【标题】Jet pressure influence on micro-abrasive waterjet trepanned hole in CFRP composite material
【参考中译】喷射压力对碳纤维增强复合材料微磨粒水喷射开孔的影响
【类型】 期刊
【关键词】 Micro-Abrasive waterjet; Trepanning; CFRP; Delamination; Over-Cut; Circularity error
【参考中译】 微研磨水刀;钻孔;碳纤维增强塑料;分层;过切;圆度误差
【作者】 Rajesh Ranjan Ravi; D. S. Srinivasu
【摘要】 Carbon fibre reinforced polymer (CFRP) composite material is widely used in various industries such as aerospace, automobile, and defence due to its high strength-to-weight ratio and stiffness. Making holes in CFRP through conventional drilling comes with issues such as fibre pull-out, fibre breakage, delamination, and chipping. On the other hand, abrasive waterjet (AWJ) is well known for machining composite material due to its unique features such as no heat-affected zone, local erosion, minimum residual stress, etc. In this study, micro-AWJ is employed to trepan holes in the CFRP composite material, and the influence of waterjet pressure (P) on the hole diameter, over-cut, circularity error, taper angle, and damage at the hole top and bottom surface are analyzed as the pressure is a dominating parameter influencing the performance. Diametrical deviation and over-cut at top and bottom planes increase, surface damage decreases, and circularity error decreases with the increase in P.
【参考中译】 碳纤维增强聚合物（MRP）复合材料因其高强度重量比和硬度而广泛应用于航空航天、汽车、国防等各个行业。通过传统钻孔在碳纤维增强塑料中钻孔会出现纤维拉出、纤维断裂、分层和碎裂等问题。另一方面，研磨水刀（AWJ）因其无热影响区、局部侵蚀、残余应力最小等独特特点而被广泛应用于复合材料的加工。本研究采用微型AWJ对碳纤维增强纤维增强纤维由于压力是影响性能的主要参数，分析了孔顶和底表面的损伤情况。随着P的增加，顶、底平面的直径偏差和过切增加，表面损伤减少，圆度误差减少。
【来源】 MTT 2023, vol.22, no.5
【入库时间】 2024/5/31
【标题】Optimizing material selection: A study of erosion-corrosion performance in homogeneous and carbide-containing materials
【参考中译】优化材料选择：均质和含碳化物材料的冲刷腐蚀性能研究
【关键词】 Erosion-corrosion; Synergistic effect; WC-Overlays; Chrome white irons; Abrasion-resistant (AR) steel; Pipeline steel; Slurry pot
【参考中译】 侵蚀腐蚀;协同效应; WC覆盖层;镀铬生铁;抗磨损（AR）钢;管道钢;泥浆罐
【作者】 Aminul Islam; Jiaren (Jimmy) Jiang; Yongsong Xie
【摘要】 Erosion-corrosion is a major factor contributing to material loss and reduced useful life of hydro-transport equipment. The combined effect of erosion and corrosion is responsible for high degradation rates. In oil sand mining, materials from different classes are used for various applications depending on the severity of degradation. In this research, we assessed the erosion-corrosion characteristics of four uniform materials (pipeline and abrasion-resistant steels) as well as five materials containing varying types and quantities of carbide (chrome white iron and WC-based overlay). The materials underwent erosion-corrosion testing within a slurry container (comprising 3.5 wt% NaCl + 35 wt% natural silica sand) at a temperature of 45℃. Under the test conditions, it was found that matrix wear influences the extent of carbide degradation for all carbide-containing materials. To provide good erosion-corrosion resistance, the surrounding matrix that supports the carbide must have sufficient wear and corrosion resistance. This study also identifies the dominant wear mechanisms for both uniform and carbide-containing materials.
【参考中译】 冲刷腐蚀是造成水运设备材料损耗和使用寿命降低的主要因素。冲刷和腐蚀的综合作用导致了高降解率。在油砂开采中，根据降解的严重程度，不同类别的材料被用于不同的应用。在这项研究中，我们评估了四种均匀材料(管道和耐磨钢)以及五种含有不同类型和数量的碳化物的材料(铬白口铸铁和WC基堆焊层)的冲刷腐蚀特性。这些材料在45℃的浆料容器(包括3.5wt%氯化钠+35wt%天然硅砂)中进行了冲刷腐蚀试验。在试验条件下，发现基质磨损对所有含碳化物材料的碳化物降解程度都有影响。为了提供良好的耐磨蚀性能，支撑碳化物的周围基质必须具有足够的耐磨性和耐腐蚀性。这项研究还确定了均匀材料和含碳化物材料的主要磨损机制。
【来源】 Wear 2024, vol.536/537
【标题】Micromechanical analysis of composite materials considering material variability and microvoids
【参考中译】考虑材料变异性和微空隙的复合材料微观力学分析
【关键词】 Fiber reinforced polymers (FRP); Microvoids; Mechanical properties; Micro-mechanics
【参考中译】 纤维增强聚合物（玻璃钢）;微空洞;机械性能;微观力学
【作者】 O. Vallmajo; A. Arteiro; J. M. Guerrero; A. R. Melro; A. Pupurs; A. Turon
【摘要】 One of the main challenges for fiber-reinforced polymers (FRP) is the difficulty to predict their mechanical behavior. At the microscale, the properties of the constituents, their spatial distribution and the defects arising from manufacturing affect the mechanical behavior. In this work, statistically representative volume elements (SRVEs) are proposed based on a micromechanical finite element model to determine the effect of content, distribution and size of microstructural defects and, material uncertainties on the elastic mesoscale properties of FRPs. To that end, different cylindrical void sizes are considered as well as irregular shaped voids between fiber tows (inter-fiber voids). Fibers and voids are randomly distributed in a SRVE. An uncertainty quantification and management analysis is employed to obtain statistical descriptors of the effective mesoscale mechanical properties of FRPs. The results obtained are compared with analytical models. It is demonstrated that, for carbon fiber/epoxy composites, SRVEs with lateral dimensions equivalent to 15 times the average fiber diameter and a length of 0.01 mm along the longitudinal direction remain statistically representative with or without the presence of voids. The results show that the presence of voids reduces the transverse and shear elastic properties of FRPs. The smaller the voids are, the bigger is the reduction. Regarding the presence of inter-fiber voids, the reduction is lower. This trend is well predicted by the Mori-Tanaka mean field theory. However, the relative difference between the numerical and the analytical predictions increases for high void volume fractions. Regarding the effective longitudinal Young's modulus, the rule of mixtures, the Mori-Tanaka mean field theory and the concentric cylinder assembly model provide similar predictions for the mean value, but the uncertainty is overestimated by the analytical models because the properties of the fibers take a single value for each calculation with the analytical model, while they more realistically change from fiber to fiber in the numerical SRVEs.
【参考中译】 纤维增强聚合物(FRP)的主要挑战之一是难以预测其力学行为。在微观尺度上，成分的性质、空间分布以及制造过程中产生的缺陷会影响材料的力学行为。本文提出了基于细观力学有限元模型的统计代表性体积元，以确定微结构缺陷的含量、分布和尺寸以及材料不确定性对玻璃纤维增强塑料弹性细观性能的影响。为此，考虑了不同的圆柱形空隙大小以及光纤丝束之间的不规则形状空隙(光纤间空隙)。纤维和空隙在SRVE中随机分布。通过不确定性量化和管理分析，获得了FRPS有效细观力学性质的统计描述子。将所得结果与解析模型进行了比较。结果表明，对于碳纤维/环氧复合材料，横向尺寸相当于平均纤维直径的15倍，纵向长度为0.01 mm的复合材料在有或没有孔洞存在的情况下仍具有统计代表性。结果表明，孔洞的存在降低了FRPS的横向和剪切弹性性能。空隙越小，减少的幅度越大。对于纤维间空隙的存在，缩减率较低。森田中平均场理论很好地预测了这一趋势。然而，对于较高的空泡体积分数，数值预测和分析预测之间的相对差异增大。对于有效纵向杨氏S模数，混合物规则、Mori-Tanaka平均场理论和同心圆柱体组装模型对平均值提供了类似的预测，但分析模型高估了不确定性，因为解析模型每次计算纤维的性质都取一个值，而在数值模型中，它们更接近于从纤维到纤维的变化。
【来源】 International Journal of Mechanical Sciences 2024, vol.263