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Laminated wood-based materials have been widely developed, and the laminating process and adhesive itself have been reported to enhance performance beyond the sum of the individual layers' performance. This phenomenon is particularly notable under loads applied in the \"edge-wise direction\", where each layer bears stress collectively. These combined effects are referred to as the \"adhesive effect\". Strength under partial compressive loads is critical in timber engineering, as partial compressive stress generates complex stress distributions influenced by boundary conditions. The adhesive effect may also be impacted by these conditions. The aim of this study was to quantitatively and directly evaluate the adhesive effect under partial and full compressive loads using various parameters. The strength of laminated veneer lumber (LVL) with adhesive was compared to that of simply layered veneers without adhesive to assess the adhesive effect. Three mechanisms contributing to the adhesive effect were proposed: Mechanism I, caused by the deformation of the adhesive layer independently from the veneers; Mechanism II, resulting from the adhesive impregnating the veneers; and Mechanism III, arising from the reinforcement provided by adjacent veneers. The results suggested the following: (i) Mechanism I had minimal impact, as the fiber direction and the presence of additional length showed strong and slight effects on the adhesive effect, respectively; (ii) Mechanism II contributed to preventing crack propagation and altering the relationships among mechanical properties, with its effectiveness increasing as the adhesive weight increased; and (iii) Mechanism III functioned as a crossband effect, reinforcing weaknesses caused by the slope of the grain and the angle of the annual rings.

Purpose This study aims to present comprehensive nonlinear material modelling techniques and simulations of reinforced concrete (RC) beams subjected to short-term monotonic static load using the robust and reliable general-purpose finite element (FE) software ANSYS. A parametric study is carried out to analyse the flexural and ductility behaviour of RC beams under various influencing parameters. Design/methodology/approach To develop and validate the numerical FE models, a total of four experimentally tested simply supported RC beams are taken from the available literature and two beams are selected from each author. The concrete, steel reinforcements, bond-slip mechanism, loading and supporting plates are modelled using SOLID65, LINK180, COMBIN39 and SOLID185 elements, respectively. The validated models are then used to conduct parametric FE analysis to investigate the effect of concrete compressive strength, percentage of tensile reinforcement, compression reinforcement ratio, transverse shear reinforcement, bond-slip mechanism, concrete compressive stress-strain constitutive models, beam symmetry and varying overall depth of beam on the ultimate load-carrying capacity and ductility behaviour of RC beams. Findings The developed three-dimensional FE models can able to capture the load and midspan deflections at critical points, the accurate yield point of steel reinforcements, the formation of initial and progressive concrete crack patterns and the complete load-deflection curves of RC beams up to ultimate failure. From the numerical results, it can be concluded that the FE model considering the bond-slip effect with Thorenfeldt’s concrete compressive stress-strain model exhibits a better correlation with the experimental data. Originality/value The ultimate load and deflection results of validated FE models show a maximum deviation of less than 10% and 15%, respectively, as compared to the experimental results. The developed model is also capable of capturing concrete failure modes accurately. Overall, the FE analysis results were found quite acceptable and compared well with the experimental data at all loading stages. It is suggested that the proposed FE model is a practical and reliable tool for analyzing the flexural behaviour of RC members and can be used for performing parametric studies.

Rehabilitation with dental implants is not always possible due to the lack of bone quality or quantity, in many cases due to bone atrophy or the morbidity of regenerative treatments. We find ourselves in situations of performing dental prostheses with cantilevers in order to rehabilitate our patients, thus simplifying the treatment. The aim of this study was to analyze the mechanical behavior of four types of fixed partial dentures with posterior cantilevers on two dental implants (convergent collar and transmucosal internal connection) through an in vitro study (compressive loading and cyclic loading). This study comprised four groups (n = 76): in Group 1, the prosthesis was screwed directly to the implant platform (DS; n = 19); in Group 2, the prosthesis was screwed to the telescopic interface on the implant head (INS; n = 19); in Group 3, the prosthesis was cemented to the telescopic abutment (INC; n = 19); and in Group 4, the prosthesis was cemented to the abutment (DC; n = 19). The sets were subjected to a cyclic loading test (80 N load for 240,000 cycles) and compressive loading test (100 KN load at a displacement rate of 0.5 mm/min), applying the load until failure occurred to any of the components at the abutment–prosthesis–implant interface. Subsequently, an optical microscopy analysis was performed to obtain more data on what had occurred in each group. Results: Group 1 (direct screw-retained prosthesis, DS) obtained the highest mean strength value of 663.5 ± 196.0 N. The other three groups were very homogeneous: 428.4 ± 63.1 N for Group 2 (INS), 486.7 ± 67.8 N for Group 3 (INC), and 458.9 ± 38.9 N for Group 4 (DC). The mean strength was significantly dependent on the type of connection (p < 0.001), and this difference was similar for all of the test conditions (cyclic and compressive loading) (p = 0.689). Implant-borne prostheses with convergent collars and transmucosal internal connections with posterior cantilevers screwed directly to the implant connection are a good solution in cases where implant placement cannot avoid extensions.

Metamaterials can control and manipulate acoustic/elastic waves on a sub-wavelength scale using cavities or additional components. However, the large cavity and weak stiffness components of traditional metamaterials may cause a conflict between vibroacoustic reduction and load-bearing capacity, and thus limit their application. Here, we propose a lightweight multifunctional metamaterial that can simultaneously achieve low-frequency sound insulation, broadband vibration reduction, and excellent load-bearing performance, named as vibroacoustic isolation and bearing metamaterial (VIBM). The advent of additive manufacturing technology provides a convenient and reliable method for the fabrication of VIBM samples. The results show that the compressive strength of the VIBM is as high as 9.71 MPa, which is nearly 87.81% higher than that of the conventional grid structure (CGS) under the same volume fraction. Moreover, the vibration and sound transmission are significantly reduced over a low and wide frequency range, which agrees well with the experimental data, and the reduction degree is obviously larger than that obtained by the CGS. The design strategy can effectively realize the key components of metamaterials and improve their application scenarios.

In this paper, a novel efficient energy absorber with free inversion of a metal foam-filled circular tube (MFFCT) is designed, and the axial compressive behavior of the MFFCT under free inversion is studied analytically and numerically. The theoretical analysis reveals that the energy is mainly dissipated through the radial bending of the metal circular tube, the circumferential expansion of the metal circular tube, and the metal filled-foam compression. The principle of energy conservation is used to derive the theoretical formula for the minimum compressive force of the MFFCT over free inversion under axial loading. Furthermore, the free inversion deformation characteristics of the MFFCT are analyzed numerically. The theoretical steady values are found to be in good agreement with results of the finite element (FE) analysis. The effects of the average diameter of the metal tube, the wall thickness of the metal tube, and the filled-foam strength on the free inversion deformation of the MFFCT are considered. It is observed that in the steady deformation stage, the load-carrying and energy-absorbing capacities of the MFFCT increase with the increase in the average diameter of the metal tube, the wall thickness of the metal tube, or the filled-foam strength. The specific energy absorption (SEA) of free inversion of the MFFCT is significantly higher than that of the metal tube alone.

Although some efforts have been made separately to investigate the effects of the partial drainage condition and the intermediate principal stress ratio on the mechanical behaviors of sand and the instability that ensues, the interplay and combined influence of these two important factors have not been adequately investigated. In this study, a series of proportional strain loading tests considering a variety of combinations of different intermediate principal stress ratios ( b  = 0, 0.5, and 1.0) and generalized drainage conditions, including excessive, full, partial, zero (undrained), and expansive drainage conditions are conducted on transversely isotropic specimens through an advanced discrete element servomechanism. The second-order work criterion is used to detect the occurrence of instability. The evolution of the load-bearing structure of granular specimens is quantified through a contact-normal-based fabric tensor. The fabric evolutions and their interplay with the external loadings are illustrated. The simulation results show that even dense specimens can fully liquefy under expansive drainage conditions. Under otherwise identical conditions, the specimens under extension loading ( b  = 1) exhibit more significant non-coaxiality between the loading direction and the major principal direction of the fabric, which induces smaller shear strength and weaker resistance to instability than that of the compressive loading condition ( b  = 0 or 0.5).

This study was conducted to investigate the chloride ion transport in coral aggregate seawater concrete (CASC) with varying water–cement ratios under different loads. The ultimate compressive strength was obtained by conducting compression testing of three groups of CASC with different water–cement ratios. Steady loads of 0%, 10%, and 20% of their respective ultimate compressive strengths were applied to the concrete specimens with different water–cement ratios. After being subjected to a seawater erosion test for 30, 60, 90, 120, and 180 days, the chloride ion concentration at different depths was measured to determine the chloride ion diffusion coefficient. Meanwhile, the chloride ion diffusion coefficients of CASC were verified by comparing them with results obtained from numerical simulations performed using COMSOL software. The test results show that the internal pore space of CASC expands, leading to acceleration of the chloride ion transport rate when applied loads are increased. The initial chloride ion concentration of CASC rises as the water–cement ratio rises, and the concentration gradient formed with artificial seawater lowers, decreasing the chloride ion transport rate. When the water cement ratio decreases and the load increases, the diffusion coefficient increases. Using the numerical simulation method of COMSOL software, it was proved that the model has good applicability and accuracy in predicting chloride ion transport in CASC.

Single-layer molybdenum disulfide (MoS2) has been a research focus in recent years owing to its extensive potential applications. However, how to model the mechanical properties of MoS2 is an open question. In this study, we investigate the nonlinear static bending and forced vibrations of MoS2, subjected to boundary axial and thermal stresses using modified plate theory with independent in-plane and out-of-plane stiffnesses. First, two nonlinear ordinary differential equations are obtained using the Galerkin method to represent the nonlinear vibrations of the first two symmetrical modes. Second, we analyze nonlinear static bending by neglecting the inertial and damping terms of the two equations. Finally, we explore nonlinear forced vibrations using the method of multiple scales for the first- and third-order modes, and their 1:3 internal resonance. The main results are as follows: (1) The thermal stress and the axial compressive stress reduce the MoS2 stiffness significantly. (2) The bifurcation points of the load at the low-frequency primary resonance are much smaller than those at high frequency under single-mode vibrations. (3) Temperature has a more remarkable influence on the higher-order mode than the lower-order mode under the 1:3 internal resonance.

In this study, a surrogate Machine Learning (ML)-based model was developed, to predict the load-bearing capacity (LBC) of concrete-filled steel square hollow section (CFSS) members, considering loading eccentricity. The proposed Artificial Neural Network (ANN) model was trained and validated against experimental data using the following error measurement criteria: coefficient of determination (R2), slope of regression, root mean square error (RMSE) and mean absolute error (MAE). A parametric study was conducted to calibrate the parameters of the ANN model, including the number of neurons, activation function, cost function and training algorithm, respectively. The results showed that the ANN model can provide reliable and effective prediction of LBC (R2 = 0.975, Slope = 0.975, RMSE = 294.424 kN and MAE = 191.878 kN). Sensitivity analysis showed that the geometric parameters of the steel tube (width and thickness) and the compressive strength of concrete were the most important variables. Finally, the effect of eccentric loading on the LBC of CFSS members is presented and discussed, showing that the ANN model can assist in the creation of continuous LBC maps, within the ranges of input variables adopted in this study.

Among many alternative building materials, soil in the form of rammed Earth is the most ancient construction material and technology. Large-scale application of the rammed Earth technology in the construction industry requires the assessment of its strength and failure behaviour. Therefore, this study focused on performing a nonlinear stability analysis of cement-stabilized rammed Earth (CSRE) specimens having a height-to-thickness (H/T) ratios—3 and 4 and loaded under varying degrees of eccentricities 0, 1/3, 1/6, and 1/12. The maximum compressive strength and the stress-strain behaviour of the CSRE specimens were determined through finite element (FE) modeling. The experimental results of the cement-stabilized rammed Earth (CSRE) have been obtained from literature for validation by FE simulation. As the H/T ratio was increased from 3 to 4, the load-bearing capacity of the CSRE specimens increased by 2.91% under concentric loading condition; however, when the eccentricity of load application was swapped from 0 to 1/12, 1/6, and 1/3, the load-bearing capacity decreased incrementally. The results of the FE analysis of the specimens showed that the compressive strength and elastic properties of the CSRE specimens did not differ significantly. The stress-strain relationships were nonlinear and elastic properties were affected by soil textural composition and density.