Mechanics of Materials最新文献_第4页

A non-local GTN model with two length scales calibrated for a low alloy steel 一个非局部GTN模型与两个长度刻度校准为低合金钢

IF 4.1 3区材料科学 Q2 MATERIALS SCIENCE, MULTIDISCIPLINARY

Mechanics of Materials

Pub Date : 2025-12-19 DOI: 10.1016/j.mechmat.2025.105579

Shuyue Wang , Pål Efsing , Jonas Faleskog

This study applies a non-local integral Gurson-Tvergaard-Needleman model, incorporating two characteristic material length scales as regularization parameters, linked to shear deformation and hydrostatic tension, to simulate fracture in low alloy A533B. The model accounts for void growth, nucleation, and coalescence, including a shear-enhanced mechanism. Experiments under various stress triaxialities were used to assess model performance, including: uniaxial tensile test, fracture test, and simple shear test. The aim is to predict both global load-deformation responses and fracture modes using a single, physically motivated parameter set. While some parameters are well-established in the literature and linked to micro-structural observations and micro-mechanical analysis, others are less studied and require calibration against experiments. The calibration process is challenging due to nonlinear parameter interactions causing complex dependencies. A trade-off between competing effects was frequently observed. To address this, three parameter sets were investigated. Set 1 used physically motivated values and successfully reproduced the cup-cone fracture in round smooth bar, but underestimated the strains to failure for round smooth bar and modified Iosipescu specimens. Set 2 employed phenomenological values to closely match all the global load-deformation responses, but failed to replicate the experimentally observed fracture mode. Set 3 slightly adjusted parameters in Set 1, achieving improved failure strain predictions and a more accurate cup-cone pattern.

本研究采用非局部积分Gurson-Tvergaard-Needleman模型，将两个特征材料长度尺度作为正则化参数，与剪切变形和静水张力相关联，模拟低合金A533B的断裂。该模型解释了空洞的生长、成核和聚并，包括剪切增强机制。采用不同应力三轴性下的试验，包括：单轴拉伸试验、断裂试验和单轴剪切试验。目的是使用单一的物理驱动参数集预测全局载荷-变形响应和断裂模式。虽然一些参数在文献中已经确立，并与微观结构观察和微观力学分析相关联，但其他参数的研究较少，需要根据实验进行校准。由于非线性参数相互作用导致复杂的依赖关系，校准过程具有挑战性。竞争效应之间的权衡经常被观察到。为了解决这个问题，我们研究了三个参数集。Set 1采用物理激励值，成功地再现了圆光滑棒的杯锥断裂，但低估了圆光滑棒和改良Iosipescu试样的破坏应变。集合2采用现象学值与所有全局荷载-变形响应紧密匹配，但未能复制实验观察到的断裂模式。Set 3略微调整了Set 1中的参数，实现了改进的失效应变预测和更准确的杯锥模式。

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引用次数: 0

Analysis of blood flow–clot interaction using a fibrinogen concentration–dependent hyperelastic constitutive model 使用纤维蛋白原浓度依赖性超弹性本构模型分析血流-凝块相互作用

IF 4.1 3区材料科学 Q2 MATERIALS SCIENCE, MULTIDISCIPLINARY

Mechanics of Materials

Pub Date : 2025-12-17 DOI: 10.1016/j.mechmat.2025.105577

Zhipeng Zhao , Xiaomin Zhang , Qiong Wu , Linlin Zhang , Libo Zhao , Ke Cheng , Yuanlin Ma , Ge Tang

Blood clot formation is a critical mechanism in physiological functioning; however, abnormal changes in the mechanical properties of blood clots can trigger various pathological responses. The fibrin network of blood clots is the greatest contributor to their structural integrity, and the microstructural characteristics of the network determine the mechanical responses of clots under different loading conditions. First, a fibrinogen concentration–dependent hyperelastic constitutive model was developed by establishing the relationship between fibrinogen concentration and modulus through microstructural characterization (mesh size) of the fibrin networks. Subsequently, uniaxial compression and shear tests were conducted on the clots with varying fibrinogen concentrations to validate the model. Both theoretical and experimental studies revealed that the clot–strengthening effect of fibrinogen diminished with increasing concentration. Finally, the proposed constitutive model was applied to numerical simulations of blood flow–clot interactions. We observed that the maximum shear stress was concentrated at the flow-facing edges of the clots. By integrating the maximum shear stress and deformation magnitude, a detachment risk index (RI) was defined, and its behavior was systematically explored through parameter scanning. The results demonstrated that RI shows a linear correlation with flow velocity and clot size. Moreover, the fibrinogen concentration exhibited a dual-effect mechanism when the shear stress weighting coefficient was relatively high (α ≥ 0.4): (1) For low–concentration clots, the detachment risk increased with concentration, with shear stress as the dominant mechanism. (2) For high–concentration clots, the detachment risk decreased with increasing concentration, and deformation response was the governing mechanism.

血凝块的形成是生理功能的关键机制；然而，血凝块力学特性的异常变化可引发各种病理反应。血凝块的纤维蛋白网络是其结构完整性的最大贡献者，网络的微观结构特征决定了血凝块在不同载荷条件下的力学响应。首先，通过纤维蛋白网络的微观结构表征（网状尺寸）建立纤维蛋白原浓度与模量之间的关系，建立了纤维蛋白原浓度依赖的超弹性本构模型。随后，对不同纤维蛋白原浓度的凝块进行单轴压缩和剪切试验，以验证模型。理论和实验研究均表明，纤维蛋白原的凝血强化作用随着浓度的增加而减弱。最后，将提出的本构模型应用于血流-凝块相互作用的数值模拟。我们观察到最大剪切应力集中在凝块的流动面边缘。通过对最大剪切应力和变形幅度的积分，定义了剥离风险指数（RI），并通过参数扫描系统地探讨了其行为。结果表明，RI与血流速度和凝块大小呈线性相关。当剪切应力权重系数较高（α≥0.4）时，纤维蛋白原浓度表现出双重作用机制：(1)低浓度血凝块剥离风险随浓度增加而增加，剪切应力是主要机制；(2)对于高浓度凝块，脱离风险随浓度的增加而降低，变形响应是控制机制。

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引用次数: 0

On estimating 3D crack density from crack traces on surfaces or cross-sections of a specimen – problem revisited 从试样表面或横截面上的裂纹迹估计三维裂纹密度的问题

IF 4.1 3区材料科学 Q2 MATERIALS SCIENCE, MULTIDISCIPLINARY

Mechanics of Materials

Pub Date : 2025-12-17 DOI: 10.1016/j.mechmat.2025.105575

Yulia Pronina , Mark Kachanov

The crack density parameter (scalar or tensor) controls the effect of cracks on the overall elastic and conductive properties of microcracked materials. However, it cannot, generally, be related to volume fractions and may be difficult to be estimated experimentally. Its estimation from the 2D density of crack traces observed on specimen surfaces or cross-sections is therefore valuable. Note that quantitative 2D–3D connections for various geometric parameters of inhomogeneities have been discussed in literature starting from the nineteenth century. However, they do not cover connections for the crack density parameter. Such 2D–3D relationship is derived for the isotropic case of random crack orientations; it corrects the previously published results that actually referred to the special case of transverse isotropy. In the latter case, the anisotropic elastic and conductive constants are derived directly in terms of the observable 2D density of crack traces.

裂纹密度参数（标量或张量）控制裂纹对微裂纹材料整体弹性和导电性能的影响。然而，它通常不能与体积分数有关，并且可能难以通过实验估计。因此，从在试样表面或截面上观察到的裂纹痕迹的二维密度估计是有价值的。请注意，从19世纪开始，文献中已经讨论了各种非均匀性几何参数的定量2D-3D连接。但是，它们不包括裂纹密度参数的连接。对于随机裂纹取向的各向同性情况，导出了这种2D-3D关系；它纠正了先前发表的结果，实际上是指横向各向同性的特殊情况。在后一种情况下，各向异性弹性常数和导电常数直接由可观察到的二维裂纹迹密度导出。

引用次数: 0

Low-cycle fatigue prediction of AM IN718 using a crystal plasticity model with precipitate shear mechanism 基于析出相剪切机制的晶体塑性模型预测AM IN718的低周疲劳

IF 4.1 3区材料科学 Q2 MATERIALS SCIENCE, MULTIDISCIPLINARY

Mechanics of Materials

Pub Date : 2025-12-16 DOI: 10.1016/j.mechmat.2025.105574

Biao Wang , Ruiping Lai , Shijie Song , Jianfeng Zhao , Liming Lei , Lei Shi , Shengchuan Wu , Wei Rao , Zishi Shen , Xu Zhang

To explore the cyclic softening behavior of additively manufactured (AM) IN718 under low-cycle fatigue, this study develops a crystal plasticity model that incorporates the dislocation shear precipitates mechanisms. By introducing irreversible factor, the model effectively captures the softening behavior by dislocation shear precipitates during cyclic loading. Simulation results reveal that both irreversible dislocations and strain amplitude critically affect softening. Irreversible dislocations shear the precipitate during cycling, resulting in a reduction in the radius of the precipitate and a strengthening of the precipitate, ultimately leading to softening. As the irreversible factor increases, the rate of softening significantly escalates. As the strain amplitude increases, the corresponding rise in dislocation density enhances the shear effect of dislocations on precipitations, accelerates the reduction in the radius of precipitates and weakens precipitation strengthening, ultimately accelerating cyclic softening. Additionally, the FIP, represented in terms of cumulative plastic strain and strain energy dissipation, effectively predicts low cycle fatigue life. The prediction results based on strain energy dissipation criteria offer superior accuracy at high strain amplitudes. The outcomes of this study enhance the understanding of the mechanical properties associated with the AM IN718 alloy, providing a critical basis for optimizing the properties of the alloy.

为了探索增材制造（AM） IN718在低周疲劳下的循环软化行为，本研究建立了包含位错剪切析出机制的晶体塑性模型。该模型通过引入不可逆因子，有效地捕捉了循环加载过程中位错剪切析出物的软化行为。模拟结果表明，不可逆位错和应变幅值对软化有重要影响。不可逆位错在循环过程中剪切析出相，导致析出相半径减小，析出相强化，最终导致软化。随着不可逆因素的增加，软化速率显著上升。随着应变幅值的增大，位错密度的相应增大增强了位错对析出的剪切作用，加速了析出半径的减小，弱化了析出强化，最终加速了循环软化。此外，以累积塑性应变和应变能量耗散表示的FIP可以有效地预测低周疲劳寿命。基于应变能耗散准则的预测结果在高应变幅值下具有较高的精度。本研究结果增强了对AM IN718合金力学性能的理解，为优化合金性能提供了重要依据。

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引用次数: 0

Bridging the scales of mechanical failure in solids 在固体中架起机械故障的桥梁

IF 4.1 3区材料科学 Q2 MATERIALS SCIENCE, MULTIDISCIPLINARY

Mechanics of Materials

Pub Date : 2025-12-11 DOI: 10.1016/j.mechmat.2025.105563

Bradley Dodd , Marc Meyers , Naresh Thadhani , Min Zhou , Yujie Wei

引用次数: 0

Semi-analytical method for frictional sliding contact of a piezoelectric layer-substrate 压电层-衬底摩擦滑动接触的半解析方法

IF 4.1 3区材料科学 Q2 MATERIALS SCIENCE, MULTIDISCIPLINARY

Mechanics of Materials

Pub Date : 2025-12-10 DOI: 10.1016/j.mechmat.2025.105572

Van Thuong Nguyen , Van Son Pham , Nguyen Dinh Duc , Tinh Quoc Bui

Layer-substrate structures are commonly used in many high-tech devices and are often composed of anisotropic piezoelectric materials. Contact analysis of layer-substrate structures with accuracy and efficiency is vital in the design process to ensure the safety and performance of devices and systems. In this paper, we introduce a semi-analytical method (SAM) for fast and efficient analysis of frictional sliding contact in the piezoelectric layer-substrate structures. In this SAM setting, the surface Green function for a piezoelectric bimaterial is first derived. This Green’s function inherently satisfies the boundary conditions of the interfaces. Thus, SAM eliminates the need for meshing along the interface between the layer and substrate, which offers benefits in terms of meshing reduction, computational cost, and time. Using this Green’s function as a kernel, the SAM further benefits from analytically computable influence matrices, which boosts both accuracy and computational efficiency. The method is broadly applicable to systems in which the materials of the layer and substrate are generally anisotropic. The punch profile can be arbitrary and is either an insulator or a conductor. To verify the correctness of the proposed semi-analytical method, numerical results are compared to those obtained by the available methods, e.g., the analytical solutions and the boundary element method, and are verified through the mesh-sensitive analysis. With the numerical data, the parametric studies are implemented to demonstrate the versatility and explore the influences of the anisotropy, thickness of the layer, friction, and many other factors on the contact responses of the layer-substrate structures. These studies offer valuable insights for the design of smart layer-substrate structures that use anisotropic piezoelectric materials.

层-衬底结构通常用于许多高科技器件，通常由各向异性压电材料组成。准确、高效地对层-基板结构进行接触分析对于保证器件和系统的安全和性能至关重要。本文介绍了一种快速有效分析压电层-衬底结构摩擦滑动接触的半解析方法（SAM）。在此SAM设置下，首先推导了压电双材料的表面格林函数。该格林函数固有地满足界面的边界条件。因此，SAM消除了沿着层和基板之间的界面进行网格划分的需要，这在网格划分减少、计算成本和时间方面提供了好处。利用格林函数作为核，SAM进一步受益于解析可计算的影响矩阵，提高了精度和计算效率。该方法广泛适用于层和衬底材料一般各向异性的系统。冲孔轮廓可以是任意的，要么是绝缘体，要么是导体。为了验证所提出的半解析方法的正确性，将数值结果与解析解和边界元法等现有方法的结果进行了比较，并通过网格敏感分析进行了验证。利用数值数据，进行了参数化研究，以证明其通用性，并探讨了各向异性、层厚度、摩擦和许多其他因素对层-基底结构接触响应的影响。这些研究为使用各向异性压电材料的智能层-衬底结构的设计提供了有价值的见解。

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引用次数: 0

An approach to predict long-term rupture life of nickel-based superalloy based on relaxation creep tests 基于松弛蠕变试验的镍基高温合金长期断裂寿命预测方法

IF 4.1 3区材料科学 Q2 MATERIALS SCIENCE, MULTIDISCIPLINARY

Mechanics of Materials

Pub Date : 2025-12-10 DOI: 10.1016/j.mechmat.2025.105573

Wen Kang, Tieshan Cao, Congqian Cheng, Jie Zhao

The measurement of creep rupture life normally requires a relatively long duration, while stress relaxation, with the advantages of fewer specimens and shorter time, is proposed as an effective method for predicting rupture life. However, considerable debate persists regarding the estimation of long-term creep rupture life derived from short-term relaxation creep data. This paper investigates the relationship between relaxation creep and constant-load creep based on a nickel-based superalloy in two states: as-received and aged. The results indicate that the prediction model derived from relaxation creep tests on the as-received specimens tends to overestimate the long-term rupture life. The relaxation creep rate increases with exposure time due to microstructural degradation. In order to account for this effect, a damage parameter D_a is introduced to modify the model. Long-term rupture-life predictions from the modified model closely match the experimental results and are comparable to those of the LM model, thereby confirming its validity at 900 °C. The micro-mechanism of the modified model is discussed in terms of Lifshitz–Slyozov–Wagner theory, and significant variations in the γ′ microstructure are quantified as a function of the damage parameter D_a in a given temperature. Accounting for the temperature dependence of microstructural degradation, the modified model has been validated across a wider temperature range. It underestimates rupture life above 900 °C but remains a useful guide. For higher accuracy, specimens should undergo an additional aging treatment at the target temperature and the modified model recalibrated accordingly.

蠕变断裂寿命的测量通常需要较长的时间，而应力松弛具有试样少、时间短的优点，是预测断裂寿命的有效方法。然而，对于从短期松弛蠕变数据中得出的长期蠕变断裂寿命的估计，仍然存在相当大的争论。本文研究了一种镍基高温合金在接收和时效两种状态下的松弛蠕变与恒载蠕变的关系。结果表明，基于实测试样的松弛蠕变试验建立的预测模型有高估长期断裂寿命的倾向。由于微观结构的退化，松弛蠕变速率随暴露时间的增加而增加。为了考虑这种影响，引入损伤参数Da对模型进行修正。修正模型的长期断裂寿命预测与实验结果非常吻合，与LM模型相当，从而证实了其在900°C下的有效性。根据Lifshitz-Slyozov-Wagner理论讨论了修正模型的微观机理，并将γ′微观结构的显著变化量化为给定温度下损伤参数Da的函数。考虑到微观结构降解的温度依赖性，修正模型已在更宽的温度范围内得到验证。它低估了900°C以上的断裂寿命，但仍然是一个有用的指南。为了获得更高的精度，试样应在目标温度下进行额外的时效处理，并相应地重新校准修正后的模型。

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引用次数: 0

Computational investigations of graded density metallic foams subjected to blast type loads 爆炸载荷作用下梯度密度金属泡沫材料的计算研究

IF 4.1 3区材料科学 Q2 MATERIALS SCIENCE, MULTIDISCIPLINARY

Mechanics of Materials

Pub Date : 2025-12-09 DOI: 10.1016/j.mechmat.2025.105568

Bhanu Pratap Sharma, Abhijit Gogulapati, Viren Menezes

Foam-like materials are highly compressible and are widely used for shock and impact mitigation. However, studies show that under extreme loading, uniform-density Aluminum foams can amplify the incoming blast wave instead of attenuating it. The present work investigates the reasons behind such amplification using finite element simulations. The mitigation performance of Aluminum based uniform-density foams (UDFs) and graded-density foams (GDFs) were analyzed. The effects of various parameters such as peak pressure, foam density, foam length, pulse duration, and density gradient are presented. The gradient in density is introduced by using a Gaussian function. The ability of a given foam to mitigate or amplify a given load is examined with the help of the standard xt-plots and two non-dimensional parameters,

{\bar{P}}_{m a x}

and

\bar{l}

. The results show that based on the relative magnitudes of these parameters, the foam response falls into three regimes—elastic amplification, plastic attenuation, and plastic amplification. In particular, critical thresholds in length, pulse duration, peak pressure, and density gradient define the transition between amplification and attenuation. Neither UDFs nor GDFs are consistently superior; their performance depends on the interplay of the input parameters.

泡沫状材料具有高度可压缩性，广泛用于减轻冲击和冲击。然而，研究表明，在极端载荷下，均密度泡沫铝会放大而不是减弱来袭冲击波。本工作利用有限元模拟研究了这种放大背后的原因。分析了铝基均密度泡沫（UDFs）和梯度密度泡沫（GDFs）的减振性能。分析了峰值压力、泡沫密度、泡沫长度、脉冲持续时间和密度梯度等参数对泡沫的影响。利用高斯函数引入了密度梯度。给定泡沫减轻或放大给定载荷的能力通过标准x - t图和两个非维度参数P ‘ max和l ’来检查。结果表明：基于这些参数的相对量级，泡沫响应可分为弹性放大、塑性衰减和塑性放大三种状态；特别是，长度、脉冲持续时间、峰值压力和密度梯度的临界阈值定义了放大和衰减之间的过渡。udf和gdf都不是一贯的优越；它们的性能取决于输入参数的相互作用。

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引用次数: 0

Shock compression of additively manufactured high solids loaded polymer composites with aligned porosity 增材制造的具有排列孔隙度的高固体负载聚合物复合材料的冲击压缩

IF 4.1 3区材料科学 Q2 MATERIALS SCIENCE, MULTIDISCIPLINARY

Mechanics of Materials

Pub Date : 2025-12-08 DOI: 10.1016/j.mechmat.2025.105571

K.B. Wagner , G. Kennedy , D. Montaigne , B.J. Jensen , M. Zhou , N.N. Thadhani

The effects of aligned porosity on the shock-compression response of additively manufactured (AM) composite structures with collinear and log-cabin geometries are investigated. The composites contain two inorganic and two organic particle populations and a UV-curable polymer binder. X-ray phase contrast imaging (X-PCI) is used as an in-material diagnostic in plate-impact experiments performed at the Dynamic Compression Sector of the Advanced Photon Source at the Argonne National Laboratory. Macroscale shock and particle velocities and microscale pore collapse velocities are measured from X-PCI images obtained from samples impacted in various orientations relative to the AM build directions. The linear shock and particle velocity relation for the structures with collinear build geometry shows directional differences, with the build direction exhibiting the highest slope and the filament print direction having the shallowest slope. Composites with log-cabin geometry, due to their slightly lower porosity and smaller sized pores, show higher shock velocities than the collinear structures at the same particle velocity. Microscale directionality effects are also observed, with the pore collapse velocity dependent on the pore configuration. Specifically, the pore collapse velocity is highest for pores elongated along the impact direction which is the case for the colinear structures impacted in the filament print direction, which is consistent with the directionality trend observed in the data for the shock and particle velocity equation of state. The pore collapse velocity approaches ∼80 % of the shock velocity and is several times the average bulk particle velocity, suggesting a highly hydrodynamic mechanism of pore collapse. Overall, both the macroscale response as measured by the shock and particle velocity relationship, and the microscale response as measured by the pore collapse velocity, are found to be anisotropic and dependent on the AM composite structure.

研究了增材制造（AM）复合材料共线结构和木屋结构的排列孔隙率对其冲击压缩响应的影响。该复合材料含有两种无机和两种有机粒子群和一种可紫外光固化的聚合物粘合剂。x射线相衬成像（X-PCI）在阿贡国家实验室先进光子源的动态压缩部门进行的板撞击实验中被用作材料内诊断。从相对于增材制造方向的不同方向的样品中获得的X-PCI图像测量了宏观冲击和颗粒速度以及微观孔隙崩溃速度。共线构建几何结构的线性激波和粒子速度关系表现出方向性差异，构建方向斜率最大，而细丝打印方向斜率最小。在相同颗粒速度下，圆木舱结构的复合材料由于孔隙率略低，孔隙尺寸较小，比共线结构的复合材料表现出更高的激波速度。微观尺度的方向性效应也被观察到，孔隙崩塌速度依赖于孔隙结构。其中，沿冲击方向拉伸的孔隙崩溃速度最高，而在长丝打印方向撞击的共线结构也是如此，这与激波和粒子速度状态方程数据中观察到的方向性趋势一致。孔隙崩溃速度接近冲击速度的80%，是平均体积颗粒速度的几倍，表明孔隙崩溃的高度水动力机制。总体而言，无论是激波和颗粒速度关系测量的宏观响应，还是孔隙崩塌速度测量的微观响应，都具有各向异性，并且依赖于AM复合材料结构。

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引用次数: 0

Secondary instability development in the post-buckling regime in soft composites 软复合材料屈曲后的二次失稳发展

IF 4.1 3区材料科学 Q2 MATERIALS SCIENCE, MULTIDISCIPLINARY

Mechanics of Materials

Pub Date : 2025-12-05 DOI: 10.1016/j.mechmat.2025.105565

Dean Chen , Yuhai Xiang , Nitesh Arora , Qi Yao , Jian Li , Stephan Rudykh

In this paper, we report the numerical observations of a distinctive phenomenon – the development of secondary buckling in soft particulate composites. After experiencing the first microstructural buckling event and consequent microstructure transformations, the composite re-enters a stable state. However, the composite may undergo a secondary buckling upon exceeding a certain deformation level. This secondary buckling event gives rise to a plethora of distinct instability patterns and behaviors. We conduct the finite-amplitude post-buckling and Bloch Floquet analyses implemented in the post-buckling regime to characterize the development of the secondary buckling. These analyses also characterize the dependence of the critical strain and wavelength of the secondary buckling on the composite's initial microstructure parameters.

本文报道了软颗粒复合材料中二次屈曲现象的数值观测结果。在经历了第一次微观结构屈曲事件和随后的微观结构转变后，复合材料重新进入稳定状态。然而，复合材料在超过一定的变形水平时可能发生二次屈曲。这种二次屈曲事件会产生大量不同的不稳定模式和行为。我们进行了有限振幅后屈曲和在后屈曲状态下实施的Bloch Floquet分析，以表征二次屈曲的发展。这些分析还表征了二次屈曲的临界应变和波长对复合材料初始微观结构参数的依赖关系。

引用次数: 0