High Impact Energy Research Articles

Use of Polymeric Energy Absorption Liners to Improve the Concrete Rock Fall Barriers

In this study, usability of polymer foam coatings on impact surfaces of concrete rock fall barriers to increase the energy absorption capacity performances was investigated with a series of experimental studies. For this purpose, impact tests were carried out on different concrete block samples within the laboratory tests. According to the results, it was determined that the displacement values of the barrier blocks due to the impact effect can be significantly reduced by using polymer energy absorption liners. Additionally, cracks and failures of the concrete block bodies resulting from high impact energies can be prevented by the polymer energy absorption liners. It was assessed that a polyurethane based thermoset foam coating with a density of 60 kg/m3 can economically and remarkably improve the concrete barriers against impact loads. Keywords: Concrete barriers; Energy absorption capacity; Rock fall barriers; Rock falls.

Effectiveness of Banana Trunk as Protection Wall from High Velocity Shrapnel During Detonation of Unexploded Ordnance (UXO)

This paper is to investigate banana trunk fibre to be constructed alternatively for the sand bag and high energy absorption. The aim of this study also for enhancing method of absorption velocity shrapnel during detonated of Unexploded Ordnance (UXO), Explosive Remnants of War (ERW) and Improvise Explosive Device (IED). The study involved blast test which is providing high energy impact based on the amount of explosive used. Type of explosive were used are Emulex 180 with velocity of detonation 4500m/s to 5700m/s, Explosive energy 4.17 MJ/kg, density 1.13g/cc to 1.21g/cc and initiation were used are No. 8 Detonator. The structure of specimen is analysed using Stereo Microscope Image Analyser (35x zoom) which is an optical instrument that can observe the structure of the fragments (banana fibre) after blast test. Results shows that banana trunk can become a protection wall as it can absorb the impact of blast from explosion.

Free Vibrations and Impact Resistance of a Functionally Graded Honeycomb Sandwich Plate

The functionally graded honeycomb has the characteristic of light weight, low density, high impact resistance, noise reduction, and energy absorption as a kind of new composite inhomogeneous materials. It has the advantages of both functionally graded materials and honeycombs. In this paper, a functionally graded honeycomb sandwich plate with functionally graded distributed along the thickness of the plate is constructed. The equivalent elastic parameters of the functionally graded honeycomb core are given. Based on Reddy’s higher-order shear deformation theory (HSDT) and Hamilton’s principle, the governing partial differential equation of motion is derived under four simply supported boundary conditions. The natural frequencies of the graded honeycomb sandwich plate are obtained by both the Navier method from the governing equation and the finite element model. The results obtained by the two methods are consistent. Based on this, the effects of parameters and graded on the natural frequencies of the functionally graded honeycomb sandwich plate are studied. Finally, the dynamic responses of the functionally graded honeycomb sandwich plate under low-speed impacts are studied. The results obtained in this paper will provide a theoretical basis for further study of the complex dynamics of functionally graded honeycomb structures.

Research on the Response Characteristics of Bio-Inspired Composite Sandwich Structure under Low Velocity Impact

In order to research the impact mechanical response characteristics of the bio-inspired composite sandwich structure, the hemispherical impactor is preloaded with different energy to impact bio-inspired and conventional composite sandwich structure, the stress distribution and dynamic response characteristics of composite sandwich structure under impact load are studied. The results show that the main damage of the upper panel is fiber shear fracture, while crushing fracture for the core, and the main damage of the lower panel is fiber tensile tearing under different impact load. The bio-inspired composite sandwich structure shows better impact resistance in terms of damage depth and maximum impact load under the same impact energy. From the perspective of energy consumption, the bio-inspired structure absorbed more energy than conventional structure under high energy impact.

MECHANICAL CHARACTERISTICS FOR COMPOSITE MATERIALS USING COMMERCIAL EPOXY RESINS AND DIFFERENT FILLERS

Epoxy resins are thermoset polymers that consist of epoxide groups in their molecular structure. It shows many attractive characteristics like strong adhesion, excellent mechanical strength, low shrinkage, excellent insulator, excellent chemical stability for acidic and basic environments, and microbial resistance due to the presence of hydroxyl groups and ether bonds and its three-dimensional structure. Many of these characteristics can be modified by adding strong bindings in the polymeric chain to give more improved characteristics. This research aims to prepare a composite material using epoxy resin and different types of fillers to achieve resistance to high kinetic energy impact. Experimental work is focused on preparing cured epoxy resin samples by using diglycidyl ether of bisphenol A (DGEBA) resin with tertiary amine as a hardener. In order to obtain different samples with different properties, we add different types of fillers, then mechanical tests are used to measure the mechanical properties of the samples. The results have proved that fiberglass is the best filler added to epoxy resins to improve its mechanical properties.

Laser-assisted preparation of highly-efficient photocatalytic nanomaterial based on bismuth silicate

Having a wide range of applications, bismuth silicate-based materials (BSO) attract attention of numerous researchers. Typically, they are synthesized either from active chemicals or through high-energy impact on their precursors. The present work is the first report on BSO-based nanomaterials prepared via laser processing in liquid phase in which the following two-step scheme was realized: (1) Individual colloids of Bi- and Si-based nanoparticles were obtained via ablating their metallic targets in distilled water and then mixed; (2) Post-treatment of the mixed colloid was performed with the same laser beam as in stage (1). The products obtained after drying of non-treated and post-treated mixed colloids (denoted as samples BSO and BSO_hν, respectively) were carefully characterized using a set of microscopic, spectroscopic and electrochemical analyses, after which their photocatalytic performance in presence of model organic dye (rhodamine B) and phenol was tested. The additional laser treatment was found to lead to active interaction between Bi- and Si-containing species and stimulated formation of phases with Bi-O-Si bonds. The post-irradiated sample BSO_hν showed improved stability and catalytic performance, thus opening avenues for wider use of laser processing in liquids as a method allowing for preparation of nanostructures with complex chemical composition.

Modification of SiO2, ZnO, Fe2O3 and TiN Films by Electronic Excitation under High Energy Ion Impact

It has been known that the modification of non-metallic solid materials (oxides, nitrides, etc.), e.g., the formation of tracks, sputtering representing atomic displacement near the surface and lattice disordering are induced by electronic excitation under high-energy ion impact. We have investigated lattice disordering by the X-ray diffraction (XRD) of SiO2, ZnO, Fe2O3 and TiN films and have also measured the sputtering yields of TiN for a comparison of lattice disordering with sputtering. We find that both the degradation of the XRD intensity per unit ion fluence and the sputtering yields follow the power-law of the electronic stopping power and that these exponents are larger than unity. The exponents for the XRD degradation and sputtering are found to be comparable. These results imply that similar mechanisms are responsible for the lattice disordering and electronic sputtering. A mechanism of electron–lattice coupling, i.e., the energy transfer from the electronic system into the lattice, is discussed based on a crude estimation of atomic displacement due to Coulomb repulsion during the short neutralization time (~fs) in the ionized region. The bandgap scheme or exciton model is examined.

A multilevel noncontiguous spinal fracture with cervical and thoracic spinal cord injury.

Introduction and importanceA multi-level non-contiguous spinal fracture (MNSF) caused by a high-energy impact is a type of complex traumatic injury that is been frequently initially missed, and resulting in delayed diagnosis which adversely affects can result in spinal deformity and neurological deficit. This report describes the operative management of a patient with MNSF with spinal cord injury involving the cervical and thoracic vertebrae by cervical orthosis and posterior thoracic decompression and fusion.Case presentationAn 18-year-old male presented with extensive neck pain and paraplegia (ASIA A), following a motor vehicle accident. Radiographic imaging revealed MNSF: a non-displaced spinous process fracture of C5 (AO Spine subaxial cervical injury classification A0) with spinal cord injury combined with fracture-dislocation of T5 to T9 (AO Spine thoracolumbar injury classification C3). Posterior thoracic decompression and fusion was performed at T3 to T8. After the patient underwent the thoracic spine and cervical orthosis treatment, He received rehabilitation program and training transfer with wheelchair without caregiver. His sitting and balance were significantly improved at the 6 months follow-up. Although the lower extremity functions (ASIA A) may not improve due to the severe spinal cord injury.Clinical discussionMNSF with spinal cord injury following a high-velocity accident is an unstable and complex injury. Important of the clinical assessment and according to the injuries the treatment may vary.ConclusionsCervical orthosis was alternative treatment to preserve cervical motion treatment and posterior thoracic decompression with fixation is an effective option for patients in this MNSF with spinal cord injury.

Development of technology for the production of a lightweight observation and protective container (LOOK) made of nanostructured ultra-strength steels

The article contains results of research and analyses concerning application of nanostructured bainitic steel in the form of plates for manufacturing of armour components. The presented results of examination of microstructure and properties include a wide range of laboratory experiments and industrial tests, which resulted in the achievement of the assumed functional properties. In the period of 2017-2021, a scientific and industrial consortium consisting of Łukasiewicz – Institute of Ferrous Metallurgy (leader); WITPiS, Tarnów Mechanical Works, Alchemia and Heatmasters Poland carried out a project funded by the POIR 04.01.04 programme aimed to develop the design and to manufacture an observation and protective container with a specified resistance to penetration by armour-piercing projectiles and with a lower mass of steel armouring in relation to that currently produced. The aim of the project was achieved by using armour plates made of nanostructured bainitic steel (nanobainitic), which are characterised by high resistance to high-energy impact concentrated in a small area. The technological tests carried out in the project mainly concerned the development of a new container and industrial technology of armour plates production and their application in the armour of this container. Based on the results of investigation of the semi-industrial scale material, the optimum chemical composition for industrial scale melting and casting was determined. An industrial technology for the production of plates of nano-structured bainitic steel was developed, which includes the following processes: smelting and casting, preliminary heat treatment and ingot hot processing, as well as hot rolling, final heat treatment, and surface treatment. A test batch of the material in the form of 1500×2470 mm armoured plates was fabricated under industrial conditions. The final result of the project is a container armoured with bainitic nanostructured steel plates with implementation documentation and a technology for producing armoured plates from this steel under the technical and technological conditions of domestic steel manufacturers.

Fatigue strength improvement in Ti-6Al-4V subjected to foreign object damage by combined treatment of laser shock peening and shot peening

The improving effects of combined laser shock peening (LSP) and shot peening (SP) treatment on the physical properties, microstructure characteristics and foreign object damage resistance of Ti-6Al-4V alloy aerofoil specimens were studied. The surface micro-hardness of specimens after combined LSP + SP treatment is 20% higher than that of the base material, with an affected layer depth of about 400 μm; while the maximum residual compressive stress of samples is −843.2 MPa with a layer depth of about 640 μm. Severe plastic deformation occurred on the subsurface of the specimen after combined LSP + SP treatment, and the depth of grain refinement layer was about 60 μm. The subsequent foreign object damage (FOD) test showed that the combined surface treatment improved the hardness of specimens to effectively resist the damage caused by low energy impact, but the effect is not so obvious for high energy impact. For LSP + SP treated specimens impacted by 1-mm-diameter steel balls, the high cycle fatigue (HCF) strength at 107 cycles improved most, which is nearly 35% higher than that of the untreated specimens. The enhancement is mainly due to micro-hardness maximization and residual compressive stress field introduced by combined LSP + SP treatment.

Poly(Vinylidene Fluoride) Nanofiber Array Films with High Strength for Effective Impact Energy Harvesting

Absorbing high mechanical impact energy and converting it into electrical energy is challenging due to the low efficiency and strength of the existing piezoelectric generators. Here, a new type of piezoelectric nanogenerator is reported that is a sandwich structure composed of upper and lower electrodes and a poly(vinylidene fluoride) (PVDF) nanofiber array film. The PVDF nanofiber array films with dense vertical alignment characteristics are successfully fabricated by a combination of electrospinning and cutting methods. Each nanofiber in the nanofiber array film becomes an independent nanogenerator with an equivalent piezoelectric response which greatly enhances the charges collection and energy conversion efficiency of the nanogenerator. The maximum instantaneous power density of 26.3 μW cm−2 can be reached under the impact of the 9.1 g ball falling freely from a height of 20 cm. The nanofiber array structure endows the piezoelectric nanogenerator with high mechanical strength in the normal direction of the surface and excellent stability. Furthermore, the power output of two parallel‐connected nanogenerators (1.5 × 1.5 cm2 each) can light up 12 LEDs without storage devices. The unique properties of the piezoelectric nanogenerator offer great potential for high mechanical impact energy harvesting and effective conversion.

Analysis of the effectiveness of operation of integrated electromagnetic motors by methods of the numerical simulation of the magnetic field

The dynamic characteristics of an integrated electromagnetic motor are calculated from the results of the numerical simulation of the magnetic field. The characteristics of its effectiveness found from the output energy are obtained. It is proposed to use the known mathematical model of the motor that has the form of the system of non-linear equations for calculating the magnetic field inside the motor volume. It is shown that the model can be simply adapted for calculating the magnetic field inside integrated electromagnetic motors. The general principles of constructing designs of integrated electromagnetic motors for impact pressing machines are also examined in the paper. In comparison with the known electromagnetic machines, they have higher impact energy and efficiency.

Derivation and validation of a quantitative screening model for blunt cerebrovascular injury.

The objective of this study was to derive and validate a new screening model using a nomogram that allows clinicians to quantify the risk of blunt cerebrovascular injury (BCVI). In this study, the authors examined 258,935 patients from a prospectively collected nationwide Japanese database (January 2009-December 2018) who experienced blunt injury. Patients were randomly divided into training (n = 129,468) and validation (n = 129,467) cohorts. First, the authors investigated the prevalence of BCVI, which was defined as blunt injury to any intracranial vessel, the extracranial vertebral artery, the extracranial carotid (common, internal) artery, or the internal jugular vein. Then, a new arterial BCVI screening model using a nomogram was derived, based on multivariate logistic regression analysis through quantifying the association of potential predictive factors with BCVI in the training cohort. The model's discriminatory ability was validated using the area under the receiver operating characteristic curve (AUC) in the validation cohort. Multivariate analysis in the training cohort showed that 13 factors were significantly associated with arterial BCVI and were included in our model. These factors were 1) male sex; 2) high-energy impact; 3) hypotension on hospital arrival; 4) Glasgow Coma Scale score < 9; 5) injury to the face; 6) injury to the neck; 7) injury to the spine; 8) skull base fracture; 9) cervical spine fracture or subluxation; and those with negative associations, i.e., 10) injury to the lower-extremity region; 11) supratentorial subdural hemorrhage; 12) lumbar spine fracture or subluxation; and 13) soft tissue injury of the face. In the validation cohort, the model had an AUC of 0.83 (95% CI 0.81-0.86). When the definition of BCVI was narrowed to include only carotid (common, internal) and vertebral artery injuries, the AUC of the model in predicting these injuries was 0.89 (95% CI 0.87-0.91). A new screening model that incorporates an easy-to-use nomogram to quantify the risk of BCVI and assist clinicians in identifying patients who warrant additional evaluation was established.

Traumatic Hip Dislocation in an NCAA DI Football Player with Occult Sequelae: A Case Report.

Background and PurposeAmerican football generates the most sports-related injuries in the United States, with tackling as the leading injury mechanism. Overall injury rate at the collegiate level has been reported as 8.61 per 1,000 athlete exposures (AEs) – twice the rate of high school levels; competition injury rates are reported as high as 36.94/1000 AEs. Traumatic hip dislocation is an uncommon injury typically arising from high-energy axial impact with only 2-5.5% occurring during sports activities.Case DescriptionA 22-year-old NCAA Division I football defensive back who experienced extreme left hip pain following contact with another player with his hip flexed during a game was diagnosed with a type 1 posterior hip dislocation, a grade 1 medial collateral ligament sprain with concomitant posterior thigh and hip muscle strains. Key impairments were limited left lower extremity motor performance, range of motion deficits, left hip pain, and diminished function and weight-bearing ability.OutcomesThe athlete reintegrated into typical defensive back off-season training approximately four to five months post injury without restrictions, however presented with new anterior hip pain seven months post injury revealing occult sequelae requiring surgical intervention. He was able to return to full play the following football season.DiscussionThis case report describes the successful return to sport of a Division I football player who sustained a traumatic posterior hip dislocation and complicated course including surgical intervention secondary to associated sequelae.Level of Evidence5

Better than concrete. Light-weight fitness floating floor solutions for reducing impacts

Structure-borne noise and vibration from weight drops and fitness activities are an ever-increasing source of disturbance within multi-residential, hospitality, and multi-tenant commercial buildings. High-mass floating floors supported on low-resonant frequency isolators have been used with good effect to reduce impact noise and vibration, but commonly require expensive supplemental supports or structural stiffening to be implemented properly. Common light-touch fitness solutions feature continuous or interlocking resilient surface treatment. This approach is often ineffectual at high-energy impact fitness areas and the pursuit of soft surface solutions to achieve greater dissipation of impact energy can create an unstable surface for weightlifting. An alternate approach to reducing structure-borne noise exists which focuses on dissipating the impact energy through constrained layer damping in conjunction with low-resonant frequency isolators. Research and development testing shows that an engineered all-dry lightweight fitness floating floor is capable of achieving equal or greater impact insulation performance than a high-mass concrete floating floor and significantly better performance than light-touch resilient surface treatment. A review of the testing and development process and underlying principles will be reviewed to illuminate the mechanisms at work in the next generation of fitness floating floors.

Study on Crack Impact Toughness Evaluation Method for Metallic Materials

For the engineering structures in service for a long period in the complex environment, crack initiation and growth are difficult to avoid. Therefore, for the engineering structures required to withstand explosion and impact, the crack impact toughness of their materials must be evaluated to prevent the possible brittle fracture under impact due to crack occurrence. This study, relying on the Instron VHS high strain rate material testing machine, develops a set of dynamic fracture testing device to measure the crack ductile-brittle transition process of 4 different kinds of metallic material with high impact energy under impact, and studies the factors influencing the crack ductile-brittle transition rate of these materials. According to the findings, the Charpy impact energy can not fully reflect the crack impact toughness,and the absence and existence of preformed cracks, the specimen constraint mode and the specimen crack tip constraint factor all have an effect on the ductile-brittle transition rate in the crack impact test of metallic materials. Based on the results above, this study finally propose the basic ideas about the crack impact toughness evaluation method for metallic materials.

Evaluation of repeated micropulse cyclophotocoagulation in patients with refractory glaucoma

PURPOSE. To evaluate the efficacy and safety of repeated micropulse transscleral cyclophotocoagulation (MP-TSCPC) in patients with previously operated refractory glaucoma.MATERIALS AND METHODS. We examined 89 patients aged 74.2±7.3 years with moderate (16), advanced (58) and terminal (15) stages of uncompensated primary openangle glaucoma (POAG) before and within 12 months after the first MP-TSCPC (SUPRA 810, “Quantel Medical”, France) using standard laser parameters — 100 J. Indications for repeated MP-TSCPC were determined for 23 patients in 3 (1 patient), 6 (14 patients), 9 (8 patients) months after the first procedure. Repeated MP-TSCPC was carried out with higher impact energy — 125 J.RESULTS. After the first procedure, the hypotensive effect was achieved in 66 (74.2%) patients with refractory glaucoma lasting up to 12 months of follow-up. Repeated MP-TSCPC in 23 patients reduced the IOP by 31.2% in moderate, 31.8% in advanced, and 22.9% in terminal stages (p&lt;0.05) by 6 months of follow-up. As a result, during 12 months of observation, MP-TSCPC (single and double) led to stabilization of the IOP in 83.1% of cases.CONCLUSION. Single and repeated micropulse TSCPC with laser energies of 100 J and 125 J is an effective and safe method of treating patients with refractory glaucoma. A single MP-TSCPC with laser energy of 100 J was effective in 66 (74.2%) patients by 12 months of observation, and single followed by repeated (laser energy of 125 J) — in 74 (83.1%) patients. It is possible to revise the basic parameters of the MP-TSCPC procedure from 100 to 125 J to achieve a longer and at the same time safe hypotensive effect in patients with refractory glaucoma.

Guest Editorial Special Issue on High-Current Discharge Plasmas

An intention to organize this Special Issue was born at the International Congress on Energy Fluxes and Radiation Effects (EFRE), which is held every two years in Tomsk under the technical sponsorship of the IEEE. The Congress brings together four conferences, namely, the Symposium on High Current Electronics (SHCE), the Conference on Modification of Materials With Particle Beams and Plasma Flows (CMM), the Conference on Radiation Physics and Chemistry of Condensed Matter (RPC), and the Conference on New Materials and High Technologies (NMHT). Conferences have joined the Congress in different years, but the oldest one is SHCE, which was organized for the first time in 1973, four years before the establishment of the Institute of High Current Electronics (IHCE) in Tomsk. The Symposium on High Current Electronics anticipated the name of the Institute for High Current Electronics due to the fact that the scientific direction of the Institute was laid in the late 60s–early 70s of the last century by the scientific team headed by Prof. Gennady Mesyets, who organized IHCE, SHCE, and subsequently EFRE. The Congress covers a wide range of problems, from pulse power to nanoelectronics, but the unifying canvas is the high-energy impact on materials and environments. In 2020, EFRE Proceedings have published 302 conference papers that the reader can find in the IEEE Xplore digital library. This is why this Special Issue was not intended to publish extended versions of the four-page Congress papers. This special issue was open to the publication of articles by authors regardless of their participation in the EFRE community. The idea of the Special Issue was to collect and analyze the scientific and engineering interests of the community related to the plasma of high-current electric discharges.

Programmed Multi-Level Ventilation: A Strategy for Ventilating Non-Homogenous Lungs.

Mechanical ventilation (MV) has been an integral method used in ICU care for decades. MV is typically viewed as a life-supporting intervention. However, it can also contribute to lung injury through stress and strain, as evidenced by ventilator-induced lung injury (VILI), even in previously healthy lungs. The negative impact may be worsened when significant lung non-homogeneity is present, eg. ALI and ARDS. Protective lung strategies to minimize VILI are to use low tidal volumes (Vt 4–6 mL/kg/PBW), plateau pressures (Pplat) <30 cmH2O and relatively high positive end-expiratory pressures (PEEP). Yet, use of constantly high PEEP levels is well recognized to result in hemodynamic compromise of the right ventricle, increased stress and strain through high mechanical energy impact on the lung and overdistension of relatively healthy lung tissue. Taking these issues into consideration, a different approach to mechanical ventilation was developed specifically for patients with non-homogeneity. This review focuses on a feature called programmed multi-level ventilation (PMLV). It is not a ventilation mode per se, but rather a form of extension that adjusts and modifies any ventilation mode (eg PCV,PSV, VCV, SIMV, etc.). PMLV is based on measured time constants (Tau) of the whole respiratory system, including artificial airways, breathing circuits, humidification devices and mechanical ventilator. Using a physiology-based approach presents a method to ventilate non-homogenous lungs through cyclic changes of different PEEP levels; recruitment takes place in lung areas with long time constants but protects relatively healthy lung areas from overdistension thus minimizing excessive mechanical power to the lung tissue.

Investigation on the Application of Taylor Impact Test to High-G Loading

Taylor impact test is characterized by high impact energy, low cost, and good repeatability, giving it the technical foundation and development potential for application in high-g loading. In this paper, the feasibility of performing high-g load impact testing to a missile-borne recorder by conducting Taylor impact test was studied by combining simulation analyses with experimental verification. Acccording to the actual dimensions of the missile-borne recorder, an experimental piece was designed based on the Taylor impact principle. The impact loading characteristics of the missile-borne recorder were then simulated and analyzed at different impact velocities. In addition, the peak acceleration function and the pulse duration function of the load were fitted to guide the experimental design. A Taylor-Hopkinson impact experiment was also conducted to measure the impact load that was actually experienced by the missile-borne recorder and the results were compared with the results of strain measurements on the Hopkinson incident bar. The results showed that the peak value of impact load, the pulse duration and the waveform of the actual experimental results were in good agreement with the results predicted by the simulations. Additionally, the strain data measured on the incident bar could be used to verify or replace the acceleration testing of the specimen to simplify the experimental process required. Based on the impact velocity, high-g loading impact was achieved with peak values in the 7,000–30,000 g range and durations of 1.3–1 ms, and the waveform generated was a sawtooth wave. The research results provide a new approach for high amplitude and long pulse duration impact loading to large-mass components, and broaden the application field of Taylor impact test.