首页/文章/ 详情

【新文速递】2024年1月7日固体力学SCI期刊最新文章

17天前浏览525

今日更新:Journal of the Mechanics and Physics of Solids 1 篇,Mechanics of Materials 1 篇,Thin-Walled Structures 8 篇

Journal of the Mechanics and Physics of Solids

Predicting protein thermal stability changes upon single and multi-point mutations via restricted attention subgraph neural network

Mohammad Madani, Anna Tarakanova

doi:10.1016/j.jmps.2023.105531

通过受限注意力子图神经网络预测单点和多点突变时蛋白质热稳定性的变化

Accurate prediction of protein stability changes due to mutations is instrumental for understanding mechanisms of disease and drug failure, as well as for engineering tailored protein-based materials. In recent years, computational tools using machine learning have been developed to predict stability changes and thereby supplement available experimental methods that may be time consuming and costly for bulk mutational analysis. Existing tools are limited, however, to predicting single point mutations and showing antisymmetric bias in direct/reverse mutations. Here, we develop structure and sequence-based models to predict protein stability changes via Gibbs free energy change upon single or multi-point mutations via two parallel augmented gated attention graph neural networks integrated with global attention blocks receiving subgraphs. These subgraphs are related to mutation sites and constructed through predicted protein contact maps to capture spatial structural information. We train our model on direct and reverse mutations obtained from the S5294 dataset and test on one independent test set and eight most commonly used test sets, including S350, P53, Ssym, S669, S1925, S250, and myoglobin. Our approach shows considerable improvement in estimating the impacts of stabilizing mutations, and consistently outperforms other methods by at least a 5.2% improvement in root mean square error. This approach can be employed for finding functionally important protein variants, helping to design new proteins with vast untapped potential for broad pharmaceutical applications.

准确预测突变导致的蛋白质稳定性变化有助于了解疾病和药物失效的机理,也有助于设计量身定制的蛋白质基材料。近年来,人们利用机器学习开发了一些计算工具来预测稳定性变化,从而对现有的实验方法进行补充。然而,现有工具仅限于预测单点突变,并在直接/逆向突变中显示出不对称偏差。在此,我们开发了基于结构和序列的模型,通过两个并行增强门控注意力图神经网络与接收子图的全局注意力块集成,通过单点或多点突变时的吉布斯自由能变化预测蛋白质稳定性的变化。这些子图与突变位点相关,通过预测的蛋白质接触图构建,以捕捉空间结构信息。我们在从 S5294 数据集中获得的直接突变和反向突变上训练模型,并在一个独立测试集和八个最常用的测试集上进行测试,包括 S350、P53、Ssym、S669、S1925、S250 和肌红蛋白。我们的方法在估计稳定突变的影响方面有很大改进,在均方根误差方面比其他方法至少提高了 5.2%。这种方法可用于寻找具有重要功能的蛋白质变体,帮助设计出具有广泛医药应用潜力的新蛋白质。


Mechanics of Materials

GHz surface waves in Al/LiTaO3/Si composite: Effect of the Drude electrode on dispersion, attenuation and mode shapes

Feng Zhu, Ernian Pan, Nian Li, Yilin Qu

doi:10.1016/j.mechmat.2024.104910

Al/LiTaO3/Si 复合材料中的 GHz 表面波:德鲁德电极对色散、衰减和模式形状的影响

In fifth generation (5G) mobile communication, radio frequency is in the super high frequency range (3–30 GHz). Thus, different from Ohm Law, electrode loss at GHz frequency becomes frequency-dependent. As such, many properties, especially attenuation of piezoelectric acoustic devices, should be reevaluated. In this paper, the attenuation of GHz surface wave propagating in composite structure made of metal electrode, piezoelectric film and elastic half space is investigated based on the loss model of Drude electrode. Specifically, the Al/LiTaO3/Si composite is considered where Rayleigh mode and SH mode are fully coupled. Based on the Stroh-type formalism, the dispersion equations of the composite with the Drude electrode are derived, and compared with the traditional perfect conductor electrode which is under the short circuit boundary condition. The phase velocity, attenuation and wave mode shapes are obtained successfully by the multidimensional moduli ratio convergence method. Numerical results are presented to reveal some interesting intrinsic features, which include two analytical upper bounds of phase velocity, nonexistent validation of intersection points in dispersion curves, and relations among veering, attenuation jumps and wave-mode conversions. These features and relations provide an in-depth insight for GHz wave motion properties in piezoelectric composites.

在第五代(5G)移动通信中,无线电频率处于超高频范围(3-30 GHz)。因此,与欧姆定律不同,GHz 频率下的电极损耗与频率有关。因此,许多特性,尤其是压电声学器件的衰减,都需要重新评估。本文基于 Drude 电极损耗模型,研究了在由金属电极、压电薄膜和弹性半空间组成的复合结构中传播的 GHz 表面波的衰减。具体来说,考虑了 Al/LiTaO3/Si 复合材料,其中瑞利模式和 SH 模式是完全耦合的。基于 Stroh 型形式 主义,推导出了带有 Drude 电极的复合材料的频散方程,并与处于短路边界条件下的传统完全导体电极进行了比较。利用多维模量比收敛法成功求得了相速度、衰减和波模形状。数值结果揭示了一些有趣的内在特征,包括两个相速度的分析上限、频散曲线交点不存在的验证,以及转向、衰减跃迁和波模转换之间的关系。这些特征和关系为压电复合材料的 GHz 波运动特性提供了深入的见解。


Thin-Walled Structures

Mechanical behaviour of a novel lattice structure with two-step deformation

Xiaodong Ma, Ning Zhang, Chuanliang Zhang, Xiaogeng Tian

doi:10.1016/j.tws.2024.111580

具有两步变形的新型晶格结构的力学性能

Lattice structures are increasingly attracting attention due to their excellent mechanical properties and broad application prospects. However, most developed lattices feature single-step deformation or single plateau stress, which confine its multi-task applications. Herein, a novel body-centered cubic (NBCC) with two-step deformation based on body-centered cubic (BCC) and bionic fractal design is introduced. NBCC exhibits bi-plateau stress in the stress-strain curves. The underlying mechanism is caused by the bending and buckling deformation of the struts. The mechanical behaviors of NBCC are investigated by finite element simulation which verified by experiment. Compared with traditional BCC, NBCC has improved modulus of elasticity by 88%, yield strength by 21.2%, and specific energy absorption by 108% when ρ′ and α are 0.07 and 0.5, respectively. Moreover, the elastic modulus as well as yield strength increase with geometrical ratio α. The specific energy absorption tends to maximum at the geometric ratio α = 0.6 ∼ 0.7. From the Ashby map, the proposed NBCC lattice possesses high energy absorption, exceeding most of the existing architected materials at the same density. Furthermore, the results show that NBCC has better isotropy of elastic modulus and tends to be more isotropic material compared to BCC. Finally, theoretical model of two-step plateau stress is established based on hinge dissipation principle. This work opens up new insights into the use of element replacement design to create multi-step pathways that can be applied to design engineering structures with multiple tasks and application for impact protection.

晶格结构因其优异的机械性能和广阔的应用前景而日益受到关注。然而,大多数已开发的晶格结构都具有单步变形或单一高原应力的特点,这限制了其多任务应用。本文介绍了一种基于体心立方体(BCC)和仿生分形设计的具有两步变形的新型体心立方体(NBCC)。NBCC 在应力-应变曲线上表现出双高原应力。其基本机制是由支柱的弯曲和屈曲变形引起的。通过有限元模拟研究了 NBCC 的力学行为,并通过实验进行了验证。与传统 BCC 相比,当 ρ′ 和 α 分别为 0.07 和 0.5 时,NBCC 的弹性模量提高了 88%,屈服强度提高了 21.2%,比能量吸收提高了 108%。此外,弹性模量和屈服强度随几何比 α 的增大而增大,比能量吸收在几何比 α = 0.6 ∼ 0.7 时趋于最大。从阿什比图来看,拟议的 NBCC 晶格具有很高的能量吸收能力,超过了相同密度下的大多数现有建筑材料。此外,研究结果表明,与 BCC 相比,NBCC 的弹性模量各向同性更好,更趋向于各向同性材料。最后,根据铰链耗散原理建立了两步高原应力理论模型。这项工作为使用元素置换设计创建多级路径提供了新的见解,可用于设计具有多重任务的工程结构和冲击防护应用。


Experimental and numerical investigation on high-velocity hail impact response of TC4 titanium alloy plates

Min Dou, Zhichao Fan, Lang Li, Xinmei Wang, Lei Li

doi:10.1016/j.tws.2024.111582

TC4 钛合金板高速冰雹冲击响应的实验和数值研究

This work studied the dynamic response of hail impacting on TC4 titanium alloy plates under different influence factors. Experiments were performed according to China Civil Aviation Regulations Airworthiness Standards. The damage to the plate was recorded by in-situ cameras. The experimental results indicate that the greater the hail velocity, the more severe the damage to the titanium alloy plate. In the simulation, Smoothed Particle Hydrodynamics (SPH) method was used to model the hail. The reliability of numerical model was verified by the comparison with the test result of hail impact response. The numerical results show that the deformation of the plate increases as the impact angle and hail diameter increases. Moreover, the changes in impact angle and position will both alter the displacement and strain distribution within the plate. Through comparative analysis of the impact velocity, hail diameter, impact angle, and impact position on the impact force peak, plastic strain energy, and maximum kinetic energy of the plate, it is found that changes of hail diameter and velocity have great effect on the response of titanium alloy plate, and the impact position has little effect on it. There is a power-law relationship between the hail impact peak force and the hail velocity with an index of 1.912.

这项工作研究了不同影响因素下冰雹撞击 TC4 钛合金板的动态响应。实验按照中国民航适航标准进行。通过原位相机记录了钛合金板的损伤情况。实验结果表明,冰雹速度越大,钛合金板的损伤越严重。模拟中采用平滑粒子流体力学(SPH)方法对冰雹进行建模。通过与冰雹冲击响应试验结果的对比,验证了数值模型的可靠性。数值结果表明,随着撞击角度和冰雹直径的增大,钢板的变形也随之增大。此外,撞击角度和位置的变化都会改变板内的位移和应变分布。通过对比分析冲击速度、冰雹直径、冲击角度和冲击位置对钛合金板冲击力峰值、塑性应变能和最大动能的影响,发现冰雹直径和速度的变化对钛合金板的响应影响较大,而冲击位置对其影响较小。冰雹冲击力峰值与冰雹速度之间存在幂律关系,指数为 1.912。


Vibration behavior and power transmission of coupled plate structures with embedded acoustic black holes joined at an arbitrary angle

Jingtao Du, Yuhang Wang, Yang Liu

doi:10.1016/j.tws.2024.111565

以任意角度连接嵌入式声学黑洞的耦合板结构的振动行为和功率传输

The Acoustic Black Hole (ABH) technology is widely recognized for its passive vibration and noise attenuation capabilities, characterized by lightweight and high efficiency. Exploring the dynamic behavior and energy transmission characteristics of the ABH coupled-plate system is a novel endeavor that provides a theoretical foundation for applying ABH structures in complex coupled systems. In this work, a semi-analytical dynamic model for the ABH coupled-plate system (comprising an ABH plate and a uniform plate) with an arbitrary connection angle is proposed by using the Rayleigh-Ritz framework. To ensure the continuity of high-order spatial derivatives at the edges, the modified version of the Fourier series is employed to describe the vibration displacement fields for transverse and in-plane vibration components. This enables the proposed model to determine the necessary derivatives of relevant quantities, namely the structural intensity and power flow, which facilitates the description of energy transmission behaviors in the ABH coupled-plate structure. Firstly, the convergence characteristics of the model are studied and the accuracy of modal information and dynamic response is verified through the comparison of those calculated from the finite element method (FEM), additionally, the experiment is carried out to verify the proposed model. Subsequently, several numerical examples are presented to study the vibrational characteristics of the ABH coupled-plate system and the good vibration attenuation of the ABH coupled-plate is observed as well. Finally, the vibrational energy transmission results are obtained and the influence of some important system parameters such as coupling angles on energy transmission characteristics in such systems are investigated. This work can shed some new light on ABH structures with potential application to such complex coupled-plate structures.

声学黑洞(ABH)技术因其轻质高效的被动振动和噪声衰减能力而广为人知。探索 ABH 耦合板系统的动态行为和能量传输特性是一项新的尝试,它为 ABH 结构在复杂耦合系统中的应用提供了理论基础。在这项工作中,利用 Rayleigh-Ritz 框架,提出了具有任意连接角度的 ABH 耦合板系统(由 ABH 板和均匀板组成)的半解析动态模型。为确保边缘高阶空间导数的连续性,采用修正版傅里叶级数来描述横向和平面内振动分量的振动位移场。这使得所提出的模型能够确定相关量(即结构强度和功率流)的必要导数,从而有助于描述 ABH 耦合板结构的能量传输行为。首先,研究了模型的收敛特性,并通过与有限元法(FEM)计算的模态信息和动态响应进行比较,验证了模态信息和动态响应的准确性。随后,通过几个数值实例研究了 ABH 耦合板系统的振动特性,并观察到 ABH 耦合板具有良好的振动衰减效果。最后,得出了振动能量传输结果,并研究了耦合角等一些重要系统参数对此类系统能量传输特性的影响。这项研究为 ABH 结构带来了新的启示,有望应用于此类复杂的耦合板结构。


Finite element simulation and industrial validation for DRX evolution of magnesium alloy thin-walled wheel formed by backward extrusion

Yanchao Jiang, Yatong Zhu, Qichi Le, Qiyu Liao, Zhaoyang Yin, Xinyue Zhang, Ping Wang

doi:10.1016/j.tws.2024.111567

镁合金薄壁轮毂反向挤压成形 DRX 演化的有限元模拟和工业验证

The physical field and dynamic recrystallization (DRX) evolution of magnesium (Mg) alloy thin-walled wheels during backward extrusion (BE) were investigated by coupling the cellular automaton (CA) model with the finite element (FE) model in this study, and the simulation results were verified by industrial experiments. Findings revealed that the wheel bottom is always in a three-way compressive stress state when the lower rim is filled, while the rim is under two-way compressive stress and one-way tensile stress in the filling process. Sufficient effective strain is accumulated at the rim compared to the wheel bottom, and different from the uniform and small grain size distribution at the rim, there was insufficient DRX at the wheel bottom, as well as local grain growth due to deformation heat. The wheel bottom is dominated by the mixed grain structure, mainly consisting of necklace-like DRXed grains and initial coarse grains, and the microstructure at the rim shows equiaxed grains except for the upper rim, where are still incomplete recrystallization grains. With the increase of extrusion temperature (360-420℃), the DRX volume fraction and the average grain size of the wheel increased, but the effect on the grain size at the rim was not significant due to severe plastic deformation (SPD) above the critical strain.

本研究通过将细胞自动机(CA)模型与有限元(FE)模型耦合,研究了镁合金薄壁车轮在向后挤压(BE)过程中的物理场和动态再结晶(DRX)演变,并通过工业实验验证了模拟结果。研究结果表明,下轮辋充填时,轮底始终处于三向压应力状态,而轮辋在充填过程中处于双向压应力和单向拉应力状态。与轮毂底部相比,轮辋处积累了足够的有效应变,而且与轮辋处均匀且较小的晶粒尺寸分布不同,轮毂底部的 DRX 不充分,同时由于变形热,轮毂底部也存在局部晶粒长大的现象。轮底以混合晶粒结构为主,主要由项链状 DRX 化晶粒和初始粗大晶粒组成,轮缘处的显微结构除轮缘上部仍有不完全再结晶晶粒外,其余均为等轴晶粒。随着挤压温度(360-420℃)的升高,车轮的 DRX 体积分数和平均晶粒大小都有所增加,但由于严重塑性变形(SPD)超过了临界应变,对轮缘处晶粒大小的影响并不显著。


Transverse impact response of GFRP tubes filled with MWCNT-reinforced syntactic foam

Jun Wang, Danfeng Zhang, Yu Zhang

doi:10.1016/j.tws.2024.111568

填充了 MWCNT 增强合成泡沫的 GFRP 管的横向冲击响应

Tubular composites made of glass fiber reinforced polymer (GFRP) have been widely used in the fields of infrastructure and automobile engineering. However, such composites are vulnerable to transverse loading occurrences and their effect on structural integrity. This paper focuses on investigating the response of hollow GFRP tubes and GFRP tubes filled with syntactic foam under transverse impacts. To enhance the stiffness of GFRP tube and improve the brittleness of syntactic foams, ribs were added to strengthen the tube wall, and multiwalled carbon nanotubes (MWCNTs) were used to reinforce the syntactic foam core. The impact response of the tubes was examined by considering the influence of ribs, MWCNTs, and the impact location. Experimental results revealed that the ribs contributed to enhancing the impact resistance of both hollow and filled tubes. However, the impact of ribs on energy absorption was less noticeable for the filled tubes. Incorporating 1.2 wt.% MWCNTs in the foam resulted in significant improvements of 25% in peak impact force and 43% in energy absorption for the filled tubes. Changing the impact location from the tube wall to the rib led to a significant increase of 33% in peak impact force and 18% in energy absorption for the hollow tubes. In contrast, the impact location had a minimal effect on the overall impact responses of the filled tubes. An analytical model was developed to predict the energy absorption capability of the composite tubes. This model accurately determined the energy absorption contribution of each component within the composite tube. The predicted results demonstrated good agreement with the experimental findings, validating the predictive capability of the model. Furthermore, multiscale finite-element (FE) models were developed to simulate the impact characteristics of foam-filled composite tube specimens. The validated FE model was subsequently utilized to conduct parametric study.

由玻璃纤维增强聚合物(GFRP)制成的管状复合材料已广泛应用于基础设施和汽车工程领域。然而,这类复合材料很容易受到横向荷载的影响,从而影响结构的完整性。本文重点研究空心 GFRP 管和填充合成泡沫的 GFRP 管在横向冲击下的响应。为了增强 GFRP 管的刚度和改善合成泡沫的脆性,在管壁上添加了加强筋,并使用多壁碳纳米管(MWCNT)来增强合成泡沫芯材。通过考虑肋条、MWCNTs 和冲击位置的影响,对管材的冲击响应进行了研究。实验结果表明,肋条有助于增强空心管和填充管的抗冲击性。然而,对于填充管而言,肋条对能量吸收的影响并不明显。在泡沫中加入 1.2 wt.% 的 MWCNT 后,填充管的峰值冲击力和能量吸收分别显著提高了 25% 和 43%。将冲击位置从管壁改为肋条,可使空心管的峰值冲击力和能量吸收分别显著提高 33% 和 18%。相比之下,冲击位置对填充管的整体冲击响应影响很小。我们建立了一个分析模型来预测复合管的能量吸收能力。该模型准确地确定了复合材料管内各成分的能量吸收贡献。预测结果与实验结果非常吻合,验证了模型的预测能力。此外,还开发了多尺度有限元(FE)模型来模拟泡沫填充复合管试样的冲击特性。经过验证的 FE 模型随后被用于进行参数研究。


Experimental and numerical investigation on vibro-acoustic performance of a submerged stiffened cylindrical shell under multiple excitations

Yang Tang, Zhe Zhao, Yuxuan Qin, Fuzhen Pang, Yuan Du, Cong Gao, Haichao Li

doi:10.1016/j.tws.2024.111569

多重激励下水下加劲圆柱壳振动声学性能的实验和数值研究

The underwater vibro-acoustic characteristics of a stiffened cylindrical shell have been investigated using experimental and numerical methods. A numerical analysis model is developed to capture the behavior of the cylindrical shell structure, and the validity of the model is verified based on experimental data. Experimental measurements are conducted in an anechoic tank to assess the vibration and acoustic radiation characteristics of the stiffened cylindrical shell under white noise excitations. Additionally, the disparities in underwater vibration noise characteristics of the stiffened cylindrical shell under both single excitation and multiple excitations are explored by numerical method. The experimental and numerical findings reveal that, within the frequency range of 10-2000 Hz, the stiffened cylindrical shell exhibits a rapid augmentation of low-frequency vibration noise followed by a gradual stabilization trend. This behavior can be attributed to the high density of low-frequency modes embedded within the structure. Furthermore, it is noteworthy that the underwater vibration noise of the cylindrical shell under multiple excitations arises not solely as a result of individual excitations being superimposed, but rather as a consequence of the intricate coupling effects induced by multiple excitations.

采用实验和数值方法研究了加劲圆柱形壳体的水下振动声学特性。建立了一个数值分析模型来捕捉圆柱形壳体结构的行为,并根据实验数据验证了模型的有效性。在消声水箱中进行了实验测量,以评估加劲圆柱壳在白噪声激励下的振动和声辐射特性。此外,还通过数值方法探讨了加劲圆柱形壳体在单一激励和多重激励下水下振动噪声特性的差异。实验和数值结果表明,在 10-2000 Hz 频率范围内,加劲圆柱形壳体的低频振动噪声迅速增大,随后呈逐渐稳定趋势。这种行为可归因于结构中嵌入了高密度的低频模态。此外,值得注意的是,圆柱形壳体在多重激励下产生的水下振动噪声并不完全是单个激励叠加的结果,而是多重激励引起的复杂耦合效应的结果。


The transverse dynamic behavior study of a beam system coupled through a local nonlinear coupling layer

Yuhao Zhao, Fanhao Guo, Deshui Xu

doi:10.1016/j.tws.2024.111570

通过局部非线性耦合层耦合的梁系统的横向动态行为研究

In engineering, some complex systems can be reduced to the beam system connected by serval coupling elements. To explore the potential application of local coupling nonlinearity on the transverse dynamic behavior of beams, this work establishes the physical model of a beam system coupled by a local nonlinear coupling layer. On the basis of ensuring the validity of the results, studies the effect of the nonlinear coupling layer on the transverse forced vibration of the beam system. Exploring the characters and reason for complex responses of the beam system coupled through a local nonlinear coupling layer. After discussing the numerical results, it can be found that the beam system presents complex responses within some parameters of the local nonlinear coupling layer, including amplitude jumping, quasi-periodic state, and targeted energy transfer, in which the change of the nonlinear restoring force is the reason for the appearance or disappearance of complex responses. For single-frequency responses, complex responses of the beam system can be motivated by changing the parameters of the local nonlinear coupling layer. With the simultaneous variation of the nonlinear stiffness and viscous damping, responses of the beam system contain both amplitude-sensitive regions and amplitude-jumping regions, in which the amplitude-sensitive region provides an effective parameter range for controlling the vibration by adjusting the local nonlinear coupling layer. On the whole, a suitable combination of nonlinear stiffness and viscous damping of the local nonlinear coupling layer can effectively reduce the vibration at the boundaries of the beam system.

在工程学中,一些复杂的系统可以简化为由伺服耦合元件连接的梁系统。为了探索局部耦合非线性对梁横向动力行为的潜在应用,本研究建立了由局部非线性耦合层耦合的梁系统物理模型。在确保结果有效性的基础上,研究非线性耦合层对梁系统横向受迫振动的影响。探讨通过局部非线性耦合层耦合的梁系统复杂响应的特征和原因。经过对数值结果的讨论,可以发现梁系统在局部非线性耦合层的某些参数范围内呈现复杂响应,包括振幅跳跃、准周期状态和定向能量转移,其中非线性恢复力的变化是复杂响应出现或消失的原因。对于单频响应,可以通过改变局部非线性耦合层的参数来激发梁系统的复杂响应。随着非线性刚度和粘性阻尼的同时变化,梁系统的响应包含振幅敏感区和振幅跳跃区,其中振幅敏感区为通过调整局部非线性耦合层来控制振动提供了有效的参数范围。总体而言,局部非线性耦合层的非线性刚度和粘性阻尼的适当组合可有效减小梁系统边界的振动。


Interference effects on the wind loads and wind-induced responses of parallel-arranged rectangular-planed air-supported membrane structures

Zhaoqing Chen, Chao Wei, Liang Yin, Ning Su, Junbin Zhao, Yue Wu

doi:10.1016/j.tws.2024.111572

对平行排列的矩形平面气撑膜结构的风荷载和风致响应的干扰效应

In many practical projects, two air-supported membrane structures are parallel-arranged. The interference effects of parallel-arranged rectangular-planed air-supported membrane structures are important in the wind-resistant design. In order to address this issue, the wind pressures on isolated and parallel-arranged structures are obtained through pressure measurement wind tunnel tests. The wind-induced responses are calculated via nonlinear dynamic time–history analysis. Consequently, the interference effects on wind loads and wind-induced responses are analyzed. The results show that the wind suctions of downstream structures are amplified by the interferences of parallel-arranged structures particularly under oblique wind directions. The mean wind loads on the most disturbed zone are amplified up to about 65%. The interference characteristics of wind-induced displacement are basically similar to mean wind loads. The membrane stresses and cable forces are significantly interfered only in oblique wind directions, which are amplified up to about 15% in all zones of downstream structures. The strongest interference effects can be observed with a spacing-span ratio of 0.2 when the wind direction is oblique or parallel to the gap between neighboring structures. The interference factors for zones are provided to analyze the interference characteristics. In addition, recommendation values of the overall response interference factors are summarized for design reference. The overall response interference factors for displacement, membrane stress, and cable force should be considered as 1.21, 1.33, and 1.20, respectively.

在许多实际工程中,两个空气支撑膜结构是平行排列的。平行排列的矩形平面空气支撑膜结构的干扰效应在抗风设计中非常重要。为了解决这个问题,我们通过压力测量风洞试验获得了孤立结构和平行排列结构上的风压。风引起的响应通过非线性动态时序分析进行计算。因此,分析了风荷载和风致响应的干扰效应。结果表明,下游结构的风吸力会因平行排列结构的干扰而放大,尤其是在斜风向情况下。最受干扰区域的平均风荷载被放大了约 65%。风致位移的干扰特性与平均风荷载基本相似。膜应力和拉索力只有在斜风向时才会受到明显干扰,在下游结构的所有区域都会被放大约 15%。当风向偏斜或平行于相邻结构之间的间隙时,间距-跨度比为 0.2 时可观察到最强的干扰效应。为分析干扰特性,提供了分区干扰系数。此外,还总结了整体响应干扰系数的推荐值,供设计参考。位移、膜应力和拉索力的整体响应干扰系数应分别考虑为 1.21、1.33 和 1.20。




来源:复合材料力学仿真Composites FEM
ACTMechanicalSystemDeform振动复合材料非线性汽车建筑ADS通信声学理论材料多尺度仿生控制
著作权归作者所有,欢迎分享,未经许可,不得转载
首次发布时间:2024-11-05
最近编辑:17天前
Tansu
签名征集中
获赞 3粉丝 0文章 690课程 0
点赞
收藏
作者推荐

【新文速递】2023年12月25日固体力学SCI期刊最新文章

今日更新:International Journal of Solids and Structures 1 篇,Mechanics of Materials 2 篇,International Journal of Plasticity 1 篇,Thin-Walled Structures 4 篇International Journal of Solids and StructuresLegendre-based node-dependent kinematics shell models for the global-local analysis of homogeneous and layered structuresE. Carrera, A. Pagani, D. Scanodoi:10.1016/j.ijsolstr.2023.112630基于 Legendre 的节点运动学壳模型,用于均质结构和层状结构的全局-局部分析The present work demonstrates the use of the node-dependent kinematics method to derive and compare several two-dimensional shell theories. The three dimensional displacement field is expressed in terms of generalized coordinates, which are subsequently expanded along the shell thickness using arbitrary functions. The in-plane unknowns, are then discretized through classical finite element approximation. Based on the Carrera Unified Formulation, the proposed method combines in a unique manner the theory of structures and the finite element method; thickness interpolation functions are defined node-wise. As a consequence, the resulting finite element model represents diverse approximation theories at each single node. In this work Taylor-based kinematics (including the Murakami Zig-Zag function) and Legendre-type nodal kinematics are incorporated at the element level without adopting mathematical artifices leading to the global-local strategy, where refined theories are selectively employed in specific areas, while maintaining acceptable computational costs. Numerical cases from the existing literature are employed to establish the effectiveness of node-dependent models in bridging a locally refined theories to global kinematics when local effects need to be considered. The analyses focus on localized loads for both homogeneous and multi-layered structures.本研究展示了如何使用节点运动学方法来推导和比较几种二维壳体理论。三维位移场用广义坐标表示,然后用任意函数沿壳厚度展开。然后通过经典的有限元近似方法对平面内的未知量进行离散化。基于卡雷拉统一公式,所提出的方法以独特的方式结合了结构理论和有限元方法;厚度插值函数是按节点定义的。因此,由此产生的有限元模型在每个节点上都代表了不同的近似理论。在这项工作中,基于泰勒的运动学(包括村上之字形函数)和 Legendre 类型的节点运动学被纳入元素级,而不采用数学人工方法,从而实现了全局-局部策略,在保持可接受的计算成本的同时,在特定区域选择性地采用精炼理论。在需要考虑局部效应时,采用现有文献中的数值案例来确定节点相关模型在将局部细化理论与全局运动学相联系方面的有效性。分析的重点是均质结构和多层结构的局部载荷。Mechanics of MaterialsBicrystallography-informed Frenkel–Kontorova model for interlayer dislocations in strained 2D heterostructuresMd Tusher Ahmed, Chenhaoyue Wang, Amartya S. Banerjee, Nikhil Chandra Admaldoi:10.1016/j.mechmat.2023.104903应变二维异质结构中层间位错的双晶学信息 Frenkel-Kontorova 模型In recent years, van der Waals (vdW) heterostructures and homostructures, which consist of stacks of two-dimensional (2D) materials, have risen to prominence due to their association with exotic quantum phenomena originating from correlated electronic states harbored by them. Atomistic scale relaxation effects play an extremely important role in the electronic scale quantum physics of these systems, providing means of manipulation of these materials and allowing them to be tailored for emergent technologies. We investigate such structural relaxation effects in this work using atomistic and mesoscale models, within the context of twisted bilayer graphene — a well-known heterostructure system that features moiré patterns arising from the lattices of the two graphene layers. For small twist angles, atomic relaxation effects in this system are associated with the natural emergence of interface dislocations or strain solitons, which result from the cyclic nature of the generalized stacking fault energy (GSFE), that measures the interface energy based on the relative movement of the two layers. In this work, we first demonstrate using atomistic simulations that atomic reconstruction in bilayer graphene under a large twist also results from interface dislocations, although the Burgers vectors of such dislocations are considerably smaller than those observed in small-twist systems. To reveal the translational invariance of the heterointerface responsible for the formation of such dislocations, we derive the translational symmetry of the GSFE of a 2D heterostructure using the notions of coincident site lattices (CSLs) and displacement shift complete lattices (DSCLs). The workhorse for this exercise is a recently developed Smith normal form bicrystallography framework. Next, we construct a bicrystallography-informed and frame-invariant Frenkel—Kontorova model, which can predict the formation of strain solitons in arbitrary 2D heterostructures, and apply it to study a heterostrained, large-twist bilayer graphene system. Our mesoscale model is found to produce results consistent with atomistic simulations. We anticipate that the model will be invaluable in predicting structural relaxation and for providing insights into various heterostructure systems, especially in cases where the fundamental unit cell is large and therefore, atomistic simulations are computationally expensive.近年来,由二维(2D)材料堆叠而成的范德华(vdW)异质结构和同质结构因其与相关电子态所产生的奇异量子现象的联系而备受瞩目。原子尺度弛豫效应在这些系统的电子尺度量子物理中发挥着极其重要的作用,为操纵这些材料提供了手段,并使它们能够为新兴技术量身定制。扭曲双层石墨烯是一种著名的异质结构体系,其特征是两层石墨烯的晶格产生摩尔纹。对于较小的扭曲角度,该体系中的原子弛豫效应与界面位错或应变孤子的自然出现有关,而界面位错或应变孤子是广义堆积断层能(GSFE)的循环性质所致,GSFE 根据两层石墨烯的相对运动测量界面能量。在这项工作中,我们首先利用原子模拟证明了双层石墨烯在大扭转下的原子重构也是由界面位错引起的,尽管这种位错的布尔矢量比在小扭转系统中观察到的位错小得多。为了揭示导致这种位错形成的异质界面的平移不变性,我们利用重合位点晶格(CSL)和位移完全晶格(DSCL)的概念,推导出二维异质结构的 GSFE 的平移对称性。这项工作的主力是最近开发的史密斯正态双晶框架。接下来,我们构建了一个双晶体学信息和框架不变的 Frenkel-Kontorova 模型,该模型可以预测任意二维异质结构中应变孤子的形成,并将其应用于研究异质受限的大扭转双层石墨烯体系。研究发现,我们的中尺度模型得出的结果与原子模拟一致。我们预计,该模型在预测结构弛豫和深入了解各种异质结构体系方面将非常有价值,尤其是在基本单元尺寸较大,因此原子模拟计算成本较高的情况下。Torsional waves in hyperelastic shells: Appearing shock waves and energy dissipationSergey V. Kuznetsovdoi:10.1016/j.mechmat.2023.104905超弹性壳中的扭转波:冲击波的出现和能量耗散Nonlinear torsional waves propagating in cylindrical shells made of hyperelastic material obeying Ogden model, are studied by a combined approach comprising theoretical and finite element analysis. It was found, apparently for the first time, that delta-like pulses of torsional waves attenuate with distance due to the appearance of shock wave fronts. Moreover, both strain and kinetic mechanical energy dissipate due to the release of thermal energy.通过理论分析和有限元分析相结合的方法,研究了在符合奥格登模型的超弹性材料圆柱形壳体中传播的非线性扭转波。研究首次发现,由于冲击波前沿的出现,扭转波的三角脉冲随距离的增加而减弱。此外,由于热能的释放,应变和机械动能都会消散。International Journal of PlasticityYield criterion for intergranular void coalescence under combined tension and shearC. Sénac, J. Hure, B. Tanguydoi:10.1016/j.ijplas.2023.103864拉伸和剪切联合作用下晶粒间空隙凝聚的屈服准则Intergranular ductile fracture is a failure mode that may arise in many metallic alloys used in industrial applications. It manifests as the successive nucleation, growth, and coalescence of cavities at grain boundaries. Thus, simulation of intergranular ductile fracture in polycrystals requires modeling those three different stages at the scale of grain boundaries, i.e. at the interface between two different crystals. In this study, a yield criterion for the coalescence of cavities at the interface between two isotropic materials obeying Mises plasticity is first developed by limit analysis in order to provide some insights into that phenomenon. This criterion is checked against numerical limit analysis under combined tension and shear and is found to agree with unit-cell simulations quantitatively. The model is then extended to crystals so as to account for the complex coupling between loading state, crystallographic orientations, and void microstructure in intergranular coalescence. This second criterion is also assessed through comparisons to numerical limit analysis for an FCC crystal lattice. The agreement is very good in the case of coalescence by internal necking and the trends displayed by coalescence under combined tension and shear are captured correctly. Some implications of the model on the competition between transgranular and intergranular ductile fracture are discussed. Finally, by combining this model with an existing criterion for void growth at grain boundaries, a multi-surface yield function relevant to intergranular ductile fracture is obtained and compared to unit-cell simulations.晶间韧性断裂是工业应用中许多金属合金可能出现的一种失效模式。它表现为晶界处空洞的连续成核、生长和凝聚。因此,模拟多晶体中的晶间韧性断裂需要在晶界尺度(即两个不同晶体之间的界面)上对这三个不同阶段进行建模。在本研究中,首先通过极限分析建立了两个服从米塞斯塑性的各向同性材料界面处空穴凝聚的屈服准则,以便对这一现象提供一些见解。在联合拉伸和剪切的情况下,将该准则与数值极限分析进行检验,发现其在定量上与单细胞模拟一致。然后将模型扩展到晶体,以解释晶间凝聚中加载状态、晶体学取向和空隙微观结构之间的复杂耦合。第二个标准也通过与 FCC 晶格的数值极限分析进行比较来评估。在内部缩颈凝聚的情况下,两者的一致性非常好,并且正确捕捉到了拉伸和剪切联合作用下的凝聚趋势。此外,还讨论了该模型对跨晶和晶间韧性断裂竞争的一些影响。最后,通过将该模型与现有的晶界空隙增长准则相结合,获得了与晶间韧性断裂相关的多表面屈服函数,并与单元模拟进行了比较。Thin-Walled StructuresThermal conductivity and nonreciprocity in wrinkled monolayer graphene ringBohan Li, Qingxiang Ji, Jinliang Wang, Changguo Wang, Muamer Kadicdoi:10.1016/j.tws.2023.111523皱褶单层石墨烯环的导热性和非互易性We explore an external tunable approach to produce thermal nonreciprocity, by means of controlling wrinkle characteristics in graphene rings. The wrinkling formation and evolution law of graphene rings under torsional deformation is studied. Results show that wrinkle patterns of monolayer graphene can be flexibly tuned by controlling mechanical torsion. We further study the dependence of graphene rings’ thermal conductivity on sizes, temperatures and torsional angles, and reveal the influential mechanism by phonon density of states. Specifically, the thermal conductivity is reduced by 20.4% when the torsional angle increases from θ=0° to θ=10.3°. Finally, nonreciprocal conductive heat transfer is demonstrated in torsion-wrinkled graphene rings. It is found that thermal nonreciprocity effect is dependent on both torsional angles and temperature differences, i.e., the thermal nonreciprocity factor increase from 1.9% to 4.5% as temperature difference varies from 100K to 400K under torsional angle θ=6.9°. Our work paves new avenues for the design and implementation of thermal metadevices by mechanical tuning approach.我们探索了一种通过控制石墨烯环的皱纹特性来产生热不折返性的外部可调方法。我们研究了石墨烯环在扭转变形下的皱纹形成和演变规律。结果表明,单层石墨烯的皱纹模式可以通过控制机械扭转进行灵活调整。我们进一步研究了石墨烯环的热导率与尺寸、温度和扭转角度的关系,并揭示了声子态密度的影响机制。具体来说,当扭转角从θ=0°增加到θ=10.3°时,导热率降低了 20.4%。最后,在扭转皱纹石墨烯环中演示了非互惠传导传热。研究发现,热非互惠效应与扭转角和温差都有关系,即在扭转角 θ=6.9° 时,当温差从 100K 变化到 400K 时,热非互惠因子从 1.9% 增加到 4.5%。我们的工作为利用机械调谐方法设计和实现热元器件开辟了新途径。AXIAL COMPRESSIVE BEHAVIOR OF THE CHORD IN HYBRID FRP-CONCRETE-STEEL DOUBLE-SKIN TUBULAR MEMBER T-JOINTSGuan Lin, Junjie Zeng, Jiaxing Li, G.M. Chendoi:10.1016/j.tws.2023.111535钢-混凝土混合结构双层管状构件 T 型接头弦杆的轴向受压行为Hybrid fiber reinforced polymer (FRP)-concrete-steel double-skin tubular members (DSTMs) are a promising form of structural members with superior mechanical performance and durability, which have great potential for application in ocean structures. Such hybrid DSTMs consist of three components: an inner steel tube, an outer FRP tube, and concrete filled between the two tubes. Despite a significant number of studies demonstrating the excellent performance of hybrid DSTMs, no studies have been concerned with the joints of these members. The lack of a reliable design method for DSTM joints is certainly a huge obstacle to their wide application in practice. Against the above background, a research project has been proposed to understand the static behavior of circular DSTM T-joints through a combined experimental, modeling, and theoretical study. This paper presents the results of an experimental program on the axial compressive behavior of the chord in DSTM T-joints. The effects of various important factors, such as FRP tube thickness, steel tube thickness, brace-to-chord diameter ratio, void ratio, and concrete strength, on the performance of the DSTM T-joints were examined in detail. The test results demonstrated that the DSTM T-joints exhibited a ductile behavior provided that the joint region was appropriately strengthened and the presence of a brace did not significantly affect the compressive behavior of the chord in the joints with a brace-to-chord diameter ratio of 0.5. Finally, a simple method was proposed to predict the axial load-axial strain behavior of the DSTM T-joints.混合纤维增强聚合物(FRP)-混凝土-钢双层管状构件(DSTM)是一种很有前途的结构构件形式,具有优异的机械性能和耐久性,在海洋结构中的应用潜力巨大。这种混合 DSTM 由三部分组成:内钢管、外玻璃钢管和填充在两根钢管之间的混凝土。尽管有大量研究表明混合 DSTM 性能卓越,但还没有研究涉及这些构件的连接问题。缺乏可靠的 DSTM 接头设计方法无疑是 DSTM 在实践中广泛应用的巨大障碍。在上述背景下,我们提出了一个研究项目,通过实验、建模和理论相结合的研究来了解圆形 DSTM T 型接头的静态行为。本文介绍了 DSTM T 型接头中弦杆轴向受压行为的实验结果。详细研究了玻璃钢管厚度、钢管厚度、支撑与弦直径比、空隙率和混凝土强度等各种重要因素对 DSTM T 型连接性能的影响。试验结果表明,DSTM T 型接头表现出延展性,前提是接头区域得到了适当的加固,并且在支撑与弦直径比为 0.5 的接头中,支撑的存在不会对弦杆的抗压性能产生显著影响。最后,提出了一种简单的方法来预测 DSTM T 型接头的轴向载荷-轴向应变行为。Tailored twisted CNT bundle with improved inter-tube slipping performancesDanyang Zhao, Xing Quan Wang, Lik-ho Tam, Cheuk Lun Chow, Denvid Laudoi:10.1016/j.tws.2023.111536 改进了管间滑移性能的定制扭曲碳纳米管束The exceptional mechanical properties of carbon nanotubes (CNTs) have encouraged the development of high-performance synthetic fibers in composite materials. To understand the effect of twisting on the mechanical and slipping performances of CNT bundles, molecular dynamics simulation is applied to investigate the tensile performances, failure mode, and pull-out responses of twisted CNT bundles. A molecular model comprising nineteen parallel aligned single-walled carbon nanotubes (SWCNTs) is twisted into bundles at angles of 0°, 10°, and 20°, and further tensile and pull-out simulations are performed. The tensile simulation indicates that compared with the non-twisted CNT bundle showing a tensile strength of about 82 GPa with obvious inter-tube slipping, the 10°-twisted bundle exhibits a tensile strength of approximately 70 GPa with SWCNTs fracture as the main failure mode, which indicates that twisting improves the inter-tube slipping performance without causing excessive strength reduction. Comparatively, when the twisting angle is 20°, no inter-tube slipping is observed and the tensile strength of the CNT bundle is measured to be 55 GPa, which decreases by approximately 32.9 %. The pull-out simulations further reveal that the pull-out forces increase as the twisting angle increases and the weakened bundle strength of twisted bundle is attributed to the repulsive van der Waals forces caused by the reduced distances between inter-tubes. Essentially, twisting is unfavorable for the overall mechanical strength while torsional densification mitigates the inter-tube slipping, which indicates that a trade-off need to be achieved. This paper provides insights into the tensile and slipping performances of twisted CNT bundles and forms a basis for enhancing the assembled CNTs bundle as the next-generation reinforcing phase in composite materials.碳纳米管(CNT)优异的机械性能促进了复合材料中高性能合成纤维的发展。为了解扭曲对碳纳米管束的机械和滑动性能的影响,本文应用分子动力学模拟研究了扭曲碳纳米管束的拉伸性能、失效模式和拉出响应。将由 19 根平行排列的单壁碳纳米管(SWCNT)组成的分子模型以 0°、10° 和 20°角扭曲成束,并进一步进行拉伸和拉出模拟。拉伸模拟结果表明,未扭转的 CNT 管束的拉伸强度约为 82 GPa,管间滑动明显,而扭转 10° 的管束的拉伸强度约为 70 GPa,SWCNT 断裂是主要的破坏模式。相比之下,当扭转角度为 20° 时,未观察到管间滑动,测得 CNT 束的抗拉强度为 55 GPa,降低了约 32.9%。拉拔模拟进一步表明,拉拔力随着扭转角度的增大而增大,扭转管束强度减弱的原因是管间距离减小导致的范德华排斥力。从根本上说,扭曲不利于整体机械强度,而扭转致密化则可减轻管间滑动,这表明需要权衡利弊。本文深入探讨了扭曲碳纳米管束的拉伸和滑移性能,为增强碳纳米管束的组装性能,将其作为复合材料的下一代增强相奠定了基础。Characterization of low-velocity and low-energy responses of elastic-plastic plate struck by elastic-plastic impactorXin Xiao, Xiaochun Yin, Hui Wang, Huaiping Ding, Bo Yu, Yuanyuan Guo, Wenhao Xiedoi:10.1016/j.tws.2023.111537弹性塑料板受弹性塑料撞击器撞击后的低速和低能响应特性分析This paper presents a study on the characterization of low-velocity and low-energy impact responses of elastic-plastic plate struck by elastic-plastic spherical impactor. The applicability of the existing impact characterization diagram is examined firstly by intensive finite element (FE) simulations for a wide range of complicated impact situations including all three types of contact: indentation, flattening and combined flattening and indentation. The limitations of the existing diagram are found in identifying the type of impact response and predicting the maximum impact force for complicated impact situations. The effects of elastic and plastic deformations of impactor on the identification and prediction by the existing diagram are analyzed. A new linear contact law is presented according to the piecewise linear characteristics of contact stiffness observed from the intensive FE results. An extended impact characterization diagram is then proposed to characterize low-velocity and low-energy impact responses of plate under complicated impact situations with arbitrary three contact types. The extended diagram is validated by the intensive FE simulations and experimental results. It is concluded that the extended impact characterization diagram can identify correctly the plate response type to complicated impacts and predict accurately the maximum impact force in a fast and simple way without the aid of FE models and experimental tests.本文研究了弹性塑料板在受到弹性塑料球形冲击器撞击时的低速和低能冲击响应特征。首先通过密集的有限元(FE)模拟,考察了现有撞击表征图的适用性,模拟了各种复杂的撞击情况,包括所有三种接触类型:压痕、压扁以及压扁和压痕组合。现有图表在确定冲击响应类型和预测复杂冲击情况下的最大冲击力方面存在局限性。分析了冲击器的弹性和塑性变形对现有图表识别和预测的影响。根据从强化 FE 结果中观察到的接触刚度的片状线性特征,提出了一种新的线性接触定律。然后提出了一个扩展的撞击特征图,以描述板材在任意三种接触类型的复杂撞击情况下的低速和低能撞击响应。强化 FE 仿真和实验结果对扩展图进行了验证。结论是,扩展的撞击特征图可以正确识别板材对复杂撞击的响应类型,并以快速、简单的方式准确预测最大撞击力,而无需借助有限元模型和实验测试。来源:复合材料力学仿真Composites FEM

未登录
还没有评论
课程
培训
服务
行家
VIP会员 学习 福利任务 兑换礼品
下载APP
联系我们
帮助与反馈