今日更新:Composite Structures 1 篇,Composites Part A: Applied Science and Manufacturing 1 篇,Composites Part B: Engineering 1 篇,Composites Science and Technology 1 篇
Ballistic perforation of aramid laminates: Projectile nose shape sensitivity
Haibo Ji, Xin Wang, Nianhua Tang, Bingyang Li, Zhen Li, Xinyu Geng, Pengfei Wang, Rui Zhang, Tian Jian Lu
doi:10.1016/j.compstruct.2023.117807
芳纶层压板的弹道穿孔:弹头形状敏感性
The influence of projectile shape on the ballistic properties and mechanism of aramid laminates is investigated through experiments and simulations. Three types of projectiles (blunt, hemispherical, and ogival) are used to obtain ballistic curves. The dynamic penetration process, deformation and damage characteristics of the targets are analyzed. A three-dimensional finite element model is established, and good agreement is observed between the simulation and test results. The findings demonstrate that projectile shape significantly impacts the ballistic response of aramid laminates. As the projectile transitions from blunt and hemispherical to ogival, the ballistic limiting velocity decreases continuously, the area of target plate deformation and damage decreases, and the occurrence of delamination becomes less pronounced. And the energy dissipation through local damage, elastic deformation and overall motion of the aramid material is decreasing and the energy dissipation through friction is increasing.
通过实验和模拟,研究了弹丸形状对芳纶层压板弹道特性和机理的影响。实验中使用了三种类型的弹丸(钝头、半球形和椭圆形)来获得弹道曲线。分析了目标的动态穿透过程、变形和损伤特征。建立了三维有限元模型,并观察到模拟结果与试验结果之间的良好一致性。研究结果表明,弹丸形状对芳纶层压板的弹道响应有很大影响。当弹丸从钝半球形过渡到椭圆形时,弹道极限速度不断降低,靶板变形和损伤面积减小,分层现象变得不那么明显。通过芳纶材料的局部损伤、弹性变形和整体运动耗散的能量在减少,通过摩擦耗散的能量在增加。
Conical shells made by 4D printing of composites
Suong Van Hoa, Mahmoud Fereidouni
doi:10.1016/j.compositesa.2023.107971
通过 4D 打印复合材料制作锥形外壳
This paper presents a new, novel method for the manufacturing of composite cones. The method utilizes the principle of 4D printing of composites. The method does not require the use of a mold of conical shape, which is essential using conventional manufacturing methods such as filament winding or hand lay up. Instead, only a flat mold is required. In this technique, layers with different fiber orientations are laid on a flat mandrel. Upon curing and cooling to room temperature, the flat stack of composite layers will curl into the shape of a conical shell. When the edges of the shell are joined together by adhesive bonding, one has a structure that has the shape of a cone. Cones made using this new technique show axial buckling strengths that are comparable to those of cones made from similar materials with the same weight, using filament winding method. The buckling load and buckling mode shape are determined using finite element method. The results agree well with experimental results.
本文介绍了一种制造复合材料锥体的新颖方法。该方法利用了复合材料 4D 打印原理。该方法不需要使用锥形模具,而使用传统制造方法(如缠绕长丝或手工铺设)则必须使用锥形模具。相反,只需要一个平面模具。在这种技术中,不同纤维方向的纤维层被铺设在一个扁平的心轴上。固化并冷却至室温后,复合材料层的平面堆叠将卷曲成圆锥形外壳的形状。当外壳的边缘通过粘合剂连接在一起时,就形成了锥形结构。使用这种新技术制造的锥体显示出的轴向屈曲强度与使用相同重量的类似材料、采用长丝缠绕法制造的锥体相当。屈曲载荷和屈曲模式形状是用有限元法确定的。结果与实验结果十分吻合。
A novel methodology to measure the transverse Poisson’s ratio in the elastic and plastic regions for composite materials
I.R. Cózar, J.J. Arbeláez-Toro, P. Maimí, F. Otero, E.V. González, A. Turon, P.P. Camanho
doi:10.1016/j.compositesb.2023.111098
测量复合材料弹性和塑性区域横向泊松比的新方法
A new methodology to measure the transverse Poisson’s ratios in fibre-reinforced composite materials was developed. Transverse tensile and transverse compressive standardised tests were instrumented using digital image correlation equipment to measure the lateral strain field of the specimens. A thermoplastic-based composite material was used to describe the proposed methodology. The elastic transverse Poisson’s ratio exhibits a different behaviour in tension than in compression, its value being greater in compression than in tension. Assuming no plastic strain in the longitudinal direction, the plastic transverse Poisson’s ratio in compression suggests no volumetric plastic strains for small axial plastic strains, however, plastic dilatancy was observed when the amount of compressive plastic axial strain increases.
开发了一种测量纤维增强复合材料横向泊松比的新方法。横向拉伸和横向压缩标准化测试使用数字图像相关设备测量试样的横向应变场。使用一种热塑性复合材料来描述所提出的方法。弹性横向泊松比在拉伸和压缩时表现出不同的行为,其值在压缩时大于拉伸时。假定纵向没有塑性应变,压缩时的塑性横向泊松比表明在较小的轴向塑性应变下没有体积塑性应变,但当压缩塑性轴向应变增加时,会出现塑性扩张。
Enhanced cryopreservation performance of PVA grafted monolayer graphite oxide with synergistic antifreezing effect and rapid rewarming
Jiali Yu, Jixiang Zhang, Wei Han, Bianhua Liu, Wei Guo, Liuyue Li, Nian Li, Zhenyang Wang, Jun Zhao
doi:10.1016/j.compscitech.2023.110404
具有协同防冻效果和快速回温功能的 PVA 接枝单层氧化石墨的低温保存性能得到增强
In cryopreservation of biological samples such as cells, the formation, growth and recrystallization of ice crystals can cause fatal mechanical damage to cells. Therefore, how to effectively regulate and inhibit ice crystals, reduce freezing damage, and improve cryopreservation efficiency is a critical scientific problem that needs to be addressed in the current cryopreservation field. In this paper, a series of PVA grafted single-layer graphite oxide (PVA-g-GO nanocomposites) with different degrees of polymerization and different proportions was ingeniously engineered by a one-step esterification reaction method to study their ice crystal control effect. The obtained PVA17-g-GO nanocomposite could effectively reduce the ice crystal size during the recrystallization process at low concentration by adsorption and lattice matching. The nanocomposite with a 10:1 mass ratio of PVA and GO exhibited the best ice control effect, which could reduce the ice crystal size to only 17 % of that of pure water. Surprisingly, the modification of PVA significantly enhanced the absorption value of GO in Visible and Near-Infrared light (380 nm–980 nm), giving it excellent photothermal conversion efficiency (39.7 %), accelerating ice thawing rate, and thus synergistically reducing the mechanical damage caused by ice recrystallization. Finally, using the prepared PVA17-g-GO as cryoprotectants (CPA), the cryopreservation experiments on Hela cells and A549 cells demonstrated that this material at low concentration of 20 μg/ml could achieve high cell survival efficiency (>85 %). The preparation and development of this efficient ice-recrystallization-inhibiting nanomaterial with bidirectional synergy can provide new ideas and methods for the safety and progress of current cryopreservation technology.
在细胞等生物样本的冷冻保存过程中,冰晶的形成、生长和再结晶会对细胞造成致命的机械损伤。因此,如何有效调节和抑制冰晶,减少冷冻损伤,提高冷冻保存效率,是当前冷冻保存领域亟待解决的关键科学问题。本文通过一步酯化反应法,巧妙地设计了一系列不同聚合度、不同比例的PVA接枝单层氧化石墨(PVA-g-GO纳米复合材料),研究了其冰晶调控效果。得到的 PVA17-g-GO 纳米复合材料通过吸附和晶格匹配作用,在低浓度再结晶过程中能有效减小冰晶尺寸。其中,PVA 和 GO 的质量比为 10:1 的纳米复合材料控冰效果最好,可将冰晶尺寸降至纯水的 17%。令人惊讶的是,PVA 的改性显著提高了 GO 在可见光和近红外光(380 nm-980 nm)中的吸收值,使其具有出色的光热转换效率(39.7%),加快了冰的解冻速度,从而协同降低了冰重结晶造成的机械损伤。最后,利用制备的 PVA17-g-GO 作为冷冻保护剂(CPA),对 Hela 细胞和 A549 细胞进行的冷冻保存实验表明,该材料在 20 μg/ml 的低浓度下可实现较高的细胞存活率(>85%)。这种具有双向协同作用的高效冰重结晶抑制纳米材料的制备和开发,为当前冷冻保存技术的安全和进步提供了新的思路和方法。