Analysis Of Mechanical Response Research Articles

Comparative Analysis of Mechanical Response in Epoxy Nanocomposites Reinforced with MXene and Other Carbon-Based Nano-Fillers: An Experimental and Numerical Study

This research introduces a finite element model tailored explicitly to assess the mechanical characteristics inherent in MXene/polymer nanocomposite. The primary focus revolves around elucidating the performance attributes through numerical simulations and subsequently aligning these findings with experimental data. The numerical analysis not only predicts mechanical behaviours but also aims to correlate these insights with experimental results obtained from fabricated epoxy nanocomposites within the study's scope. By employing this simulation-driven approach, the study investigates a deeper understanding of the mechanical response, particularly focusing on the materials' tensile properties. From the experimental results, the MXene/epoxy nanocomposite sample exhibited the highest tensile strength and modulus, measuring 50.1 MPa and 7.13 GPa, respectively. The simulation results were 50.08 MPa and 6.95 GPa, showing a difference of less than 3%. Small discrepancies in Young's modulus between the experimental and simulation results may arise from inherent sample heterogeneity. This heterogeneity, which includes microstructural variations, impurities, or defects, contrasts with the idealized homogeneous structures assumed in simulations. This research endeavours to advance predictive modelling techniques, offering valuable insights that can potentially streamline the manufacturing process and optimize MXene-based polymer composites. The goal is to tailor these materials with precise mechanical properties, ensuring their enhanced performance in various applications.

Characterization of aircraft landing impact loads: Effects on vertical tire-pavement contact characteristics and pavement performance

The comprehensive understanding of the mechanistic behavior of airport pavements under aircraft landing loads is essential for ensuring safety and durability. Addressing the limited understanding on the interaction between aircraft landing gear and airport pavement during landing, this study proposed a measurement method for the vertical dynamic contact characteristics of tire-pavement interface and internal dynamic responses based on a laboratory dynamic test device. This involved the experimental design and testing method for the dynamic characteristics of landing gear landing loads, utilizing the Tekscan pressure measurement system to evaluate the vertical dynamic contact characteristics between the aircraft tires and pavement during landing. Through comparative analysis with the static results, the study revealed the importance of landing load measurements for mechanical response analysis and durability design of airport pavements. Additionally, the study investigated the dynamic response of airport pavements under different simulated aircraft landing speeds and weights, and further quantified the impact effects of aircraft landing loads on airport pavements. The results show that the vertical tire-pavement contact characteristics under landing impact are significantly different from those under static conditions, and need to be considered. The proposed quantitative equations with acceptable good fitting effect provided more accurate and efficient vertical load inputs for numerical simulation and durability design of airport pavements, which laid the foundation for understanding the failure mechanisms of airport pavement and enhancing the safety of aircraft and airport operation.

Mechanical response analysis of primary support for shallow buried loess tunnel under surface surcharge

At present, the research on the influence of surrounding soil deformation induced by tunnel construction under the action of surcharge is generally based on the situation after the tunnel has been built, and less consideration is given to the existence of surface surcharge near the planned route of the tunnel when the tunnel is not built. Therefore, based on the Luochuan tunnel under construction, this study monitors the deformation of shallowly buried loess tunnels under different surcharge conditions and analyzes the influence of varying surcharge conditions on the deformation and stress of the tunnel through numerical simulation to determine the effective range of surface surcharge. The results show that the influence of surcharge load on tunnel stability is the most significant when located at the tunnel axis, and the influence degree increases with the increase of load. The adverse effects of surcharge load mainly occur in the range of 2 times the tunnel diameter. Once the range is exceeded, the internal force of the tunnel support structure is not sensitive to the surcharge load. In engineering, the surface surcharge can be controlled within the safety displacement limit by referring to the displacement calculation results.

Mechanical response analysis of asphalt microstructure under tensile and compressive loading based on finite element methods

This study investigates the micro-mechanical response of asphalt microstructure under tensile and compressive loads using atomic force microscopy (AFM) and digital image processing (DIP). AFM captured images of asphalt surface morphology, and DIP extracted geometric information on microstructures such as bee structures, peri phase, and interstitial structures. Five finite element models were created in ABAQUS to simulate their load-bearing capacities and stress-strain distributions under 1 % and 5 % tensile and compressive strains. The results showed minimal differences in load-bearing capacities among the five models under identical strain loads. However, compressive load-bearing capacity was significantly higher than tensile load, with the asymmetry becoming more pronounced as the load increased. Under 1 % compressive strain, the external load was about 3 % higher than under tensile strain, increasing to 36 % higher under 5 % strain. The bee structure exhibited the smallest stress distribution, while the interstitial structure showed the largest. The average maximum stress in the interstitial structure was 1.2 times that of the bee structure, with stress concentration observed at the interface between the peri phase and interstitial structure. The interstitial structure experienced the smallest strain distribution, while the bee structure endured the highest tensile or compressive strain, with the average maximum strain of the bee structure being approximately 1.25 times that of the interstitial structure. Under compressive loads, the maximum stress and strain on the asphalt surface exceeded those under tensile loads, with the difference averaging around 10 % higher. As the proportion of the peri phase increased, stress and strain distribution became more uniform, alleviating stress concentration phenomena. This study provides a potential method for analyzing the mechanical response of asphalt microstructure. The results deepen our understanding of the complex relationship between asphalt microstructure and its micro-mechanical response. Additionally, they suggest possible directions for improving asphalt performance through microstructure adjustment.

Multiphysics analysis of mechanical responses in micro-reactors under varied operating conditions

Micro-reactors are a promising alternative for power production applications where traditional methods may not be feasible (e.g., space missions). Their design requires critical selection of materials, especially for moderator and fuel, to ensure long-term operation and optimal performance. This research focuses on developing computational analysis models for micro-reactors, aiming to explore their structural behavior under thermal and mechanical loadings. The micro-reactor model is based on the Zero Energy Breeder Reactor Assembly (Zebra) Kilowatt (kW) reactor design conceptualized at Los Alamos National Laboratory. This study investigates the thermal and mechanical responses of three distinct reactor models considering factors, such as boundary conditions, material properties, and thermal-mechanical loading. In this study, Beryllium Oxide (BeO), Beryllium (Be), Aluminum Oxide (Al2O3), and Magnesium Oxide (MgO) are chosen as materials for the reflector. Yttrium Hydride (YH) and Zirconium Hydride (ZH) are chosen as moderators. Uranium Nitride (UN) and Uranium Molybdenum (UMo) are chosen as reactor fuel materials. The thermal analysis predicts the deformation due to the thermal expansion within the reactor under steady operating conditions at 25 kWth, mimicking the maximum rated power of the Zebra kW design. The mechanical study simulates the system's response to forced vibration loads applied along the cooling channels, matching the natural frequency of the system. The results from both analyses show that Beryllium Oxide, Yttrium Hydride, and Uranium Nitride demonstrate the most optimal stress distribution in the system compared to other configurations investigated here. The results of this study can be developed into datasets to facilitate future machine learning studies, enabling the prediction of mechanical and thermal responses for micro-reactors.

Enhancement in the Mechanical Properties of Newly Developed Ceramic Reinforced Al-Based Syntactic Foams: Analysis of Microstructure, Mechanical Response, and Energy Absorption Properties

Enhancement in the Mechanical Properties of Newly Developed Ceramic Reinforced Al-Based Syntactic Foams: Analysis of Microstructure, Mechanical Response, and Energy Absorption Properties

Design and mechanical response analysis of asphalt steel plastic pavement structure

In order to further study the mechanical properties of new asphalt steel plastic (ASP) pavement and explore optimal ASP pavement structures, this study analyzed the bottom tensile strain of asphalt mixture layer, the bottom tensile stress of steel plate layer, the bottom tensile stress of acrylonitrile butadiene styrene (ABS) layer, the top vertical compressive strain of subgrade and deflection. The results show that when the pavement structure adopts an 8 cm thick SMA layer, a 0.5 cm thick insulation layer, a 20 cm thick ABS layer, and 0.6 cm, 1.0 cm and 1.2 cm thick steel plate layers respectively, the mechanical properties of the ASP pavement are relatively good. The variation in the thickness of the steel plate layer has a greater impact on the bottom stress of steel plate layer. For the same pavement structure, when the dynamic load increases from 0.5 MPa to 0.9 MPa, the maximum values of the design indexes are linearly related to the dynamic load values. Under the static load, the shear stress generated in the steel plate layer is significantly lower than that in asphalt and ABS layers. The new asphalt steel plastic pavement has good mechanical properties and great application potential.

Dynamic viscoelastic properties of ultra-large particle size asphalt mixture based on fractional derivative constitutive model

The aim of this paper was to accurately grasp and precisely characterize the dynamic viscoelastic properties of Ultra-Large Particle Size Asphalt Mixture (LSAM-50), and fully explore the features and simplified forms of the generalized fractional derivative Zener (GFDZ) model. The constitutive relations of the GFDZ model with n Abel elements were first given, and a modified GFDZ (mGFDZ) model was proposed. Then the master curves of LSAM-50, AC-13 and AC-20 mixtures were constructed, and the expression effects of different models and the dynamic viscoelastic behaviors of different asphalt mixtures were compared. The results showed that LSAM-50 was a typical viscoelastic material similar to traditional mixture. Both dynamic modulus and energy storage modulus decreased with increasing temperature. The phase angle increased first and then decreased with temperature increasing, and the peak value appeared near 40℃ at low frequency. The loss modulus increased first and then decreased with the temperature increasing. When the loading frequency was 0.1 Hz∼25 Hz, the peak value appeared at 0℃∼20℃. The rutting factors of LSAM-50 became larger with temperature reduction and frequency enhancement. When the number of Abel elements reached 2 in the GFDZ model or reached 3 in the mGFDZ model, the model fitting effects would no longer change significantly. The 2-mGFDZ model with only 5 parameters fitted master curves data satisfactorily and the physical meanings of parameters were clear. Comparing among three mixtures, LSAM-50, with the lowest asphalt content, showed significantly superior elasticity and better deformation resistance at medium and high temperatures. At low temperatures, the viscosity behavior of LSAM-50 was slightly inferior, but it may have pronounced plate properties considering the effect of aggregate skeletonization. The research results would promote new pavement structural design and mechanical response analysis.

Energy absorption assessment of recovered shapes in 3D-printed star hourglass honeycombs: Experimental and numerical approaches

This study provides an experimental and numerical evaluation of the energy absorption performance of a 3D-printed star hourglass honeycomb structure with a novel design made from pure and reinforced PLA by chopped carbon fibers and continuous glass fiber. The study further investigates the energy absorption response of this structure after the shape recovery due to thermal stimuli under the quasi-static compressive loading. As an additive manufacturing process, Fused Deposition Modeling is used to produce the specimens with pure and reinforced PLA filament. The difference in the nonlinear response of PLA due to plasticity and damage in tension and compression loading directions, as a feature that helps the shape recovery, is considered in mechanical response analysis using the Finite Element approach. Then, in the obtained results distinguish constitutive laws in tension and compression mechanical properties are employed leading to a failure model using the appropriate algorithm consistent with the experiments. According to the obtained results which reveal good agreement regarding the experimental results, by designing appropriate auxetic configuration selecting suitable geometry parameters, and employing the proper material with diverse properties in tension and compression directions, it is possible to fabricate a lattice structure inherits the shape recovery after the compression deformation which exhibits acceptable energy absorption performance even the second shape recovery.

Experimental and Modeling Analysis of Mechanical Response of Composite Electrodes in Lithium Batteries.

The mechanical response is one of the main factors that influence the capacity and number of cycles of lithium batteries, which hinder its wide application. Therefore, it is crucial to perform an in-depth investigation of the electro-chemo-mechanical coupling performance and work mechanism of battery electrodes during the electrochemical reaction process. Usually, graphite is the main active material used in commercially used batteries, while silicon is gaining worldwide attention because of its large energy density. Here, graphite and silicon composite electrodes were prepared to obtain the electro-chemo-mechanical response during electrochemical cycling by an in situ bending deformation measurement. The findings indicate that the composite electrodes could induce a large bending deformation, with an increase in the state of charge (C-rate). And, with an increase in the C-rate, the deformation degree of the silicon composite electrode increases, while that of the graphite composite electrode decreases due to the hardening properties of the graphite particles. In addition, increasing the thickness ratio could induce an increase in the peak stress for both composite electrodes. This work gives a detailed analysis of the mechanical properties of composite electrodes and finds the working mechanism of the C-rate and thickness ratio, which can supply suggestions for the development of high-performance batteries.

Cross-scale mechanobiological regulation of cylindrical compressible liquid inclusion via coating

The double-bag theory in modern anatomy suggests that structures with coatings are commonly found in human body at various length scales, such as osteocyte processes covered by pericellular matrix and bones covered by muscle tissue. To understand the mechanical behaviors and physiological responses of such biological structures, we develop an analytical model to quantify surface effects on the deformation of a coated cylindrical compressible liquid inclusion in an elastic matrix subjected to remote loading. Our analytical solution reveals that coating can either amplify or attenuate the volumetric strain of the inclusion, depending on the relative elastic moduli of inclusion, coating, and matrix. For illustration, we utilize this solution to explore amplification/attenuation of volumetric strain in musculoskeletal systems, nerve cells, and vascular tissues. We demonstrate that coating often plays a crucial role in mechanical regulation of the development and repair of human tissues and cells. Our model provides qualitative analysis of cross-scale mechanical response of coated liquid inclusions, helpful for constructing mechanical microenvironment of cells.

Support mechanical response analysis and surrounding rock pressure calculation method for a shallow buried super large section tunnel in weak surrounding rock

At present, China's demand for high-speed railway construction is constantly increasing, and the construction of Multi line high-speed railway tunnels has been put on the agenda. The design and construction issues of super-large-sections tunnels urgently need to be addressed. The Xiabei mountain No. 1 and No. 2 tunnels in the Hangzhou-Taizhou Railway are typical shallow-buried super-large-section-tunnels in weak surrounding rock, and their design and construction issues are representative. Eleven monitoring sections were set up in the tunnel, including tunnel deformation, surrounding rock, shotcrete, steel frames, bolts and temporary support mechanical responses. Taking the monitoring data of the most typical cross-section as an example, the mechanical response of the support structure of a shallow-buried super-large-section tunnel was analyzed in detail. Based on previous research results, this paper discusses and summarizes the common construction problems of this type of tunnel, and puts forward corresponding suggestions. The existing formula for calculating surrounding rock pressure has poor applicability to super-large-section tunnels constructed by step excavation, resulting in conservative support parameters. Therefore, based on the monitoring values of surrounding rock pressure at 10 monitoring sections in Xiabei mountain No. 1 and No. 2 tunnels, empirical parameters reflecting the impact of step excavation were summarized. Based on the Wang formula and combined with the step excavation empirical parameters, an empirical formula for the surrounding rock pressure of shallow-buried super-large-section tunnels considering step excavation was constructed. The calculated results are in good agreement with the on-site monitoring data. This study can provide a good reference for similar projects.

Analysis of mechanical response and failure characteristics of tunnels crossing active faults considering axial force and geometrical nonlinearity

Tunnels subjected to active fault dislocation may experience significant damage. This paper establishes a novel methodology and solution procedure for analyzing the mechanical response and failure characteristics of tunnels subjected to active fault dislocation based on an elastic foundation beam model. The proposed methodology includes axial, transverse, and vertical soil-tunnel interaction terms, in addition to geometrical nonlinearity and axial force terms in the governing equation. This approach has a significantly extended application range, effectively addressing the problems encountered in tunnels crossing active faults with diverse crossing angles, dip angles, and fault types. The proposed methodology is verified by comparison to a 3D FEM model with various fault types, experimental tests, and on-site case, and the results are in excellent quantitative and qualitative agreement with the numerical, experimental, and on-site results. When fault displacement is below 0.5 m, disregarding geometric nonlinearity results in calculation errors of approximately 10% to 17% for peak axial force (Nmax), 18% to 22% for peak shear force (Vmax), and 20% to 30% for peak bending moment (Mmax). Finally, the responses caused by different factors, i.e., fault type, fault displacement, tunnel stiffness, and tunnel diameter, are investigated in detail to better understand tunnels crossing active faults. The results show that amongst the various fault types, the Vmax and the Mmax experienced by tunnels subjected to oblique slip-fault dislocation surpass those of other fault types, accompanied by the most extensive failure range. The augmentation of fault displacement, tunnel stiffness, and tunnel diameter precipitates a corresponding escalation in the Nmax, Vmax, Mmax, and failure range. Under oblique-slip fault dislocation, the tunnel undergoes an initial phase of shear failure, followed by tension-bending failure, delineated by distinct fault displacement thresholds of 0.1 m and 0.2 m, respectively. The proposed methodology provides the advantage of reliable stability analysis and design of tunnels crossing active faults.

Nonlinear mechanical response analysis and convolutional neural network enabled diagnosis of single-span rotor bearing system

The wide application of rotating machinery has boosted the development of electricity and aviation, however, long-term operation can lead to a variety of faults. The use of different measures to deal with corresponding malfunctions is the key to generating benefits, so it is significant to carry out the fault diagnosis of rotating machinery. In this work, a test bench for single-span rotor bearings was established, three faults, including spindle bending, spindle crack without end loading and spindle crack with end loading, are experimental analyzed with basic mechanical response. Moreover, a diagnosis is performed using a convolutional neural network, according to the differences in mechanical responses of the three faults obtained from experiments. For three faults, the change in the properties of spindle itself results in different axis trajectories and spectra. Compared with spindle bending fault, spindle crack fault not only cause 1×, 2×, 3× frequency component excitation, also 4×, 5× frequency component excitation. Additionally, the classification accuracy of the training set and the test set under machine learning for the three types of working conditions is 100%. This indicates that the network can significantly identify signal features so as to make effective fault classification.

Synergistically improving the edge-on impact damage resistance of composite laminates using multi-scale CNF/Z-pin toughening

Edge-on impact damage of composite structures has drawn significant attention from the engineering and academic communities because of the much more notorious damage caused than that by out-of-plane impacts. However, research focusing on improving the edge-on impact resistance of these structures has been limited. This paper proposed a synergistic toughening approach involving multi-scale carbon nanofiber (CNF) and Z-pin to improve the composite laminates' edge-on impact damage resistance. Through analysis of mechanical response, C-scan, optical and Scanning electron microscopy (SEM) photographs of unreinforced, CNF-reinforced, Z-pin-reinforced and CNF/Z-pin-reinforced laminates, the failure mechanisms of the four types of laminates and the synergistic toughening mechanism of CNF/Z-pin were revealed. The results show that the synergistic toughening of CNF/Z-pin could weaken the negative effects caused by Z-pin implantation and that CNF has the potential to increase the damage initiation energy threshold of the laminate. Furthermore, the toughening effect of Z-pin was significantly greater than that of CNF in damage propagation. Specifically, at 50 J impact energy, the damage area of CNF/Z-pin, Z-pin and CNF-reinforced laminates was reduced by 50.5 %, 39.8 %, and 8.3 %, respectively, compared to unreinforced laminates.

Analysis of Mechanical Response of Epoxy Asphalt-Repaired Pavement in Pothole Interface on Steel Bridge Deck under Coupled Temperature-Dynamic Loading

The persistence of pothole maintenance represents an enduring challenge. Past studies have largely concentrated on the materials and techniques used for remediation, with a lack of attention given to the pothole interface. This paper employed epoxy asphalt rubber (EAR-10) as the repair material, exploring the impact of coupled temperature-dynamic loading on the mechanical response of the interface. Finite element modelling (FEM), adopting the viscoelastic characteristics of EAR-10, was deployed to investigate the mechanical response of the interface under three temperature service conditions high, medium, and low when a dynamic load traversed the pothole. The stress variations in the interface at various inclinations and thicknesses of the repair blocks were also studied. In addition, the comparative analysis of high-temperature rut resistance for powdered rubber composite-modified asphalt and SBS modified asphalt was conducted via the multiple stress examination in terms of its high-temperature resilience, resistance to moisture-induced damage, and fatigue life by employing the asphalt mixture rutting test, low-temperature bending test on small beams, and the water immersion Marshall stability test, respectively. The repair efficacy of EAR-10 was appraised through post-repair water immersion rutting tests and bending tests on composite structural small beams. The results indicated that incorporating coupled temperature-dynamic loading led to a considerable increase in stress, particularly under low-temperature service conditions. An inclination angle of 30 degrees was found to be optimal for the interface. The research methodology presented here is pertinent to guiding the pothole repair in the steel bridge pavement, ensuring the strength and durability of the interface rivals that of newly constructed layers.

Mechanical response analysis of disintegrated carbonaceous mudstone based on discrete element method

Mechanical response analysis of disintegrated carbonaceous mudstone based on discrete element method

Translational medical bioengineering research of traumatic brain injury among Chinese and American pedestrians caused by vehicle collision based on human body finite element modeling

Based on the average human body size in China and the THUMS AM50 finite element model of the human body, the Kriging interpolation algorithm was used to model the Chinese 50th percentile human body, and the biological fidelity of the model was verified. We built three different types of passenger vehicle models, namely, sedan, sports utility vehicle (SUV), and multi-purpose vehicle (MPV), and used mechanical response analysis and finite element simulation to compare and analyze the dynamic differences and head injury differences between the Chinese 50th percentile human body and the THUMS AM50 model during passenger vehicle collisions. The results showed that there are obvious differences between the Chinese mannequin and THUMS in terms of collision time, collision position, invasion speed, and angle. When a sedan collided with the mannequins, the skull damage to the Chinese human body model was more severe, and when a sedan or SUV collided, the brain damage to the Chinese human body was more severe. The abovementioned results suggest that the existing C-NCAP pedestrian protection testing regulations may not provide the best protection for Chinese human bodies, and that the regulations need to be improved by combining collision damage mechanisms and the physical characteristics of Chinese pedestrians. This thorough investigation is positioned to shed light on the fundamental biomechanics and injury mechanisms at play. Furthermore, the amalgamation of clinically rooted translational and engineering research in the realm of traumatic brain injury has the potential to establish a solid foundation for discerning preventive methodologies. Ultimately, this endeavor holds the potential to introduce effective strategies aimed at preventing and safeguarding against traumatic brain injuries.

Mechanical Response Analysis of Regular and Lightweight Concrete under Bending Stresses

This study investigated the mechanical response of regular and lightweight concrete under bending stresses. We compared the stress‐strain relationships, densities, and deformation capacities of these two types of concrete to highlight their key differences. Lightweight concrete, with a lower density of 1800 kg/m³, offers significant weight reductions, making it ideal for applications with weight constraints. However, this reduced weight results in lower compressive and flexural strengths. On the other hand, normal concrete, with a density of 2400 kg/m³, exhibited higher mechanical strength and durability. The stress‐strain graphs from the study showed that both concrete types exhibit both elastic and plastic deformation, with a transition from elastic to plastic behavior at specific stress points. By balancing weight reduction against mechanical strength, this study provides valuable insights for construction professionals in selecting the appropriate concrete type for various projects.

Analysis of mechanical and electrical cardiac responses to prolonged cold-water swimming

Analysis of mechanical and electrical cardiac responses to prolonged cold-water swimming