今日更新:International Journal of Solids and Structures 1 篇,Journal of the Mechanics and Physics of Solids 1 篇,International Journal of Plasticity 1 篇,Thin-Walled Structures 1 篇
Low velocity impact and compression after impact of thin and thick laminated carbon fiber composite panels
Andrew Seamone, Paul Davidson, Anthony M. Waas, Vipul Ranatunga
doi:10.1016/j.ijsolstr.2024.112745
薄层和厚层碳纤维复合板的低速冲击和冲击后的压缩情况
This study explores the impact behavior of thin and thick composite panels, yielding insights into their behavior under increasing impact energies. Thin composite specimens demonstrated limited surface damage tolerance, while thicker panels remained visually intact but suffered internal damage, adversely affecting their compressive load capacity. The study shows a robust correlation between impact energy and key measurements, including dent depth, bottom surface matrix splitting, and internal delaminations. Moreover, the research identified a consistent pattern in damage initiation, showing that the onset of matrix splitting and delamination remained relatively constant regardless of increasing impact energy, emphasizing the predictability of damage initiation. Compression after impact study showed distinctive responses between thin and thick composites. Thin composites exhibited global buckling before final failure, with a gradual reduction in peak load-carrying capability as damage escalated. In contrast, thick composites suffered substantial damage and delamination at higher impact energies, leading to significant losses, up to 60%, in residual compressive load capacity. The study introduces a simplified quasi-static model to capture delamination effects on panel responses to low-velocity impacts. This study contributes significantly to understanding composite materials’ impact behavior, providing essential knowledge for practical applications and future research endeavors.
本研究探讨了薄复合板和厚复合板的冲击行为,深入了解了它们在冲击能量增加时的行为。薄复合材料试样表现出有限的表面损伤耐受性,而较厚的板材虽然表面完好无损,但却遭受了内部损伤,对其抗压负载能力产生了不利影响。研究结果表明,冲击能量与凹痕深度、底面基质分裂和内部脱层等关键测量值之间存在紧密的相关性。此外,研究还发现了一种一致的损伤起始模式,表明无论冲击能量如何增加,基体开裂和分层的起始时间都保持相对稳定,强调了损伤起始的可预测性。冲击后的压缩研究表明,薄复合材料和厚复合材料的反应截然不同。薄复合材料在最终失效前表现出整体屈曲,随着损伤的加剧,峰值承载能力逐渐降低。与此相反,厚复合材料在冲击能量较高时遭受严重破坏和分层,导致剩余抗压承载能力大幅下降,最高达 60%。该研究引入了一个简化的准静态模型,以捕捉分层对面板对低速冲击响应的影响。这项研究极大地促进了对复合材料冲击行为的理解,为实际应用和未来研究工作提供了重要知识。
Mapping deformation and dissipation during fracture of soft viscoelastic solid
Yuan Qi, Xueyu Li, Sairam Pamulaparthi Venkata, Xingwei Yang, Tao Lin Sun, Chung-Yuen Hui, Jian Ping Gong, Rong Long
doi:10.1016/j.jmps.2024.105595
绘制软粘弹性固体断裂过程中的变形和耗散图
Energy dissipation around a propagating crack is the primary mechanism for the enhanced fracture toughness in viscoelastic solids. Such dissipation is spatially non-uniform and is highly coupled to the crack propagation process due to the history-dependent nature of viscoelasticity. We present an experimental approach to map the dissipation field during crack propagation in soft viscoelastic solid. Specifically, we track randomly distributed tracer particles to measure the evolving deformation field. The measured deformation field is then put into a nonlinear constitutive model to determine the dissipation field. Our methodology was used to investigate the deformation and dissipation fields around a propagating crack in a Polyampholyte (PA) hydrogel. The deformation field measurements allowed us to assess whether the commonly assumed translational invariance in viscoelastic fracture theories holds true in practical experiments. Furthermore, by combining the obtained deformation fields with a nonlinear viscoelastic model, we captured the complete history of the dissipation field during crack propagation. We found that dissipation occurred even at material points that are a few millimeters away from the crack tip. The mapped dissipation field also enabled the separate determination of the intrinsic and dissipative components of fracture toughness for the viscoelastic hydrogel.
传播裂纹周围的能量耗散是粘弹性固体断裂韧性增强的主要机制。由于粘弹性的历史依赖性,这种耗散在空间上是不均匀的,并且与裂纹扩展过程高度耦合。我们提出了一种绘制软粘弹性固体裂纹扩展过程中耗散场的实验方法。具体来说,我们通过追踪随机分布的示踪粒子来测量不断变化的变形场。然后将测量到的变形场放入非线性构成模型中,以确定耗散场。我们的方法被用于研究聚酰胺(PA)水凝胶中传播裂缝周围的变形场和耗散场。通过变形场测量,我们可以评估粘弹性断裂理论中通常假设的平移不变性在实际实验中是否成立。此外,通过将获得的变形场与非线性粘弹性模型相结合,我们捕捉到了裂纹扩展过程中耗散场的完整历史。我们发现,即使在距离裂纹尖端几毫米远的材料点也会发生耗散。通过绘制耗散场图,还能分别确定粘弹性水凝胶断裂韧性的内在和耗散成分。
Multi-interface migration mechanism induced by carbide precipitation during the quenching-partitioning-tempering process in a high-carbon steel
Hongqing Zheng, Jiazhi Zhang, Xunwei Zuo, Yonghua Rong, Jianfeng Wan, Nailu Chen
doi:10.1016/j.ijplas.2024.103928
高碳钢淬火-分区-回火过程中碳化物析出诱发的多界面迁移机制
Phase-field finite element (PFFE) modeling of the quenching-partitioning-tempering (Q-P-T) process is proposed, and the two-dimensional PFFE-QPT model considering carbide precipitation and the interface migration between martensite and austenite is used to investigate microstructural evolution and the elastic/plastic strain distribution at quenching, partitioning and tempering stages in a high-carbon steel, respectively. The simulation results of the high carbon Q-P-T steel indicate that the precipitation strengthening of carbides occurs not only because they can block the movement of dislocations, but also because they can produce high internal stress. Meanwhile, the volume fractions of different phases (including primary martensite, retained austenite, secondary martensite, and carbide) and the carbon content in retained austenite predicted by the PFFE-QPT model are slightly better than those predicted by the novel one-dimensional QPT-LE (local equilibrium) model and much closer to experimental values. The PFFE-QPT model is also used to successfully predict the volume fractions of different phases in low-carbon and medium-carbon Q-P-T steels. More importantly, the microstructural morphologies closely related to mechanical properties can be demonstrated by the PFFE-QPT model and are comparable with the experimental observation. Therefore, the PFFE-QPT model will be a more powerful tool for guiding the process and microstructure design of Q-P-T steels compared with the QPT-LE model.
提出了淬火-分区-回火(Q-P-T)过程的相场有限元(PFFE)模型,并使用考虑碳化物析出以及马氏体和奥氏体之间界面迁移的二维 PFFE-QPT 模型分别研究了高碳钢在淬火、分区和回火阶段的微观结构演变和弹性/塑性应变分布。高碳 Q-P-T 钢的模拟结果表明,碳化物的析出强化不仅是因为它们能阻止位错运动,还因为它们能产生高内应力。同时,PFFE-QPT 模型预测的不同相(包括原始马氏体、残余奥氏体、二次马氏体和碳化物)的体积分数和残余奥氏体中的碳含量略好于新型一维 QPT-LE(局部平衡)模型的预测值,且更接近实验值。PFFE-QPT 模型还可用于成功预测低碳和中碳 Q-P-T 钢中不同相的体积分数。更重要的是,PFFE-QPT 模型可以证明与力学性能密切相关的微观结构形态,并且与实验观察结果相当。因此,与 QPT-LE 模型相比,PFFE-QPT 模型将成为指导 Q-P-T 钢工艺和微观结构设计的更有力工具。
Dynamic responses of steady-state transition structures under impact loading
Wenxiao Li, Mohammed El Hoseny, Jianxun Ma
doi:10.1016/j.tws.2024.111761
稳态过渡结构在冲击荷载下的动态响应
Advancements in materials science and mechanical system have spurred widespread investigation into non-traditional structures. In particular, engineers have shown interest in steady-state transition structures with phase transition properties. In this paper, a three-dimensional steady-state transition structure was established using the genetic algorithm and three-dimensional expansion, on which the low-velocity impact tests were carried out. Force response and energy absorption of the steady-state transition structures under impact were studied. From the force response and energy absorption curves, it can be seen that the steady-state transition structures absorb and store portion of impact energy temporarily, gradually releasing it after impact peak. This unique energy behavior results in a steady state transition structure with a long impact response time and a low peak impact force under impact. In addition, investigation into energy transfer within these structures reveals that energy oscillations occur among multilayered bistable surfaces during steady-state transitions, further improving the energy dissipation. Further, the dynamic response and damage modes of the honeycomb structure and the steady state transition structure were compared, showing that the damage mode of the steady state transition structure under the impact is an overall damage, in contrast to the penetration damage of the honeycomb structure. Notably, the steady-state transition structures showcase a higher proportion of elastic strain energy during impacts, effectively delaying structural damage onset, and dispersing impact energy, thus enhancing impact resistance. In light of these findings, the demonstrated behavior of steady-state transition structures in absorbing and dissipating impact energy showcases their potential as promising avenues for the development of more effective impact protection strategies.
材料科学和机械系统的进步推动了对非传统结构的广泛研究。特别是,工程师们对具有相变特性的稳态过渡结构表现出了浓厚的兴趣。本文利用遗传算法和三维展开建立了三维稳态过渡结构,并在此基础上进行了低速冲击试验。研究了稳态过渡结构在冲击下的力响应和能量吸收。从力响应和能量吸收曲线可以看出,稳态过渡结构暂时吸收并储存了部分冲击能量,并在冲击峰值后逐渐释放。这种独特的能量行为使得稳态过渡结构在冲击下具有较长的冲击响应时间和较低的冲击力峰值。此外,对这些结构内部能量传递的研究表明,在稳态转换过程中,多层双稳态表面之间会发生能量振荡,从而进一步提高了能量耗散效果。此外,还比较了蜂窝结构和稳态过渡结构的动态响应和破坏模式,结果表明稳态过渡结构在冲击下的破坏模式是整体破坏,与蜂窝结构的穿透破坏形成鲜明对比。值得注意的是,稳态过渡结构在冲击过程中显示出更高比例的弹性应变能,有效延缓了结构损伤的发生,分散了冲击能量,从而增强了抗冲击能力。鉴于这些发现,稳态过渡结构在吸收和消散冲击能量方面的表现展示了其作为开发更有效冲击防护策略的潜在途径的潜力。