Dynamic Analysis Research Articles

Integrated battery thermal management and CO2 control in electric buses using recirculated air and waste heat recovery

In recent years, electric vehicles (EVs) have significantly progressed due to their environmental protection and energy-saving advantages. However, maintaining indoor thermal comfort and effective battery thermal management are critical considerations for EVs. Unlike conventional vehicles, EVs cannot use waste heat and depend on heat pump systems for winter heating and summer cooling. This research proposes a novel system to reduce the energy consumption of heat pump systems by using recirculated air while addressing the challenges of battery temperature management and maintaining safe CO2 concentrations in the cabin. The primary objectives of this research are threefold: first, to ensure passenger comfort through an integrated approach that includes cabin CO2 concentration safety; second, to recover heat from recirculated cabin air to save energy and control battery temperature; and third, to comprehensively analyze the performance of the Electric Vehicle Thermal Management System (EVTMS) using precise Computational Fluid Dynamics (CFD) analysis and mathematical modeling. This study will significantly enhance the understanding of energy consumption related to CO2 concentration control; an aspect previously overlooked in the literature. It will develop a battery temperature management strategy that leverages bus exhaust heat. These contributions will aid in achieving both passenger comfort and battery stability in electric buses, providing practical insights for the design and optimization of thermal management systems for future electric buses.

Dynamic intelligent analysis of single-column pier bridges considering vehicle-bridge interaction

Dynamic intelligent analysis of single-column pier bridges considering vehicle-bridge interaction

Gait assessment in a female rat Sprague Dawley model of disc-associated low back pain

ABSTRACT Purpose Gait disturbances are common in human low back pain (LBP) patients, suggesting potential applicability to rodent LBP models. This study aims to assess the influence of disc-associated LBP on gait in female Sprague Dawley rats and explore the utility of the open-source Gait Analysis Instrumentation and Technology Optimized for Rodents (GAITOR) suite as a potential alternative tool for spontaneous pain assessment in a previously established LBP model. Materials and Methods Disc degeneration was surgically induced using a one-level disc scrape injury method, and microcomputed tomography was used to assess disc volume loss. After disc injury, axial hypersensitivity was evaluated using the grip strength assay, and an open field test was used to detect spontaneous pain-like behavior. Results Results demonstrated that injured animals exhibit a significant loss in disc volume and reduced grip strength. Open field test did not detect significant differences in distance traveled between sham and injured animals. Concurrently, animals with injured discs did not display significant gait abnormalities in stance time imbalance, temporal symmetry, spatial symmetry, step width, stride length, and duty factor compared to sham. However, comparisons with reference values of normal gait reported in prior literature reveal that injured animals exhibit mild deviations in forelimb and hindlimb stance time imbalance, forelimb temporal symmetry, and hindlimb spatial symmetry at some time points. Conclusions This study concludes that the disc injury may have very mild effects on gait in female rats within 9 weeks post-injury and recommends future in depth dynamic gait analysis and longer studies beyond 9 weeks to potentially detect gait.

Dynamic analysis of a 600-m-high supertall building subjected to long-period ground motions, ordinary ground motions and a super typhoon: a comparative study

Dynamic analysis of a 600-m-high supertall building subjected to long-period ground motions, ordinary ground motions and a super typhoon: a comparative study

Seismic performance of friction damped posttensioned steel frame equipped with SMA strands

The post-tensioned friction dissipating (PTFD) connection for steel frames has drawn significant attention from researchers due to its excellent seismic performance. A simplified numerical algorithm suitable for modeling the SMA strands is proposed. The simplified numerical model of the SMA-PTFD is established. Parametric analysis is performed based on hysteresis analysis and transient dynamic analysis to reveal the influence of SMA strands on the seismic performance of SMA-PTFD frames. The changing rule of seismic response of SMA-PTFD frames, along with the fmax for SMA strands and the Fmax for the friction device, is systematically investigated. The value of the objective function can be reduced by about 50 % when the fmax is increased from 1 kN to 13 kN. The fundamental frequency is 1.25 Hz for three analyzed conditions. The value of the second frequency is significantly affected by Fmax. The values of the second frequency are 1.5 Hz, 1.58 Hz, and 1.42 Hz. The characteristics of seismic response, including displacement and cable force, are deeply studied. The seismic response is also investigated in the frequency domain. The results presented in this work reveal the collaborative energy dissipation mechanism of the friction device and SMA strands.

Cumulative collision risk and population-level consequences of industrial wind-power plant development for two vulture species: A quantitative warning

Prioritizing renewable energy generation over the conservation of natural habitats and species on a large spatial scale, leads to the paradox of impacting biodiversity to mitigate climate change. In this study, we aim at quantifying the long-term demographic impact of the excess mortality caused by collisions with wind turbines on the populations of two vulture species of conservation concern. Using long-term monitoring data and Integrated Population Models (IPMs), we quantified demographic parameters and projected population trends under various wind power development scenarios. Our findings indicate that even under our most optimistic scenarios, annual collision mortality could reach up to 30 % of the current Cinereous vulture population and 7 % of the Griffon vulture population. Without further wind power expansion, both vulture populations are predicted to remain stable or increase over the next 20 years. However, the addition of 85 wind turbines is likely to drive the Cinereous vulture to local extinction within 18 years and significantly slow the growth of the Griffon vulture population. Scenarios involving larger numbers of turbines could result in the extinction of both species within two to five years for Cinereous vultures and up to 20 years for Griffon vultures, depending on space use intensity. Our results underscore the vulnerability of long-lived species to excess mortality and highlight the need for comprehensive Environmental Impact Assessments (EIAs) that incorporate population dynamics analyses. Effective conservation strategies must include rigorous pre- and post-construction monitoring, the availability of monitoring data, and cumulative impact assessments that consider the entire foraging range of these species. Additionally, strategic planning to avoid critical vulture habitats and implementing mitigation measures in buffer zones are essential. This study emphasizes the necessity of integrating biodiversity considerations into renewable energy planning to balance the goals of energy production and wildlife conservation.

Revisiting the 1934 Mw 8.2 Bihar Nepal earthquake – Simulation of Broadband ground motions

Summary The 1934 Mw 8.2 Bihar-Nepal earthquake was one of the devastating earthquakes, which made seismologists realize the importance of proper seismic hazard analysis and design aspects in India. The event occurred way before proper seismic networks were implemented and hence there are no recorded ground motions available for this event. The present study, thus aims to generate possible ground motions for the 1934 Mw 8.2 Bihar-Nepal event. The complex geographical features, ambiguous source information, and lack of ground motion data make the simulation and validation of ground motions very difficult. In this regard, the broadband (BB) ground motions are simulated and validated for the most recent well-documented Himalayan event, i.e., the 2015 Mw 7.9 Nepal earthquake in order to calibrate the model and simulation methodology. For this purpose, the computational model presented by Sreejaya et al. (2023) is extended up to a region of 1000 km × 670 km (longitude 80-89 °E and latitude 23-30 °N) in the Indo-Gangetic Basin to simulate the low-frequency (LF) ground motions using spectral element method (Komatitsch and Tromp 1999). These deterministically simulated LF ground motions are combined with stochastically simulated high-frequency (HF) ground motions based on an improved seismological model following Otarola and Ruiz (2016). The seismic moment and dimensions of the rupture plane presented by Pettanati et al. (2017) are used to generate ten samples for the finite fault source model having different slip distribution along the rupture plane as a random field (Mai and Beroza 2000; 2002). The BB ground motions (0.01–25 Hz) are obtained by merging LF and HF ground motions in the time domain by matching them at a frequency of ∼0.3 Hz. Such BB results are simulated at a grid of stations and at locations where Modified Mercalli Intensity (MMI) intensity values are available. The estimated MMI values and the observed MMI values are compared to emphasize the efficacy of the model. The maximum PGA estimated from the simulated ground motions in horizontal and vertical directions are observed to be 0.48 g and 0.4 g. Further, 5% damped response spectra and spectral amplification are analyzed concerning the sediment depth of the Indo-Gangetic Basin. The results from the study can serve as inputs for dynamic analysis and the design of earthquake-resistant structures across different locations in the Indo-Gangetic Basin.

Dynamic analysis of multi-module floating photovoltaic platforms with composite mooring system by considering tidal variation and platform configuration

Floating Photovoltaics (FPV) are emerging as an innovative technology to utilizing solar energy which advances the exploration of renewable energy technologies in the deep sea. This investigation proposes a novel methodology to verify the feasibility of the designed models in time-domain analysis via the motion responses, the mooring analysis based on the finite element method (FEM) and the airgap analysis, considering a comparison of dynamic responses between the regular hexagon shape and rectangle shape semi-submersible floating photovoltaic platform (FPVP) both combinate the cables and the tensioners mooring system to adapt the tidal variation. Initially, the response amplitude operators (RAOs) of the two configurations of the FPVP numerical models established in AQWA are derived from the frequency-domain analysis. Then, the method of rectifying the RAOs by incorporating additional damping essential to compensating the fluid viscosity due to the limitation of the potential flow theory is verified through comparison with the Computational Fluid Dynamics (CFD) solver. Subsequently, the motion responses of the two conceptualized FPVPs with the composite mooring system under different depths of water are assessed in time-domain analysis through OrcaFlex which regards the cables and tensioners as Morison type based on the FEM theory. Simultaneously, the variations in the air gap of platforms with dissimilar stiffness tensioners are compared to assess the safety of FPV systems under different water depths. The long-term extreme forecast of effective tension force for various return periods derived from the Weibull distribution model is verified. Finally, considering the factors that influence the design and safety of multi-module floating photovoltaics in variable-depth water, this study provides essential guidance for the safe construction technology of semi-submersible FPVPs, serves as a valuable reference for promoting reliable and cost-effective FPV technologies for offshore environments.

Theoretical and experimental approaches for flexible cage dynamic characteristics of four-point contact ball bearing considering multi-point contact behaviors

Multi-point contact often occurs between the balls and raceways of the four-point contact ball bearing (FPCBB) due to operating conditions and manufacturing errors, which can lead to unstable motion and wear of the cage. A dynamic analysis method for FPCBB with a flexible cage under multi-point contact is presented in this paper. Initially, the boundary conditions for different contact points (two-point, three-point, and four-point contact) are clarified through the research of the dynamic interaction and collision mechanisms between the balls and the raceways. Subsequently, based on the structure flexibility, and the collision effect among the balls, cage, and guiding ring, a dynamic model for FPCBB is constructed, and the heightened accuracy and superiority of the model are substantiated through comparative analyses with the conventional rigid cage model. Furthermore, the influence of operating conditions and manufacturing errors on the rotational stability and the wear degree of the cage are explored, and the accuracy and reliability of the model are experimentally verified. The results show that the degree of cage wear is strongly influenced by the contact state, and the maximum wear degree varies at different positions. Reasonable speeds, loads, and manufacturing error range can effectively improve the contact conditions, thereby augmenting cage motion stability and mitigating wear. This research contributes novel insights into the failure analysis and structural optimization of the FPCBB.

Time history analysis of multi- storey building with basement story accounting for soil–structure interaction

Soil-Structure Interaction (SSI) is the effects of the soil (underlying and surrounding the structure) on the response of the structure. This study is a contribution in the soil structure interaction (SSI) field, as this interaction affects the seismic behavior of structures. Two series of Time History data were used in the analysis of reinforced concrete moment resisting frame building consisting of 9 stories with embedded basement storey building. The two approaches of SSI modeling that are substructure approach and direct approaches were compared with each other. Generally, and within the limits of this study, it was found that the responses of Substructure approach were identical with that of the direct approach in the two cases for all stories except for the Ground storey. It seems that SSI affects the higher stories rather than the lower stoerys. The dynamic analysis results comparison between the two approaches of modeling soil structure interaction, favored the substructure approach on the direct approach as the direct approach is time consuming. Also, the study found out that modeling the structure with only vertical spring led to doubtable results, which reflect present that is choosing this method represents the worst option. On the other hand, and according to the analysis results, study suggested that keeping use the fixed approach in design buildings (with embedded portion) does not represent the better choice. It is concluded that, the responses of Substructure approach is identical with that of the Direct approach in all cases for all stories except for the Ground storey. It seems that SSI affects the higher stories rather than the lower storey.

Seismic assessment of glulam frames with dual-tube self-centering buckling-restrained braces

The development of resilient lateral load-resisting systems is essential for multi-story and high-rise timber buildings in earthquake-prone areas. In this paper, an attempt is made to integrate dual-tube self-centering buckling-restrained braces (DT-SCBRBs) to glulam frames, aiming to improve their structural resilience to earthquakes. To assess the seismic effectiveness of such a DT-SCBRB glulam frame, nonlinear time-history analyses (NLTHAs) were conducted on a series of prototype DT-SCBRB glulam frames with different building heights and design parameters of DT-SCBRBs. The seismic performance of these prototype structures was evaluated in terms of maximum inter-story drift ratios (MaxISDRs), residual inter-story drift ratios (ResISDRs), and inter-story drift uniformity. The results show that the frame with lower post-tensioning-to-yielding ratios of DT-SCBRBs tended to exhibit lower MaxISDRs but could sometimes lead to higher ResISDRs under major earthquakes. Low deformability of tendons could result in tendon fracture under major earthquakes. The ResISDRs of all the prototype frames were lower than 0.5 %, the drift limit for the “Repairable” performance level. Compared to minor and moderate earthquakes, the DT-SCBRB glulam frames deformed more uniformly during major earthquakes. Incremental dynamic analyses (IDAs) were also conducted on these prototype structures, developing a database to quantify performance levels of DT-SCBRB glulam frames. The MaxISDRs of 0.5 %, 0.7 %, and 2.6 % were recommended for immediate occupancy (IO), life safety (LS), and collapse prevention (CP) limit states of DT-SCBRB glulam frames.

Phonon Landau Quantization and Enhanced Lifetime in Deformed Graphene.

The pseudomagnetic field effect may offer unique opportunities for the emergence of intriguing phenomena. To date, investigations into pseudomagnetic field effects on phonons have been limited to sound waves in metamaterials. The revelation of this exotic effect on the atomic vibration of natural materials remains elusive. Our simulations of twisted graphene nanoribbons reveal well-defined Landau spectra and sublattice polarization of phonon states, mimicking the behavior of Dirac Fermions in magnetic fields. Both valley-specified helical edge currents and snake orbits are obtained. Analysis of dynamics indicates that phonon Landau states have extended lifetimes, which are crucial for the realization of Landau-level lasing. Our findings demonstrate the occurrence of the phonon pseudomagnetic field effect in natural materials, which has important implications for the mechanical tuning of phonon quantum states at the atomic scale.

Dynamical analysis and numerical treatment of pond pollution model endowed with Caputo fractional derivative using effective wavelets technique

Dynamical analysis and numerical treatment of pond pollution model endowed with Caputo fractional derivative using effective wavelets technique

Analysis of carrier dynamics and thermal effect of the GaAs photoconductive semiconductor switch in lock-on mode

Abstract The lock-on effect of the gallium arsenide photoconductive semiconductor switch (GaAs PCSS) at repetition rate aggravates the current crowding and electric field distortion, which significantly increases the risk of switch damage or even failure. Therefore, it is of great significance to investigate the carrier transport and the heat generation mechanism for improving the performance and longevity of GaAs PCSS in lock-on mode. The internal physical process of an opposed-electrode GaAs PCSS at low optical energy and strong electric field is analysed and discussed by experiment and simulation. A device-circuit hybrid simulation is employed to investigate the transient electric field, carrier concentration, and lattice temperature distribution within the GaAs PCSS in lock-on mode. The device temperature exhibits a positive correlation with the applied bias electric field, resulting in a peak temperature of 1037.25 K at an electric field of 38 kV/cm. The temperature distribution within the GaAs PCSS indicates a greater possibility for thermal breakdown and damage near the electrodes.

Modeling Aluminum Stocks and Flows in China until 2050 Using a Bottom-Up Approach: Business-As-Usual Scenario Analysis

Aluminum metal is used in a wide range of applications such as construction, transportation, power, and aerospace. Previous studies have mainly used a top-down approach to explore future aluminum stocks and flows in China. In this study, we developed a dynamic material flow analysis model using a bottom-up approach to simulate aluminum flows and stocks in China until 2050, based on current government and sector policies. The results show that China’s aluminum stocks will be nearly saturated by 2050, with a total and per capita of 591 million tons (Mt) and 449 kg/per, respectively. The domestic demand for aluminum will grow until 2030 and will remain relatively stable thereafter at around 28–30 Mt. Construction and transport are the two sectors with the highest demand for aluminum, accounting for over 60% of the total aluminum demand. The domestic aluminum scrap will increase almost sevenfold, from 2.7 Mt to 20.0 Mt between 2020 and 2050. However, even assuming a 90% recycling rate, secondary aluminum will at best meet around 70% of demand by 2050. To realize sustainable development in China’s aluminum industry, extending the life of aluminum products and increasing aluminum scrap recycling are sensible measures.

Killing two birds with one stone: gender diversity, information disclosures and financial distress

Purpose The escalating instances of financial distress (FD) in corporate houses across the globe, call for immediate attention from policymakers, practitioners and academics equally. This study aims to examine how board gender diversity (GD) and information disclosures (ID) interact with each other to drive FD. Design/methodology/approach The authors apply dynamic panel data analysis on a sample of 255 Indian-listed firms from 2016 to 2023 to arrive at the econometric results. Findings The main findings indicate that while ID exacerbates distress, GD reduces it. In addition, GD also interacts with ID to curtail the adverse effects of disclosures on FD. Therefore, GD acts like a stone that kills two birds simultaneously, first by reducing the distress directly and second by limiting the negative effects of disclosures on distress. Originality/value This study extends the understanding of the implications of GD and complements existing research by investigating its direct and indirect impact on FD. It builds on the analysis to propose that GD can foster resilience against adverse FD situations. The findings should apply to other emerging nations after careful consideration of country-specific factors.

Wall Shear Stress (WSS) Analysis in Atherosclerosis in Partial Ligated Apolipoprotein E Knockout Mouse Model through Computational Fluid Dynamics (CFD)

Atherosclerosis involves an inflammatory response due to plaque formation within the arteries, which can lead to ischemic stroke and heart disease. It is one of the leading causes of death worldwide, with various contributing factors such as hyperlipidemia, hypertension, obesity, diabetes, and smoking. Wall shear stress (WSS) is also known as a contributing factor of the formation of atherosclerotic plaques. Since the causes of atherosclerosis cannot be attributed to a single factor, clearly understanding the mechanisms and causes of its occurrence is crucial for preventing the disease and developing effective treatment strategies. To better understand atherosclerosis and define the correlation between various contributing factors, computational fluid dynamics (CFD) analysis is primarily used. CFD simulates WSS, the frictional force caused by blood flow on the vessel wall with various hemodynamic changes. Using apolipoprotein E knockout (ApoE-KO) mice subjected to partial ligation and a high-fat diet at 1-week, 2-week, and 4-week intervals as an atherosclerosis model, CFD analysis was conducted along with the reconstruction of carotid artery blood flow via magnetic resonance imaging (MRI) and compared to the inflammatory factors and pathological staining. In this experiment, a comparative analysis of the effects of high WSS and low WSS was conducted by comparing the standard deviation of time-averaged wall shear stress (TAWSS) at each point within the vessel wall. As a novel approach, the standard deviation of TAWSS within the vessel was analyzed with the staining results and pathological features. Since the onset of atherosclerosis cannot be explained by a single factor, the aim was to find the correlation between the thickness of atherosclerotic plaques and inflammatory factors through standard deviation analysis. As a result, the gap between low WSS and high WSS widened as the interval between weeks in the atherosclerosis mouse model increased. This finding not only linked the occurrence of atherosclerosis to WSS differences but also provided a connection to the causes of vulnerable plaques.

A nested non-intrusive stochastic isogeometric method for nonlinear thermal vibration of FGM plates under random loading

This paper introduces an adaptive nested non-invasive dynamic SIGA method based on RBFNN for the nonlinear thermal vibration analysis of FGM plates under random loading. This method is robust and accurate in high-dimensional input spaces regardless of the sample sequence, addresses the low convergence rate of QMCS, and solves the stochastic dynamic response probability density function under random loading. Firstly, the multidimensional input space for random loading is constructed based on several mutually independent random variables via the stationary Gaussian stochastic process simulation technique. The nonlinear FGM plate model subjected to random loading in the thermal environment is modeled using HSDT with von Kármán strain-displacement relation within the IGA framework. Subsequently, a nested non-invasive dynamic response surface analysis method, SIGA-RBFNN, is proposed based on the RBFNN technique. Analysis of the FGM plate response under random loading demonstrates that SIGA-RBFNN, compared to tensor-product-based SIGA methods, is less affected by sample sequence types. It effectively addresses high-dimensional stochasticity and offers significant advantages in robustness, accuracy, and efficiency. Finally, SIGA-RBFNN compensates for the low convergence speed of QMCS and successfully solves the FGM plate displacement response statistics and probability density function under random loading.

Cryptocurrencies under climate shocks: a dynamic network analysis of extreme risk spillovers

Systematic risks in cryptocurrency markets have recently increased and have been gaining a rising number of connections with economics and financial markets; however, in this area, climate shocks could be a new kind of impact factor. In this paper, a spillover network based on a time-varying parametric-vector autoregressive (TVP-VAR) model is constructed to measure overall cryptocurrency market extreme risks. Based on this, a second spillover network is proposed to assess the intensity of risk spillovers between extreme risks of cryptocurrency markets and uncertainties in climate conditions, economic policy, and global financial markets. The results show that extreme risks in cryptocurrency markets are highly sensitive to climate shocks, whereas uncertainties in the global financial market are the main transmitters. Dynamically, each spillover network is highly sensitive to emergent global extreme events, with a surge in overall risk exposure and risk spillovers between submarkets. Full consideration of overall market connectivity, including climate shocks, will provide a solid foundation for risk management in cryptocurrency markets.

3D printing food flow in different extruders based on crazy and adaptive salp swarm algorithm-deep extreme learning machine improved-lattice Boltzmann method

Extrusion is significant in achieving 3D printing emulsion. The piston and screw extruders are the common structures to achieve the extrusion. The chocolate emulsion is taken for example, two extruders are numerically investigated and compared based on the fluid dynamic analysis. To conduct the simulations, the crazy and adaptive salp swarm algorithm-deep extreme learning machine (CASSA-DELM) is proposed to predict the viscosity of the chocolate emulsion, which is used to replace the traditional fitted model. The built model can avoid non-consistency in the whole shearing rate range. Then, an improved lattice Boltzmann method (I-LBM) is introduced to process the non-Newtonian behavior of the emulsion. In the simulation, the CASSA-DELM model provides the viscosities for each iteration in I-LBM based on the obtained shearing rates. Because the attachment(s) may be generated on the walls, the no-attachment and with-attachment(s) cases are explored, and the necessary results are obtained, which indicate that the piston extruder is more suitable for extruding the single component of food fluid. The screw extruder is recommended for the multiple components of food fluid because the vortex in the X-Y cross-section contributes to further mixing action for the emulsion containing different materials, such as the investigated chocolate emulsion. The indirect experiments are conducted to validate the above conclusions. The current work can contribute to improving the extruding theory of material extrusion technologies.