【新文速递】2024年4月14日固体力学SCI期刊最新文章

 

今日更新：International Journal of Solids and Structures 3 篇，Journal of the Mechanics and Physics of Solids 1 篇，Mechanics of Materials 1 篇，Thin-Walled Structures 6 篇

International Journal of Solids and Structures

Dynamic characteristics of density-graded cellular materials for impact mitigation

Vijendra Gupta, Addis Kidane, Michael Sutton

doi:10.1016/j.ijsolstr.2024.112816

用于减缓冲击的密度梯度蜂窝材料的动态特性

Due to their exceptional impact resistance capabilities, density-graded cellular materials have immense potential in applications where crashworthiness requirements are of prime importance. Under impact loading, the deformation in these materials is characterized by compaction front propagation. Previous studies have utilized numerical techniques to solve the equations governing compaction wave propagation for cellular materials with density gradation. In this study, analytical solutions are formulated using compaction front position as the independent variable. The expressions for the velocity of the impinging rigid mass, energy absorption capacity, incident stress, and transmitted stress are determined. The analytical solutions are shown to be in excellent agreement with the cell-based finite element solutions. The effect of density gradient on energy absorption and stresses is studied. The impact resistance factor is employed to assess different density-graded cellular materials for their effectiveness in impact mitigation. This study demonstrates that density-graded cellular materials can offer superior impact protection to objects at both the incident and transmitted ends. Lower density toward the incident end enhances impact resistance to objects located there, and likewise, lower density at the transmitted end offers more impact resistance to objects at that end.

由于其卓越的抗冲击能力，密度梯度蜂窝材料在耐撞性要求非常重要的应用中具有巨大的潜力。在冲击载荷作用下，这些材料的变形以压实前传播为特征。以往的研究利用数值技术求解具有密度梯度的细胞材料的压实波传播方程。在本研究中，以压实前位置为自变量，制定了解析解。确定了碰撞刚体的速度、能量吸收能力、入射应力和透射应力的表达式。结果表明，解析解与基于单元的有限元解非常吻合。研究了密度梯度对能量吸收和应力的影响。采用抗冲击系数来评估不同密度梯度的蜂窝材料在减缓冲击方面的有效性。该研究表明，密度梯度蜂窝材料可以在入射端和传输端对物体提供优越的冲击保护。朝向入射端较低的密度增强了对位于那里的物体的抗冲击性，同样，在传输端较低的密度提供了对该端物体的更大的抗冲击性。

A finite-deformation isotropic non-associative viscoplasticity/damage coupled thermodynamic model for ductile fracture of thick adhesive composite joint

P.F. Liu, H.Y. Chen

doi:10.1016/j.ijsolstr.2024.112825

厚粘接复合材料接头韧性断裂有限变形各向同性非关联粘塑性/损伤耦合热力学模型

This paper develops a finite-deformation isotropic non-associative viscoplasticity/ damage coupled model to predict ductilefracture behaviors of thick adhesive composite joints within the framework of irreversible thermodynamics. First, a damage variable is introduced into the elastic constitutive model, along with the Drucker-Prager’s type yielding function and plastic potential function which take into account the variable hydrostatic pressure and non-associative plasticity. An exponential damage potential function is developed to derive the damage evolution law relating to the thermodynamic force. Second, both kinematic hardening and isotropic hardening are considered that are represented by the back stress, hardening stress, and their conjugate relationships with the corresponding internal variables derived by the Helmholtz free energy. Third, an extended version of the Perzyna’s type model is developed by incorporating an over-stress function to derive the consistency plasticity factor for the viscoplasticity/damage coupled model. Fourth, the strain, stress, back stress, thermodynamic force, damage variable and tangent modulus are updated within the corotated configuration in the integration procedure. To simplify numerical computation, the stress and strain at time n + 1 are initially updated using the frozen damage variable and the back stress at time n, and the latter two values are independently updated at time n + 1. Finally, the developed model and numerical algorithm by implicit FEA are employed to predict the strain, stress, back stress and damage behaviors of the dog-bone MMA specimens under tensile loads and the thick MMA adhesive specimens under shear loads.

在不可逆热力学框架下，建立了有限变形各向同性非关联粘塑性/损伤耦合模型来预测厚粘接复合材料接头的韧性断裂行为。首先，在弹性本构模型中引入损伤变量，同时引入考虑变静水压力和非关联塑性的Drucker-Prager型屈服函数和塑性势函数;建立了指数损伤势函数，导出了与热动力有关的损伤演化规律。其次，考虑了由背应力、硬化应力及其与由亥姆霍兹自由能导出的相应内变量的共轭关系所表示的运动硬化和各向同性硬化。第三，通过引入超应力函数推导粘塑性/损伤耦合模型的一致性塑性因子，建立了扩展版的Perzyna型模型。第四，在积分过程中，将应变、应力、背应力、热动力、损伤变量和切向模量在配位结构中进行更新。为简化数值计算，采用冻结损伤变量和n时刻的背应力对n + 1时刻的应力和应变进行初始更新，后两者分别在n + 1时刻独立更新。最后，采用隐式有限元法建立模型和数值算法，对狗骨MMA试件在拉伸荷载和厚MMA粘结试件在剪切荷载作用下的应变、应力、背应力和损伤行为进行了预测。

Numerical modelling of contact adhesion in a random assembly of elastic–plastic particles

Nils Audry, Barthélémy Harthong, Didier Imbault

doi:10.1016/j.ijsolstr.2024.112826

弹塑性颗粒随机组合中接触粘附的数值模拟

The prediction of tensile strength properties of powder compacts remains an important industrial issue. In particular, one of the main problems of the powder compaction process is the failure of compacts. Indeed, some powder compacts exhibit cracks which appear during compaction. Such defects occur due to localised tensile or shear stresses, for example close to geometrical singularities. They are also related to the ability of a powder to create enough adhesion at contacts between particles to withstand tensile stresses. Therefore, cracks are a consequence of phenomena occurring at the particle scale and below, down to the molecular scale. To help understanding this mechanism, a particle-scale, numerical method called the multi-particle finite-element method was developed using the finite-element software suite Abaqus (Abaqus 6.14 Documentation, 2016). Such a method allowed to explicitly model the microstructure of a granular media idealised as an assembly of elastic–plastic spheres. The particles were meshed such that their deformations were fully taken into account, using a continuum-mechanics-based material model. The interactions between particles were managed using finite-element contact formulations. A multi-scale, adhesive contact model was developed based on the literature and implemented into the multi-particle finite-element code. The contact model was based on a surface energy formulation weighted by the roughness model developed by Pullen and Williamson (1972). It introduced a novel aspect, the development of adhesion under the effect of external mechanical loads, which is consistent with the cold compaction process. This model was then applied to predict the mesoscopic properties of a packing of spheres, i.e. its response to mechanical stresses of any type, in particular strongly deviatoric stress paths. Such a method intends to be a help toward the development of an efficient continuum model for the modelling of the powder compaction process.

粉末压实材料抗拉强度的预测一直是一个重要的工业问题。特别是粉末压实过程的主要问题之一是压实件的失效。事实上，一些粉末压实材料在压实过程中会出现裂纹。这种缺陷的发生是由于局部的拉伸或剪切应力，例如接近几何奇点。它们还与粉末在颗粒之间接触时产生足够的附着力以承受拉伸应力的能力有关。因此，裂纹是发生在颗粒级及以下，直至分子级的现象的结果。为了帮助理解这一机制，使用有限元软件套件Abaqus (Abaqus 6.14 Documentation, 2016)开发了一种称为多粒子有限元的粒子尺度数值方法。这种方法可以明确地模拟理想的弹塑性球体组合的颗粒介质的微观结构。使用基于连续力学的材料模型，对颗粒进行网格划分，使其变形得到充分考虑。粒子间的相互作用采用有限元接触公式进行处理。在文献基础上建立了多尺度黏着接触模型，并将其实现到多粒子有限元程序中。接触模型基于一个表面能公式，该公式由Pullen和Williamson(1972)开发的粗糙度模型加权。它引入了一个新的方面，即在外部机械载荷的作用下粘附的发展，这与冷压过程是一致的。然后将该模型应用于预测球体填料的介观性质，即其对任何类型的机械应力的响应，特别是强偏应力路径。这种方法旨在为粉末压实过程建模的有效连续体模型的发展提供帮助。

Journal of the Mechanics and Physics of Solids

Dispersion and attenuation relations in Flexoelectricity

Antonios E. Giannakopoulos, Ares J. Rosakis

doi:10.1016/j.jmps.2024.105648

柔性电中的色散和衰减关系

The dispersion relations in flexoelectricity are examined for plane time-harmonic waves that propagate in the flexoelectric materials. In contrast to classic elastodynamics, dispersion is observed in the displacement field due to two micro-structural and two micro-inertial lengths that emerge from the electromechanical coupling. In the absence of such coupling, we return to the classic elastodynamic results. The problem dissociates in longitudinal and transverse waves, as is the case in classic elastodynamics. The group velocity of the mechanical field is also the velocity of the energy transfer across the planes of the waves. An optical branch of the dispersion relation appears due to the polarization field that follows the mechanical field. The longitudinal and transverse velocities of the plane waves was found to depend on the corresponding microstructural lengths and are less than or equal to the classic plane wave velocities because the micro-inertial lengths are greater than or equal to the micro-structural length. The opposite effect is expected when we encounter flexoelectric metamaterials in which case the micro-inertial lengths are less than the micro-structural length.

研究了在挠性电材料中传播的平面时谐波在挠性电中的色散关系。与经典弹性动力学相反，由于机电耦合产生的两个微观结构和两个微惯性长度，在位移场中观察到色散。在没有这种耦合的情况下，我们回到经典的弹性动力学结果。这个问题在纵波和横波中分离，就像经典弹性动力学中的情况一样。机械场的群速度也就是波平面上能量传递的速度。色散关系的光学分支是由于随力学场而来的偏振场而产生的。发现平面波的纵、横波速度与相应的微结构长度有关，由于微惯性长度大于或等于微结构长度，所以平面波速度小于或等于经典平面波速度。当我们遇到挠性电超材料时，微惯性长度小于微结构长度，则会产生相反的效果。

Mechanics of Materials

A Constitutive Model of Dual-component Shape Memory Hybrids Considering Isothermal Crystallization and Debonding Damage

Chao Yin, Taoxi Wang, Wei Min Huang, Leipeng Song, Deng Liu, Zhongkai Xi, Jian Fu, Xing Shen

doi:10.1016/j.mechmat.2024.105009

考虑等温结晶和脱粘损伤的双组分形状记忆杂化材料本构模型

The concept of shape memory hybrids (SMHs) has been proposed in recent years as a new kind of shape memory materials. By carefully selecting the actual composition of SMHs, some special features could be realized to meet the requirements of particular engineering applications. However, in terms of simulation, conventional constitutive models for shape memory polymers (SMPs) struggle to precisely characterize certain unique properties of these SMHs. In this study, a constitutive model integrating both rheology and phase transition conceptions is proposed to simulate the mechanical behaviors including shape memory effect of dual-component SMHs. The specific yielding phenomenon at room temperature of SMHs, induced by debonding between two components, is explained by incorporating particle-damage theory. Compared with the experimental and simulated results from a kind of SMH which can be programmed isothermally, it is indicated that the proposed constitutive model effectively captures the mechanical characteristics as well as the shape memory behaviors and the phenomenon of particle debonding damage of these SMHs. Furthermore, the influences of different parameters, such as component proportion, temperature, and isothermal shape fixing time, on these SMHs are discussed as well. This versatile model offers valuable insights for the development of constitutive models in this field as it is not limited to this case only, but could also be promoted to various different kinds of dual-component SMH systems.

形状记忆杂化材料是近年来提出的一种新型形状记忆材料。通过仔细选择smh的实际组成，可以实现一些特殊的功能，以满足特定工程应用的要求。然而，在模拟方面，传统的形状记忆聚合物(SMPs)的本构模型难以精确表征这些SMHs的某些独特性质。在本研究中，提出了一个结合流变和相变概念的本构模型来模拟双组分smh的力学行为，包括形状记忆效应。结合粒子损伤理论解释了两组分间脱粘引起的SMHs室温屈服现象。与一种可等温编程的SMH的实验和模拟结果比较，表明所建立的本构模型能有效地反映SMH的力学特性、形状记忆行为和颗粒脱粘损伤现象。此外，还讨论了组分比例、温度、等温定形时间等参数对SMHs的影响。该通用模型为本构模型的发展提供了有价值的见解，因为它不仅限于这种情况，而且可以推广到各种不同类型的双组分SMH系统。

Thin-Walled Structures

An optimization method of wall thickness distributions in T-shaped tube compound-forming method with unconventional tube blank

Chuang Wei, Zhiren Han, Zhen Jia, Baoming Liu

doi:10.1016/j.tws.2024.111892

非常规管坯复合成形t形管壁厚分布的优化方法

The thin-walled T-shaped tube is widely applied in aviation pipeline systems with the development of lightweight manufacturing technology. However, the severe wall thickness thickening is a bottleneck problem restricting the application of T-shaped tubes. In order to avoid excessive thickening and improve the overall performance of the formed parts, an optimization method of wall thickness distributions in T-shaped tube compound forming by using optimized unconventional tube blank is proposed. The strain spline method is adopted to investigate the stress-strain state and deformation mechanism of T-shaped compound forming. The optimization model of tube blank is established and includes two parts: the initial optimization based on the geometric analytic method and the iterative optimization based on the incremental finite element method. The optimal tube blank is achieved through two-step optimizations. The numerical simulations and experiments of T-shaped tube compound forming using conventional and optimized tube blanks are carried out to investigate the forming height and the wall thickness distributions. The simulation and experimental results agree with a no more than 20% relative error. The optimal tube blank could effectively improve the wall thickness distributions compared with the T-shaped tube compound using the conventional tube blank. The final experimental results show that the maximum thickening rate decreases from 48.67% to 28.67%, the maximum thinning rate decreases from 25.33% to 18%, and the maximum difference in the wall thickness decreases from 1.11mm to 0.7mm. The comparison results are further verified to be the correctness of the optimization method and the effectiveness of the T-shaped tube compound forming method with unconventional tube blank in the actual experiments.

随着轻量化制造技术的发展，薄壁t型管在航空管道系统中得到了广泛的应用。然而，严重的壁厚增厚是制约t型管应用的瓶颈问题。为了避免成形件过厚，提高成形件的整体性能，提出了一种利用优化后的非常规管坯进行t型管复合成形壁厚分布的优化方法。采用应变样条法研究了t形复合成形的应力-应变状态及变形机理。建立了管坯优化模型，包括基于几何解析法的初始优化和基于增量有限元法的迭代优化两部分。通过两步优化得到最优管坯。采用常规和优化后的管坯对t形管进行了复合成形的数值模拟和实验，研究了成形高度和壁厚分布。仿真与实验结果吻合，相对误差不超过20%。与常规管坯相比，优化后的管坯能有效改善t型管材的壁厚分布。最终实验结果表明，最大增厚率由48.67%降至28.67%，最大减薄率由25.33%降至18%，壁厚最大差由1.11mm降至0.7mm。对比结果在实际实验中进一步验证了优化方法的正确性和非常规管坯t型管复合成形方法的有效性。

Spatio-Temporal Autogenous Shrinkage and Cracking Behavior of Core Concrete in Full-Scale CFST: Insights from the World's Largest Span Arch Bridge

Zheng Chen, Changjie Wu, Xiaobin Luo, Wen Xu, Weiying Liang, Yunchao Tang

doi:10.1016/j.tws.2024.111899

全尺寸CFST中核心混凝土的时空自收缩和开裂行为:来自世界最大跨径拱桥的见解

A full-scale concrete-filled steel tube (CFST) examination was performed on the Tian'e Longtan Bridge, featuring a 600-meter span and 0.9-meter steel tube diameter, to assess internal autogenous shrinkage distribution. This study employed vibrating wire strain gauges and distributed optical fibers to measure the shrinkage and detect cracking in the core concrete. Analysis of the test results led to the formulation of models that describe the axial shrinkage behavior over time and space. Increased optical fiber strain highlighted regions undergoing local plastic softening and cracking. This research facilitates the early prediction and precise identification of potential cracking areas in the core concrete through optical fiber monitoring.

对跨度600米、钢管直径0.9米的天峨龙潭大桥进行了全尺寸钢管混凝土(CFST)试验，以评估其内部自收缩分布。本研究采用振动丝应变仪和分布式光纤对核心混凝土进行收缩测量和裂缝检测。对试验结果的分析得出了描述轴向收缩随时间和空间变化的模型。增加的光纤应变突出区域发生局部塑性软化和开裂。本研究有助于通过光纤监测对核心混凝土潜在开裂区域进行早期预测和精确识别。

Towards the fast buckling load prediction of composite shells via Bloch wave based numerical vibration correlation technique

Pingtao Lai, Yu Sun, Lei Huang, Hongqing Li, Zhizhong Cheng, Bo Wang, Kuo Tian

doi:10.1016/j.tws.2024.111901

基于布洛赫波数值振动相关技术的复合材料壳体屈曲载荷快速预测

The buckling load revealing structural capacity bears significant value for the design of engineering composite shells, especially in the aerospace industry. Non-destructive methods are prevailing for critical buckling load prediction. However, the experimental costs and computational time for the analysis are unaffordable, especially for large-scale and complex shells. Despite the numerical vibration correlation technique (NVCT) and its modifications proposed for faster critical buckling load prediction, the efficiency requires further improvement. For composite shells with rotational periodicity, analyzing one substructure based on the Bloch wave method can be an alternate for the analysis of the entire shell. Since the NVCT comprises the linear buckling analysis and repeated frequency analyses, twofold acceleration can be performed. Thus, the Bloch wave based numerical vibration correlation technique (BW-NVCT) is proposed. Firstly, the formulations for the Bloch wave method and the NVCT are derived. As the curve of Bloch wave numbers and buckling loads is monotonous or principally comprise a single peak, the computations in the Bloch wave method to determine the minimum buckling load are further reduced. Then, the implementation of BW-NVCT is presented wherein the Bloch wave calculations are simplified compared with the Bloch wave buckling analysis method. Secondly, three types of composite shells including the Z33 composite cylindrical shell, the pressure vessel and the nozzle are analyzed by the proposed method. By applying Bloch boundary conditions to the substructure, the linear buckling loads, natural frequencies are in high accuracy with respect to results by finite element analyses directly. In addition, predicted critical buckling loads by the BW-NVCT are in excellent precision and most importantly, remarkable efficiency is achieved compared with both the NVCT and the dynamic explicit analysis. Results show that the proposed method can capture both global and local buckling modes, even when bend-twist coupling exists. It is concluded that the BW-NVCT is widely applicable for composite shells and is substantiated as an effective method for fast buckling load prediction.

揭示结构能力的屈曲载荷对工程复合材料壳体的设计，特别是在航空航天工业中具有重要的价值。非破坏性方法是预测临界屈曲载荷的主要方法。然而，分析的实验成本和计算时间是无法承受的，特别是对于大型和复杂的壳。尽管数值振动相关技术(NVCT)及其改进可以更快地预测临界屈曲载荷，但效率有待进一步提高。对于具有旋转周期性的复合材料壳，基于布洛赫波法分析一个子结构可以替代整个壳的分析。由于NVCT包括线性屈曲分析和重复频率分析，因此可以进行双重加速。为此，提出了基于布洛赫波的数值振动相关技术(BW-NVCT)。首先推导了布洛赫波法和NVCT的计算公式。由于布洛赫波数与屈曲载荷曲线单调或主要由单峰组成，进一步减少了用布洛赫波法确定最小屈曲载荷的计算量。然后，给出了BW-NVCT的实现方法，与Bloch波屈曲分析方法相比，简化了Bloch波的计算。其次，采用该方法对Z33复合圆柱壳、压力容器和喷嘴三种复合壳体进行了分析。将Bloch边界条件应用于子结构，得到的线性屈曲载荷、固有频率与有限元直接分析结果具有较高的精度。此外，BW-NVCT对临界屈曲载荷的预测精度较高，且与NVCT和动力显式分析相比效率显著。结果表明，即使存在弯曲-扭转耦合，该方法也能捕获全局和局部屈曲模式。结果表明，BW-NVCT在复合材料壳体屈曲载荷快速预测中具有广泛的适用性，是一种有效的方法。

A novel stability analysis method of single-layer ribbed reticulated shells with roof plates

Xudong Cheng, Zhonghao Wu, Cong Zhen, Wenxuan Li, Chuan Ma

doi:10.1016/j.tws.2024.111902

一种新的带顶板单层肋网壳稳定性分析方法

The steel dome of liquefied natural gas (LNG) storage tanks comprises a curved roof plate welded onto a single-layer ribbed reticulated shell (SLRR shell). However, the roof plate may cause diaphragm effects, which may resulting in instability of the steel dome at a relatively low load level. In this paper, an innovative equivalent single-layer ribbed reticulated shell (ESLRR shell) was proposed to investigate the impact of the diaphragm effect. Specifically, the roof plate and H-shaped radial beam were equated as radial irregular beams based on the principle of plate-shell composite action. Next, we performed a systematic analysis of the instability mechanisms in the ESLRR shell, revealing the interaction between the beam buckling and the overall structural instability. Finally, through parametric study, we explored the effects of roof plate thickness and rise-to-span ratio on the ESLRR shell, and obtained the optimal structural parameters. The results show that the proposed method effectively solves the challenges associated with the presence of roof plates in LNG storage tanks steel dome stability analysis; Under the combination of weak boundary stiffness and high bending moment, radial irregular beams are more prone to buckling; Increasing roof plate thickness or rise-to-span ratio can reinforce the stability of the ESLRR shell. Overall, this research work provides theoretical guidance for the future design and optimization of LNG storage tank domes.

液化天然气(LNG)储罐的钢圆顶由焊接在单层肋网壳(SLRR壳)上的弯曲顶板组成。然而，顶板可能产生膜片效应，这可能导致钢穹顶在相对较低的荷载水平下失稳。本文提出了一种创新的等效单层肋网壳(ESLRR壳)来研究隔膜效应的影响。根据板壳复合作用原理，将屋盖板和h形径向梁等效为径向不规则梁。接下来，我们对ESLRR壳的失稳机制进行了系统的分析，揭示了梁屈曲与整体结构失稳之间的相互作用。最后，通过参数化研究，探讨了屋面板厚度和高跨比对ESLRR壳的影响，得到了最优结构参数。结果表明，该方法有效地解决了LNG储罐钢穹窿稳定性分析中存在顶板的难题;在弱边界刚度和高弯矩的组合作用下，径向不规则梁更易发生屈曲;增加顶板厚度或增大顶跨比可以增强ESLRR壳的稳定性。总体而言，本研究工作为未来LNG储罐圆顶的设计和优化提供了理论指导。

Deflation analysis of an air cushion for underwater shaking tables

Xiaodong Wen, Qinghua Han, Mingjie Liu, Hao Wu

doi:10.1016/j.tws.2024.111905

水下振动台气垫放气分析

The deflation process of inflatable membrane structures has always been a topic worthy of in-depth research. Inflatable membrane structures are employed for waterproofing in underwater environments, and their deflation process often poses safety concerns, warranting increased attention. An air cushion, which is applied to waterproof the underwater shaking table, is researched. It is arranged between the shaking table and the cover plates and can provide waterproof protection for the driving equipment of the shaking table. This article mainly studies the complete process of deflation for the waterproof air cushion. Force analysis was conducted on the air cushion membrane at different stages of deflation, and the factors that affect force during the deflation process were determined. A simulation method that combines the CEL (Coupled Eulerian-Lagrangian) method and fluid cavity method was used to analyze the deflation process of the air cushion, taking into account the effects of different deflation speeds and initial inflation pressures on the process. Based on the analysis results of the pressure-air volume curve and the deformation of the air cushion, the deflation process can be divided into three stages: elastic shrinkage stage, extrusion deformation stage, and free deformation stage. Based on the analysis results of dynamic stability, the extrusion deformation stage is further divided into two sub-stages: the extrusion stable stage and the extrusion unstable stage. It was found that the air cushion can achieve stability during both the elastic shrinkage stage and the extrusion stable stage, leading to the proposal of an evaluation method for air cushion deflation. Finally, the instantaneous leakage process of different positions on the air cushion was analyzed, and engineering suggestions were provided based on the analysis results. The research results provide a reference for the application of underwater inflatable membrane structures.

充气膜结构的放气过程一直是一个值得深入研究的课题。充气膜结构在水下环境中用于防水，其充气过程经常引起安全问题，需要引起越来越多的关注。研究了一种用于水下振动台防水的气垫。设置在振动台与盖板之间，可为振动台的驱动设备提供防水保护。本文主要研究防水气垫放气的全过程。对气垫膜在不同放气阶段进行了受力分析，确定了放气过程中影响力的因素。采用耦合欧拉-拉格朗日法和流体腔法相结合的仿真方法，考虑不同的充气速度和初始充气压力对气垫充气过程的影响，对气垫的充气过程进行了分析。根据压力-气体积曲线和气垫的变形分析结果，将气垫的放气过程分为弹性收缩阶段、挤压变形阶段和自由变形阶段。根据动态稳定性分析结果，将挤压变形阶段进一步划分为挤压稳定阶段和挤压不稳定阶段。研究发现，气垫在弹性收缩阶段和挤压稳定阶段均能实现稳定，从而提出了气垫放气的评价方法。最后对气垫不同位置的瞬时泄漏过程进行了分析，并根据分析结果提出了工程建议。研究结果为水下充气膜结构的应用提供了参考。

Experimental and numerical investigations of S960 hot-rolled ultra-high strength steel seamless circular hollow section beam–columns

Andi Su, Hua Yang, Yuyin Wang, Yajin Wang

doi:10.1016/j.tws.2024.111909

S960热轧超高强度钢无缝圆空心截面梁柱的试验与数值研究

The rapid development of manufacturing techniques and material science enables advanced hot-rolled ultra-high strength steel (UHSS) with material grades up to S960 to be available recently. The structural performance of S960 hot-rolled UHSS seamless circular hollow section (CHS) beam–columns manufactured through the advanced fabrication approach was experimentally and numerically investigated and reported in this paper. In physical testing, totally ten beam–column specimens were tested, with the complementary material testing and initial global geometric imperfection measurements through the innovative digital image correlation (DIC) method performed. FE modeling was then carried out; FE models of S960 hot-rolled UHSS seamless CHS beam–columns were established and then validated the test observations in terms of the failure loads and the load–mid-height lateral displacement curves. Parametric studies were thereafter performed, with cross-section dimensions, member lengths and loading combinations varying within a certain range, resulting in the additional 300 data to be acquired. Finally, the applicability of existing design methods, as prescribed in the European code, the Australian standard and the American specification, to S960 hot-rolled UHSS seamless CHS beam–columns was evaluated. It can be concluded from the evaluation results that all the three design codes provide accurate and consistent failure load predictions for S960 hot-rolled UHSS seamless CHS beam–columns.

制造技术和材料科学的快速发展使材料等级高达S960的先进热轧超高强度钢(UHSS)成为可能。本文对采用先进制造方法制造的S960热轧超高压不锈钢无缝圆空心截面(CHS)梁柱的结构性能进行了实验和数值研究。在物理测试中，共测试了10个梁柱试件，通过创新的数字图像相关(DIC)方法进行了互补材料测试和初始全局几何缺陷测量。然后进行有限元建模;建立了S960热轧超高ss无缝CHS梁柱的有限元模型，并从破坏荷载和荷载-中高横向位移曲线两方面验证了试验观测结果。然后进行参数化研究，截面尺寸、构件长度和载荷组合在一定范围内变化，从而获得额外的300个数据。最后，对现有设计方法(欧洲规范、澳大利亚标准和美国规范)对S960热轧超高压无缝钢管梁柱的适用性进行了评价。评价结果表明，3种设计规范均为S960热轧超高压无缝钢管梁柱提供了准确一致的破坏荷载预测。