今日更新：International Journal of Solids and Structures 1 篇，Journal of the Mechanics and Physics of Solids 1 篇，Mechanics of Materials 1 篇，Thin-Walled Structures 11 篇International Journal of Solids and StructuresA finite deformation formulation for amorphous glassy polymers under moderate and impact strain rates: Application to adhesive filmsChao Ling, Esteban P. Busso, Zian Wang, Jun Wei, Dongfeng Lidoi:10.1016/j.ijsolstr.2024.112822中等应变率和冲击应变率下非晶玻璃聚合物的有限变形公式:在胶膜上的应用This work describes a novel finite strain hypo-elastic formulation for amorphous thermoset polymers working in the glassy regime. The constitutive formulation is able to describe time and pressure-dependent behaviour under loading rates ranging from quasi-static to impact-type loading conditions and to account for thermo-mechanical coupling effects. A non-linear pressure dependent potential function is introduced to capture the non-associative visco-plastic potential flow for volumetric plastic strain control. The formulation also incorporates an internal state or deformation resistance variable to enable the description of the polymer hardening - softening behaviour, as well as a novel relation for the dissipative fraction of the plastic work in terms of the equivalent accumulated plastic strain. The constitutive model is formulated within a finite strain kinematics framework, and full details of its numerical implementation into the finite element method using a fully implicit Euler Backward algorithm are given. Model calibration is carried out for three different thermosetting resins (PR520 and RTM6 Epoxies, and MMA adhesives).To illustrate the model capabilities, two case studies are investigated: (i) the de-formation behaviour of epoxy under moderate and impact-type loading conditions under isothermal and fully adiabatic conditions, and (ii) the fracture behaviour of adhesive layers used to bond stiff metallic substrates. Results on RTM6 epoxy show that at, e.g., 60% true strain, 48.5% of the rate of plastic work is dissipative, and that the corresponding predicted increase in temperature due to the locally dissipated heat is consistent with published calorimetry data on a similar thermoset polymer. It was also found that, by coupling the proposed constitutive model with a cohesive zone model, it was possible to predict accurately the effect of an MMA adhesive layer thickness and pressure-dependency on the growth of an interfacial crack between the MMA adhesive and the metallic substrates. The proposed model should constitute a generic phenomenological formulation for the mechanical behaviour prediction of a wide range of thermoset polymers under confined and quasi-adiabatic conditions such as in composites and adhesive joints.这项工作描述了在玻璃态下工作的非晶态热固性聚合物的一种新的有限应变亚弹性配方。本构公式能够描述从准静态到冲击型加载条件下加载速率下的时间和压力相关行为，并考虑到热-机械耦合效应。引入非线性压力相关势函数捕捉非关联粘塑性势流，用于体塑性应变控制。该公式还包含一个内部状态或变形阻力变量，以实现聚合物硬化-软化行为的描述，以及根据等效累积塑性应变的塑性功的耗散分数的新关系。本构模型是在有限应变运动学框架内建立的，并给出了利用全隐式欧拉反向算法在有限元法中数值实现的全部细节。模型校准进行了三种不同的热固性树脂(PR520和RTM6环氧树脂，和MMA粘合剂)。为了说明模型的能力，研究了两个案例:(i)在等温和完全绝热条件下，环氧树脂在中等和冲击型加载条件下的变形行为，以及(ii)用于粘合硬质金属基板的粘合层的断裂行为。在RTM6环氧树脂上的结果表明，例如，在60%真应变下，48.5%的塑性功是耗散的，并且相应的预测温度升高是由于局部耗散的热量引起的，这与已发表的类似热固性聚合物的量热数据一致。研究还发现，通过将所提出的本构模型与内聚区模型相结合，可以准确地预测MMA胶粘剂层厚度和压力依赖性对MMA胶粘剂与金属基体之间界面裂纹扩展的影响。所提出的模型应构成一种通用的现象学公式，用于预测各种热固性聚合物在受限和准绝热条件下(如复合材料和粘合接头)的力学行为。Journal of the Mechanics and Physics of SolidsA predictive model for fluid-saturated, brittle granular materials during high-velocity impact eventsAaron S. Baumgarten, Justin Moreno, Brett Kuwik, Sohanjit Ghosh, Ryan Hurley, K.T. Rameshdoi:10.1016/j.jmps.2024.105644高速撞击事件中流体饱和脆性颗粒材料的预测模型Granular materials — aggregates of many discrete, disconnected solid particles — are ubiquitous in natural and industrial settings. Predictive models for their behavior have wide ranging applications, e.g. in defense, mining, construction, pharmaceuticals, and the exploration of planetary surfaces. In many of these applications, granular materials mix and interact with liquids and gases, changing their effective behavior in non-intuitive ways. Although such materials have been studied for more than a century, a unified description of their behaviors remains elusive.In this work, we develop a model for granular materials and mixtures that is usable under particularly challenging conditions: high-velocity impact events. This model combines descriptions for the many deformation mechanisms that are activated during impact — particle fracture and breakage; pore collapse and dilation; shock loading; and pore fluid coupling — within a thermo-mechanical framework based on poromechanics and mixture theory. This approach allows for simultaneous modeling of the granular material and the pore fluid, and includes both their independent motions and their complex interactions. A general form of the model is presented alongside its specific application to two types of sands that have been studied in the literature. The model predictions are shown to closely match experimental observation of these materials through several GPa stresses, and simulations are shown to capture the different dynamic responses of dry and fully-saturated sand to projectile impacts at 1.3 km/s.颗粒材料-许多离散的，不相连的固体颗粒的集 合体-在自然和工业环境中无处不在。其行为的预测模型具有广泛的应用，例如在国防，采矿，建筑，制药和行星表面的探索。在许多此类应用中，颗粒材料与液体和气体混合并相互作用，以非直观的方式改变其有效行为。尽管这些材料已经被研究了一个多世纪，但对其行为的统一描述仍然难以捉摸。在这项工作中，我们开发了一个颗粒材料和混合物的模型，可用于特别具有挑战性的条件:高速撞击事件。该模型结合了对冲击颗粒断裂和破碎过程中激活的多种变形机制的描述;孔隙崩塌与扩张;冲击载荷;以及基于孔隙力学和混合理论的热-力学框架下的孔隙流体耦合。这种方法可以同时模拟颗粒材料和孔隙流体，包括它们的独立运动和复杂的相互作用。该模型的一般形式与其在文献中研究的两种类型的砂的具体应用一起提出。模型预测结果与实验观察结果非常吻合，通过多个GPa应力对这些材料进行了模拟，可以捕捉到干砂和全饱和砂在1.3 km/s的弹丸冲击下的不同动态响应。Mechanics of MaterialsDynamic damage mechanism of basic magnesium sulfate cement composites: Experiments and 3D mesoscopic modeling studyFeng Taotao, Jing Wen, Yongshan Tandoi:10.1016/j.mechmat.2024.105011碱式硫酸镁水泥复合材料动态损伤机理:实验与三维细观模型研究Through experiments and mesoscale numerical simulations, we investigated the dynamic compression mechanical properties of steel fiber-reinforced basic magnesium sulfate cement concrete (BMSCC) containing coarse aggregates. First, the static mechanical properties of BMSCC reinforced with different amounts of steel fibers were prepared and tested. In addition, the dynamic compression properties of BMSCC under different strain-rate conditions were tested using a split-Hopkinson pressure bar (SHPB), and the dynamic increase factor (DIF) model applicable to BMSCC was determined. Then, based on the four-component characteristics of BMSCC (coarse aggregates, mortar, steel fibers, and interface transition zone ITZ), a meso-scale model considering random distribution of coarse aggregates and steel fibers was developed. Finally, the dynamic compression properties of BMSCC were numerically simulated by the numerical simulation method. The results showed that the mesoscopic model developed in this study can well predict and characterize the dynamic mechanical behavior of BMSCC.通过实验和中尺度数值模拟，研究了含粗骨料钢纤维增强碱式硫酸镁水泥混凝土(BMSCC)的动态压缩力学性能。首先，制备并测试了不同钢纤维增强量的BMSCC的静态力学性能。此外，采用split-Hopkinson压杆(SHPB)测试了不同应变率条件下BMSCC的动态压缩性能，确定了适用于BMSCC的动态增加因子(DIF)模型。然后，基于BMSCC的四组分特征(粗骨料、砂浆、钢纤维和界面过渡区ITZ)，建立了考虑粗骨料和钢纤维随机分布的细观尺度模型。最后，采用数值模拟方法对BMSCC的动态压缩特性进行了数值模拟。结果表明，本研究建立的细观模型能够较好地预测和表征BMSCC的动态力学行为。Thin-Walled StructuresStudy on fatigue behavior of butt-welded high-strength steel connections with surface cracksYining Zhang, Lili Hu, Chen Shen, Xiao-Ling Zhaodoi:10.1016/j.tws.2024.111888带表面裂纹的高强钢对接焊接接头疲劳行为研究This paper presents a study on the fatigue behavior of butt-welded high-strength steels (HSSs) Q960, Q890, and HG785. Fatigue crack growth rate (FCGR) experiments in the base metal (BM) and heat-affected zone (HAZ) are conducted, and the fatigue parameters are fitted using the Paris Law. Scanning electron microscopy (SEM) is also performed. The results reveal that the FCGR in the HAZ is slower than that in the BM for HSS; Q960 exhibits the highest fatigue crack growth (FCG) resistance, followed by Q890 and HG785. Surface crack propagation experiments are conducted at a maximum stress of half yield strength and 200 MPa. At half yield strength, the fatigue life decreases as the stress range increases, while at 200 MPa, the fatigue life decreases as the steel yield strength decreases. Furthermore, it is found that the surface cracks initially grow faster in the depth direction and then shift to the through thickness crack along the width direction. Finally, a theoretical method for predicting the fatigue life and crack propagation trajectories of surface crack specimens is proposed based on the Paris Law to consider multidimensional crack propagation behavior.对Q960、Q890和HG785对焊高强度钢的疲劳性能进行了研究。在母材(BM)和热影响区(HAZ)进行了疲劳裂纹扩展速率(FCGR)试验，并用Paris法则拟合了疲劳参数。扫描电子显微镜(SEM)也被执行。结果表明:高强度钢在热影响区内的fgr比在热影响区内慢;Q960的抗疲劳裂纹扩展性能最高，Q890次之，HG785次之。在屈服强度为一半、200mpa的最大应力条件下进行了表面裂纹扩展试验。在半屈服强度下，疲劳寿命随应力范围的增大而减小，而在200 MPa时，疲劳寿命随屈服强度的减小而减小。此外，表面裂纹在深度方向上的扩展速度更快，然后在宽度方向上向穿透厚度裂纹转变。最后，在考虑裂纹扩展行为的基础上，提出了一种基于Paris定律的表面裂纹试样疲劳寿命和裂纹扩展轨迹预测的理论方法。Finite Element Analysis for Free Vibration of Pipes Conveying Fluids–Physical Significance of Complex Mode ShapesSaher Attia, Magdi Mohareb, Michael Martens, Samer Adeebdoi:10.1016/j.tws.2024.111894流体输送管道自由振动的有限元分析——复杂振型的物理意义A finite element formulation is presented for the natural vibration analysis of pipes conveying fluids. The solution of the resulting quadratic eigenvalue problem generally yields complex eigenvalues and eigenvectors. The present study then develops a robust mathematical procedure that combines the real and imaginary components of the eigenvectors to form physically attainable (i.e., real) mode shapes. The procedure yields a family of solutions that is more general than previously known solutions. The well-known classical mode shape is shown to be recoverable as a special case from the present solution. The study provides new insights on the effects of viscous damping, axial compressive force, and the flexibility of intermediate pipe supports on the response. Additionally, the study develops a novel algorithm based on Hermitian angles between eigenvectors to automate the tracing of mode evolution in the frequency-velocity plots.提出了流体输送管道自振分析的有限元公式。所得到的二次特征值问题的解通常得到复特征值和特征向量。然后，本研究开发了一种鲁棒的数学程序，将特征向量的实分量和虚分量结合起来，形成物理上可获得的(即实的)模态振型。这个过程产生的解族比以前已知的解更一般。众所周知的经典模态振型可以作为一种特殊情况从本解中恢复。该研究为粘性阻尼、轴向压缩力和中间管支架柔性对响应的影响提供了新的见解。此外，研究还提出了一种基于特征向量间厄米角的算法，实现了频率-速度图中模态演化的自动跟踪。Dynamic response characteristics of an E-type impact isolation structure with a free mass constraintWeiwei Qin, Xianhui Wang, Xiaowang Sun, Jiahao He, Tuzao Yao, Mingxing Li, Mengyang Wu, Tiaoqi Fudoi:10.1016/j.tws.2024.111895具有自由质量约束的e型隔震结构动力响应特性In situations related to occupant impact protection, the free mass constraint of the occupants significantly influences the dynamic response characteristics of impact isolation structures. In this study, starting with the pre-bending deformation energy absorption mechanism, a static energy absorption prediction model for an E-type pre-bending folding deformation (E-PBFD) impact isolation structure was established. Based on the actual deformation state of the PBFD structure, the static energy absorption prediction theory was corrected, and quasi-static compression tests were conducted to validate the results of the corrected theoretical model. The smooth spline variance analysis method (SS-ANOVA) was used to determine the significance of high-dimensionality input variables in the theoretical prediction model. Finally, by combining the nonlinear kinematic equations of a free mass-constrained nonlinear vibration system and by considering the combined effects of the free mass constraint and the impact loading input, a theoretical dynamic energy absorption prediction model for the PBFD structure was developed. The NSGA-II algorithm was used to optimize the dynamic peak energy absorption of the structure, resulting in a 16.6% improvement in the peak energy absorption of the optimized structure. The results indicate that optimized parameters, which were based on the dynamic energy absorption theory, are conducive to fully exploiting the dynamic energy absorption characteristics of the PBFD structure. Additionally, parameter combinations that make the structure too soft or too rigid negatively affect the dynamic response behavior of the PBFD structure.在涉及乘员冲击防护的情况下，乘员的自由质量约束对冲击隔震结构的动力响应特性有显著影响。本研究从预弯曲变形吸能机理出发，建立了e型预弯曲折叠变形(E-PBFD)冲击隔震结构的静态吸能预测模型。基于PBFD结构的实际变形状态，对静态能量吸收预测理论进行了修正，并进行了准静态压缩试验，验证了修正后的理论模型结果。采用光滑样条方差分析方法(SS-ANOVA)确定理论预测模型中高维输入变量的显著性。最后，结合自由质量约束非线性振动系统的非线性运动学方程，考虑自由质量约束和冲击载荷输入的综合影响，建立了PBFD结构的理论动态能量吸收预测模型。采用NSGA-II算法对结构的动态峰值吸能进行优化，优化后结构的峰值吸能提高了16.6%。结果表明，基于动态能量吸收理论的优化参数有利于充分发挥PBFD结构的动态能量吸收特性。此外，过于柔软或过于刚性的参数组合会对PBFD结构的动态响应行为产生负面影响。An Experimental Investigation of Tensile Residual Strength of Repaired Composite Laminates After Low Velocity ImpactM. Damghani, G.A. Atkinson, P. Thapa, J. Joy, M. Monaghan, P. Maleki, C. Warddoi:10.1016/j.tws.2024.111896修复复合材料层合板低速冲击后拉伸残余强度的实验研究Low Velocity Impact (LVI) of Carbon Fibre Reinforced Polymer (CFRP) components are common during the manufacture and in-service life of aerostructures. However, the resulting effect on structural mechanical properties has not been extensively studied when the damage occurs on repaired components, which are already compromised to some degree. This research considers the relative mechanical performance of CFRP parts that are (1) pristine, (2) repaired using the stepped scarf method, and (3) repaired then impact damaged (low velocity impact at 5J energy). For each case, subsurface damage was visually investigated and detailed measurements taken including impact load-time/energy-time behaviour, and post-impact tensile maximum force, stress and strain (and homogenised Young's modulus) before fracture. Further, three different repair patch sizes were considered. The experiments show that negligible surface impact damage was present in all repair cases but that delamination and debonding occurred for all but large repairs. For small and medium repair patches, 71% and 83% of the static strength of pristine samples were observed, with nearly full recovery for large repairs. After LVI, the strength of small repairs did not decrease whereas that of medium repairs declined to 77%. Interestingly, LVI did not have any impact on load bearing capability of large repairs. Stiffness measurements increased with repair size, even exceeding the value for pristine samples in some cases. The maximum stresses sustained were 67%, 77% and 85% that of a pristine sample for small, medium, and large repairs respectively.碳纤维增强聚合物(CFRP)部件的低速冲击(LVI)是航空结构在制造和使用寿命中常见的问题。然而，当损伤发生在已修复构件上时，其对结构力学性能的影响尚未得到广泛的研究。本研究考虑了CFRP零件(1)原始状态，(2)采用阶梯围巾法修复，(3)修复后再撞击损坏(5J能量的低速撞击)的相对力学性能。对于每种情况，都对地下损伤进行了视觉调查，并进行了详细的测量，包括冲击载荷-时间/能量-时间行为，冲击后拉伸最大力，破裂前的应力和应变(以及均匀杨氏模量)。此外，还考虑了三种不同的修复补丁尺寸。实验表明，在所有修复案例中，表面冲击损伤都可以忽略不计，但除了大型修复之外，所有修复都发生了分层和脱粘。对于小型和中型修复补丁，原始样品的静态强度分别为71%和83%，对于大型修复补丁，静态强度几乎完全恢复。LVI后，小修复强度没有下降，而中等修复强度下降到77%。有趣的是，LVI对大型维修的承载能力没有任何影响。刚度测量值随着修复尺寸的增加而增加，在某些情况下甚至超过了原始样品的值。对于小型、中型和大型修复，最大持续应力分别为原始样品的67%、77%和85%。Behaviour of in-service CHS gap K-joints strengthened with external stiffenersJiafeng Lyu, Shen Yan, Xianzhong Zhao, Xiaoming Chen, Xiaofeng Wu, Xiaoming Xu, Feng Gaodoi:10.1016/j.tws.2024.111897外加劲加固在役CHS缝隙k形节点的性能This paper evaluated the behaviour of CHS gap K-joints strengthened under service load by welding in-plane external stiffeners,with a special focus on the combined effects of service load and welding process. Two identical joints were strengthened under service load but with different methods,one with stiffeners only while the other with additional cover plates,and were subsequently loaded to failure. External stiffeners significantly enhanced the joint stiffness and strength by enlarging the bearing area of the chord face and also helping the tension and compression forces in the braces to be counterbalanced above the chord face. The addition of cover plates to the chord and braces was able to enhance the strengthening effect by avoiding local ovalisation of the CHS members caused by force transmission through the stiffeners. The strengthening process by welding resulted in residual deformation reflected by a plateau on the load-deformation curve,which was unbeneficial to the ultimate resistance of strengthened joints with a maximum reduction of up to 10%. Complementary coupled thermal-mechanical FE models allowing for the effects of welding under service load,were developed and validated against the test results. A mechanical model was proposed to predict the ultimate resistance of strengthened joints,with the effects of geometric properties,service load,and welding process taken into account. The proposed model was validated against the results from comprehensive parametric FE simulations including a total of 976 models,and proved accurate for in-service CHS gap K-joint strengthened with external stiffeners.本文评估了在使用荷载作用下通过焊接面内外加强筋加固的CHS缝隙k形接头的性能，重点研究了使用荷载和焊接过程的联合影响。两个相同的节点在使用荷载作用下，采用不同的加固方法，一个节点仅加筋，另一个节点加盖板，随后加载至失效。外部加强筋通过扩大弦面承载面积，显著提高了关节的刚度和强度，也有助于将支撑中的拉力和压缩力平衡在弦面上方。在弦和支撑上增加盖板能够通过避免通过加强筋的力传递引起的CHS成员的局部卵圆而增强加固效果。焊接强化过程中残余变形在载荷-变形曲线上表现为一个平台，这不利于增强接头的极限抗力，最大降低幅度可达10%。考虑焊接在工作载荷下的影响，建立了互补的热-力学耦合有限元模型，并根据测试结果进行了验证。建立了考虑几何性能、使用载荷和焊接工艺影响的加固节点极限抗力预测力学模型。通过976个模型的综合参数有限元模拟结果验证了该模型的有效性，并证明了该模型对加外加力加固的在役CHS缝隙k节点的准确性。A study of controlling the transverse vibration of a beam-plate system by utilizing a nonlinear coupling oscillatorYuhao Zhao, Haijian Cui, Qing Shi, Yuanhang Sundoi:10.1016/j.tws.2024.111903利用非线性耦合振荡器控制梁板系统横向振动的研究In the engineering field, prolonged exposure of complex structures to high-strength vibration environments can lead to various engineering challenges. This underscores the importance of effectively managing the vibration of complex structures. Given the extensive utilization of beams and plates in the construction of intricate structures, this study incorporates a nonlinear coupling oscillator into the beam-plate system and formulates a vibration analysis model for this system. The governing equations of the system are derived theoretically and solved numerically using the Galerkin truncation method. This study focuses on the operational modes of the nonlinear coupling oscillator based on accurate numerical results. Meanwhile, the influence of parameters belonging to the nonlinear coupling oscillator on the transverse vibration responses of the beam-plate system is systemically studied. Upon meticulous examination of the numerical results, the operational states of the nonlinear coupling oscillator encompass the normal vibration suppression mode and the quasi-periodic vibration suppression mode. The alteration in the linear elastic coupling stiffness of the beam-plate system impacts the effectiveness of vibration suppression in the nonlinear coupling oscillator. This influence stems from the fact that changes in the linear elastic coupling stiffness directly affect the nonlinear forces exerted on the beam-plate system within a nonlinear coupling oscillator. Within a feasible range, the nonlinear stiffness and viscous damping can be chosen as the adjustable parameters for the nonlinear coupling oscillator to regulate the vibration of the beam-plate system by adjusting the motion mass of the nonlinear coupling oscillator, which presents a challenge. The appropriate utilization of the nonlinear coupling oscillator demonstrates favorable control effectiveness in managing the transverse vibration of the beam-plate system. The study presented in this work offers a method to simultaneously control the vibration of each component within beam-plate coupling systems.在工程领域，复杂结构长期暴露在高强度振动环境中会带来各种工程挑战。这强调了有效管理复杂结构振动的重要性。鉴于梁板在复杂结构建设中的广泛应用，本研究将非线性耦合振荡器引入梁-板系统，并建立了该系统的振动分析模型。对系统的控制方程进行了理论推导，并采用伽辽金截断法进行了数值求解。基于精确的数值结果，重点研究了非线性耦合振荡器的工作模式。同时，系统研究了非线性耦合振子参数对梁-板系统横向振动响应的影响。通过对数值结果的仔细分析，发现非线性耦合振荡器的工作状态包括正常振动抑制模式和准周期振动抑制模式。梁-板系统线弹性耦合刚度的变化影响了非线性耦合振荡器的抑振效果。这种影响源于线性弹性耦合刚度的变化直接影响非线性耦合振荡器内梁-板系统所受的非线性力。在可行范围内，选择非线性耦合振荡器的非线性刚度和粘性阻尼作为非线性耦合振荡器的可调参数，通过调节非线性耦合振荡器的运动质量来调节梁-板系统的振动，这是一个挑战。合理利用非线性耦合振荡器对梁-板系统的横向振动具有良好的控制效果。本研究提供了一种同时控制梁-板耦合系统中各部件振动的方法。Three-dimensional elastoplastic post-buckling analysis of porous FG plates resting on Winkler/Pasternak foundation using meshless RRKPMReza Vaghefidoi:10.1016/j.tws.2024.111915基于无网格RRKPM的Winkler/Pasternak地基上多孔FG板三维后屈曲弹塑性分析This paper presents a three-dimensional (3D) analysis of the elastoplastic post-buckling behavior of porous functionally graded (FG) plates resting on Winkler/Pasternak foundations under uniaxial and biaxial in-plane loadings using an enhanced meshless approach. The principle of virtual work is used to derive the governing equations, and 3D nonlinear Green-Lagrange strains are considered. Plastic deformation is modeled employing the Prandtl-Reuss flow law and the isotropic hardening von Mises criterion. A novel meshless radial basis reproducing kernel particle approach is used to obtain the discretized system of equations. The Newton-Raphson method, coupled with the arc-length technique, is used to compute post-buckling paths of porous FG plates. Numerical assessments show that post-buckling paths are significantly influenced by porosity parameter, porosity distribution, foundation parameters, material gradient, plate thickness, loading ratio, and boundary conditions (BCs).本文采用改进的无网格方法，对基于Winkler/Pasternak基础的多孔功能梯度板在单轴和双轴平面内载荷作用下的弹塑性后屈曲行为进行了三维(3D)分析。利用虚功原理推导了控制方程，并考虑了三维非线性格林-拉格朗日应变。塑性变形采用Prandtl-Reuss流动定律和各向同性硬化von Mises准则进行建模。提出了一种新的无网格径向基再现核粒子法来求解离散方程组。采用Newton-Raphson法结合弧长法计算了多孔FG板的屈曲后路径。数值计算表明，屈曲后路径受孔隙率参数、孔隙率分布、基础参数、材料梯度、板厚、加载比和边界条件(BCs)的显著影响。Ultra-thin ventilated metasurface pipeline coating for broadband noise reductionYuze Liu, Weiquan Zhang, Guangming Cao, Gang Zuo, Chongrui Liu, Fuyin Madoi:10.1016/j.tws.2024.111916宽频降噪的超薄通风超表面管道涂层This paper proposes a method of designing a metasurface muffling coating for pipeline ventilation and noise reduction, which realises low-frequency broadband noise reduction by laying ultra-thin labyrinth-channel acoustic absorbing metasurface structures on the inner wall surface of the pipeline. With the advantage of relatively loose size constraints in the length direction of the fluid conveying pipeline, the thickness dimensions required for low-frequency broadband sound absorption are transferred to the length direction, which significantly increases the effective ventilation area, and the ventilatable area is as high as 55.5% of the overall structural section area. Since sound waves can be gradually attenuated in the pipeline as the fluid medium flows along the length of the pipeline rather than needing to be attenuated at the same time as in a flat plate acoustic structure, the performance requirements of the acoustic structure are substantially reduced, enabling a significant increase in the operating bandwidth. We have tried the arrangement method of coating layers with gradient thickness, which shows that the combination of different thicknesses of metasurface coating layers can broaden the muffling frequency band and improve the transmission loss of the muffling structure. The design is equally suitable for the noise reduction of liquid-filled piping systems, and the peak transmission loss can be as high as 54.6 dB, which represents a pleasing combination of low-frequency muffling and lightweight design, as well as excellent ventilation capability, and embraces a promising future for application.本文提出了一种管道通风降噪超表面消声涂层的设计方法，通过在管道内壁铺设超薄迷宫通道吸声超表面结构，实现低频宽带降噪。利用输液管道长度方向尺寸约束相对宽松的优势，将低频宽带吸声所需的厚度尺寸转移到长度方向，显著增加了有效通风面积，可通风面积高达整体结构截面面积的55.5%。由于声波在管道中可以随着流体介质沿管道长度流动而逐渐衰减，而不像在平板声结构中需要同时衰减，因此大大降低了声结构的性能要求，从而使工作带宽显著增加。我们尝试了梯度厚度涂层的排列方法，结果表明，不同厚度的超表面涂层组合可以拓宽消声频带，改善消声结构的传输损失。该设计同样适用于充液管道系统的降噪，峰值传输损耗可高达54.6 dB，将低频消声与轻量化设计完美结合，通风性能优异，具有广阔的应用前景。Experimental Database and Analysis of In-Plane Seismic Behaviour of Double Steel-Plate Composite Walls for Wind Power TowerMu-Xuan Tao, Yu-Lun Wang, Zhi-Yuan Ma, Ji-Zhi Zhaodoi:10.1016/j.tws.2024.111917风力发电塔双钢板组合墙面内抗震性能试验数据库及分析A double-steel-plate composite wall (DSCW) is composed of two steel plates, infilled concrete, and connectors. Because of their superior mechanical performance, DSCWs have been widely used in engineering, especially in the field of wind power tower. However, only a few studies have been conducted on the in-plane seismic performance of DSCWs. This study focused on the in-plane seismic performance of DSCWs, and a dataset of the in-plane flexural and shear behaviours of DSCWs including over 200 specimens from more than 30 studies was built. First, various structural configurations and mechanical response parameters were adjusted to the same standard. The same parameters studied by different scholars were extracted and analysed to obtain the general rules of the influence of these parameters on the hysteresis performance of DSCWs (forward analysis), such as the distance-to-thickness ratio, axial load ratio, shear span ratio, connector type, steel plate thickness, material strength, and partition number. Second, a backward analysis using the entire database was conducted on the factors influencing different mechanical response parameters, including the failure modes, yield displacement angle, ultimate displacement angle, ductility, and energy dissipation capacity. Finally, the accuracy of the shear capacity equations in the different codes was verified using shear failure specimens from a database to provide suggestions for engineering practice.双钢板组合墙(DSCW)由两块钢板、填充混凝土和连接件组成。由于其优越的力学性能，dscw在工程中得到了广泛的应用，特别是在风力发电塔架领域。然而，对dscw的面内抗震性能的研究很少。本研究重点研究了dscw的面内抗震性能，并建立了dscw的面内弯曲和剪切性能数据集，其中包括来自30多项研究的200多个样本。首先，将各种结构构型和力学响应参数调整到同一标准。对不同学者研究的相同参数进行提取分析，得到这些参数对dscw滞回性能影响的一般规律(正向分析)，如距厚比、轴向载荷比、剪跨比、连接件类型、钢板厚度、材料强度、隔板数等。其次，利用整个数据库对不同力学响应参数的影响因素进行了反向分析，包括破坏模式、屈服位移角、极限位移角、延性和耗能能力。最后，利用数据库中的抗剪破坏试件，验证了不同规范中抗剪承载力方程的准确性，为工程实践提供建议。Full-field deformation reconstruction of beams using the inverse Finite Element Method: Application to thin-walled structuresRinto Roy, Cecilia Surace, Marco Gherlonedoi:10.1016/j.tws.2024.111907梁的全场变形反演有限元法:薄壁结构的应用This work presents a methodology for the real-time structural deformation reconstruction of solid or thin-walled prismatic beams using discrete strains. Based on the 1D inverse Finite Element Method (iFEM), the approach combines the beam kinematics of Timoshenko theory, strain–displacement relations, and the finite element discretisation framework to reconstruct the full-field deformations of beams with any general cross-section. Although applicable for any general class of beams, the present work investigates its experimental application specifically to conventionally and additively manufactured thin-walled beams discretised using various low- and high-order inverse beam elements. The results demonstrate the method’s accuracy and robustness, albeit influenced by the element discretisation scheme and the number of strain sensors used.这项工作提出了一种方法，实时结构变形重建的固体或薄壁棱镜梁使用离散应变。该方法基于一维反有限元法(iFEM)，将Timoshenko理论的梁运动学、应变-位移关系和有限元离散化框架相结合，重构任意一般截面梁的全场变形。虽然适用于任何一般类型的梁，本工作研究了它的实验应用，特别是传统和增材制造薄壁梁离散使用各种低阶和高阶逆梁单元。结果表明，该方法具有较高的精度和鲁棒性，但受到单元离散化方案和应变传感器数量的影响。A friction-strip hybrid damper with multi-phase energy dissipation mechanism: Cyclic test and numerical verificationYujie Lu, Qingfang Lv, Ye Liu, Tongfei Sun, Huiqun Yandoi:10.1016/j.tws.2024.111913具有多相耗能机理的摩擦条混合阻尼器:循环试验与数值验证By combining the frictional and plastic energy dissipation modules (FEDM and PEDM), a novel multi-phase friction-strip hybrid damper (MFSHD) is proposed in the current study. The theoretical analyses demonstrate that, when applied in a self-centering structure, the MFSHD is able to provide higher strength, secondary stiffness and energy dissipation and maintain the self-centering capacity compared with conventional friction dampers. A series of quasi-static tests was conducted on the MFSHD to evaluate the effects of different parameters on the hysteresis performance of the MFSHD. The results showed that increasing the strip number or the bolt pre-tension force could both improve the mechanical performance of the MFSHD. The MFSHD with sandglass-shaped strips had a better performance than that with I-shaped strips. In the MFSHD with lower slipping displacement, the PEDM was activated earlier and provided higher strength, stiffness and energy dissipation, whereas its low-cycle fatigue life was reduced. The numerical analyses based on the model validated by the test results showed that the self-centering braced frame substructure equipped with the MFSHD exhibited hysteresis behavior in consistency with the theoretical model. The superior performance of the MFSHD compared with conventional friction dampers was verified numerically.将摩擦和塑性耗能模块(FEDM和PEDM)相结合，提出了一种新型多相摩擦条混合阻尼器(MFSHD)。理论分析表明，应用于自定心结构时，与传统摩擦阻尼器相比，MFSHD能够提供更高的强度、二次刚度和耗能，并保持自定心能力。对MFSHD进行了一系列准静态试验，以评估不同参数对MFSHD滞回性能的影响。结果表明，增加带钢数或螺栓预张紧力均能提高MFSHD的力学性能。沙漏形带的MFSHD比i形带的性能更好。在滑移位移较小的MFSHD中，PEDM的激活时间较早，提供了更高的强度、刚度和耗能，但降低了其低周疲劳寿命。基于该模型的数值分析结果与试验结果相吻合，表明安装MFSHD的自定心支撑框架子结构表现出与理论模型一致的滞回特性。数值验证了MFSHD相对于传统摩擦阻尼器的优越性能。来源：复合材料力学仿真Composites FEM
