今日更新：Journal of the Mechanics and Physics of Solids 1 篇，Mechanics of Materials 1 篇，International Journal of Plasticity 1 篇，Thin-Walled Structures 7 篇
Journal of the Mechanics and Physics of Solids
A Chemo-Mechanical Model for Growth and Mechanosensing of Focal Adhesion
Jiashi Xing, Fuqiang Sun, Yuan Lin, Ze Gong
doi:10.1016/j.jmps.2024.105863
聚焦黏附生长和机械传感的化学-力学模型
Focal adhesion (FA), the complex molecular assembly across the lipid membrane, serves as a hub for physical and chemical information exchange between cells and their microenvironment. Interestingly, studies have shown that FAs can grow along the direction of contractile forces generated by actomyosin stress fibers and achieve larger sizes on stiffer substrates. In addition, the cellular traction transmitted to the substrate was observed to reach the maximum near the FA center. However, the biomechanical mechanisms behind these intriguing findings remain unclear. To answer this important question, here we first developed a one-dimensional (1D) chemo-mechanical model of FA where key features like adhesion plaque deformation, active contraction by stress fibers, force-dependent association/dissociation of integrin bonds connecting two surfaces, and substrate compliance have all been considered. Within this formulation, we showed that the rigidity-sensing capability of FAs originates from the deformability of stress fibers while the force-dependent breakage of integrin bonds leads to the appearance of the traction peak at the FA center. Furthermore, by extending the model into three-dimensional as well as incorporating assembly/dis-assembly kinetics of adhesion proteins, we also demonstrated how anisotropic stress/strain field within the adhesion plaque will be induced by the presence of contractile forces which eventually leads to the directional growth of the FA.
Hybrid Modelling of Dynamic Softening using Modified Avrami Kinetics under Gaussian Processes
Nedjoua Matougui, Mohamed Imad Eddine Heddar, Oualid Chahaoui, John .Joseph Jonas
doi:10.1016/j.mechmat.2024.105153
高斯过程下基于改进Avrami动力学的动态软化混合建模
This paper presents a new method of modelling that combines several approaches to anticipate the softening of nickel-niobium alloys during dynamic recrystallization (DRX). The study employs an extensive dataset obtained from hot torsion deformation tests conducted on high-purity nickel and six nickel-niobium alloys. The niobium concentration in these alloys varies from 0.01 to 10 wt. % [48]. The hybrid technique integrates the Avrami model to provide early predictions about the kinetics of recrystallization and then uses mechanistic modelling to assess the progression of softening caused by dynamic recrystallization (DRX). The integrated technique is improved by using Gaussian process regression analysis, which investigates the softening properties and offers useful insights into the effects of niobium additions on dynamic softening behaviour. This unique hybrid framework combines multiple modelling tools to reveal intricate connections impacted by solute addition, therefore enhancing our comprehension of the physical events that take place during the hot deformation of superalloys. The use of empirical, mechanistic, and machine learning methods in this hybrid model provides a more thorough and detailed investigation of DRX processes in these alloys.
In this study, we investigate the intrinsic mechanism of intensive and progressive transformation-induced plasticity (TRIP) effects and their different strength-ductility synergies using a resource-efficient 15Cr-2Ni duplex stainless steel. The progressive TRIP material exhibits a ductility that is more than twice that of the intensive TRIP material, as well as, a larger product of the ultimate tensile strength and ductility. This is attributed to the dislocation accumulation caused by different grain sizes of strain-induced martensite depending on the stability of the γ phase, which determines the strength and work hardening of steel. When the stability is low, the γ phase is sensitive to loaded stress and transformed into dispersed fine martensite immediately after yielding at a high rate. It induces a sigmoid-shaped dislocation accumulation to an approximately 10-fold increase in the dislocation density at a limited strain, resulting in intensive work hardening and a large ultimate tensile strength. As the stability is adequate, the γ phase is transformed into coarse martensite laths with a high critical load stress, which is initiated from a delayed strain at an extremely low rate and steadily accelerated as the strain increases. This process induces a gradually increased dislocation accumulation to a 2–3-fold increase in the dislocation density at large strains, resulting in progressive work hardening and an excellent ductility.
This paper proposes an efficient semi-analytical method using auxiliary sine series for transverse vibration and sound radiation of a thin rectangular plate with edges elastically restrained against translation and rotation. The formulation, constructed by two-dimensional sine and/or cosine series, can approximately express the bending displacement, and calculate vibration and sound radiation under excitation of point force, arbitrary-angle plane wave, or diffuse acoustic field with acceptable accuracy. It is also applied for baffled or unbaffled conditions. A post-process program is developed to predict vibrating frequencies and modes, mean square velocity spectrum, and sound transmission loss via reduced-order integrals of radiation impedances. The method is validated by experiment and simulation results, demonstrating accurate and efficient computation using a single program for transverse vibration and sound radiation of a plate under different elastic boundary conditions and different excitations. Formulas given in this paper provide a basis for the code development on transverse vibration and sound radiation analysis of thin plates.
Passing-through I-plates-to-SHS moment resisting joints subjected to symmetric bending moments
Mouad Madhouni, Maël Couchaux, Mohammed Hjiaj, Alper Kanyilmaz
doi:10.1016/j.tws.2024.112442
对称弯矩作用下的贯通工字板- shs抗弯矩节点
When using hollow structural section (HSS) members in multi-storey buildings, beam-to-column moment resisting connections’ design raises critical questions to tackle. With conventional welded and bolted joints’ response being generally very flexible, the design resistance becomes governed by a deformation criterion rather than a strength criterion. This underscores the necessity for smart reinforcement techniques. A widespread solution is the diaphragm approach, in which the stiffeners usually protrude over the tubular column. The solution of plates passing through the HSS column is another stiffening option which was studied recently for CHS, yet, SHS columns have not been subject to comparable scrutiny. The objective of this paper is to study experimentally, numerically, and analytically the mechanical behaviour of I-beam-to-SHS column moment resisting joints using passing through I-plates under symmetric bending moments. The testing of two full-scale specimens corroborates previous findings with CHS columns in the elastic regime. However, significant deviations were observed in the post-peak response, revealing new insights into the behaviour of SHS columns. Failure was due to progressive buckling of passing through plates and yielding of tube-wall in transverse compression. A finite element model using solid and contact elements is developed and validated against experimental data. This model underscores how loads are redistributed between the tube wall and passing plates. A simplified version of the FE model is used to perform a thorough parametric numerical analysis on 101 configurations expanding upon the experimental test database by varying geometrical parameters such as passing plate thickness, tube, and beam dimensions. Finally, an analytical model integrating the different components of the joint is proposed to evaluate the initial rotational stiffness and the bending resistance.
Currently, the research on wind-induced response of membrane structures focuses on the normal wind field, and there is little research on typhoon with greater disaster. In this paper, the wind-induced response of saddle membrane structures under typhoon is studied by numerical simulation. Firstly, the wind field information of typhoon is simulated according to the Weather Research and Forecasting model, and the information is used as the inlet boundary condition of Computational Fluid Dynamics. The vibration modal analysis is carried out, considering the influence of wind field intensity, wind direction angle, rise-span ratio, and pretension on the displacement of the membrane. The results show that the probability density curve of wind-induced response has a certain skewness. The saddle membrane structure has the largest vibration amplitude of the membrane at 0°wind direction angle, and the most unfavorable wind pressure value of the membrane is negative. In reducing the displacement of the membrane, the effect of reducing the wind-induced vibration response by increasing the rise-span ratio of the structure is better than that of the pretension. This paper reveals that the law of wind-induced response can provide a theoretical basis for the design of membrane structures against typhoons.
Nonlinear performance analysis and rapid prediction of out-of-plane deformation in graded honeycombs
Rui Yang, Shenghua Li, Shiyong Sun, Bin Niu, Ruixin Wang, Xiao chan Han
doi:10.1016/j.tws.2024.112456
梯度蜂窝的非线性性能分析及面外变形快速预测
Honeycomb structures, known for their excellent properties, are widely used in various advanced applications, including adaptive mirrors and soft wearable devices, due to their out-of-plane deformation capabilities. However, predicting the out-of-plane deformation of graded honeycombs remains challenging. A novel approach for rapidly predicting the out-of-plane deformation of graded honeycombs, considering their isotropic and nonlinear behavior, is presented in this study. Discrete material property spaces for seven honeycomb types were derived using a stiffness-updating nonlinear homogenization method and validated through digital image correlation (DIC) experiments. Prediction of nonlinear equivalent properties within two seconds was achieved by utilizing a hyperparameter optimization neural network (HONN). Graded honeycomb connection criteria (GHCC) were established to ensure performance stability. A rapid and accurate prediction method was enabled by the developed deformation-to-color mapping, which effectively bypasses costly numerical computations. Out-of-plane deformation is accurately forecasted by this approach, which also facilitates the transformation of flat surfaces into various shapes with distinct Gaussian curvatures, thereby opening new possibilities for large-scale deformable structures.
Compressive properties and biocompatibility of additively manufactured lattice structures by using bioactive materials
Shuai Li, Tianqi Wang, Shuai Chen, Yingze Li, Yajun Zou, Bo Cao, Jiqiang Hu, Xiaojun Tan, Bing Wang
doi:10.1016/j.tws.2024.112469
利用生物活性材料增材制造的晶格结构的压缩性能和生物相容性
Porous bioactive materials were widely used in orthopedic implant fields because of their excellent mechanical properties and porous spaces. However, most porous types are predominantly stacked in two-dimensional configurations, which significantly limits their mechanical property range and adversely affects the modulus matching between the porous implants and surrounding bone tissues. Hence, various lattice structures were prepared using 3D printing technology with bioactive materials, and characterized by mechanical and biological tests. Numerical simulations were conducted to analyze the effect of relative density and geometric parameters on the equivalent compressive properties of the lattice structures. The results showed that the lattice structure exhibited a broad elastic modulus range, which can be adjusted to align with the mechanical properties of human cortical and cancellous bones, thereby helping to mitigate stress shielding in orthopedic implants. The biocompatibility of the 3D-printed solid materials was assessed in vitro using a cell counting assay kit-8 (CCK-8). The results indicated that poly-ether-ether-ketone (PEEK), carbon fiber reinforced PEEK (CFR/PEEK), nylon, and titanium (Ti) alloy all exhibited good biocompatibility, with no significant differences observed among the four materials. This study further enhances the understanding of bioactive lattice structures in the biomedical field and offers new possibilities for orthopedic repair.
The deformation mechanism and life prediction model of titanium alloy laser-arc hybrid welded joint during fatigue were studied. At the relatively small maximum cyclic stresses σmax (310 MPa to 350 MPa), the fatigue cracks initiated at the interface of lamellar α′ and needle-like α′ around the pore. At σmax = 370M Pa, the elongated lamellar α′ around the pore promoted fatigue crack propagation, leading to the formation of secondary cracks. At σmax = 390 MPa, the formation of two fatigue crack initiation locations and the occurrence of secondary cracks led to the maximum fatigue damage and the minimum fatigue life. In addition, the plastic deformation mainly occurred in β at σmax = 310M Pa, and it transformed into the phase interface of secondary α-β and granular β-α′ at σmax = 350M Pa. At σmax = 390M Pa, the main deformation forms were the cross-slip in β and the dislocations entanglement in α′. Finally, the fatigue life prediction model was established based on the equivalent cyclic stress, and the predicted fatigue life fell within a 3-fold error band.
Acoustic emission and multiscale computation-guided tensile damage identification in woven composite laminates at cryogenic temperatures as low as 20 K
Lianhua Ma, Xiyan Du, Wei Zhou, Chuanjun Huang, Wentao Sun, Biao Wang
doi:10.1016/j.tws.2024.112464
低至20k低温下复合材料层合板的声发射和多尺度计算导向拉伸损伤识别
For laminated composite structures as key components of storage tanks serving at cryogenic temperature, it is crucial to identify the damage mechanisms for evaluating their mechanical properties and guiding structural design. In this work, the cryogenic tensile damage behavior of a thin-walled woven composite laminate was investigated through the acoustic emission (AE) monitoring and multiscale finite element (FE) computation at typical low temperatures of 153 K, 77 K and 20 K. We first established temperature-dependent constitutive laws for the microscale and mesoscale constituents of such composites based on experimental data, followed by the development of a hierarchical computational framework for modeling multiscale damage characteristics at different low temperatures. A fiber-optic acoustic emission measurement system was constructed to provide online monitoring of tensile damage of the woven composite laminates at cryogenic temperatures as low as 20K. The comparations were made between the predicted cryogenic damage characteristics and in-situ AE signal analysis, assisted by scanning electron microscope (SEM) observations. The computed cryogenic damage evolution closely matched the AE signal identification results. The results indicate that fiber breakage and matrix cracking are the dominant cryogenic damage modes, and that the different low temperatures exert significant effects on the properties of the epoxy matrix, yarns and composite laminates. The combination of the AE monitoring system and the computational scheme provides a valuable tool for evaluating structural integrity and guiding the microstructural design of composite laminates used in cryogenic environments.
