Lateral Impact Research Articles

Dynamic behavior of bridge columns reinforced with shape memory alloy rebar and UHPFRC under lateral impact loads

This paper numerically evaluates the combined effect of ultra-high-performance fiber-reinforced concrete (UHPFRC) jacket and shape memory alloy (SMA) rebar on the dynamic response of a reduced-scale bridge pier under lateral impact loads of different velocities. The performance of the columns is assessed considering the variations of different parameters including the type of SMA rebars, thickness of UHPFRC jacket (tU), impact velocity (Vimp), and axial load ratio (ALR). From the FE simulations, it is found that the SMA rebars have a more positive influence on the lateral strength of the conventional columns with normal concrete (NC) compared to UHPFRC-strengthened columns when subjected to impact loadings at 5 m/s and 15 m/s velocities that represent relatively low- and medium-rate impacts, respectively. However, the positive effect of the SMA rebar is more pronounced on the resistance of UHPFRC-strengthened columns under a high-rate impact loading with Vimp = 25 m/s. In addition, a 60 mm-thick UHPFRC jacket is recognized as the optimal level based on the behavioral trend of the UHPFRC-strengthened columns when they are subjected to impact loads with velocities higher than 10 m/s (representing a medium-rate impact). From the evaluation of the effectiveness of ALR, an absolute positive influence of ALR on the impact resistance of the steel-reinforced columns is found when it ranges between 0.1 and 0.15. However, the increase of ALR beyond a critical value of 0.125 demonstrates a negative influence on the lateral strength of SMA-reinforced UHPFRC columns.

Mechanical energy dissipation due to the propagation of elastic waves during the lateral impact of elastic cylinders

The lateral impact between elastic cylinders is studied using two dynamic models. We propose an elementary example to justify the mechanical energy dissipation in a pure elastic contact and to define the parameters needed for its quantification. A finite element model is presented as the theoretical basis for the quantification of the mechanical energy dissipation produced by the propagation of elastic waves in continuous deformable impacting cylinders. The results are exploited to build an accurate and more numerically efficient dynamic lumped parameter model. The models are applied to the lateral impact of identical cylinders with various diameters and different impact speeds. The impact of the cylinders with a different mass and radius is also analyzed. The calculation of the coefficient of dissipation enables the global loss of mechanical energy to be quantified, and an equivalent damping ratio associated with the impact is calculated. The obtained damping values can be used as a reasonable underestimate of the dissipation produced in the engagement of spur gears, thus allowing a conservative prediction of the dynamic overloads of the system in resonant conditions.

Postural analysis of side impact WorldSID 50th ATD in highly reclined seats

Objective The anthropomorphic test device (ATD) used in NCAP frontal impact, the Thor 50th, has undergone substantial changes for safety restraint systems testing of upcoming autonomous vehicles (AVs), resulting in the Thor-AV 50 M. Likewise, a deep analysis of the ATD for lateral impacts, the WorldSID 50th, is needed to determine the requirements it has to fulfill to accurately replicate the human body response under lateral impact. This study sets out general considerations regarding the WorldSID 50th ATD design in order to assess its suitability for AV testing scenarios. Methods The WorldSID 50th ATD was placed in a driver seat at a conventional upright driving posture. Relevant body landmarks and angles as well as profile streams of the mockup and the ATD were recorded. The seatback was then reclined stepwise. The ATD was repositioned and the recording procedure repeated at every posture until the seatback was fully reclined. Examination of the ATD assemblies and hinge mechanisms was performed, searching for limitations that could result on inadequate positioning or performance under impact. An eventual SAEJ3016 Level 3 cross-legged posture (SAE J3016, 2021) was considered for examination as well. Results Most relevant anthropometric constraints were noticed at the abdomen and the shoulder and neck assemblies: At the abdomen, a gap between the pelvis and the lower torso appeared at seatback recline angles larger than 30°, likely promoting belt intrusion in case of a test event, and the lumbar spine rubber deformed progressively in a manner that might cause tearing damage. The number and arrangement of the shoulder clevis detents, on the other hand, did not allow the arm to be placed at intermediate positions. Finally, the current neck bracket design allowed head orientation only along the sagittal plane. The head could neither be level at seatback angles larger than 43° nor be placed resting on the head restraint for seatback angle values larger than 59°. Conclusions The WorldSID ATD stands as an accurate 50th percentile human being surrogate in upright and low/mid reclined postures. Some limitations that might constrain its use in AV scenarios, though, appeared at mid/high reclined positions. Hence, design updating of the lumbar, neck and shoulder clevis assemblies, and the implementation of instrumented lower abdomen and lower arms assemblies should be taken into consideration.

Numerical Simulation of Mechanical Coupling for Low-Back Booster with a 6-Year-Old Child during a Crash Test

This research assessed a mechanical coupling for the ISOFIX Child Restraint System using the Finite Element Method (FEM) in a critical condition (simultaneous frontal and lateral collision). The mechanism was designed according to the R129 standard, and it consists of a set of springs and dampers that allows displacements in the three Cartesian axes (x, y, z) to dissipate a portion of the energy produced by a traffic accident. Two case studies are presented. The first one evaluates the behavior of the mechanism by applying the equivalent weight of a child and the LBB during a frontal and lateral impact according to the FMVSS 213 standard. The second evaluates the injuries generated in the head, neck, and thorax with a six-year Hybrid III model during a frontal impact when implementing the coupling system. The outcomes show that both axes reach a maximum deceleration of 23 G, and it remains from 17 G to 21 G in 30 ms. After 65 ms, it decreases from 17 G to 0 G. Overall, the injury rates are compared when using mechanical coupling with LBB and only LBB to analyze the system’s efficiency, showing a significant reduction in head and neck injuries, obtaining a 24% variation in the HIC36, and reducing the neck range motion by 19.3°.

An integrated energy absorbing module for battery protection of electric vehicle under lateral pole impact

Nowadays, the importance of energy conservation and environmental sustainability issues has led to developments of environmentally friendly products like electric vehicles (EVs). The EVs are not already as widespread as internal combustion engine vehicles (ICEVs) and also the complicated inherent crash behaviour put their crashworthiness at the first development steps. However, besides the battery safety, other major issues such as corresponding vehicle crashworthiness as a consequence of engine and sub-related components elimination and also battery packaging should be addressed. Although before reaching a more specific crash limits for EVs safety evaluation test cases, one could use the ICEV’s conventional crash scenarios for the structural crashworthiness evaluations. In this article, the side pole impact as the severe load case according to ENCAP was introduced and protection of the battery pack is improved by implementing a novel energy absorber element into the body sill side. The analyses have performed based on validated computational simulations. The finite element model of the structure is prepared by ANSA and the simulations carried out via ABAQUS and the non-linear explicit finite element software of PAM-CARSH. The various assessment criteria such as pole intrusion, internal energy, section loads before and after the conversion are analysed in order to find an optimum configuration of the structure for battery protection. Obtained results show a significant enhancement in vehicle crashworthiness performance.

Development and Evaluation of Top-Mounted Sockets for Weak-Post, Midwest Guardrail System on Culverts

New top-mounted sockets for use with the weak-post, Midwest Guardrail System (MGS) on low-fill culverts were developed and evaluated. The system was adapted from the MGS bridge railing for attachment to the top slab of a concrete box culvert. Three design concepts were developed and evaluated through dynamic component testing. Both lateral and longitudinal impact tests were conducted on the design concepts while mounted to simulated concrete culverts. Two concepts, a cylindrical concrete foundation and a steel tube socket assembly, proved strong enough to withstand the impact loads transferred from the posts without sustaining significant damage or displacements. However, the third concept, a concrete slab, fractured and allowed the sockets to rotate back without developing the post bending strength. Thus, only the cylindrical concrete foundation and the steel tube socket assembly in combination with the weak-post, MGS were determined to be crashworthy according to the Manual for Assessing Safety Hardware (MASH) Test Level 3 safety criteria. The new top-mounted, socketed, weak-post, W-beam MGS for low-fill culverts has multiple advantages over other guardrail treatments for culverts. The guardrail system has an unrestricted system length and does not require a transition when attached to the MGS. The top-mounted system can be placed parallel to the roadway with a constant lateral offset regardless of the position and orientation of the culvert headwall. Additionally, the attachment configurations were designed utilizing epoxy anchors, enabling the system to be installed on new or existing culverts. Finally, the sockets remain undamaged during impact events, allowing for quick repairs.

Analysis of chest response characters for drivers in lateral and oblique automotive impact

Chest injury frequently occurs in oblique and side impacts. Apart from the loading of airbags and seatbelts, secondary impacts with door panels and armrests also cause severe chest injuries. This study aims to investigate the characteristics of the chest injury of occupants in the oblique and lateral impact. It focuses on the secondary impact between occupants and vehicle side structure. A model comprising GHBMC and components of Toyota Camry is established with acceleration curves. Combined with typical impact directions in NCAP tests, four sets of simulations are carried out. Results indicate that the maximum deflection occurs in oblique far-side impact, reaching 53 mm. Additionally, the maximum stress occurs in lateral near-side impact, reaching 259 MPa. In contrast, the stresses of far-side lateral and oblique impacts are only 2% and 3% smaller than the maximum one. Therefore, the occupant injury is serious in the far-side impact. Due to the lower lateral acceleration and the better seatbelt protection, the minimum deflection and stress are found in the near-side oblique impact. In conclusion, when the seatbelt can restrain the movement of the occupant during oblique and lateral impact, the injury level will be reduced. In addition, in the oblique and lateral impact simulations, the lowest rib stress exceeds the tolerance, while the highest chest deflection is still lower than the tolerance. This study provides a reference for the subsequent improvement of the restraint system.

A Study on the Buckling Stability due to Lateral Impact of Gas Pipe Installed on the Sea-bed

A Study on the Buckling Stability due to Lateral Impact of Gas Pipe Installed on the Sea-bed

Experimental study on dynamic response of 6082-T6 aluminum alloy circular tubes under lateral low-velocity impact loading

Aluminum alloy components have been increasingly used in spatial structures in recent years for their advantages of high strength to mass ratio, great corrosion resistance, and low environmental pollution. In this study, impact tests on the 6082-T6 aluminum tube with circular hollow section were carried out to reveal its dynamic response under lateral impact loading, considering the accidental impact or terrorist attack that the aluminum alloy spatial structures may suffer. Four failure modes were observed from the test results, including “three plastic hinges” mode, crack at the impact position, crack at the support, and fracture at the support. The impact process was divided into four stages for the aluminum tubes without fracture: initial collision, coupling deformation, global deformation, and elastic recovery stages. Meanwhile, three stages including initial collision, coupling deformation, and failure stages were identified for the fractured tubes. The impact force, displacement, and surface strain were recorded and discussed in detail. Moreover, the impact energy transmitted to the aluminum tube was calculated based on the test results to investigate the energy absorption process of the tube under lateral impact loading. Finally, the influence of geometric parameter (section size and span of the tube), impact energy (initial impact velocity and hammer weight), impact position, and hammer shape on the dynamic behavior of the aluminum tube under lateral impact loading was analyzed based on the impact test results.

The role of the default mode network in longitudinal functional brain reorganization of brain gliomas

The study of patients after glioma resection offers a unique opportunity to investigate brain reorganization. It is currently unknown how the whole-brain connectomic profile evolves longitudinally after surgical resection of a glioma and how this may be associated with tumor characteristics and cognitive outcome. In this longitudinal study, we investigate the impact of tumor lateralization and grade on functional connectivity (FC) in highly connected networks, or hubs, and cognitive performance. Twenty-eight patients (17 high-grade, 11 low-grade gliomas) underwent longitudinal pre/post-surgery resting-state fMRI scans and neuropsychological assessments (73 total measures). FC matrices were constructed considering as functional hubs the default mode (DMN) and fronto-parietal networks. No-hubs included primary sensory functional networks and any other no-hubs nodes. Both tumor hemisphere and grade affected brain reorganization post-resection. In right-hemisphere tumor patients, regardless of grade and relative to left-hemisphere gliomas, FC increased longitudinally after the intervention, both in terms of FC within hubs (phubs = 0.0004) and FC between hubs and no-hubs (phubs-no-hubs = 0.005). Regardless of tumor side, only lower-grade gliomas showed longitudinal FC increases relative to high-grade tumors within a precise hub network, the DMN. The neurocognitive profile was longitudinally associated with spatial features of the connectome, mainly within the DMN. We provide evidence that clinical glioma features, such as lateralization and grade, affect post-surgical longitudinal functional reorganization and cognitive recovery. The data suggest a possible role of the DMN in supporting cognition, providing useful information for prognostic prediction and surgical planning.

МОДЕЛЬ ОЦЕНКИ УСТОЙЧИВОСТИ ДВИЖЕНИЯ АВТОТРАНСПОРТНОГО ПОЕЗДА И РЕЗУЛЬТАТЫ ЕЕ АНАЛИЗА

Motor transport trains (MTT) – continue to be one of the main modes of transport in agriculture. However, their accident rate is quite high. Scientific studies of the process of movement of motor vehicles mainly provide for the improvement of their design characteristics and operating modes. The main way to reduce the accident rate of MTT is to limit the speed limit. There are ways to ensure the stability of the movement of MTT by changing the design of trailers. The purpose of the research is to analyze the mathematical model of the stability of the movement of the MTT to identify critical factors for its violation, optimize the design and operational parameters of the MTT, increase the predictability of the behavior of the MTT on the track (in the presence of lateral external influences: simulating sharp turns, displacement of cargo in the vehicle, etc.), formulating the main directions for improving its stability and manageability. We used the methods of analysis and synthesis, mathematical analysis, vector geometry. Lateral impact leads to an increase in the MTT momentum (lateral oscillations increase the speed), or to a violation of stability (movement amplitude beyond the track, overturning) of its movement. An increase in the momentum of the trailer reduces the overall stability of the MTT (the critical angle of displacement of the drawbar, at which the road train begins to “fold”, decreases by 9–56%). Increasing the momentum of the transport vehicle increases stability (the critical angle of displacement of the drawbar increases by 33–173%). The geometric dimensions of the drawbar and the trailer have little effect on the stability of the MTT. An increase in the length of the drawbar reduces stability (reduces the critical angle of its “folding”) by 5.5–14.7%. Increasing the length of the trailer increases stability: the critical angle of "folding" increases by 8–22%. Lateral displacement (“skidding”) of MTT elements on the track by more than 0.5–0.95 m will lead to its going beyond the boundaries of the safe transport corridor (driving out of the track), or increase the likelihood of a collision with oncoming vehicles

Dynamic Behavior of RC Columns Confined with Micro-Expansive Concrete-Filled Steel Tubes Subjected to Lateral Low-Velocity Impact: Experimental and Numerical Study

In order to improve the anti-collision capacity of existing reinforced concrete (RC) columns under vehicle impact load, an experimental study on the anti-collision performance of RC columns strengthened with micro-expansive concrete filled steel tube was carried out. By combining an experiment and finite element calculation, the influence of steel tube strength, micro-expansive concrete strength and steel tube wall thickness on the anti-collision performance of strengthened RC columns were studied. The results showed that the peak displacement of an SM-RC column is 25.9% lower than that of an RC column, due to the increased stiffness, the peak impact force increased by 138.2%. The micro-expansive concrete filled steel tube reinforcement method can significantly improve the anti-collision performance of RC columns and reduce the lateral deformation. Increasing the strength grade of steel tube and thickness of steel tube can greatly improve the impact resistance of strengthened RC columns and reduce the lateral deflection deformation of short columns, compared with steel tube strength Q235, the displacement of Q690 is reduced 47.4%. the displacement of the 8-mm thick steel tube is reduced by 48.1% compared with the 4-mm one. while the strength grade of micro-expansive concrete has little effect on the impact resistance and lateral deflection deformation of strengthened RC columns.

3D-SLIP model based dynamic stability strategy for legged robots with impact disturbance rejection

Inspired by biomechanical studies, the spring-loaded inverted pendulum model is an effective behavior model to describe the running movement of animals and legged robots in the sagittal plane. However, when confronted with external lateral disturbances, the model has to move out of the 2-D plane and be extended to 3-D locomotion. With the degree of freedom increasing, the computational complexity is higher and the real-time control is more and more difficult, especially when considering the complex legged model. Here, we construct a control strategy based on the classical Raibert controller for legged locomotion under lateral impact disturbances. This strategy, named 3D-HFC, is composed of three core modules: touchdown angle control, body attitude angle control and energy compensation. The energy loss in each step is taken into consideration, and the real-time measured energy loss of the current step is adopted to predict that of the next step. We demonstrate the efficiency of the proposed control strategy on a simulated 3D-SLIP lower order model and a simulated running quadruped, which are perturbed by different impact forces. Furthermore, a quadruped bionic prototype named MBBOT was set up, on which lateral impact experiments were designed and implemented. Both simulation and experimental results show that the proposed approach can realize the impact disturbance rejection.

A hierarchical kriging approach for multi-fidelity optimization of automotive crashworthiness problems

Multi-fidelity optimization schemes enriching expensive high-fidelity functions with cheap-to-evaluate low-fidelity functions have gained popularity in recent years. In the present work, an optimization scheme based on a hierarchical kriging is proposed for large-scale and highly non-linear crashworthiness problems. After comparison to other multi-fidelity techniques an infill criterion called variable-fidelity expected improvement is applied and evaluated. This is complemented by two innovative techniques, a new approach regarding initial sampling and a novel way to generate the low-fidelity model for crash problems are suggested. For the former, a modified Latin hypercube sampling, pushing samples more towards design space boundaries, increases the quality of sampling selection. For the latter, a projection-based non-intrusive model order reduction technique accelerates and simplifies the low-fidelity model evaluation. The proposed techniques are investigated with two application problems from the field of automotive crashworthiness—a size optimization problem for lateral impact and a shape optimization problem for frontal impact. The use of a multi-fidelity scheme compared to baseline single-fidelity optimization saves computational effort while keeping an acceptable level of accuracy. Both suggested modifications, independently and especially combined, increase computational performance and result quality in the presented examples.

Balance Control of a Quadruped Robot Based on Foot Fall Adjustment

To balance the diagonal gait of a quadruped robot, a dynamic balance control method is presented to improve the stability of the quadruped robot by adjusting its foot position. We set up a trunk-based coordinate system and a hip-based local coordinate system for the quadruped robot, established the kinematics equation of the robot, and designed a reasonable initial diagonal gait through the spring inverted pendulum model. The current trunk posture of the quadruped robot is obtained by collecting the data of its pitch and roll angle, and the foot position is predicted according to the current posture and initial gait of the quadruped robot. To reduce the impact of one leg landing on the ground and increase the stability of the quadruped robot, we adjust the landing point of the robot according to the landing time difference between the diagonal legs. The proposed method can adjust the body in such scenarios as planar walking and lateral impact resistance. It can reduce the disturbance during the robot motion and make the robot move smoothly. The validity of this method is verified by simulation experiments.

Clinical characteristics of adolescent nasal bone fractures.

BackgroundThere have been many reports of nasal bone fractures in adults, but there are few clinical reports of them in adolescents, although adolescence is the main growth period of the nasal bone. In addition, previous studies have tended to classify and describe child and adolescent nasal fractures in the same category. The aim of this study was to identify the clinical aspects of nasal fractures in adolescents, and to evaluate the characteristics of nasal fractures in the growth period.MethodsOur institution’s database was reviewed to extract data on adolescent patients between the age of 13 to 18 who had isolated nasal bone fractures from March 2012 to February 2020. The study excluded patients with other facial fractures, previous facial fractures, or congenital deformities.ResultsThis study included 243 boys and 26 girls. Interpersonal violence and sports-related accidents accounted for 85 and 79 cases, respectively. There were 128 frontal impact injuries and 132 lateral impact injuries, and 97 patients had accompanying septal fractures. An accompanying septal fracture was present in 36.06% of all patients, but in 51.20% of those who underwent surgery.ConclusionThe prevalence of adolescent nasal fractures was significantly higher in boys, to a greater extent than observed for pediatric or adult fractures. The main causes of fractures were interpersonal violence and sports-related accidents. An explanation for these results is that adolescent boys are more prone to have violent accidents or companionship with active sports than other age or sex groups, leading to substantially more fractures.

Effect of CFRP strengthening on response of RC columns to lateral static and impact loads

The paper presents results of an experimental study of twenty RC columns, with and without carbon fibre-reinforced polymer (CFRP) wrapping, subjected to the combined action of axial and transverse loads. To better understand how the rate of the transverse load application affects the behaviour of both unstrengthened and strengthened columns, half of the specimens were tested under transverse static loading, while the other half – under transverse impact loading. Six different configurations of CFRP layers were used to strengthen the specimens. The test results presented in the paper include the maximum transverse static and impact forces, load–deflection curves, time-histories of impact and reaction forces, deflections, strains, crack patterns and failure modes. Comparison between the results of the static and impact tests demonstrates that the resistance of the specimens to impact loading was significantly higher than that established in the case of static loading. The corresponding dynamic increase factor (DIF) had values mainly between 8 and 12. The results also show that CFRP strengthening can increase the resistance of RC columns to lateral static and impact loads. However, the increase depends strongly on the configuration of CFRP layers.

Lateralization in feeding is food type specific and impacts feeding success in wild birds.

Current research suggests that hemispheric lateralization has significant fitness consequences. Foraging, as a basic survival function, is a perfect research model to test the fitness impact of lateralization. However, our understanding of lateralized feeding behavior is based predominantly on laboratory studies, while the evidence from wild animals in natural settings is limited. Here we studied visual lateralization in yellow‐footed green pigeons (Treron phoenicoptera) feeding in the wild. We aimed to test whether different types of food objects requiring different searching strategies elicit different eye/hemisphere biases. When feeding on relatively large, uniformly colored food objects (mahua flowers) which can be present or absent in the viewed patch, the majority of pigeons relied mostly on the left eye–right hemisphere. In contrast, when feeding on smaller and more abundant food objects, with color cues signaling its ripeness (sacred figs), right‐eye (left‐hemisphere) preference prevailed. Our results demonstrate that oppositely directed visual biases previously found in different experimental tasks occur in natural feeding situations in the form of lateralized viewing strategies specific for different types of food. The results suggest that pigeons rely on the hemisphere providing more advantages for the consumption of the particular type of food objects, implying the relevance of brain lateralization as a plastic adaptation to ecological demands. We assessed the success of food discrimination and consumption to examine the link between lateralization and cognitive performance. The use of the preferred eye resulted in better discrimination of food items. Discrimination accuracy and feeding efficiency were significantly higher in lateralized individuals. The results showed that visual lateralization impacted pigeons’ feeding success, implicating important fitness benefits associated with lateralization.

The Effect of Strengthening Methods on the Performance of Reinforced Concrete Columns against Vehicle Impact

Columns at the ground floor and parking garages that could be hit by a car pose a significant risk to the structural stability of the building superstructures. Generally, these columns are not built to sustain the lateral impact force generated by car–column collision. In this study, the performance of axially loaded retrofitted reinforced concrete (RC) columns against car impact is evaluated using finite element (FE) simulation. The FE model of the RC column with axial load was validated with experimental results. For the car-crushing simulations, two SUV car models with a mass of about 2250 kg, which had been experimentally validated, were used to simulate the car–column collision. The results of the FE analysis revealed that once the impact speed exceeds 30 km/h, the horizontal impact force has a significant effect on the column joint at the foundation. The impact force increases linearly as the impact velocity of the car increases up to 20 km/h. When car impact velocities are more than 20 km/h, the generated impact force increases in power to the car-crashing velocity. Both types of cars have almost the same effect on the generation of impact force and the lateral displacement of the column. It is found that the generated impact forces are higher than the recommended design values of Eurocode 1. To protect the column from car impact damage, two types of column-strengthening systems were investigated. One form of strengthening system involves retrofitting the lower half of the column with an aramid fiber-reinforced polymer (AFRP) warp, while the other involves putting a reinforced concrete jacket of up to 1.3 m in the height of the column. Based on the comparative study, design recommendations are suggested to protect the RC column from accidental car-crashing damage.

Analytical Analysis: Hybrid Triple Skin Stainless Steel Tubular Columns Filled with Uhpfrcand Externally Gfrp-Jacketed Under Lateral Impact Load

Analytical Analysis: Hybrid Triple Skin Stainless Steel Tubular Columns Filled with Uhpfrcand Externally Gfrp-Jacketed Under Lateral Impact Load