今日更新:International Journal of Plasticity 1 篇,Thin-Walled Structures 5 篇
International Journal of Plasticity
Yield surface of multi-directional gradient lattices with octet architectures
Lei Yue, Hu Liu, Zhengqiang Cheng, Qianhua Kan, Guozheng Kang
doi:10.1016/j.ijplas.2024.104140
具有八元结构的多向梯度晶格的屈服面
In this paper, a theoretical method is developed to delineate the effective elastic properties and yield surface of the gradient cellular structure. Additionally, a technique is presented for the construction of multi-directional gradient lattices, and two novel tri-directional gradient lattices (TD-GLs) by assembling octet unit cells with side lengths following specified gradient topological parameters serve as an illustrative example. Their effective elastic properties and yield surfaces are systematically investigated with the aid of theoretical, experimental, and finite element methods. It is found that the effective elastic modulus of the proposed TD-GLs exceeds by 48.80% as compared to that of conventional uniform octet lattices. Moreover, the normalized yield surfaces are proposed to emphasize the predominant role of structural topological features by eliminating the influence of the relative density on the yield behavior of TD-GLs, and this method that also can be extrapolated to other tension-dominated lattices. Subsequently, a theoretical model is developed to establish closed-form yield functions for characterizing the yield behavior of TD-GLs. The predicted yield surfaces from the proposed theoretical model demonstrate good agreement with the simulated results. Finally, the proposed TD-GLs demonstrate outstanding yield performance in various directions deviating from their orthogonal principal axes or planes, compared to lattices with uni- or dual-directional gradient topological configurations. In summary, the proposed multi-directional gradient lattices in this study exhibit the exceptional stiffness and outstanding yield performance in various directions, offering valuable insights for the structural design and engineering applications of lattice structures.
Analytical models for predicting the moment‒rotation relationships of steel hub joints with bolted steel side plates in single-layer wood reticulated domes
A very popular and efficient pattern of joints adopted for wood reticulated domes is steel hub joints featuring end-bearing and bolt-connected wood members (EBBC joints). This type of joint shows clear semi-rigidity, which affects the rigidity and overall stability of the structures. This study developed analytical models for predicting the moment‒rotation curves of EBBC joints, considering the effect of axial compression. Specifically, two models termed the WR and WEP models, were developed assuming rigid and elastic-plastic constitutive behaviour, respectively, of the wood in the compression zone of the joint. A tri-linear model for the lateral force-slip relationship of bolt connections was derived. A formula for calculating the deformation modulus and predicting the shear failure of wood members under local compression was proposed and verified. The moment–rotation relationship of the joint was established with equilibrium and compatibility conditions. The accuracy of the analytical models was verified by comparison with a series of experimental results as well as the parametric study results obtained using a refined finite element model. It was revealed that both the WR and the WEP models can predict the moment–rotation relationships accurately for joints without axial compression, whereas for the case of non-negligible axial compression loads, the WEP model offers more accurate predictions. The analytical WEP model proposed in the current paper provides a versatile tool for general design practice to predict moment–rotation curves for traditional or novel EBBC joints.
To investigate the energy distribution characteristics of a laminated structure with an acoustic black hole (ABH), this study introduces the dynamic modeling and power flow analysis of an ABH laminated thin beam (ABH laminated beam) with elastic boundary conditions for the first time. ABH profile is defined by a power function in the dynamic modeling process. Utilizing the Euler-Bernoulli beam theory, the constitutive equation of ABH laminated beams is formulated by using the isogeometric method. Three sets of artificial springs are employed to replicate the elastic boundary conditions, incorporating the potential energy of the springs. Subsequently, the dynamic model of the ABH laminated beam is developed by solving the Lagrange equation concerning the total energy within the uniform region, ABH region, and boundary. Through numerical examples, the convergence and accuracy of the proposed modeling approach are validated by comparing the results with those obtained from COMSOL Multiphysics and experimental data. The analysis of power flow and structural intensity elucidates the energy propagation behavior in ABH laminated beams and the underlying mechanism of the ABH effect. The results demonstrate that the ABH laminated beam displays remarkable absorption and dissipation characteristics, introducing a new perspective for the design and application of ABH structures.
Post-fire flexural buckling and resistances of square recycled aggregate concrete-filled stainless steel tube (RACFSST) columns
Ziyi Wang, Yukai Zhong, Andi Su, Meini Su, Ou Zhao
doi:10.1016/j.tws.2024.112490
方形再生骨料不锈钢管混凝土柱的火灾后弯曲屈曲和抗力
The flexural buckling behaviour and residual resistances of square recycled aggregate concrete-filled stainless steel tube (RACFSST) columns after exposure to fire are studied in this paper, based on experiments and numerical modelling. Twelve column specimens, fabricated from concretes with three recycled coarse aggregate replacement ratios (0%, 35% and 70%), were tested after exposure to the ISO 834 standard fire for 0 min (i.e. at ambient temperature), 15 min, 30 min and 45 min. The experimental investigation included heating of specimens, cylinder tests as well as post-fire initial global geometric imperfection measurements, tensile coupon tests and pin-ended column tests. The test setups, procedures and results were fully reported and the ductility indices, lateral deflection distributions and longitudinal strains were discussed and analysed. A numerical investigation was afterwards carried out, where the test results were used to validate thermal and mechanical finite element models; upon validation, parametric studies were conducted to expand the test data bank over a wider range of cross-section dimensions and member lengths. On the basis of the test and numerical data, the relevant design rules for square natural aggregate concrete-filled carbon steel tube columns at ambient temperature, as set out in the European code, Australian/New Zealand standard and American specification, were assessed, using post-fire material properties, for their applicability to square RACFSST columns after exposure to fire. It was found from the assessment results that the three design codes resulted in overall accurate and consistent post-fire flexural buckling resistance predictions but some were unsafe.
Low-velocity impact response and damage mechanism of cosine function cell-based lattice core sandwich panels
Guohua Zhu, Haoqian Ren, Zhen Wang, Lulu Wei, Xuan Zhao
doi:10.1016/j.tws.2024.112499
基于余弦函数单元格芯夹层板的低速冲击响应及损伤机理
This study aims to investigate the impact response and damage mechanism of cosine-function cell-based (CFCB) lattice core sandwich panels. Several low-velocity impact tests were conducted to explore their advantages in impact resistance by comparing them with traditional body-centered cubic (BCC) lattice-core sandwich panels. The impact response and deformation patterns of CFCB lattice core sandwich panels with two different faceplate materials (aluminum alloy and carbon fiber reinforced plastic composite) were experimentally investigated. The CFCB lattice core sandwich panels exhibited higher impact resistance and energy absorption capacity than their BCC lattice core counterparts. Furthermore, sandwich panels with aluminum alloy faceplates provided better impact resistance capacity than those with CFRP faceplates. Subsequently, several numerical models were developed to explore the deformation mechanisms and energy absorption characteristics of CFCB lattice core sandwich panels. In addition, the effects of the core structural parameters on mechanical performance were numerically investigated. Results indicated that increasing the cell rod diameter and/or reducing the cosine period length could decrease the indentation depth and enhance crush force efficiency. Finally, based on the principle of minimum potential energy, a theoretical model was developed to predict the initial peak load of CFCB lattice core sandwich panels with isotropic faceplates. This study aimed to explore the impact response and provide design guidance for CFCB lattice core sandwich panels.
Triaxial Hybrid Simulation and Cyclic Tests of Full-Scale Circular Steel Tube Columns
Baofeng Huang, Xiangfei Zhang, Yurong Guo, Yan Xiao
doi:10.1016/j.tws.2024.112501
圆钢管柱全尺寸三轴混合仿真及循环试验
Circular steel tube (CST) columns are fundamental structural components of infrastructure such as buildings and bridges. Although extensive experimental and analytical studies have been conducted to investigate their seismic performance, full-scale three-dimensional (3D) loading tests of CST columns have rarely been reported owing to the limitations of experimental facilities. In this study, an effective 3D multi-use structural testing (3D-MUST) system was employed to fill this gap. Three full-scale CST columns with and without concrete infill were fabricated for cyclic and hybrid simulation (HS) tests. The finite element models of the three columns were constructed using a commercial software package. In the cyclic tests, the presence of concrete in the CST delayed the buckling damage at the ends of the column. In the HS tests, the concrete-filled CST column was visually intact during the excitation of the original earthquake motion. The nonlinear behavior was more apparent in the enlarged excitations until buckling failure occurred at the ends of the column. The experimental and numerical results were generally in agreement. The experimental amplitudes of the bending moments were underestimated using the code provisions for earthquake excitations. An identical trend was observed in the interactive curve of the cyclic test, in which the bending moment occasionally exceeded that of the HS with the original earthquake motion.