
今日更新:Journal of the Mechanics and Physics of Solids 1 篇,International Journal of Plasticity 4 篇,Thin-Walled Structures 6 篇
Universal Fourier Neural Operators for periodic homogenization problems in linear elasticity
Binh Huy Nguyen, Matti Schneider
doi:10.1016/j.jmps.2025.106418
线性弹性周期均匀化问题的通用傅里叶神经算子
Solving cell problems in homogenization is hard, and available deep-learning frameworks fail to match the speed and generality of traditional computational frameworks. More to the point, it is generally unclear what to expect of machine-learning approaches, let alone single out which approaches are promising. In the work at hand, we advocate Fourier Neural Operators (FNOs) for micromechanics, empowering them by insights from computational micromechanics methods based on the fast Fourier transform (FFT). We construct an FNO surrogate mimicking the basic scheme foundational for FFT-based methods and show that the resulting operator predicts solutions to cell problems with arbitrary stiffness distribution only subject to a material-contrast constraint up to a desired accuracy. In particular, there are no restrictions on the material symmetry like isotropy, on the number of phases and on the geometry of the interfaces between materials. Also, the provided fidelity is sharp and uniform, providing explicit guarantees leveraging our physical empowerment of FNOs. To show the desired universal approximation property, we construct an FNO explicitly that requires no training to begin with. Still, the obtained neural operator complies with the same memory requirements as the basic scheme and comes with runtimes proportional to classical FFT solvers. In particular, large-scale problems with more than 100 million voxels are readily handled. The goal of this work is to underline the potential of FNOs for solving micromechanical problems, linking FFT-based methods to FNOs. This connection is expected to provide a fruitful exchange between both worlds.
在同质化中解决细胞问题是困难的,可用的深度学习框架无法与传统计算框架的速度和通用性相匹配。更重要的是,人们通常不清楚对机器学习方法的期望是什么,更不用说挑出哪些方法有希望了。在手头的工作中,我们提倡将傅里叶神经算子(FNOs)用于微力学,通过基于快速傅里叶变换(FFT)的计算微力学方法的见解赋予它们力量。我们构建了一个FNO代理,模拟基于fft方法的基本方案,并表明由此产生的算子预测具有任意刚度分布的单元问题的解决方案,仅受材料对比约束达到所需的精度。特别是对材料的对称性,如各向同性,相的数量和材料之间界面的几何形状没有限制。此外,所提供的保真度是清晰而统一的,提供了明确的保证,利用我们对fno的物理授权。为了显示期望的普遍近似性质,我们明确地构造了一个不需要训练的FNO。尽管如此,所获得的神经算子符合与基本方案相同的内存要求,并且具有与经典FFT解算器成比例的运行时间。特别是,超过1亿体素的大规模问题很容易处理。这项工作的目的是强调FNOs在解决微力学问题方面的潜力,将基于fft的方法与FNOs联系起来。这一组合有望在两个世界之间提供富有成效的交流。
A coupled crystal plasticity-phase field framework for anisotropic fracture in Ni-based single crystals
H.T. Li, X.M. Wang, H. Cheng, Z.L. Ding, S.Y. Sun, W.Z. Yang, Y. Wang
doi:10.1016/j.ijplas.2025.104541
镍基单晶各向异性断裂的晶体塑性-相场耦合框架
Crack nucleation, propagation and coalescence in anisotropic Ni-based single crystal superalloys are critical to the durability of aero engines hot-section components. This study develops a coupled crystal-plasticity and phase-field model to capture the fracture behavior for the materials and account for the coupling effects between plasticity and damage. The framework incorporates a fracture toughness degradation function driven by plastic strain energy, directly illustrating the influence of plastic deformation on crack resistance. Additionally, a yield surface degradation function, incorporated into power-law flow theory, accounts for damage-induced strength reduction and prevents numerical instabilities in severely damaged zones. Furthermore, elastoplastic constitutive relations are decomposed into crack-driving and persistent components within a variational framework, addressing tension-compression asymmetry for fracture behavior and satisfying the orthogonality decomposition condition for anisotropic materials. The proposed model is validated through numerical examples, demonstrating its ability to accurately predict experimental results and elucidate the anisotropic fracture processes in Ni-based single crystal superalloys. This work provides a robust framework for understanding and predicting fracture in anisotropic materials, with potential applications for advancing aerospace hot-section component design.
各向异性镍基单晶高温合金裂纹的形核、扩展和聚结对航空发动机热断面部件的耐久性起着至关重要的作用。本研究建立了一种晶体-塑性和相场耦合模型,以捕捉材料的断裂行为,并考虑塑性和损伤之间的耦合效应。该框架包含了由塑性应变能驱动的断裂韧性退化函数,直接说明了塑性变形对抗裂性能的影响。此外,纳入幂律流动理论的屈服面退化函数解释了损伤引起的强度降低,并防止了严重损伤区域的数值不稳定。此外,在变分框架内将弹塑性本构关系分解为裂纹驱动和持久分量,解决了断裂行为的拉压不对称问题,并满足各向异性材料的正交性分解条件。通过数值算例验证了该模型的正确性,表明该模型能够准确预测实验结果,并能很好地解释ni基单晶高温合金的各向异性断裂过程。这项工作为理解和预测各向异性材料的断裂提供了一个强大的框架,具有推进航空航天热截面部件设计的潜在应用。
Shock-induced hierarchical plastic deformations in high entropy (Zr0.2Hf0.2Ti0.2Nb0.2Ta0.2)C at high strain rate
Lanxi Feng, Wanghui Li, Wenxuan Tang, Zhuochen Chen, Xiaoqing Zhang, Yilun Xu, Guglielmo Vastola, Fu-Zhi Dai, Yong-Wei Zhang, Xiaohu Yao
doi:10.1016/j.ijplas.2025.104543
高熵(Zr0.2Hf0.2Ti0.2Nb0.2Ta0.2)C在高应变速率下冲击诱发的分层塑性变形
Conventional ceramics have ultra-high strength but often lack plasticity. The high-entropy carbide ceramics (HECCs) offer a new perspective to enhance the plasticity of ceramics, which may extend their applicability as components operating under extreme conditions. However, there still lacks research on the dynamic behavior of HECCs, causing a poor understanding of their plastic response to dynamic loading. In this work, the dynamic behavior of a high-entropy ceramic (Zr0.2Hf0.2Ti0.2Nb0.2Ta0.2)C (denoted as HEC) under shock compression is investigated, for the first time, by the plate impact experiments with two-stage gas gun and molecular dynamics simulations utilizing a deep learning potential based on accurate first-principles data. With increasing shock pressure, HEC undergoes a pronounced elastic-plastic transition characterized by the formation of multiple plastic deformation bands, local phase transition and amorphization, which involve the activations of <1ࣥ1 0>{1 1 0} and <1ࣥ1 0>{1 1 1} slip systems simultaneously. The local lattice distortions in HEC are found to influence the behavior of dislocation propagation during shock compression. Instead of following predefined paths, dislocations tend to deviate at the propagation front, resulting in the formation of vacancies. Our findings reveal the hierarchical plastic deformation mediated by multi-competing mechanis ms in HEC under extreme conditions, suggesting a promising strategy for achieving HECCs that are both strong and ductile.
传统陶瓷具有超高的强度,但往往缺乏可塑性。高熵碳化物陶瓷(HECCs)为提高陶瓷的可塑性提供了一个新的视角,可以扩展其作为极端条件下工作的部件的适用性。然而,对于hecc的动力行为研究仍然缺乏,导致对其在动荷载下的塑性响应的理解较差。在这项工作中,首次通过两级气 枪板冲击实验和基于精确第一原理数据的深度学习潜力的分子动力学模拟,研究了高熵陶瓷(Zr0.2Hf0.2Ti0.2Nb0.2Ta0.2)C(记为HEC)在冲击压缩下的动态行为。随着冲击压力的增加,HEC发生了明显的弹塑性转变,其特征是形成多个塑性变形带,局部相变和非晶化,同时涉及<1ࣥ1 0>{1.1 0}和<1ࣥ1 0>{1.1 1}滑移体系的激活。在激波压缩过程中,发现HEC中的局部晶格畸变会影响位错的扩展行为。而不是按照预定的路径,位错往往偏离在传播前沿,导致空位的形成。我们的研究结果揭示了极端条件下HEC中由多种竞争机制介导的分层塑性变形,为实现既强又延展性的HEC提供了一个有希望的策略。
Excellent mechanical properties and superelasticity: bimodal heterostructure enhances NiTi alloy fabricated via laser powder bed fusion
Minqian Liu, Danyang Lin, Yankun Zhang, Dong Wang, Bo Xiao, Lianyong Xu, Yongdian Han, Fumiyoshi Minami
doi:10.1016/j.ijplas.2025.104544
优异的力学性能和超弹性:双峰异质结构增强了激光粉末床熔合制备的NiTi合金
Heterostructure (HS) materials are selected in natural evolution to exhibit superior mechanical and functional properties that traditional homogeneous materials cannot achieve. However, it is an open issue how to prepare HS alloys without destroying the advantages of laser powder bed fusion (LPBF) to directly form complex components. Here, based on the high stored energy of LPBF components, we obtained bimodal HS LPBF-NiTi shape memory alloys (S MAs) by recrystallization and abnormal grain growth induced by simple heat treatment after LPBF for the first time. The grain size of LPBF-NiTi S MAs can be regulated by modulating the heat treatment temperature. Homogeneous equiaxed fine grains (FGs), homogeneous coarse grains (CGs), and bimodal HS can be obtained after heat treatment at 780℃, 880℃, and 980℃, respectively. It is shown that LPBF-NiTi alloys with bimodal HS exhibit extraordinary strength-ductility (σMTS-δ balance: 13810 MPa•%) and superelasticity (SE) (σC-δC balance: 2232 MPa•% and 96% of SE recovery rate in 4% applied strain). The intrinsic mechanis m leading to property enhancement was studied through in-situ experiments and simulations. It is due to the strain optimization induced by heterogeneous regions, which promotes phase transformation and alleviates plastic deformation, avoiding strain localization. This work provides theoretical and practical significance for the property improvement and application promotion of the LPBF-NiTi alloy and may open a novel avenue for fabricating other LPBF alloys with HS.
异质结构(HS)材料是在自然进化过程中被选择出来的,具有传统均质材料无法达到的优越的力学和功能性能。然而,如何在不破坏激光粉末床熔合(LPBF)直接形成复杂部件的优点的情况下制备HS合金是一个悬而未决的问题。本文首次利用LPBF组分的高存储能量,通过LPBF后的再结晶和简单热处理引起的异常晶粒长大,获得了双峰HS LPBF- niti形状记忆合金(S MAs)。通过调节热处理温度可以调节LPBF-NiTi s ma的晶粒尺寸。780℃、880℃和980℃热处理后,可获得均匀等轴细晶、均匀粗晶和双峰HS。结果表明,具有双峰HS的LPBF-NiTi合金表现出优异的强度-塑性(σMTS-δ平衡:13810 MPa•%)和超弹性(σC-δ c平衡:2232 MPa•%,在4%的应变下SE回收率为96%)。通过现场实验和模拟,研究了性能增强的内在机理。这是由于非均质区引起的应变优化,促进了相变,缓解了塑性变形,避免了应变局部化。本研究为LPBF- niti合金的性能改善和应用推广提供了理论和实际意义,并为利用HS制备其他LPBF合金开辟了新的途径。
Data-inspired atomic environment-dependence of vacancy formation energy in high-entropy alloys
Fusheng Tan, Xin Liu, Xuefeng Liang, Yinan Cui
doi:10.1016/j.ijplas.2025.104545
高熵合金中空位形成能对原子环境的依赖
Vacancy properties in High-entropy alloys (HEAs) play a critical role in governing high-temperature microstructural stability, yet the fundamental relationship between Vacancy Formation Energy (VFE) and heterogeneous Local Atomic Environments (LAE) in HEAs remains far from well understood, owing to the complex and heterogeneous nature of LAE. To address this, we developed an interpretable machine learning framework integrating high-throughput molecular dynamics simulations and physics-informed features. Using CoNiCrFeMn as model system, our approach achieves exceptional prediction accuracy (R² = 0.98) for VFE. It is found that the LAE within the first-nearest-neighbor shell around vacancy dominates VFE variations, and the local atomic spatial ordering exerts influence on VFE comparable in magnitude to local chemical composition. Based on the designated LAE descriptor, namely multilevel element pair probability, and feature ana lysis-guided physics interpretation, we identify for the first time the physical origin of LAE-mediated VFE as the synergistic strong/weak-bond elements competition and lattice distortion effects. Specifically, coexisting strong-bond (e.g., Ni) and weak-bond (e.g., Mn) atoms in 1NN shell around central vacancy drive offsetting displacements through lattice distortion, dynamically tailoring VFE. The mechanis m explains anomalously high lattice distortion and elevated vacancy concentrations observed in Mn-containing CoNiCrFeMn HEAs, and further enables a strategy for enhancing vacancy stability via annealing-induced elemental aggregation. These results establish a theoretical framework for defect engineering in the design of complex solid-solution alloys.
高熵合金(HEAs)的空位性质在高温显微组织稳定性中起着至关重要的作用,但由于高熵合金中空位形成能(VFE)与非均相局部原子环境(LAE)的复杂性和非均相性,空位形成能(VFE)与非均相局部原子环境(LAE)之间的基本关系尚不清楚。为了解决这个问题,我们开发了一个可解释的机器学习框架,集成了高通量分子动力学模拟和物理信息功能。使用CoNiCrFeMn作为模型系统,我们的方法对VFE的预测精度很高(R² = 0.98)。发现空位周围第一近邻壳层内的LAE主导着VFE的变化,局域原子空间排序对VFE的影响程度与局域化学成分相当。基于指定的LAE描述符,即多层元素对概率,以及特征分析指导的物理解释,我们首次确定了LAE介导的VFE的物理起源是强/弱键元素竞争和晶格畸变效应的协同作用。具体来说,围绕中心空位的1NN壳层中共存的强键(如Ni)和弱键(如Mn)原子通过晶格畸变驱动偏移位移,动态地调整VFE。该机制解释了在含锰的CoNiCrFeMn HEAs中观察到的异常高晶格畸变和高空位浓度,并进一步实现了通过退火诱导元素聚集来增强空位稳定性的策略。这些结果为复杂固溶合金缺陷工程设计提供了理论框架。
Effect of compaction rate during cyclic compaction on compaction response of vacuum infusion consumables
Tongtong Wang, Tao Zheng, Fanlin Zeng, Licheng Guo
doi:10.1016/j.tws.2025.114173
循环压实速率对真空输液耗材压实响应的影响
Compaction response is a critical property of Vacuum Infusion (VI) processes. However, common thickness measurement methods capture combined changes from fabrics and consumables, complicating the isolation of fabric compaction response. This study establishes a foundational baseline by characterizing the compaction response of consumables alone in Automatically Controlled Pressure Vacuum Infusion (ACPVI). Using a custom-built automated workstation with Linear Variable Differential Transformer (LVDT) thickness measurement (1 μm resolution), pressure control (0.1 kPa resolution), and machine vision flow monitoring, dry consumables (vacuum bag, semi-permeable membrane, flow media, and peel ply) were subjected to 15 compaction cycles at either 2 kPa/s or 4 kPa/s. Following cyclic compaction, consumables were degassed for 20 min before silicone oil infusion at 49.5 kPa injection pressure, then underwent pressure equilibration for 20 min. Compaction pressure evolution followed an exponential saturation model with rate constants of 0.0881 ± 0.0018 s−1 (2 kPa/s) and 0.1704 ± 0.0032 s−1 (4 kPa/s). Consumables exhibited viscoelastic–plastic behavior, with compaction response normalizing after 10.0 ± 1.8 cycles independent of compaction rate. Compaction rate did not significantly affect minimum compaction thickness or maximum relaxation thickness but influenced elastic deformation during compaction: the 4 kPa/s group exhibited 1.32 ± 0.06 times greater deformation than the 2 kPa/s group. Average infusion time was 31.8 ± 5.2 s with average flow speed of 8.35 ± 1.10 mm/s. Thickness increased 0.002 ± 0.001 mm at full infusion and 0.001 ± 0.001 mm during pressure equilibration. This apparatus and methodology enable precise characterization of consumables’ compaction response, essential for decoupling fabric behavior in full layups.
压实响应是真空注入(VI)过程的一个重要特性。然而,常用的厚度测量方法捕获了织物和消耗品的组合变化,使织物压实响应的隔离变得复杂。本研究通过表征自动控制压力真空输液(ACPVI)中单独耗材的压实响应建立了基础基线。使用特制的自动化工作站进行线性可变差动变压器(LVDT)厚度测量(1微米分辨率)、压力控制(0.1 kPa分辨率)和机器视觉流量监测,干燥耗材(真空袋、半透膜、流动介质和剥离层)以2 kPa/s或4 kPa/s的速度进行15次压实循环。循环压实后,将耗材脱气20 min,注射压力49.5 kPa注入硅油,然后进行压力平衡20 min。压实压力演化遵循指数饱和模型,速率常数分别为0.0881±0.0018 s−1 (2 kPa/s)和0.1704±0.0032 s−1 (4 kPa/s)。耗材表现出粘弹塑性行为,在10.0±1.8次循环后,与压实速率无关的压实响应归一化。压实速率对最小压实厚度和最大松弛厚度没有显著影响,但影响压实过程中的弹性变形,4 kPa/s组的变形比2 kPa/s组大1.32±0.06倍。平均注射时间为31.8±5.2 s,平均流速为8.35±1.10 mm/s。厚度在完全注射时增加0.002±0.001 mm,压力平衡时增加0.001±0.001 mm。该设备和方法能够精确表征耗材的压实响应,这对于解耦织物在全分层中的行为至关重要。
Reduced-order modeling and optimization of sandwich pipe beams with graded corrugated cores based on the mechanics of structure genome
Yayun Yu, Dongli Ma, Liang Zhang, Muqing Yang, Xiaopeng Yang, Hao Guan
doi:10.1016/j.tws.2025.114205
基于结构基因组力学的梯度波纹芯夹芯梁降阶建模与优化
Solar-powered unmanned aerial vehicles (UAVs) are prone to excessive flexibility and structural instability because of their ultralightweight design. The NASA Helios aircraft incident exemplifies this risk, as structural flexibility was a major contributing factor to the pitch oscillations that led to structural breakup. Improving the stiffness-to-weight ratio of the tubular structures—the primary load-bearing members—is thus essential for improving aircraft performance. For this purpose, in this paper, sandwich pipe beams with longitudinal trapezoidal corrugated cores—either uniform or graded—were proposed, and their bending capacity was investigated. To overcome the computational complexity of such structures and enable iterative optimization, we extend the mechanics of structure genome (MSG), which, through its explicit and reversible macro–micro strain mapping, is further advanced to predict not only stiffness but also failure loads, thereby serving as the foundation of the model reduction framework. Case studies revealed that the framework reduces degrees of freedom to less than 5% of those of the full finite element models while retaining high accuracy, with discrepancies of 2–6% for stiffness and failure loads and 14.1% for local buckling loads, enabling efficient evaluation and optimization of the proposed structures. An experimental study also validated the method’s accuracy. Combined with Bayesian optimization, sandwich pipe beams with graded and uniform corrugated cores were optimized and compared with those with common isotropic cores. The optimization results revealed that the optimal beam with a corrugated core achieved 31.0% and 32.3% increases in bending stiffness and failure load, respectively, compared with those with a polymethacrylimide (PMI) core, whereas the weightiness of the graded core further decreased by 10.6%, offering new insights for load-bearing structure design for solar-powered UAVs.
太阳能无人机由于其超轻的设计,容易产生过大的灵活性和结构不稳定性。美国宇航局太阳神号飞机事故就是这种风险的例证,因为结构的灵活性是导致结构破裂的俯仰振荡的主要因素。因此,提高管状结构(主要承重构件)的刚度重量比对于提高飞机性能至关重要。为此,本文提出了纵向梯形波纹芯-均匀或梯度-夹芯管梁,并对其抗弯能力进行了研究。为了克服此类结构的计算复杂性并实现迭代优化,我们扩展了结构基因组(MSG)的力学,通过其显式和可逆的宏微观应变映射,进一步推进了结构基因组(MSG)的力学,不仅可以预测刚度,还可以预测破坏载荷,从而作为模型约简框架的基础。案例研究表明,该框架在保持高精度的同时,将自由度降低到完整有限元模型的5%以下,刚度和破坏载荷的误差为2-6%,局部屈曲载荷的误差为14.1%,从而能够有效地评估和优化所提出的结构。实验研究也验证了该方法的准确性。结合贝叶斯优化,对梯度均匀波纹芯夹层管梁进行了优化,并与普通各向同性波纹芯夹层管梁进行了比较。优化结果表明,与采用聚甲基丙烯酰亚胺(PMI)芯材相比,采用波纹芯材的优化梁的弯曲刚度和破坏载荷分别提高了31.0%和32.3%,而分级芯材的重量则进一步降低了10.6%,为太阳能无人机的承载结构设计提供了新的思路。
A novel unified solution framework for free vibration of non-Lévy-type porous FGM plates
Jinghui Zhang, Yu Du, Yiming Chen, Jiale Lu, Qingxin Zhao, Salamat Ullah, Rui Li
doi:10.1016/j.tws.2025.114215
一种新的非lcv型多孔FGM板自由振动统一解框架
This study presents new ana lytic free vibration solutions of porous functionally graded material (FGM) rectangular plates subjected to various non-Lévy-type boundary conditions (BCs) by a successful extension of the finite integral transform (FIT) method, which, unlike traditional semi-inverse methods, eliminates the need for assumed deflection functions. The rigorous solution method ensures exact satisfaction of both the governing partial differential equation and BCs. The unified solution framework based on the FIT is suitable for porous FGM plates under arbitrary combinations of free, clamped, and simply supported boundaries. A convergence a nalysis demonstrates the excellent convergence characteristics of the present method. The accuracy of the present solutions is verified through comparisons with finite element solutions and literature results. Further, the effects of FGM models, aspect ratios, porous distribution patterns, BCs, and porosity coefficients on the natural frequencies of the plates are systematically investigated. This study provides valuable benchmarks for studying the vibration behavior of porous FGM plates, which in turn advances the field of plate dynamics.
本文通过有限积分变换(FIT)方法的成功推广,给出了多孔功能梯度材料(FGM)矩形板在各种非l<s:1>型边界条件(bc)下的自由振动解析解,与传统的半逆方法不同,该方法消除了假设挠度函数的需要。严格解法保证了控制偏微分方程和bc的精确满足。基于FIT的统一解框架适用于自由边界、夹紧边界和简支边界任意组合的多孔FGM板。收敛性分析证明了该方法具有良好的收敛性。通过与有限元解和文献结果的比较,验证了本文解的准确性。此外,系统地研究了FGM模型、宽高比、多孔分布模式、bc和孔隙系数对板固有频率的影响。该研究为研究多孔FGM板的振动行为提供了有价值的基准,从而推动了板动力学领域的发展。
Large-Scale 3D RVE Modelling of Closed-Cell Foams for Structural Ana lysis
Lifeng Ni, Da Chen, Wei Gao
doi:10.1016/j.tws.2025.114184
闭孔泡沫结构分析的大尺度三维RVE模型
Closed-cell foams are highly valued for their superior stiffness-to-weight ratios and energy absorption capacities, making them appealing for various lightweight structural applications. The accurate prediction of their mechanical properties is hindered by the random nature of foams, which is addressed in this paper by proposing a large-scale three-dimensional (3D) representative volume element (RVE) framework containing 1000 cells. This RVE model is generated by randomly distributing seed points within a cubic domain to form polyhedral cells via Voronoi tessellation. Adopting such a large number of internal cells is essential to effectively capture the statistical and geometric characteristics of target foams. Representative elastic properties are then extracted for the subsequent multi-scale structural ana lysis with a five-layer functionally graded (FG) beam model to investigate its global buckling and vibration behaviours. A symmetric porosity distribution is defined along the thickness, and Timoshenko beam theory is employed to account for both bending and shear effects. Parametric studies further explore the influence of porosity gradient, and the structural responses calculated from the proposed model are benchmarked against results from an established two-dimensional (2D) strut-based low-density RVE model and empirical equations based on CT-scanned foam structures. The advantages of using large-scale 3D RVEs are highlighted via accurate mechanical behaviour prediction, indicating their enhanced physical representativeness. The tuneable microstructural design from the proposed framework offers broad applicability for modelling and optimisation of closed-cell foam structures.
闭孔泡沫因其优越的刚度重量比和能量吸收能力而受到高度重视,使其在各种轻量化结构应用中具有吸引力。泡沫的随机性阻碍了其力学性能的准确预测,本文通过提出包含1000个单元的大型三维(3D)代表性体积单元(RVE)框架来解决这一问题。该RVE模型是在三次域中随机分布种子点,通过Voronoi镶嵌形成多面体细胞。为了有效地捕捉目标泡沫的统计和几何特征,采用如此大量的内部细胞是必不可少的。然后提取具有代表性的弹性特性,用于随后的五层功能梯度(FG)梁模型的多尺度结构分析,以研究其整体屈曲和振动行为。定义了沿厚度对称的孔隙率分布,并采用Timoshenko梁理论来解释弯曲和剪切效应。参数研究进一步探讨了孔隙度梯度的影响,并将该模型计算的结构响应与已建立的二维(2D)基于支柱的低密度RVE模型和基于ct扫描泡沫结构的经验方程的结果进行了基准测试。通过精确的力学行为预测,强调了使用大规模3D rve的优势,表明它们具有增强的物理代表性。提出的框架的可调微结构设计为闭孔泡沫结构的建模和优化提供了广泛的适用性。
Bidirectional payload enhancement of soft actuator via nested dual-chamber origami structure
Xiaohuang Liu, Zhonggui Fang, Shaowu Tang, Fang Chen, Dihan Liu, Sicong Liu, Juan Yi, Hongqiang Wang, Zheng Wang, Jian S. Dai
doi:10.1016/j.tws.2025.114187
基于嵌套双腔折纸结构的软执行器双向有效载荷增强
Pneumatic soft robots offer promising solutions for safe human–robot interaction and exploration tasks in unstructured environments. However, compared with the positive pressure (≫1 atm) input, the limited driving capacity of the negative pressure (<1 atm) input restricts the bidirectional payload output performance of the soft pneumatic actuators (SPAs). In this paper, we propose the nested dual-chamber origami (NDO) structure which enables the bidirectional compounding actuation, i.e. applying positive and negative pressure input simultaneously to generate linear motions in opposite axial directions, to enhance the SPA’s bidirectional payload performance. Based on the ana lysis on the correlation of the symmetries and the motion modes of the soft origami chambers, a linear NDO actuator is constructed by coaxially nesting the external Yoshimura origami (EYO) chamber and the internal Pleated origami (IPO) chamber. The quasi-static models of the chambers are derived to present the NDO deformations. The resisting force of curved convergent creases is derived by defining the proportional relation between the length of the folding region and width of the origami facet based on the s mall-strain folding (SSF) principle. The theoretical models are validated by the mechanical behaviors of the 3D-printed NDO actuator in experiments and the payload enhancement is verified. The average enhancement of the contraction force (and elongation force) of the NDO actuator reaches 101.7% (and 70.5%) over the single-chamber EYO actuator and 21.2% (and 19.7%) over the sum of independent single-chamber EYO actuator and IPO actuator. The practicality of the NDO actuator is verified by driving a compact gripper with high payload performance in both gripping and stretching motions. The bidirectional enhancement with compact design will promote the development and application of soft pneumatic actuators.
气动软机器人为安全的人机交互和非结构化环境中的探索任务提供了有前途的解决方案。然而,与正压(≫1 atm)输入,负压(<1atm)输入限制了软气动执行器(spa)的双向有效载荷输出性能。本文提出了嵌套式双腔折纸(NDO)结构,实现双向复合驱动,即同时施加正负压输入,产生相反轴向的线性运动,以提高SPA的双向有效载荷性能。在分析软折纸腔对称性和运动模式相关性的基础上,将外吉村折纸腔(Yoshimura origami, EYO)和内折纸腔(Pleated origami, IPO)同轴嵌套,构建了线性NDO驱动器。建立了模拟腔室NDO变形的准静态模型。基于小应变折叠(SSF)原理,定义折纸区域长度与折纸面宽度的比例关系,推导出弯曲收敛折痕的阻力。通过3d打印NDO作动器的力学性能对理论模型进行了验证,并对载荷增强进行了验证。NDO执行器的收缩力(伸长力)比单腔EYO执行器平均提高101.7%(70.5%),比独立的单腔EYO执行器和IPO执行器的总和平均提高21.2%(19.7%)。NDO驱动器的实用性是通过驱动紧凑型夹持器在夹持和拉伸运动中具有高负载性能来验证的。紧凑设计的双向增强将促进柔性气动执行器的发展和应用。
Polyurea-coated metal cylindrical shell structure subjected to repeated explosion loads: From material mechanical properties to structural damage evolution
Kun Zhang, Xin Wang, Haojie Zhu, Wenqian Wan, Gang Wu, Yue Yu, Kaikai Zhang, Chong Ji
doi:10.1016/j.tws.2025.114207
反复爆炸载荷下聚氨酯涂层金属圆柱壳结构:从材料力学性能到结构损伤演化
The damage evolution of polyurea-coated metal cylindrical shells under repeated explosion loads was investigated in this study, with particular emphasis placed on the effects of polyurea thickness, explosion frequency, and interfacial bonding properties on structural blast resistance. Experimental and finite element method (FEM) ana lyses revealed that under an initial explosion loads, polyurea coatings significantly reduced dent depth and deflection deformation by 40-60% compared to uncoated steel pipes, indicating a notable protective effect. Coating failure modes demonstrated strong thickness dependence: thin coatings (1-2 mm) primarily failed through ablation and tearing, whereas thicker coatings (4-6 mm) exhibited interfacial debonding. A minimum thickness of 6 mm was required to suppress cracking under repeated explosion loads. Polyurea layers reduced stress peaks of the pipe by 30-50%, effectively attenuating stress propagation and concentration. Energy dissipation capacity varied non-linearly with thickness; although thicker coatings improved energy absorption during the initial blast, pipes with 4 mm coatings showed negligible energy reduction (≤5%) under repeated explosions.
本研究研究了聚脲涂层金属圆柱壳在重复爆炸载荷下的损伤演变,重点研究了聚脲厚度、爆炸频率和界面结合性能对结构抗爆性能的影响。实验和有限元分析表明,在初始爆炸荷载作用下,聚脲涂层与未涂层钢管相比,可显著减少凹痕深度和挠曲变形40-60%,具有显著的保护作用。涂层失效模式表现出很强的厚度依赖性:薄涂层(1-2毫米)主要通过烧蚀和撕裂而失效,而厚涂层(4-6毫米)则表现出界面脱粘。在重复爆炸荷载作用下,最小厚度要求为6mm,以抑制开裂。聚脲层使管道的应力峰值降低了30-50%,有效地减弱了应力的传播和集中。能量耗散能力随厚度呈非线性变化;虽然较厚的涂层改善了初始爆炸时的能量吸收,但在重复爆炸中,4mm涂层的管道的能量减少可以忽略不计(≤5%)。