关键词： Cavitation studies   Composite propellers   Hydro-elasticity   Numerical model   Acoustics vibration  

摘要： Understanding the behaviour of composite marine propellers during operating conditions is a need of the present era since they emerge as a potential replacement for conventional propeller materials such as metals or *** offer several benefits,such as high specific strength,low corrosion,delayed cavitation,improved dynamic stability,reduced noise levels,and overall energy *** addition,composite materials undergo passive deformation,termed as“bend-twist effect”,under hydrodynamic loads due to their inherent flexibility and *** performance analysis methods were developed in the past for marine propellers,there is a significant lack of literature on composite *** article discusses the recent advancements in experimental and numerical modelling,state-of-the-art computational technologies,and mutated mathematical models that aid in designing,analysing,and optimising composite marine *** the initial sections,performance evaluation methods and challenges with the existing propeller materials are ***,the benefits of composite propellers are critically *** and experimental FSI coupling methods,cavitation performance,the effect of stacking sequence,and acoustic measurements are some critical areas discussed in detail.A two-way FSI-coupled simulation was conducted in a non-cavitating regime for four advanced ratios and compared with the literature ***,the scope for future improvements and conclusions are mentioned.

关键词： ZIF-L咪唑酸盐框架材料   ZIF-L@Ag复合材料   抗菌材料  

摘要： ZIF系列是类沸石的咪唑酸盐框架材料.ZIF-L是Zn^(2+)与2-甲基咪唑的N原子配位后自组装形成的材料,具有良好的加载和吸附能力.通过水溶液合成方法,合成了叶状ZIF-L,并与Ag纳米颗粒(NPs)吸附结合,形成叶片状ZIF-L@Ag复合材料.通过最小抑制浓度(MIC)、CFU计数法分析,发现ZIF-L@Ag复合材料对耐碳青霉烯铜绿假单胞菌表现出了优异的抗菌性能.细胞膜通透性测定结果表明,ZIF-L@Ag NPs复合材料能够改变细菌细胞膜的通透性.

关键词： 低烟无卤   低热释放总量   低热释放速率峰值   电缆材料   锥形量热仪   磷氮阻燃剂  

摘要： 以聚烯烃树脂为基体,氢氧化镁、氢氧化铝为阻燃剂,采用密炼造粒工艺制备了低烟无卤阻燃聚烯烃复合材料,并研究了树脂、阻燃剂、硅酸盐类阻燃协效剂,以及磷氮阻燃剂等对低烟无卤阻燃聚烯烃复合材料热释放速率峰值和热释放总量的影响。结果表明,乙烯-醋酸乙烯酯共聚物(ethylene-vinyl acetate copolymer,EVA)、聚烯烃弹性体(polyolefin elastomer,POE)、线性低密度聚乙烯(linear low density polyethylene,LLDPE)等3种树脂对热释放速率峰值和热释放总量的影响从大到小依次为POE、LLDPE、EVA,低热释放材料中应尽量减少POE的使用;使用氢氧化镁与氢氧化铝复配比单独使用氢氧化铝或氢氧化镁的热释放速率峰值(peak heat release rate,PHRR)和热释放总量(total heat release,THR)低,其中当氢氧化镁与氢氧化铝的复配比例为1∶5时,材料的热释放最小;有些硅酸盐类阻燃协效剂在燃烧后虽然炭层完整度好,但燃烧后的热释放较大,这可能是由于使用的有机改性剂类型不同或有机改性剂含量高,使材料在燃烧初期更容易被点燃;磷氮类阻燃剂可与氢氧化铝搭配使用,不仅能降低材料的热释放,还能进一步增强炭层强度,而磷系阻燃剂与氢氧化镁搭配使用反而会导致材料的阻燃性能下降。

关键词： Halpin-Tsai模型   横截面形状   弹性模量   代表性体积单元(RVE)   体积分数  

摘要： 为预测不同截面形状对复合材料弹性常数的影响,以碳纤维增强环氧树脂为例,采用细观复合材料力学方法,建立纤维复合材料的代表性体积单元(random volume element,RVE)模型,研究纤维截面形状和纤维的体积分数对其弹性常数的影响,通过改进的Halpin-Tsai模型得到了修正的形状因子与体积分数、横截面积以及几何因子之间的关系。结果表明:纤维-基体接触界面和几何因子越大,弹性模量越高;并对比有限元模型和改进的Halpin-Tsai模型得到的复合材料的4个弹性常数,最大误差分别为4.50%、0.75%、1.40%、1.00%。因此,改进的Halpin-Tsai模型能够较为准确地预测碳纤维增强复合材料的弹性常数,具有较高的工程应用价值。

关键词： Coal mines  

摘要： Laser cladding technology plays an important role in impact, friction and corrosion Performances of coal mine machinery components. Mechanical Performances of composite material after laser cladding are crucial for their adaptability to Underground environment of coal mines to determine further promotion of laser cladding technology. Here, to further study Performances of composite material after cladding, a pneumatic horizontal impact experimental device was used to simulate impact environment in coal mines. A composite target plate coated with Fe-based alloy on surface of commonly used material 27SiMn steel Substrate in coal mine machinery was taken as the study object, damage behavior and energy absorption characteristics of the target plate under different impact pressures were analyzed using the combination of finite element Simulation and experimental study method. The results showed that surface damage area, craterdepth, damage morphology and ränge obtained with numerical Simulation have an error of no more than 10% compared to experimental results to verify the correctness of Simulation model;with increase in impact pressure, damage form of target plate gradually evolves from plastic deformation and microcrack initiation to shear failure and complete fracture;laser cladding Fe-based alloy coating can absorb and disperse part of impact energy to effectively reduce impact damage of Substrate material;the study results can provide experimental methods and theoretical analysis basis for studying surface impact damage behavior of coal mining machinery equipment. © 2025 Chinese Vibration Engineering Society. All rights reserved.

关键词： 土建工程   无机非金属材料   复合材料  

摘要： 文章基于土建工程中传统无机非金属材料现状分析,说明了土建工程中传统与新型无机非金属材料结合的原则,提出了土建工程中传统与新型无机非金属材料结合的策略,包括加强复合材料研发、创新施工工艺、创新和完善材料标准及应用规范、加强技术人才培养,并结合实例进行了深度分析,最后还对土建工程中传统与新型无机非金属材料的结合进行了反思,以促进土建工程的高质量建设,提高土建工程的发展水平。

关键词： 碳纤维复合材料   模压成型工艺   力学性能  

摘要： 文章依托于相关概念,结合试验设计探讨了碳纤维层数、碳纤维方向、模压温度、模压压力、模压时间、树脂类型与添加剂、环境条件等因素对碳纤维复合材料模压制品力学性能的影响,旨在提升材料的应用性能和经济效益。

关键词： Hot pressing  

摘要： In order to meet the requirements for both high thermal conductivity and large latent heat storage and release of thermal management materials for spacecraft, a multidimensional carbon-based, thermally enhanced microencapsulated phase change composite is prepared by using a hot-pressing technique in this work. This method solves the limitations of traditional phase change materials, which suffer from low thermal conductivity and a propensity for liquid leakage. The effects of different content values and ratios of microencapsulated phase change materials, flake graphite, and pitch-based carbon fibers on the composite’s thermal properties, specifically thermal conductivity and latent heat are systematically investigated by integrating experimental assessments with finite element numerical simulations. Furthermore, the mechanism for forming an internal multidimensional heat conduction network is elucidated. These results indicate that introducing multidimensional thermally conductive materials into the microencapsulated phase change system, can establish a continuous and dense multidimensional carbon-based conduction network through optimizing component composition and structure. Using the synergistic effects of these conductive materials and a multi-size flake graphite filling strategy, the overall thermal conductivity of the composite is significantly enhanced, reaching 1.021 W/(m·K), while maintaining a high latent heat of 81.540 J/g. These findings provide theoretical and practical guidance for optimizing and applying advanced thermal management materials to spacecraft. © 2025 Institute of Physics, Chinese Academy of Sciences. All rights reserved.

关键词： 碳纤维   聚酰胺6   复合材料   熔融沉积成型   力学性能   压力传感性能  

摘要： 采用熔融沉积成型(FDM)技术制备碳纤维增强尼龙6复合材料(ePA 6-CF)打印件,研究ePA 6-CF打印件在拉伸、弯曲、压缩时的力学性能及不同厚度下的电磁屏蔽性能,并设计3种介电层微结构打印图案,研究其压力传感性能。结果表明:ePA 6-CF打印件具有优异的力学性能,抗拉强度为41.08 MPa,弯曲强度为3.08 MPa,断裂伸长率为89.09%,杨氏模量为9.98 MPa,弹性模量为40.05 MPa;ePA 6-CF打印件还具有较好的电磁屏蔽性能,厚度为4 mm的打印件在X波段的电磁屏蔽值达13.53 dB;以蜂窝六边形微结构的ePA 6-CF打印介电层组装的传感器表现出较好的压力传感性能,在相对压力变化量为0~40 kPa、40~160 kPa时灵敏度分别为1.086,0.037 kPa^(-1),在20 kPa载荷下其响应及恢复时间均为120 ms,手指连续敲击实验表明其能精准捕捉手指敲击信号。

关键词： 硅锰渣   沙漠砂   水泥基复合材料   水化产物   微观结构   力学性能  

摘要： 【目的】以硅锰渣、沙漠砂为掺料制备水泥基复合材料,研究水泥基复合材料的微观结构和力学性能,实现节能减排、有效利用资源。【方法】以硅酸盐水泥和标准砂水泥作为对照组,制备硅锰渣、沙漠砂水泥基复合材料试样;利用扫描电子显微镜和X射线衍射分析仪分析4组水泥基材料的微观结构和水化产物;分别对4组试样进行抗折和抗压强度试验,研究水泥基复合材料的力学性能。【结果】4组试样的水化产物均为氢氧化钙、钙矾石和水化硅酸钙,但水化产物含量不同。4组试样的抗折、抗压强度均随养护龄期的增大而增大;养护龄期为28d时,抗折、抗压强度由大到小的4组试样依次为硅酸盐水泥、硅锰渣水泥、标准砂水泥、沙漠砂水泥,试样的抗折强度分别为2.8、2.6、2.4、1.6MPa,抗压强度依次为58.8、57.6、41.7、24.1MPa,硅酸盐和硅锰渣水泥试样的抗压、抗折强度较为接近,且均高于标准砂和沙漠砂水泥的。在硅锰渣质量分数为15%、养护龄期为28d时,硅锰渣水泥基试样的微观结构致密,与硅酸盐水泥试样的力学性能接近。【结论】硅锰渣水泥基试样的微观结构致密,标准砂水泥试样的微观结构中含有较多孔隙,沙漠砂水泥试样中因存在明显的结团堆积现象导致结构稳定性降低;与沙漠砂相比,硅锰渣更适合替代部分水泥制备水泥基复合材料。