High-speed Collision Research Articles

Emergency Cricothyrotomy in a 51-Year-Old Woman with Traumatic Airway Obstruction After a High-Speed Collision

Emergency Cricothyrotomy in a 51-Year-Old Woman with Traumatic Airway Obstruction After a High-Speed Collision

Development of an epoxy-metallic powder sublayer for the cold spray metallization of carbon-fiber reinforced thermoset composites

This paper investigates the development of a composite sublayer for the cold spray metallization of carbon-fiber reinforced thermoset composites. The hybrid sublayer/carbon-fiber reinforced structure is prepared using a vacuum assisted infusion process. The sublayer consists of a mixture of epoxy with micron-sized metallic powder particles and is directly embedded onto the carbon-fiber reinforced structure during the infusion process. During the cold spray metallization, the erosion of this biphasic sublayer has the capability to produce a metal-to-metal bonding between the cold sprayed powder particles and the sublayer powder particles. The mechanical response of the sublayer due to the high-speed collision of the cold spray powder is investigated using a computational analysis. A decohesion at the epoxy/metallic particle interface within the sublayer, along with the fragmentation of the epoxy matrix upon impact, eases an erosion that prevents the coating formation onto the sublayer. The erosion/coating formation strongly depends on the mechanical property of the spray powder compared to the powder of the sublayer. In the case of a sublayer made of soft metal particles, the plastic deformation during the high-speed collision is better absorbed by such a biphasic sublayer. This circumstance is conducive to an adhesion of the sprayed particles onto the sublayer despite an occurrence of an erosion. Thus, the cold spray deposition of Cu powder onto a biphasic epoxy/Al sublayer results in deposit formation, with Cu particles bonding to Al particles and anchoring to the epoxy matrix.

Exploration of Quantum Chemistry Methods to Explain Mechanism of Mechanochemical Degradation of Typical Organic Pollutants.

The high-efficiency ball milling treatment technology primarily combines the excitation of oxidation processes with high-speed physical collisions, thereby promoting the reaction processes and enhancing the degradation effectiveness of materials. This technology has gained widespread attention in recent years for its application in the degradation of organic solid chemical pollutants. In this study, quantum chemical density functional theory (DFT) was employed to first analyze the impact of electron addition and subtraction on molecular chemical bonds. The molecular energies of the target pollutants and their possible intermediates were then calculated, and the theoretical energies required for the degradation pathways of the target organic compounds under oxidative-enhanced ball milling were computed. This further validated the accuracy of the ball milling experimental results. The theoretical energy required for the complete mineralization of solid organic chemicals through ball milling degradation was calculated, with values of 16,730.74 kJ/mol for lindane, 20,162.46 kJ/mol for tetrabromobisphenol A, 10,628.04 kJ/mol for sulfamethoxazole, and 4867.99 kJ/mol for trimethoprim. By combining different ball milling experimental conditions, the theoretical reaction time required for the complete mineralization of the target organic chemicals can be calculated. The comparison of theoretical calculations with the experimental results provides new insights into the ball milling degradation process and degradation pathways of the target pollutants.

Study on Collision Dynamics Similarity of Thickness Distortion Model of Train Five-Hole Thin-Walled Structure

Full-scale train collision tests are rarely carried out because of high cost, but small-scale model tests have good economy and repeatability, providing a new research method for train crashworthiness design. The metal thin-walled tube is a commonly used energy-absorbing structure for trains. Its collision characteristics directly affect the impact resistance and collision behavior evolution process of trains. This paper studies the collision dynamics similarity of the small-scale model of a five-hole thin-walled energy-absorbing structure at the end of a high-speed train. Firstly, the dynamic mechanical behavior and governing equations of high-speed train collision were analyzed, and the applicable similarity criterion was derived by similarity transformation to develop a similarity scale model. According to the simulation, the energy absorption, peak force and other key responses of the full-scale prototype collision were analyzed. Then, the applicability of the thickness distortion scale model of the five-hole energy-absorbing structure in the high-speed train was proved by equation analysis and error analysis. The impact dynamic responses of the complete similarity model and the distortion similarity model were discussed. A correction program with collision deceleration as the dependent variable was proposed for the distortion similarity model, and the fitting relationship between the distortion factor and the correction factor was obtained. The results calculated by the proposed method prove that the peak force-deformation-energy absorption error of the thickness distortion similarity model in predicting the dynamic responses of the prototype collision is less than 8%, which means the thickness distortion scale model has good accuracy in the prediction of full-scale prototype collision dynamics responses.

A young female patient with severe traumatic hemifacial degloving avulsion injury successfully managed with reconstruction and full thickness skin graft: case report

Introduction and importance: Road traffic accidents can result in severe ocular injuries, jeopardizing vision. High-speed collisions may lead to facial avulsion and degloving injuries, which pose risks such as airway compromise, bleeding, soft tissue loss, disfigurement, and post-traumatic impairments that necessitate prompt reconstruction. Case presentation: A 24-year-old woman sustained injuries in a motorcycle accident, which resulted in a left hemifacial avulsion, a degloving injury, and the loss of her left brow. Additionally, she lost the lower eyelid on the left side and a portion of the left maxilla near the medial canthus. Despite these injuries, the movements of her left eye remained normal. Clinical discussion: The primary objectives of periorbital reconstruction are to restore the patient’s vision with minimal discomfort while ensuring stable coverage for orbital protection and achieving functional reconstruction of the defect. Although there are various surgical reconstruction techniques available, skin grafting and regional flap reconstruction methods are the most commonly employed. Conclusion: The patient expressed satisfaction with the outcome and reported improved social comfort. After a one-year follow-up, both the patient’s facial functions and vision were found to be normal.

Non-instrumented management of traumatic atlanto-axial rotatory subluxation: surgical technique.

Atlantoaxial rotatory subluxation (AARS) in the adult population is primarily trauma-induced. Conservative and surgical treatments have both been used successfully in treating AARS. In cases where AARS cannot be reduced by conservative measures, open reduction and fusion is the conventional treatment approach. This report details a novel approach for treating adult AARS, where an open reduction was performed without instrumentation or fusion. The patient, a 48-year-old female involved in a high-speed vehicular collision, initially underwent conservative treatment with Gardner Wells Tongs and manual traction. Despite these efforts, X-ray and computed tomography (CT) scans indicated persistent subluxation. Subsequently, the patient was taken to the operating room, where successful open reduction was achieved without the need for fusion or instrumentation. Preoperative imaging revealed rotatory subluxation of C1-2 with a comminuted and displaced fracture of the right C1-2 facet joint and a nondisplaced fracture of the base of the occiput. The surgical technique involved precise manual manipulation using a Cloward spreader and real-time assessment with O-arm 3D X-ray tomography to ensure successful reduction. The absence of significant laxity or instability during intraoperative testing led to the conclusion that fusion was unnecessary. This approach minimizes invasive tissue dissection and preserves natural cervical range of motion (ROM). Postoperatively, the patient was asymptomatic with no joint instability and demonstrated satisfactory alignment at follow-up.

An Image Simulator of Lunar Far-Side Impact Flashes Captured from the Earth-Moon L2 Point

Impact flashes on the moon are caused by high-speed collisions of celestial bodies with the lunar surface. The study of the impacts is critical for exploring the evolutionary history and formation of the Moon, and for quantifying the risk posed by the impacts to future human activity. Although the impacts have been monitored from the Earth by a few projects in past 20 years, the events occurring on the lunar far side have not been explored systematically so far. We here present an end-to-end image simulator dedicated to detecting and monitoring the impacts from space, which is useful for future mission design. The simulator is designed for modularity and developed in the Python environment, which is mainly composed of four components: the flash temporal radiation, the background emission, the telescope and the detector used to collect and measure the radiation. Briefly speaking, with a set of input parameters, the simulator calculates the flash radiation in the context of the spherical droplet model and the background emission from the lunar surface. The resulting images are then generated by the simulator after considering a series observational effects, including the stray light, transmission of the instrument, point spread function and multiple kinds of noise caused by a CCD/CMOS detector. The simulator is validated by comparing the calculation with the observations taken on the ground. The modular design enables the simulator to be improved and enhanced by including more complex physical models in the future, and to be flexible for other future space missions.

Endovascular Management of Aortic Rupture Secondary to Thoracolumbar Spine Fracture From a Domestic Fall: A Case Report and Clinical Challenges.

Instances of aortic lesions combined with thoracolumbar spine fractures have been rarely described, primarily occurring in high-speed motor vehicle collisions and falls from heights. We present a unique case of a 71-year-old woman with a thoracic aortic rupture caused by a thoracolumbar spine fracture during an accidental domestic fall. She experienced an injury at the level of the celiac trunk on the posterior aspect of the aorta. Hemorrhagic shock and profound hemodynamic instability prompted the swift initiation of a percutaneous endovascular approach, involving the use of REBOA (Resuscitative Endovascular Balloon Occlusion of the Aorta) followed by the parallel graft technique in a sandwich configuration. Subsequently, thoracolumbar spinal fixation was carefully scheduled and performed 20 days after achieving clinical stabilization. This case underscores the importance of a multidisciplinary approach in managing complex aortic and spinal injuries. The combined use of REBOA and the sandwich graft technique can be life-saving in managing acute thoracic aortic injuries, allowing for the staged stabilization and repair of associated spinal fractures. This case highlights a novel approach to managing a rare thoracic aortic rupture caused by an accidental domestic fall. The application of REBOA for immediate hemodynamic stabilization, combined with the use of a sandwich graft configuration, underscores the adaptability of advanced endovascular techniques in complex, life-threatening situations. These interventions demonstrate the importance of tailoring treatment strategies to individual patient needs, especially in cases involving atypical mechanisms of injury. The findings emphasize the value of early multidisciplinary collaboration and dynamic procedural planning, paving the way for improved outcomes and the refinement of clinical protocols in the management of similar trauma cases.

Multimodal flexible electronic skin with adjustable module size for robot collision detection

Purpose This paper aims to present a modular multimodal flexible electronic skin that can be used for robot collision detection in human–robot interactions. This type of electronic skin will meet the requirements of performance indicators such as sensing mode, sensing domain coverage and dynamic data update rate in human–robot interactions. Design/methodology/approach The electronic skin uses a modular architecture, and the sensing module is designed to be adjustable in size so that it can be easily deployed on complex robot surfaces, increasing area coverage, reducing power consumption, and improving data update rates. Findings The authors evaluated electronic skin through experiments using a UR5 robot. Electronic skin has high static scene perception differentiation and dynamic scene perception abilities. Moreover, the robot realizes a high-speed collision response based on the electronic skin proposed in this study. Originality/value The proposed electronic skin provides crucial technical support for advancing robotic technologies, and holds promising prospects for industrial applications.

Novel Use of Obsidio Conformable Embolic in Thoracic Duct Embolization

AbstractChylothorax is a potentially serious condition resulting from thoracic duct injury. When chyle output remains high despite medical management, invasive interventions such as surgical ligation or percutaneous thoracic duct embolization (TDE) may be necessary. Obsidio is a novel conformable embolic agent that shares properties of both coil and liquid embolic agents. A 37-year-old man presented with left-sided chylothorax, refractory to medical management, following a high-speed motorcycle collision. The thoracic duct was successfully embolized using Obsidio placed between coil packs with fibered coils. This case report demonstrates the first successful use of Obsidio for TDE in a patient with traumatic chylothorax.

The study of the calculation method of the triboelectric rate of particles and surface materials at different collision velocities

In this paper, a triboelectric rate calculation model based on the relative collision velocity between the material and the particle is put forward. The model demonstrates distinct trends of the triboelectrification rate's increase with velocity, ranging from a 9/5 power to a linear function increase. Meanwhile, a test system is devised to simulate the high-speed collision process between ions and materials, and the derived model is validated through experiments.

Discrete element method simulation of high-speed vehicle collisions with road barrier systems

AbstractThe behavior of road or perimeter protection barriers under vehicle impact are usually investigated based on crash tests and finite element (FE) numerical approaches, which are ether expensive or time-consuming. Several studies have proposed to reduce the computation time of the numerical analysis by substituting the complex FE models of vehicles using simplified mass–spring–damper system models. However, these models have drawbacks since consideration of different vehicle impact angles is difficult and they are unable to correctly simulate the risk of high-speed vehicle collision running over the barrier. In this paper, a new approach is proposed to simulate the collision of vehicles with barriers based on the discrete element method (DEM). Here, to save computation time only a handful of 3D non-spherical particles are used to represent the barrier and vehicle. These particles are generated based on the super-quadric function, which is capable of generating a variety of shapes needed for the model. The contact detection and evaluation are carried out based on discrete function representation of the particles with uniform sampling. The bond between two discrete elements is defined using a nonlinear cohesive beam model since the distance between the elements is relatively large. The simulation results obtained based on this approach are more accurate and complete than the simplified mass–spring models and computationally more efficient than the FE model.

Atomistic simulation on the deposition behavior of cold spray

Cold spray is an effective method for surface coating, which has been applied in various engineering areas. However, it is difficult to directly observe the dynamic deformation process in experiments. This paper applies the molecular dynamics simulation to model the deposition of a monocrystalline Cu particle onto a Cu substrate and, subsequently, carries out a systematic study on the deposition mechanism and microstructure evolution. The results indicate that the deposition process consists of an impact stage and a relaxation stage. It is mainly the high speed collision and the friction following the collision that lead to particle deposition, which, under different circumstances, can be defined as surface deposition or penetration deposition. Two methods, namely, drastic shear deformation and cooling in the relaxation stage, can help form nanocrystallines. Jetting and melting are not the necessary factors for the deposition of nano-sized particles. The formation of dislocation lines is influenced by impact velocities. At lower impact velocities, the dislocation lines are mainly distributed near the contact surface. However, when the impact velocity is higher, dislocation lines are almost uniformly distributed in the particle.

Resilience of DNA chains to molecular fracture after PCR heating cycles and implications on PCR reliability.

Soon after its introduction in 1987, polymerase chain reaction (PCR) has become a technique widely employed in diagnostic medical devices and forensic science with the intention of amplifying genetic information. PCR prescribes that each of its cycles must include a heating subprocess at 95 °C or more (denominated DNA denaturation and provided for allowing a claimed orderly separation of the two complementary nucleotides strands), which can produce significant damage to DNA, caused by high-speed collisions with surrounding molecules. Since such disruption should be prevented in order to reliably employ PCR, a study of the mechanics of such loss of structural integrity is herein presented, preceded by a review of the fundamental literature which has elucidated the effects of molecular agitation on DNA fragmentation. The main conclusion of this retrospective survey is that the body of examined theoretical and experimental evidence consistently and redundantly confirms scarce resilience and significant loss of structural integrity when DNA is heated at temperatures above 90 °C, even for 1minute. Such conclusion contradicts the claimed paradigm of PCR fidelity and raises the concern that, at least for long sequences, if PCR can amplify some information, such amplified information may be unreliable for diagnostic or forensic applications, since it originates from sequences of nucleotides subjected to random fragmentation and reaggregation. Such a low-reliability scenario should be preventively considered in the various fields where DNA amplification methodologies are employed which provide for high-temperature heating under conditions equal to or similar to those prescribed by the PCR protocols reviewed in this study.

Meniscus Injuries in Soccer.

Soccer is considered the most popular sport in the world. The game involves frequent agile maneuvers, such as rapid accelerations/decelerations and pivoting, and carries an inherent risk of high-speed collisions, which can lead to lower extremity injury. Knee and meniscus injuries can cause significant pain and disability, precluding participation in the sport. Understanding the diagnosis and management of meniscal injuries in soccer players is essential to the care of these athletes. This paper reviews meniscal anatomy, biomechanics, and mechanisms of injury; discusses the work-up, diagnosis, and management of meniscus injuries; and reports on rehabilitation, return to sport, and outcomes after meniscal injuries in soccer players.

Dynamic deformation behavior of Fe-0.22C-1.65Si-1.98Mn quenching and partitioning steel over a wide range of strain rates and constitutive model establishment

During traffic accidents, automobiles often experience rapid deformation at high strain rates spanning from 10² to 10³ s⁻¹. The dynamic deformation behavior and the constitutive model of the materials are crucial for precisely analyzing and simulating vehicle collisions and damage. This study focuses on a high-strength quenching-partitioning steel (Q&P steel) compositionally tailored for automotive applications, specifically Fe-0.22C-1.65Si-1.98Mn. Tensile tests were conducted under quasi-static (10⁻⁴–10⁻¹ s⁻¹) and dynamic (1–10³ s⁻¹) conditions to obtain stress-strain data, based on which the deformation behavior and instability mechanism of the Q&P steel were revealed. A Johnson-Cook (J-C) constitutive model was established to predict the stress-strain behavior. This model was further improved by incorporating the nonlinear influence of strain rate on stress, resulting in a significant reduction of prediction error by 60.9 % in the high strain rate range. Based on the modified J-C model, the finite element simulations of the high-speed collision for U-shaped and tubular components were conducted. The simulations exhibit excellent agreement with experimental results, thus confirming the accuracy of the model in predicting high-speed deformation behavior of the Q&P steel. This validation enables precise simulations of dynamic collision characteristics and energy absorption.

Head injury mechanisms of the occupant under high-speed train rear-end collision

To improve the passive safety of high-speed trains, it is very important to understand the mechanism of head injury in high-speed train collisions. In this study, the head injury mechanisms of occupants in high-speed train rear-end collisions were investigated based on the occupant-seat coupling model, which included a dummy representing the Chinese 50th percentile adult male. The typical injury responses in terms of skull fractures, brain contusions, and diffuse axonal injury (DAI) were analyzed. Meanwhile, the influences of collision speed and seat parameters on head injury response were examined. The simulation results indicate that the skull fractures primarily occur at the skull base region due to excessive neck extension, while the brain contusions and DAI result from the relative displacement of different brain regions. The increase in collision speed will promote the probability of skull fracture, brain contusion, and DAI. Seat design modifications, such as reduced seat spacing, increased seat backrest angles, and selecting the appropriate cushion angle (76°) and friction coefficient (0.15), can effectively mitigate probably occupant's head injury.

Iliac transposition technique for reconstruction of aortic bifurcation in pediatric blunt abdominal aortic injury

Blunt abdominal aortic injuries, especially in pediatric patients, represents a rare and critical challenge. We report a unique case of a 10-year-old boy who presented after a high-speed motor vehicle collision resulting in injury to the aortic bifurcation, alongside other intra-abdominal trauma. A novel surgical approach for aortoiliac reconstruction in a contaminated field was used. This technique consisted of the mobilization of the distal aorta and common iliac arteries, ligation of right internal iliac artery, and creation of aortoiliac and common to internal iliac artery anastomoses. This method demonstrates a potentially lifesaving technique in select patients.

Implementation of three-dimensional contact algorithm in numerical manifold method for the structural impact simulation

Structural impact often accompanies large amounts of contacts and leads to complex mechanical phenomena. In solid mechanics, the numerical manifold method (NMM) is proposed to address problems featuring continuous-discontinuous transitions by utilizing a dual coverage system encompassing both mathematical and physical covers. In the present work, a penalty contact algorithm for 3DNMM based on cover-based contact theory is programmed and applied to impact mechanics problems. The accuracy of the developed contact algorithm is firstly calibrated through free-falling blocks and collision blocks. The influence of contact parameters on contact convergence is systematically studied, and three preliminary criteria for how to set contact parameters are provided. The effectiveness of the contact algorithm is verified by conserving system momentum during block collisions. Subsequently, the contact algorithm is applied to Taylor rod and car-streetlight impact simulation, further confirming its effectiveness in modeling high-speed collisions, large displacements, and large deformations of structures. By comparing the 3DNMM results with those from Abaqus, the contact algorithm developed here performs exceptionally well in solving collision problems and produces results consistent with commercial software. The research results in the present work verify the applicability and accuracy of the proposed contact algorithm in solving structural dynamic impact problems. The present work also provides guidance for contact parameter setting in impact problems.

On the Ion Implantation Synthesis of Ag-Embedded Over Sr-Substituted Hydroxyapatite on a Nano-Topography Patterned Ti for Application in Acetabular Fracture Sites.

There is an ongoing need for improved healing response and expedited osseointegration on the Ti implants in acetabular fracture sites. To achieve adequate bonding and mechanical stability between the implant surface and the acetabular fracture, a new coating technology must be developed to promote bone integration and prevent bacterial growth. A cylindrical Ti substrate mounted on a rotating specimen holder was used to implant Ca2+, P2+, and Sr2+ ions at energies of 100 KeV, 75 KeV and 180 KeV, respectively, using a low-energy accelerator to synthesize strontium-substituted hydroxyapatite at varying conditions. Ag2+ ions of energy 100 KeV were subsequently implanted on the as-formed surface at the near-surface region to provide anti-bacterial properties to the as-formed specimen. The properties of the as-formed ion-implanted specimen were compared with the SrHA-Ag synthesized specimens by cathodic deposition and low-temperature high-speed collision technique. The adhesion strength of the ion-implanted specimen was 43 ± 2.3 MPa, which is well above the ASTM standard for Ca-P coating on Ti. Live/dead cell analysis showed higher osteoblast activity on the ion-implanted specimen than the other two. Ag in the SrHA implanted Ti by ion implantation process showed superior antibacterial activity. In the ion implantation technique, nano-topography patterned surfaces are not concealed after implantation, and their efficacy in interacting with the osteoblasts is retained. Although all three studies examined the antibacterial effects of Ag2+ ions and the ability to promote bone tissue formation by MC3T3-E1 cells on SrHA-Ag/Ti surfaces, ion implantation techniques demonstrated superior ability. The synthesized specimen can be used as an effective implant in acetabular fracture sites based on their mechanical and biological properties.