Vehicle Safety Research Articles

Effects of wind barriers on the aerodynamic forces and driving safety of vehicles on a wide bridge girder at various angles of attack

This paper presents the effects of angles of attack (AOA) on the windproof effect of wind barriers and the driving safety of highway vehicles on a wide bridge girder. The aerodynamic force coefficients of the vehicles were obtained using the force measurement technique. Computational fluid dynamics simulations were employed to investigate the mean wind velocity field on the upper surface of the girder. A comparison was made between the aerodynamic forces on a vehicle at various AOA on a bridge deck with guardrails and a deck with wind barriers. The windproof effect of wind barriers at various AOA was accessed by the safety factor of a vehicle. The results showed that the maximum of the aerodynamic forces of vehicles was not typically observed at a 0° AOA. The windproof effect of wind barriers became more pronounced as the magnitude of the AOA increased. As AOA increases, the height of the low wind velocity zone above the deck shows an upward trend. Compared to the deck with the guardrails, the height of the low wind velocity zone was much higher in the presence of wind barriers. The increase in the height of the low wind velocity zone will result in a decrease in the aerodynamic side force and an increase in the rolling moment acting on vehicles. It is also noteworthy that the installation of wind barriers can cause a reduction of overturning and side-slip safety factors of vehicles at specific AOA. This suggests that the wind barrier may potentially compromise driving safety at specific AOA.

Dynamic characteristics and damage identification with interface damage of slabs in movable point crossing

As the operating density of China’s high-speed railway increases, the phenomenon of interlayer debonding in movable point crossing (MPC) is becoming more prevalent, which can lead to failure of the frog’s slab track. Meanwhile, vehicle impacts and interlayer debonding can exacerbate abnormal vibration of the vehicle and even lead to derailment. Therefore, based on the theory of rigid-flexible coupling dynamics, a vehicle-turnout-slab coupling dynamics model is established for the first time. In this model, the crossing rails with variable cross sections is considered and the interlayer debonding between turnout slabs is modelled by nonlinear springs. Then, the characteristics of the debonding is identified by applying a wavelet transform to the dynamic response of the vehicle. Finally, different types and sizes of debonding between the layers are considered. The results show that different debonding can lead to two types of contact, partial contact and complete voiding, which can further lead to detrimental effects on vehicle safety. And the limit of the defect size that causes the track slab to void is 1 mm. On this basis, it was found that when MPC’s slab tracks were voided, longer debonding can cause high frequency vibration acceleration of approximately 700 Hz in the vehicle axle box. The new insights obtained by this study could provide guidance for the maintenance period and avoid the development of the damage. This study not only obtained a mechanism for the effect of interlayer debonding on the dynamic response of the vehicle-track system, but also provides a theoretical basis of detecting interlayer debonding for future study.

Cooperative control of multi-vehicle formation based on cooperative game

In this paper, an optimization decision-making method of vehicle fleet queue based on game theory is proposed. By adopting the upper and lower controller structure, the longitudinal motion stability problem of the vehicle fleet is solved. The upper controller utilizes a game control algorithm specially developed for this study. The game payoff function is constructed by considering real-time vehicle information and comprehensively evaluating factors such as expected distance, vehicle safety, and stability. The optimal expected acceleration of the vehicle is determined. Subsequently, the lower controller adjusts the engine throttle opening or brake pressure to regulate the vehicle operation according to the desired acceleration. Simulation results show that the designed game strategy can effectively reduce vehicle spacing and speed errors, thus significantly improving the stability as well as safety of fleet operation.

Handover management in vehicle communication: applications, techniques, issues, and challenges: a review

Vehicle-to-everything (V2X) communication is an emerging technology that facilitates communication among vehicles and numerous environmental entities. However, it encounters certain challenges throughout the handover process. This study analyses the challenges and complexity of managing handover, specifically in maintaining uninterrupted connection and meeting the service criteria outlined in the 3GPP 5G new radio (NR) standard. Various applications of V2X technology that require handover management are explored, such as vehicle safety and traffic management, enhanced driver assistance, and autonomous driving. Furthermore, this paper illuminates the most recent developments in V2X communication, highlighting the significance of efficient handover management, resolving technical issues, based on the full potential of the use of V2X apps that contribute to the establishment of a transportation ecosystem that is characterized by enhanced safety, increased intelligence, and improved connectivity. This paper can be used as a starting point for thinking about how to improve C-V2X communication.

BRAKE SHOE OVERHEAT INDICATION SYSTEM FOR HEAVY VEHICLES IN HILL STATIONS USING THERMOCOUPLE AND ARDUINO

This paper introduces a novel Brake Shoe Overheat Indication System designed to enhance the safety of heavy vehicles operating in hill stations. The system utilizes a combination of thermocouples and Arduino microcontroller to monitor and indicate brake shoe temperatures. A threshold temperature of 300 degrees Celsius is set, and the system provides visual indications through green and red lights along with an audible alarm, thereby preventing accidents due to brake overheating.

Effects of impedance-boundary-controlled casing treatment on the fan performance with eccentric inlet swirl

An eccentric inlet swirl, a source of circumferential non-uniformity in aero-engines, can compromise the stable operational range of the compression system and potentially jeopardize the safety of the entire flight vehicle. This study experimentally examined the additional effects of an eccentric inlet swirl on an axial fan in comparison with a concentric inlet condition. Then, the effectiveness of an impedance-boundary-controlled (IBC) casing treatment (CT) in extending the stable operating range of the fan under eccentric inlets is evaluated. Steady-state loading and prestall disturbance analyses were conducted using a five-hole probe and high-frequency response pressure transducers to elucidate the instability mechanisms of fans exposed to eccentric inlets. The findings indicate that the eccentric swirl generates localized over-loading regions around the circumference, where abnormal prestall disturbances amplify in amplitude across a frequency range of 0.3 to 0.5 times the blade passing frequency. These characteristics were mitigated when IBC CT was applied over the rotor tip, allowing the fan to operate under concentric inlet conditions. The IBC CT enhances the stall margin of the fan by 9.3–19.6% in response to a range of swirl inlet conditions, suggesting its potential to address the irregularity problems in fans/compressors. The mechanisms by which IBC CT extends the stall margin are discussed from the unique perspective of evaluating steady loading and system damping.

Safety and Efficacy of Low-Dose CD19-Targeted CAR T Cells in Refractory Pediatric Systemic Lupus Erythematosus (SLE)

Safety and Efficacy of Low-Dose CD19-Targeted CAR T Cells in Refractory Pediatric Systemic Lupus Erythematosus (SLE)

Safe and potent anti-CD19 CAR T-cells with shRNA-IL-6 gene silencing element in patients with refractory or relapsed B-cell acute lymphoblastic leukemia.

Severe cytokine release syndrome (sCRS) and immune effector cell-associated neurotoxicity syndrome (ICANS) have limited the widespread use of chimeric antigen receptor T (CAR T)-cell therapy. We designed a novel anti-CD19 CAR (ssCART-19) with a small hairpin RNA (shRNA) element to silence the interleukin-6 (IL-6) gene, hypothesizing it could reduce sCRS and ICANS by alleviating monocyte activation and proinflammatory cytokine release. In a post hoc analysis of two clinical trials, we compared ssCART-19 with common CAR T-cells (cCART-19) in relapsed/refractory B-cell acute lymphoblastic leukemia (r/r B-ALL). Among 87 patients, 47 received ssCART-19 and 40 received cCART-19. Grade ≥3 CRS occurred in 14.89% (7/47) of the ssCART-19 group versus 37.5% (15/40) in the cCART-19 group (p = 0.036). ICANS occurred in 4.26% (2/47) of the ssCART-19 group (all grade 1) compared to 15% (2/40) of the cCART-19 group. Patients in the ssCART-19 group showed comparable rates of treatment response (calculated with rates of complete remission and incomplete hematological recovery) were 91.49% (43/47) for ssCART-19 and 85% (34/40) for cCART-19 (p = 0.999). With a median follow-up of 21.9 months, cumulative nonrelapse mortality was 10.4% for ssCART-19 and 13.6% for cCART-19 (p = 0.33). Median overall survival was 37.17 months for ssCART-19 and 32.93 months for cCART-19 (p = 0.40). Median progression-free survival was 24.17 months for ssCART-19 and 9.33 months for cCART-19 (p = 0.23). These data support the safety and efficacy of ssCART-19 for r/r B-ALL, suggesting its potential as a promising therapy.

Analysis of Vibration Characteristics of Cryogenic Insulated Cylinders Based on ANSYS

Abstract To ensure the safety of vehicle mounted cryogenic insulated cylinders during transportation, a finite element model for analyzing the vibration characteristics of vertical cryogenic insulated cylinders considering the frame was established based on ANSYS. The vibration characteristics of vertical cryogenic insulated cylinders under no-load conditions were studied, and the natural frequency patterns of cylinders under different filling rates were compared. The results showed that the connection between the bottom head of the inner liner and the cylinder, the operating frame, and the root of the bottom support were the locations where resonance occurs with larger amplitude. As the filling rate increased, the natural frequencies of each order of the cylinder decreased, and the maximum vibration amplitude of the inner cylinder decreased.

Dynamic compressive behavior of functionally graded triply periodic minimal surface meta-structures

Triply periodic minimal surface (TPMS) lattice structures have gained considerable attention because of their light weight, high strength, and excellent energy absorption capabilities. However, the effect of the amplitude that can control the topological morphology of a TPMS on the dynamic properties of the TPMS structure is not yet fully understood, as previous studies have focused on the relative density and size as well as their quasi-static mechanical properties. In this study, three types of uniform sheet-based TPMS structures with different amplitudes and three types of functionally graded sheet-based TPMS structures were proposed. Experiments and numerical simulations were conducted under quasi-static and dynamic loading conditions. Six types of TPMS lattice structures made of 316L stainless steel were manufactured via powder bed fusion. Quasi-static compression tests were performed at a strain rate of 0.001 s⁻¹. The experimental results indicate that increasing the amplitude can increase the elastic modulus, plateau stress, and energy absorption capacity of a structure. Moreover, the functional gradient amplitude structure has a higher energy absorption capacity, and the structures with line and log gradient strategies improved by 17.38% and 35.43%, respectively, compared to the uniform structure with an amplitude of 1. Additionally, an idealized rigid-linear plastic hardening (R-LPH) model was proposed to predict the mechanical response of the structures. The finite element method (FEM) was used to construct dynamic compression numerical models, and their validity was verified through split Hopkinson pressure bar (SHPB) tests at a strain rate of 695 s⁻¹. The mechanical response, deformation modes, and stress enhancement effects of the structures under dynamic compression were systematically studied. The results show that the mechanical performance and energy absorption capacity of the structures under dynamic impact loading increase with increasing strain rate. The critical velocity for the transition from the quasi-static mode to the impact mode increases with amplitude. For strain rates below 6000 s⁻¹, the strain rate effect is the main factor influencing the dynamic stress enhancement. As the strain rate continues to increase, the dynamic stress enhancement results from the combined effects of inertia and strain rate, with inertia effects gradually becoming the dominant factor. This study shows that functional gradient TPMS meta-structures have excellent mechanical and energy absorbing properties under quasi-static compression and dynamic compression, with potential applications in passive safety protection.

Public Support for a Safe System Approach to Reducing Motor Vehicle Crashes Deaths in the United States

Conventional road safety strategies are yielding diminishing returns. The Safe System approach is based on the premise that human errors will occur on the roadway and that the system should be designed to accommodate these errors, so they do not result in death or serious injury. Elements of the system include the roadway infrastructure, vehicle engineering, and speed management.Political support for U.S. Safe System implementation gained momentum with $5 billion in appropriated funds in the 2021 Bipartisan Infrastructure Law. The purpose of this study was to measure public support for Safe System implementation. We fielded a nationally representative survey of US adults from May 4 to June 10, 2022 (N=2,274). We measured whether respondents considered individual- or systems-oriented approaches as the most effective way to prevent traffic deaths. We also assessed support for various roadway interventions and vehicle safety technologies. Most respondents agreed that system-level changes were the most effective way to prevent traffic deaths. Endorsement for system-level changes was significantly higher among younger age groups. Support for roadway improvements and vehicle safety technologies varied according to the type of intervention that was proposed. Public support for a Safe System approach is high, particularly among younger adults, which suggests that the momentum for the movement can be sustained over the long term.

Precharge switch based on metal–oxide–semiconductor‐controlled thyristor for power relay assembly of battery electric vehicles

AbstractThe power relay assembly (PRA) is an essential component to ensure the safety of an electric vehicle. We propose a semiconductor‐based precharge switch to overcome the shortcomings of the conventional mechanical relay, which is currently used as the precharge switch in the PRA. The gate‐driving circuit uses a photocoupler instead of a gate‐driving integrated circuit to reduce complexity and cost. Five devices, namely, two insulated‐gate bipolar transistors (IGBTs), two silicon carbide metal–oxide–semiconductor field‐effect transistors (SiC MOSFETs), and one metal–oxide–semiconductor‐controlled thyristor (MCT) are tested as candidate precharge switches. Each device is analyzed under varying battery voltage and fixed measurement conditions. The IGBT and SiC MOSFET burn below 600 V, while the MCT exhibits normal operation up to 800 V. The MCT precharge switch can solve shortcomings of the conventional mechanical relay and increase the performance with a simple gate‐driving circuit. Furthermore, the PRA with an MCT precharge switch can reduce the volume, weight, and cost while improving reliability.

Optimal design and control strategy for enhanced battery thermal management

The Battery Thermal Management System (BTMS) plays a crucial role in the safety and performance of new energy vehicles. This study proposes an innovative cooling structure design that ingeniously combines the advantages of air cooling, water cooling, and Phase Change Materials (PCMs) to enhance the cooling efficiency of the battery system. Through numerical simulations, the effectiveness of this cooling system was validated and further supported by experimental evidence confirming the accuracy of the simulation results. Subsequently, this research utilized the Response Surface Methodology (RSM) to optimize key parameters of the cooling structure, including the fin height, gap length, and PCM thickness, with their optimal values determined to be 5.20 mm, 17.69 mm, and 3.38 mm, respectively. This parameter optimization work provides precise guidance for the design of battery thermal management systems, contributing to enhanced heat dissipation performance. To further enhance the intelligence of battery thermal management, this study introduced a novel neural network model based on Temporal Convolutional Networks (TCN) and Bidirectional Long Short-Term Memory (BiLSTM) with Multi-Head Attention (MHA). This model is capable of predicting temperature changes during the battery discharge process in real-time with high accuracy. Based on the prediction results, this research designed an efficient control strategy that, compared to a scenario without a control strategy, demonstrated a reduction in energy consumption by 20.87 %, a decrease in maximum temperature by 2.52 K, and a reduction in the maximum temperature difference by 0.05 K. These results not only prove the effectiveness of the control strategy but also provide a new direction for the optimization of battery thermal management systems.

Research on improving the safety of new energy vehicles exploits vehicle operating data

New energy vehicles (NEV), a four-wheel vehicle that employs non-traditional fuels, develops rapidly, lacking in research and application on vehicle operating data mining to improve the safety status of NEV. In this study, the method to improve the safety of new energy vehicles through vehicle operating data was researched systematically. First, known combustion accidents of NEV were counted from multiple dimensions to present the current safety situation. Subsequently, the study delves deeper into the specific causes of combustion in battery electric vehicles with lithium-ion batteries by examining parameter trends and performance discrepancies. Then, a novel approach for detecting abnormal self-discharge in power battery cells using operational data was proposed. This method aids in the early diagnosis of abnormalities and has been successfully utilized to issue advance warnings for vehicles exhibiting such issues. In conclusion, the study offers strategic recommendations for digital interventions by regulatory bodies and manufacturers. These recommendations aim to foster a robust and sustainable NEV industry, prioritizing safety and fostering innovation.

Multi-fault diagnosis of lithium battery packs based on comprehensive analysis of locally weighted Manhattan distance and voltage ratio

The diagnosis of faults in lithium-ion battery packs is pivotal to ensuring the operational safety of electric vehicles. A fault diagnosis method is introduced to address the lack of a discharge phase and the existence of a single fault type in traditional diagnostic methods. This method relies on a comprehensive assessment involving locally weighted Manhattan distance and voltage ratio anomalies. The KD-Tree-MLLE dimensionality reduction technique is utilized for fast data processing, which improves the computational efficiency by 1.3 % compared to the original MLLE algorithm. The fault detection method utilizing locally weighted Manhattan distance can meet the same threshold evaluation criteria as the charging phase. This approach resolves the constraint of a single phase and accomplishes comprehensive fault detection. The precision and efficacy of the methodology are confirmed through F1-score evaluation. Accuracy and recall rates are compared under varying thresholds during the charging and discharging phases to determine the optimal threshold value. The ratio between the voltage data of the defective battery and the average voltage data of the normal batteries is calculated, and the comprehensive anomaly analysis method based on the voltage ratio and temperature is proposed. The use of comprehensive data such as voltage ratio and temperature to judge the type of fault can simultaneously achieve the judgment of a single fault and mixed fault types. The applicability of locally weighted Manhattan distance under dynamic circumstances and the efficacy of the voltage ratio analysis method across charging and discharging phases are confirmed through the establishment of an experimental and simulation platform dedicated to lithium-ion batteries. Findings indicate that all faults in both phases can be accurately located when the threshold is set to 0.17. This affirms the superior accuracy of the proposed method in detecting and localizing individual faults and combinations of faults quickly and reliably.

Vienna road crashes: a multivariate approach to understanding driver-related risks

Road safety is worldwide researched field where crashes play a causal role and injuries are counted as outcomes. Approaches and techniques are diverse, but with same goal—contribute to safer road environment for everyone included. Drivers of personal vehicles are the most protected traffic group due to protection provided by vehicle and mandatory safety belt in comparison to pedestrians as the most venerable participants. Also, this group of drivers is characterized by the high presence of very young drivers whose psychological characteristics place them in a vulnerable risky subgroup. According to the original data of the traffic police on crashes of personal car drivers in the town of Vienna, since 2010 they have had the highest number of crashes in 2012 and after slow decrease is recorded. Still high in total number of crashes involving only drivers of personal vehicles from a traffic safety point of view this still represents an extremely worrying problem that has not received proper social attention. In response to knowledge gaps, this research is essential to address leading characterizations in crashes with aim to answer what is trend in crash occurrence during 2010–2020 inside Vienna municipality, and what is predicted trend. Is there significant and distinctive difference based on gender and age with conditions under which crashes are occurring influencing different injury degree. Multiple regression undoubtedly points fields for action in statistically based findings providing the most important answer to this research: why there are so many injuries and what is leading cause of them. Answering this question contributes toward higher safety environment for all participants.

Application of neural networks specific forms for estimation of crushing signal parameters of multilevel structural absorbers implemented in passive safety research

In case of classic thin-walled energy absorber the energy dissipation is not sufficiently controlled during a collision. A significant part of the columns does not participate in plastic deformation sufficiently. This is due to a lack of proper crush initiators for the formation of subsequent joints. The research problem of the article is to presents a method of applying artificial intelligence methods for determining the optimal parameters of crush initiators, in order to make proper use of plastic deformation zones and improve the efficiency of energy absorption. The methodology is based on the artificial neural network models made possible to select the best and optimal design parameters of multilevel crush initiators. The results of numerical tests were verified on the test bench. The values of all crashworthiness indicators improved, the PCF has been reduced up to 30% from for certain geometric parameters of the multilevel crush initiator.

Sinding-Larsen-Johansson disease. Clinical features, imaging findings, conservative treatments and research perspectives: a scoping review.

This review aims to consolidate existing research on the pathogenesis, clinical diagnosis, imaging outcomes, and conservative treatments of Sinding-Larsen-Johansson disease (SLJD), identifying literature gaps. Scoping Review. A comprehensive literature search was conducted across databases including PubMed, Scopus, Medline OVID, Embase, Web of Science, and Grey literature following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) extension for scoping reviews. The quality of included studies was assessed using the Joanna Briggs Institute (JBI) checklist. The body of evidence on SLJD, primarily derived from case studies, reveals limited and often conflicting data. Key findings include: (1) SLJD commonly presents as localized knee pain in physically active adolescents, particularly males, (2) ultrasound and MRI are the most effective diagnostic tools, (3) conservative treatment, which mainly focuses on activity limitation, yields positive outcomes within two to eight months. Our review shows that SLJD mainly affects physically active adolescents aged 9-17 years. The authors recommend conservative treatment, rest and/or cryotherapy, passive mobilization, muscle restraint, isometric exercise, and NSAIDs. Further cohort studies are necessary to refine the management and application of the SLJD treatment database.

GNSS/INS integrated navigation algorithm framework based on cascade vector tracking algorithm for USV

The safety of Unmanned Surface Vehicle during the autonomous phase of navigation relies heavily on the onboard navigation equipment. However, in the face of changing and diverse navigation environments, global satellite navigation systems utilizing radio communication often face signal occlusions. This significantly reduces the positioning accuracy of navigation systems. To ensure the navigation accuracy of vehicles in various harsh environments, a Global Navigation Satellite Systems and Inertial Navigation System (GNSS/INS) integrated navigation system structure based on cascaded vector-tracking loop is proposed in this paper. The integrated navigation scheme not only improved the positioning accuracy of the navigation system but also effectively improved the robustness of the system. Compared with the traditional scalar-tracking loop and vector-tracking loop methods, it exhibits better performance. The experimental results show that the proposed method can reduce the horizontal position positioning error by 73.7% compared with the traditional vector-tracking loop method in the case of signal occlusion. Simultaneously, it can continuously output reliable and high-precision positioning information in the case of serious signal occlusion. The integrated navigation scheme proposed in this paper can be used as a research direction for the development of Unmanned Surface Vehicle navigation applications and provides solutions for the development of related navigation systems.

Bond between alkali-activated steel slag/fly ash lightweight mortar and concrete substrates: Strength and microscopic interactions

The fire-retardant lightweight mortar spalling from the tunnel lining substrates can threaten the safety of vehicles. The use of steel slag (SS) in alkali-activated cement can reduce the carbon emission and cost of lightweight mortar. The effects of SS on the bond strength and the microstructure of the interface between alkali-activated SS/fly ash (FA) lightweight mortar (ASFm) and concrete substrates was studied. The SS contents, namely, the mass ratio of SS to the summation of FA and SS, were 0 %, 20 %, 40 %, 60 %, and 80 %. The properties of ASFm, including compressive strength, fire resistance and bond strength, were studied. Results demonstrated that the bond strength of ASFm increases and then decreases with the increase in SS content. The highest bond strength of 0.65 MPa was obtained at 40 % SS content. Bond strength was determined by the pore structure and micromechanical properties of the matrix. When the SS content was increased from 0 % to 40 %, the content of C-A-S-H gel and C-N-A-S-H gel contents increased, and the porosity was reduced; hence, the bond strength of ASFm became larger. When the SS content increased from 40 % to 80 %, SS acted as an inhibitor, which reduced the micromechanical properties and increased the porosity of ASFm; therefore, the bond strength of ASFm decreased. This achievement provides an alternative way for the application of SS in tunnels.