今日更新:Composite Structures 5 篇,Composites Part A: Applied Science and Manufacturing 3 篇,Composites Science and Technology 2 篇
Memeplex-based memetic algorithm for the multi-objective optimal design of composite structures
Carlos Conceição António
doi:10.1016/j.compstruct.2023.117789
基于 Memeplex 的复合结构多目标优化设计记忆算法
Hybrid construction is proposed to decrease costs in lightweight structures using fiber-reinforced plastics (FRP) composite materials. Minimum weight, minimum strain energy (stiffness), and minimum energy variability of the structural system response are the objectives of the robust design optimization approach applied to composite shell structures with stiffeners. The trade-off depends on given stress, displacement, and buckling constraints imposed on composite structures considering non-linear geometric behavior. The design variables are ply angles and ply thicknesses of shell laminates, the cross-section dimensions of stiffeners, and the variables related to the selection of materials and their distribution at the laminate level and subsequently of the laminates along the structure. A Multi-Objective Memetic Algorithm (MOMA) applies multiple learning procedures exploring the synergy of different cultural transmission rules. An enlarged virtual population with a dual age-dominance nature captures and updates the Pareto curve. The concept of memeplex controls the meme selection and their propagation along the hybrid genetic and cultural evolution path. The success of memetic learning procedures is analyzed by measuring each meme's relative and absolute success events according to different approaches, depending on the reference time used in evolutionary history. Results show that MOMA is promising in multi-objective optimization of composite hybrid structures.
为了降低使用纤维增强塑料(FRP)复合材料的轻质结构的成本,提出了混合结构。结构系统响应的最小重量、最小应变能(刚度)和最小能量变化是应用于带加劲件复合壳体结构的稳健设计优化方法的目标。考虑到非线性几何行为,权衡取决于对复合材料结构施加的给定应力、位移和屈曲约束。设计变量包括壳体层压板的层角和层厚、加强筋的横截面尺寸,以及与材料选择和材料在层压板上的分布有关的变量,以及层压板沿结构的分布。多目标记忆算法(MOMA)采用多种学习程序,探索不同文化传播规则的协同作用。具有双重年龄主导性质的扩大虚拟人口捕捉并更新帕累托曲线。memeplex的概念控制着meme的选择及其在遗传和文化混合进化路径上的传播。记忆学习程序的成功与否,可根据进化史中使用的参考时间,按照不同的方法测量每个记忆的相对和绝对成功事件进行分析。结果表明,MOMA 在复合混合结构的多目标优化方面大有可为。
Void formation and suppression in CFRP laminate using newly designed ultrasonic vibration assisted RTM technique
Yunfei Peng, Maojun Li, Xujing Yang
doi:10.1016/j.compstruct.2023.117796
利用新设计的超声波振动辅助 RTM 技术抑制 CFRP 层压板中空洞的形成和消失
This study introduces an ultrasonic vibration assisted resin transfer molding (RTM) technique as an innovative approach to address the inherent challenges associated with traditional methods for producing CFRP laminates. It investigates the mechanism of void formation in CFRP composites under ultrasonic vibration using 3D X-ray microscopy. Numerical calculations and simulation analyses are also employed to validate the impact of ultrasonic vibration on mechanical properties of CFRP. The findings indicate that ultrasonic vibration results in CFRP laminates with more uniform thickness, leading to a substantial increase in fiber volume fraction up to ∼16%. Concurrently, there are significant improvements in flexural strength (∼20%) and fracture energy (∼90%). Ultrasonic vibration also effectively reduces CFRP porosity by at least 25%, resulting in a more consistent distribution of voids, primarily consisting of small circular voids. This porosity reduction is attributed to the cavitation effect and enhancing wettability, consequently improving the mechanical properties of CFRP. Moreover, simulations and numerical calculations demonstrate the significant occurrence of cavitation effect within the resin under specific process conditions. The intensity of cavitation is influenced by factors such as the initial bubble radius, acoustic pressure amplitude, and static pressure of the resin. The ultrasonic-assisted RTM process is proved as a promising method for producing CFRP laminates with superior properties.
本研究介绍了一种超声波振动辅助树脂传递模塑(RTM)技术,它是一种创新方法,可解决与生产 CFRP 层压材料的传统方法相关的固有挑战。研究利用三维 X 射线显微镜研究了 CFRP 复合材料在超声波振动下形成空隙的机理。此外,还采用了数值计算和模拟分析来验证超声波振动对 CFRP 机械性能的影响。研究结果表明,超声波振动可使 CFRP 层压板的厚度更加均匀,从而使纤维体积分数大幅增加,最高可达 ∼ 16%。同时,抗弯强度(∼20%)和断裂能(∼90%)也有显著提高。超声波振动还能有效降低 CFRP 的孔隙率至少 25%,使空隙分布更加一致,主要由小圆形空隙组成。孔隙率的降低归因于空化效应和润湿性的增强,从而改善了 CFRP 的机械性能。此外,模拟和数值计算表明,在特定的工艺条件下,树脂内部会产生显著的空化效应。空化强度受初始气泡半径、声压振幅和树脂静压等因素的影响。超声波辅助 RTM 工艺被证明是生产具有优异性能的 CFRP 层压板的一种可行方法。
Mechanically robustandconductive zwitter ionic polymer coated electrospun nanofibrous electrolyte membranes for wireless human motion detection and capacitor applications
Mehdihasan I. Shekh, Mintao Wang, Guangming Zhu, Florian J. Stadler, Jun Ma, Bing Du
doi:10.1016/j.compstruct.2023.117797
用于无线人体运动检测和电容器应用的机械坚固性和导电性齐聚物离子聚合物涂层电纺纳米纤维电解质膜
To address the limitations of poor ionic conductivity, low toughness, and high mass ratios in hydrogel-based electrolytes for flexible energy storage and wearable devices, here in a simple synthesis method of poly(ionic liquids) (PILs) based electrolyte membrane was developed. Briefly, PILs were utilized to coat electrospun PVDF-HFP nanofibrous membranes, resulting in ionically conducting composite electrolyte membranes (CPEMs) with enhanced physio-chemical properties. The obtained CPEMs exhibited an ionic conductivity of 0.056 S/m, along with a high tensile strength of 5.06 MPa and elongation to break of 156%. Furthermore, we utilized these CPEMs as the electrolyte in symmetric capacitors by sandwiching them between carbon nanotube (CNT) coated Ni-foams. The resulting capacitors demonstrated a specific capacitance of 170 F/g, an energy density of 53.41 Wh/kg, and a power density of 108.9 W/kg at an applied current of 1 mA. The suitability of these CPEMs as chemo-resistive sensors was investigated by attaching them to different body parts and monitoring changes in resistance during physical motion. The results demonstrated that the CPEMs exhibited effective gauge factors ranging from 1.85 to 6.44 and could detect movements up to 1% strains.
为解决柔性储能和可穿戴设备中水凝胶基电解质离子传导性差、韧性低和质量比高等限制,本文开发了一种基于聚(离子液体)(PILs)的电解质膜的简单合成方法。简而言之,利用 PILs 包覆电纺 PVDF-HFP 纳米纤维膜,得到了物理化学性能更强的离子导电复合电解质膜(CPEMs)。获得的 CPEM 具有 0.056 S/m 的离子电导率、5.06 MPa 的高抗拉强度和 156% 的断裂伸长率。此外,我们还将这些 CPEMs 夹在碳纳米管(CNT)涂层镍泡沫之间,用作对称电容器的电解质。所制成的电容器的比电容为 170 F/g,能量密度为 53.41 Wh/kg,外加电流为 1 mA 时的功率密度为 108.9 W/kg。通过将这些 CPEM 附着在不同的身体部位并监测身体运动时的电阻变化,研究了这些 CPEM 作为化学电阻传感器的适用性。结果表明,CPEM 的有效测量系数在 1.85 到 6.44 之间,可检测到高达 1%应变的运动。
Micromachined piezoelectric sensor with radial polarization for enhancing underwater acoustic measurement
Xingxu Zhang, Zichen Cui, Hao Wu, Jian Luo, Tao Ye, Xiaobiao Shan, Tao Xie, Binghe Ma
doi:10.1016/j.compstruct.2023.117798
用于增强水下声学测量的径向极化微机械压电传感器
This work presents an underwater acoustic sensor featuring a radial polarized piezoelectric diaphragm, which aims to work in d33 mode to enhance its performance. For the sake of accomplishing the in-plane polarization, interdigital electrodes based on semi-circular ring patterns are designed on both sides and aligned along the thickness direction of the diaphragm. Effects of electrode parameters on the polarization orientation are numerically analyzed by the conversion relationship between different coordinates. Using the Kirchhoff plate theory and Rayleigh-Ritz method, a mathematical model is developed to investigate the dynamic properties of the sensor. The results indicate that the output voltages increase with the increase of the electrode inner radius, width, and spacing but decrease with the increase of the diaphragm thickness and radius. Sensor prototypes are fabricated by the microelectromechanical system (MEMS) technology in a clean room and characterized by impedance spectrums. An underwater testing system is established to conduct the experimental verification, whose results are in good accord with those of mathematical modeling. The sensor output voltage has fine linearity with the underwater acoustic pressure and achieves a flat frequency response. Moreover, the sensor has a sensitivity of -172.7 dB (Ref. 1V/μPa) superior to the reported devices in the same categories. This work provides significant guidance for modeling radial field piezoelectric diaphragms and designing more efficient piezoelectric microsensors, which have a fine application prospect in underwater acoustic measurement.
本研究提出了一种水下声学传感器,其特点是采用径向极化压电膜片,旨在以 d33 模式工作以提高其性能。为实现平面内极化,在膜片两侧设计了基于半圆环形图案的数字间电极,并沿膜片厚度方向排列。通过不同坐标之间的转换关系,对电极参数对极化方向的影响进行了数值分析。利用基尔霍夫板理论和雷利-里兹方法,建立了一个数学模型来研究传感器的动态特性。结果表明,输出电压随电极内半径、宽度和间距的增加而增加,但随膜片厚度和半径的增加而减少。传感器原型是在无尘室中利用微机电系统(MEMS)技术制造的,并通过阻抗谱进行了表征。建立了一个水下测试系统来进行实验验证,其结果与数学建模结果十分吻合。传感器输出电压与水下声压具有良好的线性关系,并实现了平坦的频率响应。此外,传感器的灵敏度为 -172.7 dB(参考值 1V/μPa),优于已报道的同类设备。这项研究为径向场压电膜片建模和设计更高效的压电微型传感器提供了重要指导,在水下声学测量领域具有广阔的应用前景。
Influence of polyurea on dynamic response behaviors of cylindrical composite shells under internal explosion load
Chao Tian, Sha Yang, Jiahe Feng, Qi Dong
doi:10.1016/j.compstruct.2023.117800
聚脲对内部爆炸载荷下圆柱形复合材料壳体动态响应行为的影响
The dynamic responses of open-ended cylindrical shells with different polyurea layers under explosion load are studied in the current paper. The influences of polyurea thickness and position on the response characteristics of the composite shell are analyzed in detailed. The results indicate that the polyurea layer has significant influence the failure mode and energy absorption of the composite shell. Both polyurea in the interlayer and on the outer layer will decrease the bending moments of the composite shells of equal mass in the initial deformation process, which is easier to make the increase of the deformation heights of metal liner of composite shells with polyurea layers. The polyurea in the interlayer will weaken the constraint of metal liner, delay the fracture of fiber and restrain the bulking phenomenon of metal liner. With increase of polyurea thickness, the bulking phenomenon becomes less obvious and the deformation height of liner decreases non-monotonously. On the contrary, the outer layer polyurea will cause the bulking phenomenon of metal liner more obviously with increase of the polyurea thickness.But the outerlayer polyurea will restrict the deformation of the inner materials and limit the scattering of fiber fragment, improving the safety distance of the explosion vessel. In the whole process of anti-explosion, both polyurea in interlayer and outer layer absorb less than 10% of total energy, but they can significantly change the energy absorption of metal liner and fiber composite.
本文研究了带有不同聚脲层的开口圆柱形壳体在爆炸载荷下的动态响应。详细分析了聚脲厚度和位置对复合材料壳体响应特性的影响。结果表明,聚脲层对复合材料壳体的失效模式和能量吸收有显著影响。夹层聚脲和外层聚脲都会减小等质量复合材料壳体在初始变形过程中的弯矩,更容易使带有聚脲层的复合材料壳体金属衬里的变形高度增加。夹层中的聚脲会减弱金属内衬的约束,延缓纤维的断裂,抑制金属内衬的膨胀现象。随着聚脲厚度的增加,膨胀现象变得不那么明显,衬垫的变形高度非单调地减小。相反,随着聚脲厚度的增加,外层聚脲会使金属衬里的鼓包现象更加明显,但外层聚脲会限制内层材料的变形,限制纤维碎片的散落,提高爆炸容器的安全距离。在整个防爆过程中,夹层聚脲和外层聚脲吸收的能量均小于总能量的 10%,但它们能显著改变金属衬里和纤维复合材料的能量吸收。
Co-modifying geopolymer composite by nano carbon black and carbon fibers to reduce CO2 emissions in airport pavement induction heating
Gonghui Gu, Tao Ma, Feng Chen, Chengjia Han, Heng Li, Fang Xu
doi:10.1016/j.compositesa.2023.107951
用纳米炭黑和碳纤维共同改性土工聚合物复合材料,减少机场路面感应加热中的二氧化碳排放
CO2 emissions during airport pavement induction heating for ice and snow melting are primarily determined by the electrothermal behavior of electrically conductive layer (ECL). A single type of conductive filler is difficult to significantly improve the electrothermal performance of ECL while maintaining its mechanical properties. This work introduces nano carbon black (NCB) into carbon fiber-reinforced geopolymer to prepare NCB-carbon fiber co-modified geopolymer composites (NMGC) with great potential to dramatically improve the electrothermal performance of ECL and reduce CO2 emissions during induction heating. Furthermore, in order to provide guidance support for the ECL design, the evolution mechanisms of the electrothermal and mechanical properties of NMGC were inquired through electrochemical impedance spectroscopy (EIS) analysis and geopolymerization rate characterization, respectively. Results show that introducing 1 wt.% NCB into the carbon fiber-reinforced geopolymer can effectively increase the reaction rate within NMGC and improve its electrothermal performance due to the enhanced electron transition. Indoor induction heating tests further indicate that the optimized NMGC can reduce the CO2 emissions by 13.7 kg/m2 comparing to the NMGC without NCB during 30 min of induction heating.
机场路面感应加热融冰融雪过程中的二氧化碳排放主要取决于导电层(ECL)的电热行为。单一类型的导电填料很难在保持导电层机械性能的同时显著改善其电热性能。本研究在碳纤维增强土工聚合物中引入纳米炭黑(NCB),制备出纳米炭黑-碳纤维共改性土工聚合物复合材料(NMGC),有望显著改善 ECL 的电热性能,并减少感应加热过程中的二氧化碳排放。此外,为了给 ECL 的设计提供指导支持,还分别通过电化学阻抗谱(EIS)分析和土工聚合速率表征,探究了 NMGC 的电热性能和力学性能的演变机理。结果表明,在碳纤维增强土工聚合物中引入 1 wt.% 的 NCB 可有效提高 NMGC 内部的反应速率,并由于电子转变的增强而改善其电热性能。室内感应加热试验进一步表明,与不添加 NCB 的 NMGC 相比,优化后的 NMGC 在 30 分钟的感应加热过程中可减少 13.7 kg/m2 的二氧化碳排放量。
Piecewise damage model for SiC/SiC composites with multilevel experimental validation
Duoqi Shi, Zhenyu Wang, James Marrow, Changqi Liu, Fan Wan, Xiaoguang Yang
doi:10.1016/j.compositesa.2023.107952
通过多级实验验证 SiC/SiC 复合材料的片状损伤模型
Using multiscale and multidimensional data from experiments and advanced microscopic characterisation, a piecewise damage model for SiC/SiC composite structures has been proposed. First, the geometric information of the microstructure was acquired using scanning electron microscopy (SEM) and X-ray computed tomography (X-CT). High-precision and total-factor finite element models were established, and a piecewise damage model was introduced to simulate in detailing the initiation and propagation of damage. Subsequently, in-situ experiments using the digital image correlation method were conducted to capture the strain fields. After failure, the failure modes were observed and analysed by SEM and X-CT. In the piecewise damage model, observed failure modes were associated within the progressive failure analysis concretely. Combining the multisource data during and after loading, the validity and reliability of this damage model based on failure mechanisms are demonstrated in the accurate prediction of the properties, deformation and stress fields in multilevel structures of SiC/SiC composites.
利用来自实验的多尺度和多维数据以及先进的微观表征技术,我们提出了一种 SiC/SiC 复合结构的片状损伤模型。首先,利用扫描电子显微镜(SEM)和 X 射线计算机断层扫描(X-CT)获取了微观结构的几何信息。建立了高精度和全因子有限元模型,并引入了片状损伤模型来详细模拟损伤的发生和传播。随后,使用数字图像相关方法进行了原位实验,以捕捉应变场。失效后,通过扫描电子显微镜和 X-CT 对失效模式进行了观察和分析。在片状破坏模型中,观察到的破坏模式与渐进破坏分析具体相关。结合加载过程中和加载后的多源数据,证明了这种基于破坏机制的破坏模型在准确预测 SiC/SiC 复合材料多层结构的性能、变形和应力场方面的有效性和可靠性。
Resolving 3D microstructure evolution of ceramifiable composites at elevated temperatures using in-situ X-ray computed tomography
Huanfang Wang, Tianfei Zhao, Zheng Gong, Jiahui Gu, Yong Deng, Chao Zhang.
doi:10.1016/j.compositesa.2023.107953
利用原位 X 射线计算机断层扫描技术解析陶瓷复合材料在高温下的三维微观结构演变过程
Ceramifiable polymer composites suffers significant microstructure change during the polymer-to-ceramic conversion as the environmental temperature increases. The present study employs in-situ X-ray computed tomography (XCT) to reveal the microstructure evolution of high-silica/boron-phenolic composites modified with B4C and talc (B4C-talc_HSF/BPR) in three dimensions as the composites is heated to 1000 °C. The cracks are classified based on their locations, and the temporal sequence of their formation is identified. The evolution of internal pore distribution is reconstructed and analyzed quantitatively. Furthermore, the 3D deformation fields of composites during in-situ heating were calculated using digital volume correlation. It is found that the equivalent strain along the thickness direction shows a multi-stage behavior corresponding to the thermal degradation and ceramization transformation processes. The findings provide a 3D visualization of crack propagation and deformation during the polymer-to-ceramic conversion process, which can provide a foundation for further developments in material design.
随着环境温度的升高,在聚合物向陶瓷转化的过程中,可陶瓷聚合物复合材料的微观结构会发生显著变化。本研究采用原位 X 射线计算机断层扫描(XCT)技术,揭示了用 B4C 和滑石粉改性的高硅/硼酚醛复合材料(B4C-talc_HSF/BPR)在加热至 1000 °C 时的三维微观结构演变过程。根据裂纹的位置对裂纹进行了分类,并确定了裂纹形成的时间顺序。对内部孔隙分布的演变进行了重建和定量分析。此外,还利用数字体积相关技术计算了复合材料在原位加热过程中的三维变形场。研究发现,沿厚度方向的等效应变表现出与热降解和陶瓷化转变过程相对应的多阶段行为。研究结果提供了聚合物向陶瓷转化过程中裂纹扩展和变形的三维可视化图像,为材料设计的进一步发展奠定了基础。
Interphase enhanced low-velocity impact energy absorption in liquid crystal elastomer-based woven composites
Beom-Gon Cho, Jinsu Kim, Young-Bin Park, Jungwon Kim, Min Wook Lee, Woong-Ryeol Yu, Seung-Yeol Jeon
doi:10.1016/j.compscitech.2023.110377
液晶弹性体基编织复合材料中相间增强的低速冲击能量吸收能力
A reasonable approach to enhancing the energy absorption capability of composites is to incorporate elastomers that possess viscoelastic properties capable of enduring considerable elastic deformations and absorbing significant energy without fracturing. From this perspective, using liquid crystal elastomers (LCEs) as a matrix for fiber-reinforced composites could be an excellent option for developing impact-absorbing materials since LCEs possess an outstanding energy dissipation ability compared with amorphous elastomers. Herein, we report excellent energy-dependent impact properties of LCE composites reinforced with carbon fiber (CF) woven fabric. We discovered that the LCE/CF composite can effectively dissipate high amounts of low-velocity impact energy. The exceptional characteristics of LCE, which make it adaptable to impact energy absorption, combined with the presence of an interphase featuring a higher loss modulus compared to the individual composite components, were demonstrated to significantly enhance impact energy absorption of the composite. The developed LCE/CF composite panel is capable of absorbing up to 60 J of impact energy despite its thickness of only about 1 mm and has a substantial damping loss coefficient of about 0.1, which is two orders of magnitude higher than those of typical fiber-reinforced composites.
增强复合材料能量吸收能力的一个合理方法是加入具有粘弹性能的弹性体,这种弹性体能够承受相当大的弹性变形,吸收大量能量而不会断裂。从这个角度来看,使用液晶弹性体(LCE)作为纤维增强复合材料的基体可能是开发冲击吸收材料的绝佳选择,因为与非晶弹性体相比,液晶弹性体具有出色的能量耗散能力。在此,我们报告了用碳纤维(CF)编织物增强的 LCE 复合材料的优异的能量相关冲击性能。我们发现 LCE/CF 复合材料能有效消散大量低速冲击能量。LCE 的优异特性使其能够适应冲击能量吸收,再加上与单个复合材料成分相比,中间相具有更高的损失模量,这些都证明 LCE 可显著增强复合材料的冲击能量吸收能力。所开发的 LCE/CF 复合材料板厚度仅约 1 毫米,却能吸收高达 60 焦耳的冲击能量,而且阻尼损失系数高达 0.1 左右,比典型的纤维增强复合材料高出两个数量级。
Lightweight multi-layer graded pyramid folded structure based on tucked kirigami for green manufacturing
Hao Qiu, Yixiong Feng, Zhaoxi Hong, Yicong Gao, Jianrong Tan
doi:10.1016/j.compscitech.2023.110383
基于折纸的轻质多层分级金字塔折叠结构,实现绿色制造
Lightweight structures are extensively utilized in various applications that demand exceptional mechanical properties and low densities, such as aerospace, vehicles, and construction components. However, the production of lightweight structures often entails significant material consumption and the emission of pollutants during the pressing and welding processes. Additive manufacturing (AM) has been hailed as a green technology that offers superior flexibility, reduces material wastage, and enables personalized design compared to traditional approaches. In this study, we present a novel lightweight multi-layer graded pyramid folded structure (PFS) based on tucked kirigami, with a focus on green manufacturing principles. The PFSs consist of nested pyramid cells connected by flat triangular plates. By leveraging stereolithography and a two-stage curing process, we achieve AM of multi-layer PFSs with excellent mechanical properties and shaping quality. Experimental studies were conducted on two-dimensional and three-dimensional graded PFSs under lateral and vertical quasi-static compressive loading to investigate the influence of gradient types and values on the mechanical performance of 3D printed PFSs. Our findings reveal that length gradients parallel to the load induce buckling deviations from the center, negatively impacting the performance of single-layer PFSs. Conversely, a height gradient along the z-direction further enhances specific energy absorption (SEA) and compressive strength. The results of this study provide a novel and viable approach to the design and manufacturing of multi-layer graded PFSs with programmable non-uniform stiffness. These graded PFSs hold significant potential for environment-friendly lightweight engineering applications.
轻质结构被广泛应用于航空航天、车辆和建筑构件等各种需要优异机械性能和低密度的应用领域。然而,轻质结构的生产往往需要消耗大量材料,并在压制和焊接过程中排放污染物。与传统方法相比,快速成型制造(AM)被誉为一种绿色技术,它具有卓越的灵活性,可减少材料浪费,并实现个性化设计。在本研究中,我们介绍了一种新型轻质多层分级金字塔折叠结构(PFS),该结构基于褶裥叽里格米(kirigami),注重绿色制造原则。金字塔折叠结构由嵌套的金字塔单元组成,单元之间用三角形平板连接。利用立体光刻技术和两阶段固化工艺,我们实现了多层折叠结构的自动机械加工,并具有优异的机械性能和成型质量。我们对横向和纵向准静态压缩载荷下的二维和三维梯度 PFS 进行了实验研究,以探讨梯度类型和数值对三维打印 PFS 机械性能的影响。我们的研究结果表明,与载荷平行的长度梯度会导致屈曲偏离中心,从而对单层 PFS 的性能产生负面影响。相反,沿 Z 方向的高度梯度可进一步增强比能量吸收(SEA)和抗压强度。这项研究成果为设计和制造具有可编程非均匀刚度的多层分级 PFS 提供了一种新颖可行的方法。这些分级 PFS 在环境友好型轻质工程应用方面具有巨大潜力。