Analysis Of Mechanical Response Research Articles

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.

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.

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

Multi-field coupling analysis of mechanical responses in methane hydrate exploitation with a practical numerical approach combining T + H with DEM

The methane hydrate (MH) is widely distributed in deep-sea sedimentary layers, considered as the most promising clean energy to replace conventional oil and gas in the 21st century. Large-scale exploitation of MH may lead to a series of geotechnical engineering problems. To numerically estimate the seabed stability during MH exploitation which should involve multi-field coupling simulation of complex mechanical behaviors of methane hydrate bearing sediment (MHBS), a new practical hybrid numerical method is proposed, which combines the TOUGH + HYDRATE (T + H) code, targeting multiphase flow analysis of hydrate-bearing geologic systems, with the improved Distinct Element Method (DEM). Porosity, temperature, pressure, salinity fields are exchanged between DEM and T + H to realize the thermal-hydro-mechanical-chemical (THMC) coupling and to reproduce the progressive discontinuous failure process. The results of verification show obvious uniformity between numerical and analytical results for one-dimensional (1D) consolidation and 1D heat conduction tests on soils. The paper tries to analyze evolutions of THMC fields, gas production, hydrate bond breakage and other mechanical behaviors of actual depressurization production by using this method, focusing on geotechnical risks of exploitation. In addition, study observes significant changes within certain range from the wellbore for gas production and mechanical responses in the early stage.

Holistic Exploration of Structural, Electronic, Magnetic, Transport, Mechanical, and Thermodynamic Characteristics, Including Curie Temperature Analysis.

Through intricate calculations, the density functional theory (DFT) implemented in the Wien2k code was employed to comprehensively investigate a wide range of material characteristics. Our study encompasses an exhaustive analysis of structural stability, electronic properties, magnetic behaviors, transport phenomena, mechanical responses, and thermodynamic profiles of two notable instances of filled Skutterudites, namely, CeNi4P12 and DyCo4Sb12, which have been thoroughly explored. These computations were performed using the WIEN 2K code, combining local orbitals and the full-potential linearized augmented plane-wave approach. The findings provided insight into the wide range of properties of these materials. In this methodology, the exchange-correlation potential relies on the local-density approximation. We conducted the calculations with and without incorporating spin-orbit interactions. The results obtained provide information about the lattice constant, bulk modulus, and pressure derivative. The stability, as indicated by the P-V graphical plot, suggests that there are no structural phase transitions from the cubic symmetry structure. Notably, our work includes an examination of Curie temperatures, which are pivotal in understanding magnetic phase transitions. The validated elastic properties further support the material's stability and corroborate its ductile nature. These alloys should be considered for spintronic and thermoelectric applications due to their estimated transport characteristics and the observed ductile nature. To enhance our understanding of the thermal stability of antimony-based compounds, we have made reliable estimations of the thermophysical characteristics. By integrating theoretical insights with practical implications, we bridge the gap between fundamental understanding and material design applications. Using DFT in the Wien2k framework, we discover connections and patterns among different properties, showing how to create materials with specific functions and better performance. This approach not only advances our fundamental comprehension of materials but also promises innovation across various technological domains.

In-depth analysis of mechanical and electrical responses of PDMS/MWCNT micro-composite films under cyclic loading conditions

This study has comprehensively examined the variations in the mechanical and electrical properties of PDMS/MWCNT micro-composite (PMMC) films under cyclic tensile loading. While previous studies have primarily focused on the electrical performance of wearable sensors, it is essential that wearable sensors need to meet both electrical characteristics and mechanical reliability throughout their designed operational lifespan. We conducted cyclic tensile tests for PMMC films with different MWCNT mass fractions of 3-wt%, 4-wt%, and 5-wt% and obtained cyclic mechanical properties and electrical conductivity. Each PMMC film exhibited distinct stabilization trends in both mechanical and electrical responses under cyclic loading. Additionally, the stabilised cyclic hyperelastic material properties were defined from the test results to enable predicting structural behaviour of PMMC films using finite element analysis. The results of this study provide valuable insights into the material properties and mechanical/electrical responses under cyclic loads for the structural integrity assessment of wearable sensors employing PMMC films.

Mechanical response and field measurement analysis of custom-shaped steel sleeves during urban shield tunnel construction

Urban shield tunnel construction is typically affected by limited construction space and the inability to begin from the main line. Conventional lateral initiation solutions result in construction delays and incurs additional construction costs. Hence, based on the Beijing Metro Line 27 project, a novel custom-shaped steel sleeve for lateral initiation is proposed. Numerical simulations are conducted to analyse the stress and deformation characteristics of the steel sleeve during shield initiation. The simulation results, which are validated based on on-site measurements, show that the maximum tensile stress of the shaped steel sleeve structure increases with the shield thrust, and that the average maximum stress occurred at the waist position at the long side of the barrel. However, the stress at the base reduced significantly and a stress concentration occurred at the connection between the sleeve and tunnel portal. The deformation of the sleeve is characterised by a larger long side and a smaller short side owing to the constraint of the tunnel portal. The axial force on the connection bolts below the waist of the sleeve is the highest, whereas the axial force near the tunnel portal is lower. The waist position and the lower section of the sleeve structure are areas where the stress and deformation are weak during the shield initiation of the steel sleeve. Results of engineering test shows that using a shaped steel sleeve for lateral initiation is safe and feasible. However, the waist and bolt connections of the shaped steel sleeve must be scrutinised when used in engineering practice, and standardised construction operations and strengthened monitoring should be implemented.

Effects of the injection molding processing settings on the phase morphology and mechanical anisotropy of thermoplastic vulcanizates

AbstractThermoplastic vulcanizates show significant anisotropic mechanical properties when processed to components via injection molding. This effect is related to a process‐dependent distortion of the incorporated elastomer particles in high‐shear regions during the injection phase. In a plate geometry, the elastomer particles in the shear regions are oriented and deformed in the flow direction. However, the ongoing distortion processes and the influencing factors of the process parameters on the resulting phase morphology and mechanical response are not entirely understood. Therefore, in this study, the effect of the injection molding machine settings for the production of a plate component on the local phase morphology and mechanical anisotropy is investigated. The investigations are conducted on two commercial material grades with different Shore‐A hardness 30 and 90. A significant inverse effect of the injection volume flow rate on the particle distortion and anisotropy is found. Increasing the volume flow rate results in a reduction of the anisotropy. This is counterintuitive from the experience of other materials with process‐dependent anisotropy. Also, a significant influence of the process on the overall stiffness of the compounds is observed.Highlights Sturcture–property relation for phase morphology in thermoplastic vulcanizates Quantitative microstructure analysis in injection molded plates Macroscopic analysis of anisotropic mechanical response under uniaxial loading Effect analysis of injection molding parameters on the mechanical anisotropy Additional effects of process settings on overall stiffness of the material

Uniform moduli characterization of asphalt mixtures under dynamic and static loading conditions

The modulus is a crucial material parameter reflecting stiffness characteristics of asphalt mixture in the elastic stage. Under specific conditions such as identical temperatures, loading velocities, and stress amplitudes, the moduli under the same stress state are theoretically identical. However, the moduli were artificially divided into dynamic moduli and static moduli based on loading methods during test, which brought uncertainties and disunity for estimating the stiffness performance of asphalt mixture. In this study, the dynamic and static moduli under distinct temperatures, loading velocities, and stress states were measured. The relationship between dynamic and static moduli was established by applying loading velocities as independent variable and moduli as the dependent variable. Through Sigmoidal function and WLF function fitting, the uniform characterization master curves of dynamic and static moduli under distinct temperatures, loading velocities, and stress states were established. The moduli of asphalt mixture under distinct test temperatures, loading velocities, and stress states can be obtained by the models, which provide material parameters for mechanical response analysis of asphalt pavements under distinct service environments. This resolves the issue of inconsistent moduli parameter selection.

Steady-state and transient mechanical response analysis of superelastic nitinol lattice structures prior to additive manufacturing: An in-silico study

The additive manufacturing (AM) of nitinol (NiTi) has gained considerable attention due to the capability of this material and processing combination to produce complex structures with desired shape memory or superelastic properties. Finite element analysis models were developed in this work to simulate the load-bearing capability of Laser Powder Bed Fusion (PBF-LB) produced NiTi lattice structures. The Auricchio numerical method, with exponential hardening law, was implemented within the FEA model to take account of the martensite-austenite reorientation upon change of stress state. The strut diameter and the unit cell side length were varied which in turn varied the lattice relative density. The lattice structures were subjected to 7 % compressive strain under isothermal conditions. The highest energy absorption efficiency of 40 % was achieved from the lattice structure with a strut diameter of 2 mm, a 6 mm unit cell side length, and a relative density of 42 %; however, the highest specific peak stress was recorded within the lattice structure having a strut diameter of 2.5 mm, a 4 mm unit cell side length, and a relative density of 62 %. Transient analysis was performed by varying the compression rate from 0.25 mm/s to 1 mm/s. For all loading conditions, the energy absorption increased linearly until a stable stress plateau was reached. Moreover, for these examined compression rates, the maximum stress absorption efficiencies varied within the range of 25 %–33 %.

Enrichment of three-dimensional numerical manifold method with cover-based contact theory for static and dynamic mechanical response analysis

Based on the mathematical grid of 4-node tetrahedral finite element form, the dual cover system, weight function and displacement function of three-dimensional numerical manifold method (3D-NMM) are proposed. The derivation process of element stiffness matrix, inertial force matrix, loading point matrix, etc. are systematically demonstrated in the present work. Based on the cover-based contact theory, the contact detection algorithm among discrete 3D blocks is realized, and the 3D manifold framework is programmed. The accuracy of the developed code is firstly calibrated through two continuum deformation analysis: cantilever beam bending model and axial tensile model of thin plate with circular hole. Then it is applied to three complex discontinuous instability simulation (SHPB, brick wall structure and cliff slope) to verify the effectiveness and accuracy of the proposed contact algorithm. The classic Steven low velocity impact process is also simulated, and the deformation and failure of polymer bonded composites (PBC) are predicted, which further verifies the feasibility and robustness of the developed code in dealing with dynamic impact problems.