【新文速递】2023年10月11日固体力学SCI期刊最新文章

今日更新：Composite Structures 1 篇，Composites Science and Technology 2 篇Composite Structures3D viscoelastic solutions for bending creep of layered rectangular plates under time-varying loadLi Xiaolong, Wu Peng, Fang Hai, Wang Jie, Yu Yunweidoi:10.1016/j.compstruct.2023.117590层状矩形板在时变载荷作用下弯曲蠕变的三维粘弹性解法Creep behavior is an inevitable problem for viscoelastic layered structures and needs to be predicted for long-term service situations. In this study, a new technique to obtain analytical solutions for three-dimensional (3D) viscoelastic equations for layered rectangular plates under time-varying loads is developed to predict bending creep behavior. In the analytical model, all the constituent materials of the plate, including the laminar layers and interlayers, exhibit viscoelastic properties, which are simulated by the Burgers model. The slip effect between neighboring laminar layers due to a relatively soft interlayer is considered. The stresses and displacements of each laminar layer in the layered plates are described by 3D elasticity theory combined with the Boltzmann superposition principle. The viscoelastic analytical solutions are obtained by means of series expansions and the Laplace transformation method. The present solution has good accuracy and agrees with the finite element (FE) solution. The influence of various parameters, such as the modulus degradation pattern, modulus ratio and viscoelastic constants, on the creep of the plate are studied.蠕变行为是粘弹性层状结构不可避免的问题，需要针对长期使用情况进行预测。在本研究中，开发了一种新技术来获得矩形分层板在时变载荷作用下的三维（3D）粘弹性方程的解析解，从而预测弯曲蠕变行为。在分析模型中，板的所有组成材料，包括层状层和夹层，都表现出粘弹性能，这些粘弹性能由 Burgers 模型模拟。由于夹层相对较软，相邻层板之间的滑移效应也被考虑在内。层状板中各层状层的应力和位移由三维弹性理论结合玻尔兹曼叠加原理描述。粘弹性解析解是通过序列展开和拉普拉斯变换法得到的。本求解具有良好的准确性，并与有限元（FE）求解一致。研究了各种参数（如模量退化模式、模量比和粘弹性常数）对板材蠕变的影响。Composites Science and TechnologyPolyacrylonitrile nanofiber reinforced polyimide composite aerogels with fiber-pore interpenetrating structures for sound absorption, air filtration and thermal insulationZhao Xingyu, Ruan Kunpeng, Qiu Hua, Zhang Yali, Gu Junweidoi:10.1016/j.compscitech.2023.110275具有纤维孔穿插结构的聚丙烯腈纳米纤维增强聚酰亚胺复合气凝胶，用于吸音、空气过滤和隔热Prolonged noise pollution and its induced vibration would not only lead to the failure of instruments and equipment, but also endanger human health. In this work, with water-soluble polyamide acid (PAA) as the matrix and polyacrylonitrile nanofiber (PANNF) as the reinforcement, PANNF reinforced polyimide (PANNF/PI) composite aerogels with fiber-pore interpenetrating structures are fabricated by the method of “homogeneous mixing, freeze-drying and heat treatment”. PANNF that intersperses among pores can effectively inhibit the shrinkage of PI aerogels and enhance sound absorption and mechanical properties. With PANNF dosage of 10 wt%, the composite aerogels own the excellent sound absorption performance, with noise reduction coefficient (NRC) of 0.398, and average sound absorption coefficient (SAC) of 0.913 in the frequency range of 2000∼6300 Hz. The composite aerogels also have excellent mechanical properties, with Young's modulus of 12.42 kPa, stress loss of 3.64% and energy loss coefficient of 0.203. 10 wt% PANNF/PI composite aerogels also possess satisfying air filtration performance (97.2% filtration efficiency for PM2.5, quality factor (QF) value of 0.0396 Pa-1; and 99.4% filtration efficiency for PM10, QF value of 0.0567 Pa-1) and thermal insulation performance (thermal conductivity coefficient as low as 0.036 W/(m·K)).长时间的噪声污染及其引起的振动不仅会导致仪器和设备故障，还会危害人体健康。本研究以水溶性聚酰胺酸（PAA）为基体，聚丙烯腈纳米纤维（PANNF）为增强体，采用 "均匀混合、冷冻干燥、热处理 "的方法制备了具有纤维孔穿插结构的 PANNF 增强聚酰亚胺（PANNF/PI）复合气凝胶。穿插在孔隙中的 PANNF 能有效抑制 PI 气凝胶的收缩，提高吸声性能和机械性能。当 PANNF 的用量为 10 wt%时，复合气凝胶具有优异的吸声性能，降噪系数（NRC）为 0.398，在 2000∼6300 Hz 频率范围内的平均吸声系数（SAC）为 0.913。复合气凝胶还具有优异的机械性能，其杨氏模量为 12.42 kPa，应力损失为 3.64%，能量损失系数为 0.203。10 wt% PANNF/PI 复合气凝胶还具有令人满意的空气过滤性能（对 PM2.5 的过滤效率为 97.2%，质量因子 (QF) 值为 0.0396 Pa-1；对 PM10 的过滤效率为 99.4%，质量因子 (QF) 值为 0.0567 Pa-1）和隔热性能（导热系数低至 0.036 W/(m-K)）。Constructing interfacial barrier from tribo-positive shell microcapsules to suppress space charge in thermochromic phase change composites for smart electronicsGao Jian, Wu Kangning, Xie Zongliang, Li Jianying, Li Shengtaodoi:10.1016/j.compscitech.2023.110291利用三正壳微胶囊构建界面屏障，抑制用于智能电子产品的热致变色相变复合材料中的空间电荷Thermochromic phase change composites (TPC) exhibit versatile functions under electrothermal stimuli, which are extensively applied as packaging, insulation and circuit components in considerable advanced smart electronics. However, space charge accumulation under DC voltages is still a critical and universal issue for the serious deterioration of functionalities and life-span of TPC and electronics. This study presents a novel strategy of suppressing space charge in thermochromic phase change epoxy composites (TPCE) by constructing interfacial barrier from tribo-positive shell thermochromic phase change microcapsules. The strong tribo-positive melamine-formaldehyde (MF) shell of microcapsules can establish negative charge barriers in the interfaces between microcapsules and epoxy matrix through triboelectrification, which is directly verified by Kelvin probe force microscopy. Pulsed electroacoustic measurement results exhibit the space charge accumulation in TPCE under an extreme electric field strength of 50 kV/mm and an elevated temperature 70 °C can be significantly diminished by 39.3% compared to that of neat epoxy resin after incorporating merely 1 ph MF shell microcapsules, affirming the effect of interfacial barrier on space charge inhibition. The interfacial barrier could improve the charge carrier dissipation and mitigating the space charge accumulation as confirmed by hopping conduction analysis. Moreover, DC breakdown strength of TPCE can also be enhanced by 12.3% and 6.1% with 1phr microcapsules at 30 °C and 70 °C compared to that of neat epoxy resin owing to the suppressed space charge. The results provide a potential approach of designing high-performance thermochromic phase change composites for smart electrical and electronic devices.热致变色相变复合材料（TPC）在电热刺 激下具有多种功能，被广泛应用于各种先进智能电子产品的封装、绝缘和电路元件。然而，直流电压下的空间电荷积累仍然是一个严重的普遍问题，会导致热致变色相变复合材料和电子器件的功能和寿命严重衰减。本研究提出了一种抑制热致变色相变环氧树脂复合材料（TPCE）中空间电荷的新策略，即利用三正壳热致变色相变微胶囊构建界面屏障。微胶囊的三聚氰胺-甲醛（MF）强正壳可通过三电化作用在微胶囊与环氧基体之间的界面上建立负电荷屏障，开尔文探针力显微镜直接验证了这一点。脉冲电声测量结果表明，在 50 kV/mm 的极端电场强度和 70 ℃ 的高温条件下，与纯环氧树脂相比，仅加入 1 ph MF 微胶囊后，TPCE 中的空间电荷积累就能显著减少 39.3%，这肯定了界面屏障对空间电荷抑制的作用。跳变传导分析证实，界面阻挡层可改善电荷载流子耗散，缓解空间电荷积累。此外，由于空间电荷受到抑制，与纯环氧树脂相比，在 30 °C 和 70 °C 温度下，含有 1phr 微胶囊的 TPCE 直流击穿强度分别提高了 12.3% 和 6.1%。这些结果为设计用于智能电气和电子设备的高性能热致变色相变复合材料提供了一种潜在的方法。来源：复合材料力学仿真Composites FEM