今日更新:Composite Structures 1 篇,Composites Part A: Applied Science and Manufacturing 2 篇,Composites Part B: Engineering 1 篇,Composites Science and Technology 1 篇
On the nonlinear dynamics and flutter response of hybrid shape memory alloy composite beams
Qianlong Zhang, Fabio Semperlotti
doi:10.1016/j.compstruct.2024.117973
论混合形状记忆合金复合梁的非线性动力学和扑动响应
This study presents a theoretical and numerical investigation of the dynamic response of a hybrid SMA composite beam. Particular emphasis is given to the evaluation of the equivalent damping, the aeroelastic stability, and the possibility to tune the composite’s dynamics by means of pre-strain applied locally to the SMA layers. The model of the hybrid composite beam (HCB) accounts for both the material nonlinearity associated with the phase transformation of the SMA and the geometric nonlinearity (in the von Kármán sense) due to potentially large displacements. The nonlinear governing equations of the HCB are solved by the finite element method and the dynamic behavior of the HCB is assessed for different design parameters, such as thickness, position, and pre-strain level of the SMA layers. Results help understand the role played by the different design parameters in improving the dynamic characteristics of the HCB, with particular attention to effective damping. Furthermore, it is of particular interest to understand the aeroelastic stability of hybrid layered composites due to their widespread applications in aerospace engineering. A simplified model of the nonlinear flutter response of the HCB under supersonic flow conditions is presented and analyzed with particular emphasis on bifurcations and limit cycle oscillations.
本研究对混合 SMA 复合梁的动态响应进行了理论和数值研究。其中 特别强调了对等效阻尼、气动弹性稳定性的评估,以及通过在 SMA 层局部施加预应变来调整复合材料动态响应的可能性。混合复合梁(HCB)模型考虑了与 SMA 相变相关的材料非线性以及潜在大位移导致的几何非线性(von Kármán)。采用有限元法求解 HCB 的非线性控制方程,并根据不同的设计参数(如 SMA 层的厚度、位置和预应变水平)评估 HCB 的动态行为。研究结果有助于了解不同设计参数在改善 HCB 动态特性方面的作用,尤其是有效阻尼。此外,由于混合层状复合材料在航空航天工程中的广泛应用,了解它们的气动弹性稳定性尤其重要。本文提出并分析了混合层状复合材料在超音速流动条件下的非线性扑翼响应简化模型,并特别强调了分岔和极限循环振荡。
Preparation of a water-based carboxylated Poly(phthalazione ether nitrile) sizing agent for interfacial reinforcement of CF/PPESK composites
Heming Wang, Shan Cheng, Jingyao Feng, Qingguang Bao, Jiangang Liu, Bing Wang, Binlin Jiang, Zaiyu Wang, Nan Li, Xigao Jian
doi:10.1016/j.compositesa.2024.108091
制备用于 CF/PPESK 复合材料界面加固的水基羧基聚(酞嗪醚腈)施胶剂
This study focuses on synthesizing a range of hydrolysis-modified poly(phthalazione ether nitrile) polymers with different quantities of carboxyl groups (HPPEN-COOH). These polymers are intended to enhance the bonding strength between carbon fibers (CFs) and poly(phthalazine ether sulfone ketone) (PPESK). The chemical structure of HPPEN-COOH was elucidated using FTIR spectroscopy, and the presence of HPPEN-COOH as a coating on the CFs surface was confirmed by XPS analysis. Compared with the UCF/PPESK composite, the interlaminar shear strength of the CF-5/PPESK composite increased by 39%. In the DMA test, the service temperature and storage modulus of the CF-5/PPESK composite were increased to 268°C and 112 GPa, respectively. Furthermore, the composite showed satisfactory performance in hydrothermal aging studies. This method is simple and easy to implement, has the potential for large-scale industrial production, and is an environmentally friendly method to improve the interface properties of the CF/PPESK composite.
本研究的重点是合成一系列具有不同数量羧基(HPPEN-COOH)的水解改性聚(酞嗪醚腈)聚合物。这些聚合物旨在增强碳纤维(CF)与聚(酞嗪醚砜酮)(PPESK)之间的粘合强度。利用傅立叶变换红外光谱阐明了 HPPEN-COOH 的化学结构,并通过 XPS 分析证实了 HPPEN-COOH 作为涂层存在于碳纤维表面。与 UCF/PPESK 复合材料相比,CF-5/PPESK 复合材料的层间剪切强度提高了 39%。在 DMA 测试中,CF-5/PPESK 复合材料的使用温度和储存模量分别提高到 268°C 和 112 GPa。此外,该复合材料在水热老化研究中也表现出令人满意的性能。该方法简单易行,具有大规模工业化生产的潜力,是一种改善 CF/PPESK 复合材料界面性能的环保方法。
A novel phosphorus/nitrogen-containing vinyl imidazolium ionic liquid for improving flame retardancy and mechanical properties of vinyl ester resin, and its carbon fiber composites
Zeqi Zhang, Xue Bi, Wenchao Zhang, Rongjie Yang
doi:10.1016/j.compositesa.2024.108092
一种新型含磷/氮乙烯基咪唑离子液体,用于改善乙烯基酯树脂及其碳纤维复合材料的阻燃性和机械性能
In daily life, the application of vinyl ester resin (VER) and its carbon fiber composites is limited by their flame retardancy and mechanical properties. In this work, we synthesized an ionic liquid, VIDHP, from diethyl hydroxymethyl phosphate (DHP) and 1-vinylimidazole (VIM). VIDHP can not only cross-links with VER but also enhances the interaction between the resin and the carbon fiber. The flame retardancy and mechanical properties of VER and its carbon fiber composites were effectively improved by the addition of VIDHP. In particular, the addition of 15 wt% VIDHP increased the flexural strength and flexural modulus of the carbon fiber composites by 29.3 % and 42.4 %, while reducing the total heat release and total smoke release by 15.4 % and 18.4 %. The flame retardant mechanism of VIDHP was also investigated. This approach provides a new idea to improve the flame retardant and mechanical properties of VER and its carbon fiber composites.
在日常生活中,乙烯基酯树脂(VER)及其碳纤维复合材料的应用因其阻燃性和机械性能而受到限制。在这项工作中,我们用羟甲基磷酸二乙酯(DHP)和 1-乙烯基咪唑(VIM)合成了一种离子液体 VIDHP。VIDHP 不仅能与 VER 交联,还能增强树脂与碳纤维之间的相互作用。通过添加 VIDHP,VER 及其碳纤维复合材料的阻燃性和机械性能得到了有效改善。特别是,添加 15 wt% 的 VIDHP 后,碳纤维复合材料的抗弯强度和抗弯模量分别提高了 29.3% 和 42.4%,而总放热量和总释烟量则分别降低了 15.4% 和 18.4%。此外,还研究了 VIDHP 的阻燃机理。这种方法为提高 VER 及其碳纤维复合材料的阻燃性和机械性能提供了新思路。
Winding pattern design of composite cylinders considering the effect of fiber stacking
Yuchen Dai, Chuanxiang Zheng, Jiao Lin, Yangtao Liu, Dawei Wang, Jinjie Lu
doi:10.1016/j.compositesb.2024.111306
考虑纤维堆叠效应的复合材料圆柱体缠绕模式设计
Winding pattern design is a critical step in the production of composite cylinders. Traditional design methods often overlook the impact of stacking fibers layer by layer, leading to deviations between the actual and intended winding trajectories. To ensure consistence between the actual winding outcomes and design objectives, the effect of fiber stacking on the winding patterns was examined in this study. Two winding pattern design methods were proposed: the fixed tangent-point method (FTPM) and the minimum center angle deviation method (MCADM). A comparison was conducted on the variations in the number of tangent points, thread guide round trips, and the radius of the polar hole under the two different methods. Winding experiments were then employed to verify the feasibility of these approaches. The results showed that fiber stacking on the dome was the main reason for the change in winding patterns. Priority can be given to schemes within the design overlap domain for the design of multi-layer winding patterns. While FTPM ensures consistent fiber coverage and tape spacing, it may lead to hole expansion. Additionally, applying multiple layers can alter the dome's shape significantly from the original design. In contrast, MCADM offers slightly variable fiber coverage and spacing without causing hole expansion, achieving the desired dome shape more accurately.
缠绕模式设计是生产复合材料圆筒的关键步骤。传统的设计方法往往会忽略纤维逐层堆叠的影响,从而导致实际缠绕轨迹与预期缠绕轨迹之间出现偏差。为确保实际缠绕结果与设计目标保持一致,本研究探讨了纤维堆叠对缠绕模式的影响。研究提出了两种卷绕模式设计方法:固定切点法(FTPM)和最小中心角偏差法(MCADM)。比较了两种不同方法下切线点数量、导线往返次数和极孔半径的变化。然后通过缠绕实验来验证这些方法的可行性。结果表明,穹顶上的纤维堆叠是造成缠绕模式变化的主要原因。在设计多层缠绕模式时,可优先考虑设计重叠域内的方案。虽然 FTPM 可确保一致的纤维覆盖率和带间距,但它可能会导致孔扩大。此外,应用多层缠绕会大大改变圆顶的形状,使其与原始设计大相径庭。相比之下,MCADM 可提供略微可变的纤维覆盖范围和间距,而不会导致孔扩展,从而更精确地实现所需的圆顶形状。
Mesoscale modeling of woven composite twisted structures combining digital element embedded model and affine transform
Zengfei Liu, Jingran Ge, Hao Li, Xiaodong Liu, Bing Wang, Jun Liang
doi:10.1016/j.compscitech.2024.110504
结合数字元素嵌入模型和仿射变换的编织复合扭曲结构中尺度建模
The mesoscale model with realistic yarn geometries could improve the accuracy of property prediction of woven composite structures. This paper aims to propose a novel mesoscale modeling method for the woven composite twisted structures. Firstly, the torsional deformation of the yarns in the unit cell model is simulated with high-fidelity using digital element fibers embedded into the matrix solid meshes. Then, the solid geometry model of the twisted composite structures is reconstructed from the digital element deformation model by combining the affine transforms. Finally, the elastic responses of the twisted composite structure under cantilever loading are predicted by assigning the element information of the established mesoscale model to the macroscale model. It is shown that the geometric morphology and predicted mechanical responses of the high-fidelity model are consistent with the experimental results. Furthermore, the effect of twist angles on the stiffness properties of the twisted composite structures is analyzed using the presented numerical method. The proposed digital modeling method could provide a guide for the early design of woven composite structures.
具有真实纱线几何形状的中尺度模型可以提高编织复合材料结构性能预测的准确性。本文旨在针对编织复合材料加捻结构提出一种新的中尺度建模方法。首先,利用嵌入基体实体网格中的数字元素纤维高保真地模拟了单元格模型中纱线的扭转变形。然后,结合仿射变换从数字元素变形模型重建扭曲复合结构的实体几何模型。最后,通过将已建立的中尺度模型的元素信息分配到宏观模型中,预测扭曲复合材料结构在悬臂载荷作用下的弹性响应。结果表明,高保真模型的几何形态和预测的力学响应与实验结果一致。此外,还利用所提出的数值方法分析了扭曲角度对扭曲复合材料结构刚度特性的影响。所提出的数字建模方法可为编织复合材料结构的早期设计提供指导。