Search Results (1,607)

Through mechanical analysis, a comparison of the same type of cold rolled steel produced by two steel manufacturers, supplier 1 and supplier 2, has been carried out. The considered material is a steel that has undergone a quenching and partitioning heat treatment, i.e., a rapid cooling from the austenitizing temperature, followed by a holding treatment at a suitable temperature, so that the residual austenite is stabilized at room temperature. The following tests for mechanical properties were carried out: formability, through Nakajima test, tensile test, bending test, hole expansion test and fatigue strength analysis, through high cycle fatigue and low cycle fatigue test. In addition, to derive useful data for future simulations, tensile and Nakajima tests were analyzed by digital image correlation, which uses a monochrome camera to capture frames during the test, in order to analyze local deformations on investigated samples. Finite elements modeling has been carried out. A suitable calibration of a material card for the Abaqus Finite Element Analysis software has been performed. Through the combination of obtained results, a rational comparison of the two analyzed products has been obtained. Full article

Addressing the issue of porosity evolution during the curing process of thermosetting epoxy resin-based composites, a simulation model has been developed to describe the flow–compaction behavior of the composites aiming to predict changes in porosity throughout the curing process. Initially, a multi-physics coupling model encompassing sub-models for thermo-chemical, fiber bed compression, void compression, and percolation flow was established. This model accurately describes the changes in porosity within the composites during the flow–compaction process. The UMAT subroutine of the ABAQUS finite element analysis software was utilized to integrate these sub-models into the software. The validity of the simulation model was verified through corresponding experimental porosity measurements. The research further indicates that the porosity at the fillet of L-shaped composite components is higher than that in flat areas due to insufficient shear slip capacity. The results show that the porosity of the rounded corners of the L-shaped composite members is higher than that of the flat plate region due to the lack of shear slip capacity, and the fiber bed stiffness and inter-ply friction coefficient play an important role in the change in porosity. Full article

In this study, seven wet joint specimens of contact U-bars are designed in order to evaluate the flexural behavior of the wet joints in precast concrete slabs through four-point bending tests. This study investigates the effects of lap length, wet joint width, and water stop strips on the flexural behavior. The test results show that the ultimate bending capacity of the specimen with a lap length of 240 mm is 13.4% and 17.7% higher than that of the specimens with 160 mm and 80 mm. Water stop strips weaken the ductility of the specimen. The numerical model is established in ABAQUS finite element software and verified by the experimental results. Based on both test outcomes and finite element analysis, this study analyzes the deterioration effect of U-bars on the concrete within wet joints and proposes a calculation formula for flexural bending capacity that accounts for this deterioration. The proposed formula is shown to effectively predict the flexural capacity, since the theoretical predictions and the test results differ by less than 10%. Full article

In the chlorination industry, the reactor is a crucial equipment in which the chlorination reaction takes place. However, when the reactor is subjected to complex conditions such as high temperatures (e.g., >200 °C) and high pressures (e.g., >10 MPa), its structural integrity is significantly compromised, leading to severe safety issues. In this study, the fatigue life of a reactor is analyzed, with particular focus on the fatigue behavior of the cyclone separator under varying working conditions, such as changes in the temperature, pressure, and chemical environment. Using finite element simulations under steady-state conditions and the S-N curve from fatigue testing, the fatigue life and potential weak points of the reactor under different amplitudes and vibration frequencies are analyzed and predicted. This analysis is conducted using a combined simulation approach with ABAQUS and Fe-Safe software, v 6.14. This work also considers the periodic vibrations at the base of the cyclone separator within the reactor. Fatigue simulations under different vibration conditions are performed to further assess the fatigue life of the reactor, providing a theoretical basis for the optimization of design and ensuring operational safety. In addition, the influence of welding zones on the fatigue life is discussed. The results indicate that the welding defects and stress concentration may cause the welded joint to become a critical weak point for fatigue failure. Therefore, the fatigue performance of the welding zone should be carefully considered during the design phase. Full article

Under the action of near fault earthquakes, the LRB bearings of long-period isolated buildings are prone to significant deformation and failure under compression shear conditions. Therefore, it is necessary to analyze the damage of LRB and its impact on the superstructure. Finite element analysis methodology was selected and Abaqus was used to simulate hysteresis curve of LRB and the separation between rubber layer and steel layer when horizontal deformation reaches 400%. A simplified four-stiffness isolation bearing model is proposed and applied to seismic isolation damage analysis on 8-story seismic structure under near-fault earthquakes. Damage on different positions and numbers of bearings are also compared. It concludes that under the compressive and shearing state, when the horizontal deformation of the isolator exceeds 300%, the stiffness enhancement section appears. Moreover, it is found that the damage of all LRBs show the most significant scale-up effect on acceleration and story drift. Full article

This study develops a finite element solution to analyze the vibration response of multi-layer shape memory alloy (SMA) composite beams. Using Euler–Bernoulli beam motion equations with tension–compression asymmetry, based on Poorasadion’s model, the Newmark method and Newton–Raphson technique are employed. Validating the model against ABAQUS/Standard results for a homogeneous SMA beam shows good agreement. This research explores the dynamic characteristics of bi-layer and tri-layer SMA beams, presenting deflection–time, stress–strain, and velocity–deflection profiles. SMAs’ hysteresis property effectively reduces early-stage vibration amplitudes, and their energy-dissipating feature during phase transformations makes them promising for controlling dynamic performance in engineering applications. Full article

This study investigates the dynamic response of large-diameter monopile foundations subjected to ice loads, emphasizing sustainable design in cold-region offshore wind energy development. Through a combined ice–structure–soil model test and subsequent development of a three-dimensional ice–OWT–soil system model using Abaqus software 2022, this research addresses the sustainability of infrastructure exposed to harsh environmental conditions. The dynamic ice loads are simulated using the coupled CEM–FEM approach, while the Mohr–Coulomb model calculates soil–structure interactions. The calibration and verification processes include comparisons of simulated ice forces, ice-crushing processes, and pile deflections with experimental results. This study comprehensively assesses the effects of ice velocity and thickness on ice actions, as well as the monopile’s top displacement, shear force, and bending moment. The findings indicate that ice thickness significantly influences the dynamic response more than ice velocity, guiding the design toward more sustainable and resilient offshore wind infrastructures. Additionally, a semi-empirical calculation method incorporating the aspect ratio effect is proposed, enhancing the predictive accuracy and sustainability of large-diameter monopile foundations, as validated against field monitoring data from the Norströmsgrund lighthouse. Compared to traditional ice pressure calculation methods, the proposed approach focuses on the influence of the aspect ratio of large-diameter monopile foundations, enabling a more realistic and objective assessment of ice load calculations for OWTs in cold regions. The results demonstrate the efficacy of the proposed approach and offer a new perspective for the design of OWT structures under ice loads. Full article

It is difficult to meet environmental requirements via the coarse treatment methods of landfilling and open-air storage of construction waste. At the same time, the consumption of building materials in highway engineering is enormous. Using construction waste as a filling material for proposed roads has become a research hotspot in recent years. This paper starts with basic performance tests of recycled construction waste materials, and then moves on to laboratory experiments conducted to obtain the road performance of the recycled materials, the testing of key indicators of post-construction filling quality of the roadbed, and analyses of the deformation pattern of roadbed filled with construction waste. Additionally, the ABAQUS finite element software was used to establish a numerical model for roadbed deformation and analyze the roadbed deformation under different compaction levels and vehicle load conditions. The experimental results show that the recycled material has a moisture content of 8.5%, water absorption of 11.73%, and an apparent density of 2.61 g/cm³, while the liquid limit of fine aggregates is 20% and the plasticity index is 5.4. Although the physical properties are slightly inferior to natural aggregates, its bearing ratio (25–55%) and low expansion characteristics meet the requirements for high-grade highway roadbed filling materials. The roadbed layer with a loose compaction of 250 mm, after eight passes of rolling, showed a settlement difference of less than 5 mm, with the loose compaction coefficient stabilizing between 1.15 and 1.20. Finite element simulations indicated that the total settlement of the roadbed stabilizes at 20–30 mm, and increasing the compaction level to 96% can reduce the settlement by 2–4%. Vehicle overload causes a positive correlation between the vertical displacement and shear stress in the base layer, suggesting the need to strengthen vehicle load control. The findings provide theoretical and technical support for the large-scale application of recycled construction waste materials in roadbed engineering. Full article

This study investigated the compressive behavior of 30 vol.% boron carbide (B₄C)/2024 aluminum (Al) composites under quasi-static and dynamic loading at different temperatures. Building on the experimental findings, the Johnson–Cook (JC) model was modified, and a complete failure criterion was proposed. These were validated in Abaqus employing the user subroutine for hardening (VUHARD), which incorporated both the modified JC (MJC) model and the complete failure criterion. Experimental results revealed that strain softening was an important feature of the stress–strain curve. The analysis of mechanisms contributing to yield strength revealed that Taylor and load transfer mechanisms dominated, accounting for 89.6% of the total enhancement. Microstructural analysis identified particle fracture and matrix damage were the primary mechanisms driving material failure. Microcracks mainly propagated through the matrix and interface or directly through the ceramic particles and the matrix. The MJC model demonstrated high accuracy in describing the plastic deformation behavior of the composite, with a mean absolute error (MAE) below 15% under dynamic loading. Further simulation confirmed that finite element analyses using the VUHARD subroutine accurately captured the plastic deformation and crack propagation behaviors of the composite under dynamic loading. This study offers a novel approach to describe the plastic deformation and failure behaviors of ceramic-reinforced aluminum matrix composites under dynamic loading conditions. Full article

While fiber-reinforced polymer (FRP) sheets effectively enhance the flexural strength of reinforced concrete (RC) slabs, excessive flexural strengthening can reduce ductility and lead to brittle failure. This study provides an overview of the failure limits for the end spans of continuous RC slabs, considering the relationship between moment and shear capacities. A design approach for maximizing the strength contribution and amount of carbon FRP (CFRP) while ensuring ductile failure in strengthened slabs was developed and refined based on ACI standard recommendations. The failure mode of the strengthened slab was validated through numerical analysis using Abaqus software by further investigating the stress distribution of flexural members. Analytical results indicated that a 0.15 mm thick CFRP layer could enhance the nominal failure load by 148% while preserving desirable ductile failure behavior, demonstrating the effectiveness and feasibility of the proposed approach. Full article

In response to the increasing safety concerns posed by low, slow, and small unmanned aerial vehicles (UAVs), the use of flexible nets for interception emerges as a promising solution due to its high tolerance, minimal requirements, and cost-effectiveness. To enhance the effectiveness of the flexible net capture system for these types of UAVs, an optimization of the system’s parameters is conducted. A dynamic model of the flexible net capture system is developed, and its deployment process is simulated and analyzed through a combination of ABAQUS 2022/Explicit and MATLAB R2020b software. The coverage rate and hang time are proposed as the key performance indicators for quantitatively assessing the interception capabilities of the rope net. A mathematical model is formulated to optimize the capture system parameters, considering both spatial and temporal tolerances. The Multi-objective Wolf Pack Algorithm, which incorporates an Elite Leadership Strategy and a crowding distance-based population update mechanism, is utilized to optimize the design variables. This approach leads to the derivation of the optimized design parameters for the flexible net. Ultimately, the optimal parameter configuration for the flexible net capture system is achieved through the application of the Multi-objective Wolf Pack Algorithm to the design variables. This optimization ensures the system’s peak performance in intercepting low, slow, and small UAVs. Full article

Relying on a foundation pit project leveraging the covered semi-top-down method with synchronous construction of the superstructure and substructure in Beijing, the whole process of construction was simulated by using ABAQUS finite-element software. The impact of the whole construction on the surrounding ground, the adjacent building, and the retaining structure were studied, and the influence of the existing building, the strength of diaphragm wall, and the construction process were carried out. As shown from the results, the foundation pit and the existing building are in a safe state during the whole construction process. The ground settlement shows an obvious groove shape. The deformation of the diaphragm wall has obvious spatial effects, which changes from “single peak” to “double peaks”. The maximum horizontal displacement of strata behind the diaphragm wall occurs at a depth of 22.5 m, which is 1.4–2.0 times the top horizontal displacement. The presence of existing buildings reduced the ground settlement between the buildings and the excavation surface. The construction process has little impact on the settlement of adjacent existing buildings, which can be adjusted appropriately. Full article

Background/Objectives: High-translucency zirconia is a dental ceramic offering excellent aesthetic results but with mechanical limitations restricting its applications. This study aimed to simulate the mechanical behavior of anatomical dental prostheses made from high-translucency zirconia using the finite element method (FEM) to assess the material’s reliability. Methods: Samples of high-translucency zirconia were compacted, sintered, and characterized for relative density. Structural and microstructural analyses were performed using X-ray diffraction (XRD) and scanning electron microscopy (SEM). Its mechanical properties, including hardness, fracture toughness, and flexural strength, were measured. Additionally, elastic parameters such as Young’s modulus and Poisson’s ratio were determined using the impulse excitation technique and subsequently employed in numerical simulations under various masticatory loads (50 to 500 N). These simulations modeled an anatomical molar (tooth 26) using the HyperMesh and ABAQUS codes, applying loads from three directions: vertical, angular (45°), and horizontal, at different points on the prosthesis. Results: The sintered zirconia ceramics exhibited excellent densification and a microstructure composed of cubic and tetragonal grains (c-ZrO₂ and t-ZrO₂). The measured properties included a hardness of 1315 ± 48 HV, fracture toughness of 3.7 ± 0.2 MPam^1/2, and flexural strength of 434 ± 67 MPa. Elastic parameters were determined as a Young’s modulus of 192.2 ± 4.8 GPa and a Poisson’s ratio of 0.31. Numerical simulations demonstrated that vertically applied loads of 500 N resulted in a maximum stress of approximately 299.2 MPa, horizontal stress reached 320.8 MPa at a 200 N load, and angular stress peaked at 447.3 MPa under a 350 N load. These findings indicate that the material can safely withstand these conditions without failure. Conclusions: Within the limits of this investigation, the methodology proved to be an effective tool for predicting the mechanical behavior of new dental ceramics. For high-translucency zirconia, the material demonstrated high reliability under masticatory vertical loads up to 500 N, angular loads up to 350 N, and horizontal loads up to 200 N. Full article

This study explores the mechanical behaviour of intra-laminar hybrid flax/E-glass composites, focusing on the role of micro-scale irregularities in flax fibres. By employing computational micromechanics and Monte Carlo simulations, it analyses the influence of flax fibre geometry and elastic properties on the performance of hybrid and non-hybrid composites. A Non-Circular Fibre Distribution (NCFD) algorithm is introduced to generate microstructures with randomly distributed non-circular flax and circular E-glass fibres, which are then modelled using a 3D representative volume element (RVE) model developed in Python 2.7 and implemented with Abaqus/Standard. The RVE dimensions were specified as ten times the mean characteristic length of flax fibres (580 μm) for the width and length, while the thickness was defined as one-tenth the radius of the E-glass fibre. Results show that Monte Carlo simulations accurately estimate the effect of fibre variabilities on homogenised elastic constants when compared to measured values and Halpin-Tsai predictions, and they effectively evaluate the fibre/matrix interfacial stresses and von Mises matrix stresses. While these variabilities minimally affect the homogenised properties, they increase the presence of highly stressed regions, especially at the interface and matrix of flax/epoxy composites. Additionally, intra-laminar hybridisation further increases local stress in these critical areas. These findings improve our understanding of the relationship between the natural fibre shape and mechanical performance in flax/E-glass composites, providing valuable insights for designing and optimising advanced composite materials to avoid or delay damage, such as matrix cracking and splitting, under higher applied loads. Full article

In order to further study the effect of welding residual stress on the fatigue strength of a TC4 titanium alloy sheet during laser welding, a laser welding butt joint model for TC4 titanium alloy sheets was established using ABAQUS (2022) software. The temperature and residual stress fields generated during the welding process were comprehensively simulated, and the melt pool shape and residual stress magnitudes were experimentally verified. The experimental parameters included a laser power range of 900–1200 W, welding speeds of 12.5 and 25 mm/s, and a double-sided welding approach with a cooling interval of 20 s between passes. The findings indicate that welding residual stress is primarily concentrated around the weld and the heat-affected zone, predominantly as tensile stress, with the maximum value observed at the weld’s initiation point, reaching 920 MPa—close to the material’s tensile strength limit. Under ideal conditions (without considering welding residual stress), the fatigue life at the weld area is estimated to reach 188,799 cycles, while the fatigue life of the base material without welding is calculated to be 167,109 cycles. However, when accounting for welding residual stress, the fatigue strength of the sheet decreases significantly, with the minimum fatigue life occurring at the weld toe, measured at 10,471 cycles. This study demonstrates that welding residual stress has a substantial impact on the fatigue life of TC4 titanium alloy sheets, particularly in the heat-affected zone, where the fatigue life is reduced by nearly 94% compared to the ideal condition. These results provide critical insights for improving the fatigue performance of laser-welded TC4 titanium alloy components in engineering applications. Full article