulated slug.Compared with the traditional pure copper shaped charge jet,the penetration depth of the double-layer shaped charge liner increased by 11.4% and>10.8% respectively.In summary,the test results are good,and the numerical simulation is in good agreement with the test,which verified the feasibility of using the CVD method to fabricate double-layer charge liners with a high-density and high-strength refractory metal as the inner liner.

Performance and Application of Double-layered Microcapsule Corrosion Inhibitors

Double-layered microcapsule corrosion inhibitors were developed by sodium monofluorophosphate as the core material,polymethyl methacrylate as the inner wall material,and polyvinyl alcohol as the outer wall material combining the solvent evaporation method and spray drying method.The protection by the outer capsule wall was used to prolong the service life of the corrosion inhibitor.The dispersion,encapsulation,thermal stability of microcapsules,and the degradation rate of capsule wall in concrete pore solution were analyzed by ultra-deep field microscopy,scanning electron microscopy,thermal analyzer,and sodium ion release rate analysis.The microcapsules were incorporated into mortar samples containing steel reinforcement,and the effects of double-layered microcapsule corrosion inhibitors on the performance of the cement matrix and the actual corrosion-inhibiting effect were analyzed.The experimental results show that the double-layered microcapsules have a moderate particle size and uniform distribution,and the capsules were completely wrapped.The microcapsules as a whole have good thermal stability below 230 ℃.The monolayer membrane structure microcapsules completely broke within 1 day in the simulated concrete pore solution,and the double-layer membrane structure prolonged the service life of the microcapsules to 80 days in the simulated concrete pore solution before the core material was completely released.The mortar samples containing steel reinforcement incorporated with the double-layered microcapsule corrosion inhibitors still maintained a higher corrosion potential than the monolayer microcapsule corrosion inhibitors control group at 60 days.The incorporation of double-layered microcapsules into the cement matrix has no significant adverse effect on the setting time and early strength.

季冻区OGFC沥青混合料车辙预估模型研究

目的研究季冻区OGFC沥青混合料的高温抗车辙能力,建立车辙预估模型,推广OGFC沥青混合料在季冻区的应用。方法采用车辙试验系统进行车辙试验,分析轴载作用次数、试件高度、温度、抗剪强度、冻融循环次数对OGFC沥青混合料车辙深度的影响;基于经验法建立季冻区OGFC沥青混合料车辙预估模型,通过最小二乘法拟合模型参数,对建立的预估模型进行室内试验验证以及有限元对比分析。结果各影响因素与车辙深度呈现幂函数关系,冻融循环作用加速车辙形成,室内试验实测车辙深度与模型预估的车辙深度相对误差为0.11%~9.81%。结论经验法建立的季冻区OGFC沥青混合料车辙预估模型预估精度较高,预估模型误差受试验条件和材料参数影响,其中材料参数影响较明显。

PAM-10/OGFC-10沥青混合料渗水性能对比研究

【目的】探讨多孔沥青混合料PAM-10与开级配排水沥青混合料OGFC-10渗水性能的差异,为排水路面沥青混合料类型的选取提供一定的参考。【方法】对空隙率为12.5%、14.0%、15.5%、17.0%的PAM-10及空隙率为22.0%的OGFC-10沥青混合料试件开展连通空隙率试验、计算机断层扫描(computed tomography,CT)空隙内部特征试验、竖向渗透系数试验、抗冲刷性及抗堵塞性试验,对比分析两种排水沥青混合料的渗水性能。【结果】PAM-10的内部空隙结构比OGFC-10的更容易形成连通空隙;空隙率为17.0%的PAM-10竖向渗透系数与空隙率为22.0%的OGFC-10的相当;动水冲刷对OGFC-10的影响大于对PAM-10的影响;OGFC-10的抗堵塞性能比PAM-10的差。【结论】PAM-10的竖向渗透性、抗冲刷性能及抗堵塞性能均比OGFC-10的更优。

Time-sequenced damage behavior of reactive projectile impacting double-layer plates

The time-sequenced damage behavior of the reactive projectile impacting double-layer plates is discussed.The analytical model considering the combined effect of kinetic and chemical energy is developed to reveal the damage mechanism.The influences of impact velocity and reactive projectile chemical characteristics on the damage effect are decoupled analyzed based on this model.These analyses indicate that the high energy releasing efficiency and fast reaction propagation velocity of the reactive projectile are conducive to enhancing the damage effect.The experiments with various reactive projectiles impact velocity increasing from 702 to 1385 m/s were conducted to verify this model.The experimental results presented that,the damage hole radius of the rear-plate increases with the increase of impact velocity.At the impact velocity of 1350 m/s,the radius of damage hole formed by PTFE/Al/Bi_(2)O_(3),PTFE/Al/MoO_(3),PTFE/Al/Fe_(2)O_(3)projectile on the rear-plate become smaller in sequence.These results are consistent with the analytical model prediction,demonstrating that this model can predict the damage effect quantitatively.This work is of constructive significance to the application of reactive projectiles.

Gas-and plasma-driven hydrogen permeation behavior of stagnant eutectic-solid GaInSn/Fe double-layer structure

Gas-driven permeation(GDP)and plasma-driven permeation(PDP)of hydrogen gas through Ga In Sn/Fe are systematically investigated in this work.The permeation parameters of hydrogen through Ga In Sn/Fe,including diffusivity,Sieverts'constant,permeability,and surface recombination coefficient are obtained.The permeation flux of hydrogen through Ga In Sn/Fe shows great dependence on external conditions such as temperature,hydrogen pressure,and thickness of liquid Ga In Sn.Furthermore,the hydrogen permeation behavior through Ga In Sn/Fe is well consistent with the multilayer permeation theory.In PDP and GDP experiments,hydrogen through Ga In Sn/Fe satisfies the diffusion-limited regime.In addition,the permeation flux of PDP is greater than that of GDP.The increase of hydrogen plasma density hardly causes the hydrogen PDP flux to change within the test scope of this work,which is due to the dissolution saturation.These findings provide guidance for a comprehensive and systematic understanding of hydrogen isotope recycling,permeation,and retention in plasma-facing components under actual conditions.

Preparation and Microwave Absorbing Properties of Double-layer Fine Iron Tailings Cementitious Materials

To develop the microwave absorbing(MA)properties of cementitious material mixed with mine solid waste,the iron tailings cementitious microwave absorbing materials were prepared.The iron tailings was treated into different particle sizes by planetary ball mill,and the physicochemical properties of iron tailings were tested by laser particle size analyzer and scanning electron microscope(SEM).The electromagnetic parameters of iron tailings cementitious materials were characterized by a vector network analyzer and simulated MA properties,and the MA properties of iron tailings-cement composite system with steel fiber as absorber was studied.Based on the design of the single-layer structure,optimum mix ratio and thickness configuration method of double-layer structure were further studied,meanwhile,the mechanical properties and engineering application were analyzed and discussed.The results show that the particle size of iron tailings can afiect its electromagnetic behavior in cementitious materials,and the smaller particles lead the increase of demagnetisation efiect induced by domain wall motion and achieve better microwave absorbing properties in cementitious materials.When the thickness of matching layer and absorbing layer is 5 mm,the optimized microwave absorbing properties of C1/C3 double-layer cementitious material can obtain optimal RL value of-27.61 dB and efiective absorbing bandwidth of 0.97 GHz,which attributes to the synergistic efiect of impedance matching and attenuation characteristics.The double-layer microwave absorbing materials obtain excellent absorbing properties and show great design flexibility and diversity,which can be used as a suitable candidate for the preparation of favorable microwave absorbing cementitious materials.

Double-Layer-Optimizing Method of Hybrid Energy Storage Microgrid Based on Improved Grey Wolf Optimization

To reduce the comprehensive costs of the construction and operation of microgrids and to minimize the power fluctuations caused by randomness and intermittency in distributed generation,a double-layer optimizing configuration method of hybrid energy storage microgrid based on improved grey wolf optimization(IGWO)is proposed.Firstly,building a microgrid system containing a wind-solar power station and electric-hydrogen coupling hybrid energy storage system.Secondly,the minimum comprehensive cost of the construction and operation of the microgrid is taken as the outer objective function,and the minimum peak-to-valley of the microgrid’s daily output is taken as the inner objective function.By iterating through the outer and inner layers,the system improves operational stability while achieving economic configuration.Then,using the energy-self-smoothness of the microgrid as the evaluation index,a double-layer optimizing configuration method of the microgrid is constructed.Finally,to improve the disadvantages of grey wolf optimization(GWO),such as slow convergence in the later period and easy falling into local optima,by introducing the convergence factor nonlinear adjustment strategy and Cauchy mutation operator,an IGWO with excellent global performance is proposed.After testing with the typical test functions,the superiority of IGWO is verified.Next,using IGWO to solve the double-layer model.The case analysis shows that compared to GWO and particle swarm optimization(PSO),the IGWO reduced the comprehensive cost by 15.6%and 18.8%,respectively.Therefore,the proposed double-layer optimizationmethod of capacity configuration ofmicrogrid with wind-solar-hybrid energy storage based on IGWO could effectively improve the independence and stability of the microgrid and significantly reduce the comprehensive cost.

复合阻燃剂对OGFC沥青混合料路用性能的影响

通过极限氧指数评价3种复合阻燃剂改性沥青的阻燃性能,借助室内车辙试验、低温弯曲试验、浸水马歇尔试验、劈裂疲劳试验研究了3种复合阻燃剂对OGFC沥青混合料路用性能及疲劳性能的影响,结果表明:复配阻燃体系阻燃效果明显优于单一无机系阻燃剂,且HL+APP复配的无机膨胀型阻燃体系效果最佳;在保证阻燃性能的同时,3种复配阻燃体系下混合料的路用耐久性能无负面影响,高温性能、水稳定性和疲劳性能有一定提升,低温性能稍有下降。

新型高粘改性剂改性OGFC混合料性能研究

本文研究了一种新型的开级配沥青磨耗层(OGFC)改性剂ATS,并通过实验测试了其改性效果。由于OGFC的孔隙率较大,易受外界环境的影响,因此要求采用的沥青具有耐久的握裹力、较强的粘着力及抗老化性能。本文在水稳定性、低温性能及动稳定度等方面对ATS进行了研究,并与传统改性剂TPS进行了对比。实验结果表明,通过ATS进行改性的OGFC混合料在各项性能表现上均优于TPS,具有更好的耐久性和稳定性,表明ATS是一种具有潜力的OGFC改性剂。

OGFC生产过程碳排放计算和碳减排技术研究

针对降低道路沥青混凝土路面设计、生产、施工、管养过程的碳排放问题,开展对排水性沥青面层OGFC沥青混合料包括原材料准备、原材料运输到生产基地、混合料生产拌和阶段在内的生产过程碳排放计算方法进行研究。将排水性沥青面层OGFC沥青混合料的生产过程划分为材料准备和混合料生产拌和两个阶段,根据混合料的配合比设计、材料准备方案、生产工艺等,按排放因子法计算系统边界内各阶段的碳排放,分析各分项碳排放占比,提出合适的碳减排措施。以上海市浦东新区高等级道路金海路改建工程为例,对研究提出的碳排放计算方法和碳减排技术进行实际应用分析,结果显示碳减排效果比较显著。

基于不同纤维改性的OGFC-13沥青混合料路用性能研究

纤维沥青利用纤维的改性作用改善混凝土材料的路用性能。为探究OGFC-13沥青混合料在各类纤维不同体积掺量条件下的路用性能表现,本文特制备聚丙烯腈纤维、聚酯纤维、木质素纤维、玄武岩纤维4种纤维外掺剂的沥青混合料进行路用性能试验。研究结果表明:(1)OGFC-13沥青混合料随纤维掺量的增加,其动稳定度不断增长,当各种纤维掺量超过0.3%时,动稳定度呈下降趋势;(2)当纤维体积掺量为0.3%时,含玄武岩纤维的沥青混合料动稳定度为3252次/mm,高温稳定性表现最佳;(3)当聚酯纤维与玄武岩纤维掺量为0.2%时,沥青混合料低温最大弯拉应变相同,为2834,但聚酯纤维在纤维沥青混合料低温抗裂性能方面的作用存在不稳定性;(4)掺入纤维材料的OGFC-13沥青混合料排水性能呈下降趋势,尤其是木质纤维对渗透系数的影响最大,当掺量为0.2%时,渗水系数由1154 ml/s陡降至635 ml/s,降幅达到44.97%;(5)综合来看,玄武岩纤维在OGFC-13沥青混合料中的改性效果最佳,但其掺量体积分数应控制在0.3%以内。本文成果可为温拌沥青薄层罩面的工程应用提供一点借鉴。

OGFC薄层罩面在沥青路面病害处治中的应用

为了改善沥青路面使用性能,采用OGFC薄层罩面技术进行病害处治。以某试验段为研究对象,首先对沥青路面病害状况进行了调查分析,然后确定了OGFC-13薄层罩面混合料的级配组成,最后结合试验段施工情况,具体阐述了OGFC-13薄层罩面层施工工艺和质量控制要点。结果表明,通过采用OGFC薄层罩面,路面性能得到了改善,可为类似工程实践提供参考。

纤维对OGFC沥青混合料耐久性能的影响

为明确纤维改性开级配抗滑磨耗层(Open Graded Friction Course,OGFC)沥青混合料的耐久性,以某国道改建工程为依托,采用木质素纤维、玄武岩纤维和玻璃纤维制备OGFC沥青混合料,利用烘箱加热法模拟沥青混合料的老化程度,研究了老化前后混合料的高低温性能、水稳定性和抗冻性。结果表明:相比普通沥青混合料,纤维改性沥青混合料的各项性能均有所改善,其中玄武岩纤维对OGFC沥青混合料性能提升效果最显著;随着老化时间的延长,纤维改性OGFC沥青混合料的马歇尔稳定度和浸水飞散损失持续增大,说明老化作用对OGFC沥青混合料的高温性能有提升效果,但对水稳定性不利。

基于CAVF法的OGFC路面排水设计与应用

本文旨在解决南方多雨区道路排水困难问题,以提高路面行车安全性。通过采用大空隙OGFC-13路面设计,结合CAVF法进行配合比设计。实验结果表明,本文所设计的OGFC-13混合料在稳定性、耐久性和排水性能方面均达到或超过设计要求。特别是在高温下具有良好的稳定性,能迅速排水,抗风化性能优良。

OGFC排水性沥青混凝土路面在紫惠高速公路项目中的应用

随着社会主义市场经济的繁荣发展,我国各省市的沟通交流日益密切。在这样的时代背景下,公路是链接各地的桥梁,具有极为重要的价值。为了有效防止路面积水渗透进路面内部,对公路寿命造成负面影响,具有良好排水性的OGFC 排水性沥青混凝土材料受到了各建设项目的关注与青睐。本论文将基于此,以河惠莞高速公路河源紫金至惠州惠阳段(下简称“紫惠高速”)作为案例,尝试分析OGFC排水性沥青混凝土路面施工技术的运用方式,希望能够给予工程业同仁一定的参考与启示。

SBS改性沥青OGFC-10最佳油石比确定及击实工艺研究

开级配沥青磨耗层(OGFC)作为一种先进的排水性路面材料,其特殊结构是由沥青和矿物质混合而成,并形成紧密的、互相连接的空隙结构。这个结构不仅能够提供出色的排水性能,还具有卓越的抗滑功能,同时能够有效地降低路面温度。因此,这种特殊的混合料引起了道路领域专业人士的广泛关注。尽管传统的开级配路面在排水和抗滑方面取得了一定的效果,但由于其沥青用量较低、空隙率较高,导致了一系列问题,如路面强度不足和耐久性差。为了解决这些问题,本文深入研究了OGFC在国内外的发展和应用状况。为了系统地评估OGFC-10混合料的性能,我们采用了不同油石比和加工工艺,制备了一系列试件,并进行了多项试验,包括马歇尔稳定度试验、沥青析漏试验和浸水飞散试验。通过对试验数据的综合分析,我们研究了不同油石比对沥青混合料参数的影响规律。深入分析了混合料析漏损失和飞散损失的影响因素,从而确定了最佳沥青用量范围。此外,为了更全面地了解OGFC-10混合料在不同条件下的性能,我们进行了不同击实温度下的马歇尔稳定度试验,以揭示不同温度对OGFC-10混合料参数的影响规律。这一研究不仅为深入理解混合料在不同温度条件下的性能提供了重要数据支持,而且强调了在施工过程中对SBS改性沥青OGFC-10混合料施工温度进行有效控制的必要性。

Double-layer model updating for steel-concrete composite beam cable-stayed bridge based on GPS

In order to establish the relationship between the measured dynamic response and the health status of long-span bridges, a double-layer model updating method for steel-concrete composite beam cable-stayed bridges is proposed. Measured frequencies are selected as the first-layer reference data, and the mass of the bridge deck, the grid density, the modulus of concrete and the ballast on the side span are modified by using a manual tuning technique. Measured global positioning system （GPS） data is selected as the second-layer reference data, and the degradation of the integral structure stiffness EI of the whole bridge is taken into account for the second-layer model updating by using the finite element iteration algorithm. The Nanpu Bridge in Shanghai is taken as a case to verify the applicability of the proposed model updating method. After the first-layer model updating, the standard deviation of modal frequencies is smaller than 7%. After the second-layer model updating, the error of the deflection of the mid-span is smaller than 10%. The integral structure stiffness of the whole bridge decreases about 20%. The research results show a good agreement between the calculated response and the measured response.

Computation of the Fatigue Life of Road Wheel with Double-Layer Rubber Flange

In order to increase the fatigue life (FL) of road wheels (RW), a kind of double layer rubber flange (DLRF) is put forward. It consists of two layers of rubber, where metal wires are laid in the inner layer and the outer layer has no inlaid metal wires. Stress, strain and temperature field of DLRF were calculated with ANSYS finite element analysis (FEA) software, FL of DLRF RW was also computed with fracture mechanics fatigue theory. The results of computation indicate that the heat generated in RW's rubber flange (RF) can be reduced by the use of DLRF, and the FL of RW can be increased without affecting the mechanical intensity of RW.

考虑黏层油迁移影响的OGFC面层空隙结构表征

为了保证沥青路面层间的充分黏结,在层间撒布黏层油是目前路面施工的必要工序。由于开级配磨耗层(OGFC)的大空隙结构,在压实过程中黏层油倾向于通过界面处OGFC的空隙向上迁移,从而影响界面处OGFC的空隙结构并进而影响其功能。本文选取2种下卧层材料、1种OGFC材料和4种黏层油掺量制作OGFC和下卧层组合试件;通过CT扫描、三维重构和一系列图像处理方法对OGFC面层的空隙结构进行表征和分析;选取截面空隙率、平均空隙半径和平均配位数对OGFC面层的空隙结构进行定量表征。研究结果表明:当层间不撒布黏层油时,OGFC面层的空隙率分布与密级配沥青混凝土的类似,呈现两端空隙率高、中间空隙率低的规律;当黏层油掺量为0.5、1.0和1.5 kg/m^(2)时,黏层油向上迁移,使得界面处OGFC的空隙率显著降低,并且黏层油掺量越大,迁移的高度越大;黏层油迁移对平均空隙半径和平均配位数的影响规律与空隙率的基本一致;下卧层的表面构造也会对黏层油的迁移造成显著影响。