今日更新:International Journal of Solids and Structures 1 篇,Mechanics of Materials 1 篇,Thin-Walled Structures 3 篇
A flexible, reusable and adjustable high-performance energy absorption system inspired by interlocking suture structures
Jiaxuan Li, Chao Sui, Yuna Sang, Yichen Zhou, Zifu Zang, Yushun Zhao, Xiaodong He, Chao Wang
doi:10.1016/j.ijsolstr.2024.112839
一种灵活、可重复使用和可调节的高性能能量吸收系统,灵感来自于联锁缝合结构
Energy absorption systems play a very important role in impact protection under complex load conditions. However, traditional protective structures cannot adjust the mechanical properties on demand to accommodate variable load characteristics once manufactured. Therefore, inspired by the superior compression resistance of the diabolical ironclad beetle, a modular energy absorption system is proposed by combining the efficient mechanical properties of thin-walled tubes and the robust connectivity of interlocking suture structures, which can be easily assembled from only bio-inspired tubes without external constraints. FEM simulations were performed to systematically investigate the static and dynamic mechanical properties of the proposed system, and its crushing performance was demonstrated experimentally. Additionally, the influence of geometric parameters on the mechanical properties of the system has been investigated, and the insensitivity of secondary geometrical parameters and assembly defects has been verified, which shows that the system has a certain safety margin to avoid catastrophic accidents caused by fabrication defects. Moreover, the system exhibits excellent reusability under multi-impact load environments and its energy absorption capacity does not degrade after the primary impact. Furthermore, the system exhibits good designability thanks to the discrete modular structures, its mechanical properties can be tuned by stiffness design without affecting the energy absorption capacity, and its specific energy absorption can be effectively improved by lightweight design. This study provides a novel design strategy for the protection system applied used in multiple complex environments.
能量吸收系统在复杂载荷条件下的冲击防护中起着非常重要的作用。然而,传统的保护结构一旦制造出来,就不能根据需要调整机械性能以适应可变的载荷特性。因此,受恶魔般的铁甲甲虫优越的抗压缩性能的启发,我们提出了一种模块化的能量吸收系统,结合了薄壁管的高效机械性能和互锁缝合结构的坚固连接,可以很容易地由仿生管组装而不受外部约束。通过有限元模拟系统地研究了该系统的静态和动态力学性能,并对其破碎性能进行了实验验证。此外,还研究了几何参数对系统力学性能的影响,验证了二次几何参数和装配缺陷的不敏感性,表明该系统具有一定的安全裕度,可以避免制造缺陷引起的灾难性事故。在多次冲击载荷环境下,系统具有良好的可重复使用性,在一次冲击后,系统的能量吸收能力不会下降。该系统采用离散模块化结构,具有良好的可设计性,通过刚度设计可以在不影响吸能能力的情况下调整其力学性能,通过轻量化设计可以有效提高其比能吸收。该研究为应用于多种复杂环境的保护系统提供了一种新的设计策略。
On the development of a constitutive model for steel subjected to fire
Gustavo Provençano Vilardo, Theodoro Antoun Netto
doi:10.1016/j.mechmat.2024.105012
火灾作用下钢的本构模型的建立
The behavior of steel under thermal and mechanical loading including high transient temperatures and strain rates (e.g., fire, creep or explosion) is extremely complex. To study this behavior, we propose a constitutive model accordance with the laws of thermodynamic, the principle of virtual power and experimental results. The thermodynamic framework considers the Clausius-Duhem inequality and maximum dissipation rate principle, as well as the theory of finite deformations, linear isotropic viscoelasticity, nonlinear isotropic and kinematic hardening, local and non-local viscoplasticity, local and non-local anisotropic viscodamage and parameters associated to material behavior dependent on loadings. The components of the thermodynamic conjugate forces are defined from the Helmholtz free energy function and the rate of energy dissipation, which are postulated considering the creep phenomenon, thermal-mechanical transient phenomenon, cyclic phenomenon and plastic wave propagation phenomenon. The balance of microforces is defined based on the principle of virtual power. A novel rule of non-associated thermo-viscoplastic flow of the Perzyna type and a novel rate dependent local and non-local damage evolution law are introduced from constitutive model. The verification of the model was carried out in two benchmark studies composed of fire tests. The predictions of the model have shown in according with the results of the experiments. A sensitivity study was also performed with a view to analysis the influence of the parameters in achieved results. From this study a simplified constitutive model is presented. Benchmark studies composed of explosion tests are part of future work.
钢在热载荷和机械载荷下的性能,包括高瞬态温度和应变率(例如,火灾、蠕变或爆炸)是极其复杂的。为了研究这种行为,我们根据热力学定律、虚功率原理和实验结果提出了一个本构模型。热力学框架考虑了Clausius-Duhem不等式和最大耗散率原理,以及有限变形理论,线性各向同性粘弹性,非线性各向同性和运动硬化,局部和非局部粘塑性,局部和非局部各向异性粘损伤以及与材料行为相关的参数依赖于载荷。考虑蠕变现象、热-力瞬变现象、循环现象和塑性波传播现象,从亥姆霍兹自由能函数和能量耗散率定义了热力学共轭力的分量。基于虚功率原理定义了微力平衡。从本构模型出发,提出了一种新的Perzyna型非关联热粘塑性流动规律和一种新的速率相关的局部和非局部损伤演化规律。模型的验证是在两个由火试验组成的基准研究中进行的。该模型的预测结果与实验结果相吻合。还进行了敏感性研究,以分析参数对所取得结果的影响。在此基础上提出了一种简化的本构模型。由爆炸试验组成的基准研究是未来工作的一部分。
Utilizing Optimal Physics-Informed Neural Networks for Dynamical Analysis of Nanocomposite One-Variable Edge Plates
Nguyen Cong Tan, Nguyen Manh Dzung, Nguyen Duc Tien, Nguyen Hoang Ha, Nguyen Thanh Dong, Dinh Gia Ninh
doi:10.1016/j.tws.2024.111928
利用最优物理信息神经网络进行纳米复合材料单变量边板的动力学分析
This study presents an innovative Physics-Informed Neural Network (PINN) approach designed to predict the dynamic responses of the One-Variable Edge Plate (OVEP), a unique plate structure characterized by an edge defined by arbitrary mathematical functions. The OVEP is constructed from a nanocomposite material reinforced with graphene nanoplatelets. Utilizing an optimized PINN pipeline, this research successfully predicts the vibration characteristics of the OVEP, encompassing linear, nonlinear vibrations, and beating phenomena. The study also demonstrates that the optimal PINN outperforms conventional neural network in terms of stability, accuracy (achieving above 99% accuracy), and efficiency in predicting long-duration vibrations. Additionally, the computational time required for generating testing results is notably diminished compared to traditional partial differential equation (PDE) solvers (reduced by about 3 to 12 times). To demonstrate model robustness, synthetic noise is intentionally introduced into the training data. The results not only enhance our understanding of the complex dynamics of the OVEP but also highlight the effectiveness of the proposed PINN framework in capturing and forecasting the dynamic behaviors of advanced plate structures. This research presents a promising potential for addressing dynamic problems in the fields of aerospace, civil, and mechanical engineering.
本研究提出了一种创新的物理信息神经网络(PINN)方法,旨在预测单变量边缘板(OVEP)的动态响应,OVEP是一种独特的板结构,其特征是由任意数学函数定义的边缘。OVEP由石墨烯纳米片增强的纳米复合材料构成。利用优化的PINN管道,本研究成功地预测了OVEP的振动特性,包括线性、非线性振动和跳动现象。该研究还表明,最优的PINN在稳定性、精度(达到99%以上的精度)和预测长时间振动的效率方面优于传统神经网络。此外,与传统的偏微分方程(PDE)求解器相比,生成测试结果所需的计算时间显著减少(减少约3到12倍)。为了证明模型的鲁棒性,在训练数据中有意地引入了合成噪声。结果不仅增强了我们对OVEP复杂动力学的理解,而且突出了所提出的PINN框架在捕获和预测先进板结构动力学行为方面的有效性。这项研究为解决航空航天、土木和机械工程领域的动态问题提供了一个有希望的潜力。
Experimental and numerical study on the blast performance of the corrugated double steel plate concrete composite wallboard under blast loads
Chunfeng Zhao, Li Zhang, Honghao Ma, Jingfeng Wang, Xiaojie Li
doi:10.1016/j.tws.2024.111921
波纹双钢板混凝土组合墙板在爆炸荷载作用下爆破性能的试验与数值研究
The corrugated double steel plate concrete composite wallboard (CDSCW) exhibits superior axial compressive load-bearing capacity, lateral flexural stiffness, impact resistance, and seismic performance compared to the traditional reinforced concrete wallboard and plane double steel plate concrete composite wallboard (PDSCW). Therefore, it has great potential application in offshore engineering and military engineering. This study designs and fabricates two types of CDSCW specimens. Firstly, a comparative analysis is conducted to examine the damage patterns and dynamic responses of the two specimens under near-field explosion experiments. Secondly, the damage mechanisms and explosion response of CDSCW and PDSCW subjected to close-in explosions are numerically investigated by using ANSYS/LS-DYNA, and the results are then compared with experimental findings. Parameter analysis is performed to assess the influence of concrete thickness, steel plate thickness, and explosive charge on the blast resistance of CDSCWs. Furthermore, a nonlinear resistance equation and an equivalent single degree of freedom (ESDOF) theoretical model for simply supported beams is established to predict the dynamic response of CDSCWs under near-blast loads. This theoretical model considers the constitutive model of bilinear materials and the effect of plastic hinges. The reliability of the proposed theoretical model is verified by comparing the residual deflection of CDSCWs obtained from explosion tests with validated numerical simulation results. The results demonstrate that the CDSCWs, with the same concrete and component dimensions (length, width), exhibit greater flexural stiffness and superior energy dissipation capacity subjected to close-in explosion. Moreover, their blast resistance significantly surpasses that of PDSCWs. In particular, an increase in corrugation depth effectively improves the blast resistance of CDSCWs. The dynamic response equations, based on the established elastic-plastic model and primarily considering bending deformation of the components, precisely predict the dynamic response of simply supported CDSCWs under near-blast loads. consequently, these findings can provide a robust foundation for further research and the design of blast-resistant structures.
与传统的钢筋混凝土墙板和平面双钢板混凝土复合墙板(PDSCW)相比,波纹双钢板混凝土复合墙板(CDSCW)具有优越的轴压承载能力、横向抗弯刚度、抗冲击性和抗震性能。因此,它在海洋工程和军事工程中具有很大的应用潜力。本研究设计并制作了两种类型的CDSCW试件。首先,对比分析了两种试样在近场爆炸试验下的损伤形态和动力响应。其次,利用ANSYS/LS-DYNA软件对CDSCW和PDSCW在近距离爆炸作用下的损伤机理和爆炸响应进行了数值研究,并与实验结果进行了比较。通过参数分析,评价了混凝土厚度、钢板厚度、炸药装药对cdscw抗爆性能的影响。在此基础上,建立了简支梁的非线性阻力方程和等效单自由度(ESDOF)理论模型,用于预测简支梁在近爆炸荷载作用下的动力响应。该理论模型考虑了双线性材料的本构模型和塑性铰的影响。通过将爆炸试验得到的cdscw残余挠度与验证的数值模拟结果进行比较,验证了理论模型的可靠性。结果表明,在混凝土和构件尺寸(长、宽)相同的情况下,cdscw具有较大的抗弯刚度和较好的近距离爆炸消能能力。而且,它们的抗爆能力明显优于pdscw。特别是波纹深度的增加有效地提高了cdscw的抗爆能力。基于所建立的弹塑性模型,主要考虑构件的弯曲变形,建立的动力响应方程能够准确地预测简支梁结构在近爆炸荷载作用下的动力响应。因此,这些发现可以为进一步研究和设计防爆结构提供坚实的基础。
Significantly enhanced joint strength and fatigue life of aerospace composite joints by using novel PEEK/PPS woven meshes as joining agent
Dong Quan, Long Qin, Han Chen, Jia Liu, Jun Lin, Guiwei Dong, Guoqun Zhao
doi:10.1016/j.tws.2024.111926
采用新型PEEK/PPS编织网作为连接剂,可显著提高航空航天复合材料接头的连接强度和疲劳寿命
The development of advanced joining methods for carbon fibre/epoxy composites is critical for aerospace applications. Herein, advanced PEEK/PPS meshes were used to join carbon fibre/epoxy composites upon a novel co-curing process. The meshes were surface-activated upon an atmospheric plasma technique, which largely promoted the chemical interactions between the meshes and the composite epoxy matrix. The quasi-static joint strengths at both of 22 °C and 130 °C and fatigue loading resistance of the composite joints were evaluated using a single-lap joint test and the corresponding failure mechanisms were investigated. Encouragingly, the lap-shear strengths and fatigue resistance of the PEEK/PPS mesh-joined composites were larger than that of their counterparts bonded by an aerospace adhesive. Subsequent analysis on the failure surfaces proved PEEK/PPS fibre damage and epoxy crack were the main failure mechanisms of the PEEK/PPS co-cured joints. This work proposed a novel method for the production of robust aerospace joints by co-cure joining the composites using advanced PEEK/PPS meshes.
碳纤维/环氧复合材料的先进连接方法的发展对航空航天应用至关重要。本文采用新型共固化工艺,采用先进的PEEK/PPS网格连接碳纤维/环氧复合材料。采用大气等离子体技术对网格进行表面活化,极大地促进了网格与复合环氧基之间的化学相互作用。采用单搭接试验对复合材料接头在22℃和130℃下的准静态强度和抗疲劳载荷性能进行了评价,并对其失效机理进行了研究。令人鼓舞的是,PEEK/PPS网接复合材料的搭接剪切强度和抗疲劳性能比航空胶粘剂连接的复合材料大。对破坏表面的分析表明,PEEK/PPS纤维损伤和环氧裂缝是PEEK/PPS共固化接头的主要破坏机制。本文提出了一种利用先进的PEEK/PPS网格共固化连接复合材料制造坚固航空航天接头的新方法。