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Background: Biomechanical research on the lumbar intervertebral disc (IVD) provides valuable information for the diagnosis, treatment, and prevention of related diseases, and has received increasing attention. Using bibliometric methods and visualization techniques, this study investigates for the first time the research status and development trends in this field, with the aim of providing guidance and support for subsequent research.Methods: The Science Citation Index Expanded (SCI-Expanded) within the Web of Science Core Collection (WoSCC) database was used as the data source to select literature published from 2003 to 2022 related to biomechanical research on lumbar IVD. VOSviewer 1.6.19 and CiteSpace 6.2.R2 visualization software, as well as the online analysis platform of literature metrology, were utilized to generate scientific knowledge maps for visual display and data analysis.Results: The United States is the most productive country in this field, with the Ulm University making the largest contribution. Wilke HJ is both the most prolific author and one of the highly cited authors, while Adams MA is the most cited author. Spine, J Biomech, Eur Spine J, Spine J, and Clin Biomech are not only the journals with the highest number of publications, but also highly cited journals. The main research topics in this field include constructing and validating three-dimensional (3D) finite element model (FEM) of lumbar spine, measuring intradiscal pressure, exploring the biomechanical effects and related risk factors of lumbar disc degeneration, studying the mechanical responses to different torque load combinations, and classifying lumbar disc degeneration based on magnetic resonance images (MRI), which are also the hot research themes in recent years.Conclusion: This study systematically reviews the knowledge system and development trends in the field of biomechanics of lumbar IVD, providing valuable references for further research. [ABSTRACT FROM AUTHOR]

Of the 604,485 bridges in the United States, approximately 21% are culverts having a span of 6 m (20 ft) or greater. The load rating of typical bridges presents numerous challenges. Developing load ratings for non-typical structures, such as buried arch-shaped culverts is more complex because of the culverts' unique geometric configuration and their interaction with soil media. This paper proposes an alternative analytical method for load rating in-service reinforced concrete (RC) arch culverts that overcomes the limitations of the widely used elastic frame concept while being straightforward to implement. The proposed analytical method uses two-dimensional finite element models of the arch structure and surrounding soil media. The finite element model was first validated against experimental tests on a full-scale RC arch culvert, subjected to simulated live loads. The validated FE model was used in load rating analysis of 21 RC arch culverts with large fills. It was found that for arch culverts with fills exceeding 2.43 m (8 ft.), the controlling actions are bending moments at the crown and haunch. For culverts with fills greater than 3.05 m (10 ft.), live load effects become negligible. A revised rating formula is proposed for culverts with this characteristic. [ABSTRACT FROM AUTHOR]

Recent severe ice storms across the United States severely damaged trees resulting in extensive electrical power outages. Furthermore, trees and branches can fall on nearby roads, blocking traffic flow and reducing the safety of drivers. In this study, trees subjected to ice loads were analyzed using the finite element method and Monte Carlo simulation to develop analytical fragility curves. Two-dimensional, fractal trees were constructed with randomly generated geometric and mechanical parameters for four deciduous tree species: Acer saccharum, Tilia americana, Fagus grandifolia, and Quercus alba. Two load case scenarios were considered – with and without the effects of leaves – which were then subjected to varying ice accumulation thicknesses. The resulting fragility curves suggest that leaves have a substantial impact on tree branch damage under ice loads, which is significant because of the increase in unseasonably early ice storms due to climate change. [ABSTRACT FROM AUTHOR]

• A splitting resistance equation was proposed for highly prestressed UHPC girders. Ultra-high performance concrete (UHPC) has gained popularity gradually because of its superior mechanical properties, including high compressive and tensile strengths, and exceptional durability. Many researchers have explored the possibility of using long, precast prestressed UHPC girders in buildings and bridges. To do so, the girders generally require a large number of prestressing strands, which causes concern about potential cracking in the end zones at prestress release. Currently, there are no specifications or codes on end zone designs for precast prestressed UHPC girders in the United States. Thus, this paper presents an analytical study that explores highly prestressed UHPC girders' end zone behavior. Finite element analyses were conducted to analyze the end zones of a series of UHPC girders, including one 889-mm-deep and two 813-mm-deep I-girders, and the analysis results were validated with test data. Additional finite element models were developed for other girders with heights of 1,829 mm and 2,743 mm using various reinforcement details. Bursting stress variations in the reinforcement and UHPC were reported based upon the analytical and test results. An equation for splitting resistance attributable to the reinforcement and UHPC was proposed for highly prestressed girders. [ABSTRACT FROM AUTHOR]

In the context of green aviation, as an internationally recognized solution, hydrogen energy is lauded as the "ultimate energy source of the 21st century", with zero emissions at the source. Developed economies with aviation industries, such as Europe and the United States, have announced hydrogen energy aviation development plans successively. The study and development of high-energy hydrogen fuel cells and hydrogen energy power systems have become some of the future aviation research focal points. As a crucial component of hydrogen energy storage and delivery, the design and development of a safe, lightweight, and efficient hydrogen storage structure have drawn increasing consideration. Using a hydrogen-powered Unmanned Aerial Vehicle (UAV) as the subject of this article, the crash characteristics of the UAV's hydrogen storage structure are investigated in detail. The main research findings are summarized as follows: (1) A series of crash characteristics analyses of the hydrogen storage structure of a hydrogen-powered UAV were conducted, and the Finite Element Analysis (FEA) response of the structure under different impact angles, internal pressures, and impact speeds was obtained and analyzed. (2) When the deformation of the hydrogen storage structure exceeds 50 mm, and the strain exceeds 0.8, an initial crack will appear at this part of the hydrogen storage structure. The emergency release valve should respond immediately to release the gas inside the tank to avoid further damage. (3) Impact angle and initial internal pressure are the main factors affecting the formation of initial cracks. [ABSTRACT FROM AUTHOR]

In this study, a full-scale test on the bending performance of concrete sandwich laminated floor slabs with integrated thermal and sound insulation was carried out, and the effects of different reinforcement ratios on the bending performance of concrete sandwich laminated floor slabs were investigated as well as the variation law of the failure modes, characteristic loads, load-mid span deflection, load-rebar strain curves, and anti-slip performance. The results indicate that the concrete sandwich laminated floor slabs present typical bending failure characteristics. According to bending failure characteristics, the damage process can be divided into three stages, i.e., elasticity, cracking, and failure. The bearing capacity significantly increases with the increase in reinforcement ratio. The normal service, yield, and ultimate loads of bearing capacity of the floor slabs with a larger reinforcement ratio increase by 54.55%, 52.94%, and 46.46%, respectively. Moreover, the mid-span deflection decreases significantly with the increase in reinforcement ratio, and the cracking expansion is also delayed. Before cracking, the prefabricated layer and laminated layer can realize load bearing together, and the floor slab is in a state of complete interaction. When the floor slabs reach the ultimate state, the superimposed surface produces a sliding effect, and the floor slab is in a state of partial interaction. The finite element analysis software ABAQUS (with the version number of ABAQUS 2020, the chief creator of David Hibbitt, and the sourced location of the United States) was used to perform nonlinear numerical simulation. The test results accord well with the simulation results, which verifies the correctness of the finite element model. Based on finite element simulation, the influence of post-cast concrete strength on the ultimate load can be ignored. [ABSTRACT FROM AUTHOR]

The Hybrid III 50th percentile (H350) Anthropomorphic Test Devices (ATD) is the most widely used crash test dummy to identify the best seatbelt and airbags configuration for frontal impact load cases. However, the H350 was developed based on the United States (US) anthropometric size, back in 1976. In other words, the restraint system optimized using the H350 is not optimized for other popula- tions. To investigate this issue, a finite element model of Hybrid III 50th percentile (H350M) of Malaysian population was developed and analysed in this work. Validation of the new biofidelity corridors was performed to ensure that this newly crash test dummy can represent the population under consideration. In this study, the H350M was integrated into a finite element vehicle model, to simulate a frontal rigid barrier crash load case performed at 56 km/h and compared with the existing H350. The H350 integrated vehicle-occupant simulation model has been correlated with a physical test. The model managed to achieve the average Correlation and Analysis (CORA) rating of 0.722. The simulation results showed that the newly H350M experienced a higher head acceleration, Head Injury Criterion (HIC15), 3 ms chest acceleration and chest displacement compared to the H350, as they were increased from 64.3 g to 70.6 g, 370 to 542, 49.6 g to 52.6 g, and from 26.5 mm to 26.6 mm, respectively. Generally, higher head acceleration, HIC15 and chest dis- placement lead to higher injuries during frontal crash accidents. Hence, the recommendations to reduce injuries are also discussed and explored in this study. [ABSTRACT FROM AUTHOR]