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AbstractThis paper is a development of the well-known Riera approach (1968, 1980) for the calculation of the loading force applied by an aircraft crashing on a rigid target. The purpose is to present a formula that provides the peak value of the loading force so that running time-response analysis is not any more necessary. For this purpose, we first develop a non-dimensional approach of Riera equations and we provide analytical solution of them. Then, we calculate the non-dimensional response of five different types of aircraft at different impact velocities. For every aircraft, we identify the non-dimensional peak force as a function of the non-dimensional velocity, and we translate it into Fpeak in the physical domain. In a next step, we derive an upper bound F̂peak  of Fpeak, and we introduce Fpeak* , an approximate of Fpeak. The accuracy of Fpeak* with respect to Fpeak is examined for the considered series of aircrafts and impact velocities. Eventually, we explain how the non-dimensional approach enables to derive the peak force generated by a given aircraft at a given velocity from the one of another aircraft at another velocity, provided that both aircrafts have some non-dimensional features in common. [ABSTRACT FROM AUTHOR]

A large fireball is usually created during an aircraft impact. The fireball may engulf a building and impart great thermal radiation onto nearby targets. A series of numerical simulations with parametric studies was conducted for a real aircraft crash accident. The effects of fuel distribution in the aircraft and fuel spray angle on the fireball characteristics associated with an aircraft crash are investigated. By comparing with the fireball diameter and center height obtained from video footage reported in the literature, the simulated fireball diameter is closest to that observed in the video footage when the fuel spray angle is 15° regardless of the number of dynamic fuel sprays. Furthermore, when the fuel distribution in the airplane is simulated with four dynamic sprays, the effect of spray angle on the predicted fireball center height is negligible. Based on the comparison of the simulated fuel droplet distribution with the fire zone after aircraft crash, we infer that the reliability of the simulation for the fireball generated by an aircraft crash depends on generation of a fuel jet in the front of the aircraft's nose. This work provides numerical simulation with validation of the fireball characteristics generated by an aircraft impact. [ABSTRACT FROM AUTHOR]

Resisting an accidental impact of large commercial aircrafts is an important aspect of advanced nuclear power plant (NPP) design. Especially after the 9·11 event, some regulations were enacted, which required the design of NPPs should consider the accidental impact of large commercial aircrafts. Normal working of equipment is important for stopping reactor under an impact when an NPP is in operation. However, there is a lack of reliable analysis and research on the impact test of nuclear prototype equipment. Therefore, in order to study the response of the equipment under high acceleration impact, a centrifugal pump is selected as the research object to perform the impact test. A horizontal half-sinusoidal pulse wave was applied to the working pump. The test results show that the horizontal response of the motor and flange is greater compared to other parts, as well as the vertical response of the coupling. The stress response of the pump body support and motor support is high, hence these parts should be considered in the design of the pump. Finally, combined with the damage and stress evaluation results of the pump under different amplitudes, the ultimate impact acceleration that the pump can withstand is given.

This study examines patterns of skeletal trauma in propeller‐driven aircraft crashes and blast‐related ground loss incidents from WWII. Specifically, descriptions and criteria used to characterize aircraft deceleration‐ versus blast‐related skeletal injuries are examined from 35 recently identified forensic anthropology cases to determine possible diagnostic traits and characterize skeletal trauma associated with these events. Among these cases, blast trauma is more localized within the skeleton and is associated with one or few primary directions of force. It is recommended that analysts differentiate between secondary and nonspecific blast trauma categories. Conversely, aircraft crash deceleration trauma is more widespread throughout the skeleton, with torsional fractures and injuries occurring from multiple or indeterminate directions. These traits reflect factors such as more complex loading environments than is seen in blast events. Two case studies are presented in detail to further illustrate differences in aircraft crash and blast‐related incidents. Both studies emphasize consideration of the body as a whole unit to facilitate interpretations. While the cases presented herein result from historic war‐related casualties that characterize the Defense POW/MIA Accounting Agency's (DPAA) casework, these skeletal cases provide guidelines more appropriate than clinically derived criteria developed through assessments of soft tissue injuries. These guidelines can be used by anthropologists and pathologists working with skeletal remain from mass disasters and other complex contexts, as well as provide avenues for future research. [ABSTRACT FROM AUTHOR]

This study examines patterns of skeletal trauma in propeller‐driven aircraft crashes and blast‐related ground loss incidents from WWII. Specifically, descriptions and criteria used to characterize aircraft deceleration‐ versus blast‐related skeletal injuries are examined from 35 recently identified forensic anthropology cases to determine possible diagnostic traits and characterize skeletal trauma associated with these events. Among these cases, blast trauma is more localized within the skeleton and is associated with one or few primary directions of force. It is recommended that analysts differentiate between secondary and nonspecific blast trauma categories. Conversely, aircraft crash deceleration trauma is more widespread throughout the skeleton, with torsional fractures and injuries occurring from multiple or indeterminate directions. These traits reflect factors such as more complex loading environments than is seen in blast events. Two case studies are presented in detail to further illustrate differences in aircraft crash and blast‐related incidents. Both studies emphasize consideration of the body as a whole unit to facilitate interpretations. While the cases presented herein result from historic war‐related casualties that characterize the Defense POW/MIA Accounting Agency's (DPAA) casework, these skeletal cases provide guidelines more appropriate than clinically derived criteria developed through assessments of soft tissue injuries. These guidelines can be used by anthropologists and pathologists working with skeletal remain from mass disasters and other complex contexts, as well as provide avenues for future research. [ABSTRACT FROM AUTHOR]

The accidental or intentional crash upon structures of Nuclear Power Plant (NPP) by an aircraft cause the fuel spreading followed by a fireball formation. This fireball is large enough to engulf the entire NPP and radiates a large amount of heat. This engulfment may lead to a local rise in temperature, which causes the spallation of concrete structure and fatalities to the human being. This may affect the integrity of NPP structures and has safety implications. The building structures influence the spatial evolution of fireball due to the generation of large turbulent structures, which further increases the local temperature. The evolution of fireball following fuel dispersion due to the aircraft crash upon an NPP is presented in this article. Numerical simulation to study the effect of fireball on the target NPP structure and its surrounding has been performed using a three-dimensional computational fluid dynamics (CFD) code. This analysis is used to study the evolution of fireball and thermal hazard associated with the radiated heat. It is found that some parts of fireball energy go as heat input to containment and the remaining portion is dissipated to the atmosphere by convection and radiation. CCPS: Centre for Chemical Process Safety; CID: Controlled Impact Demonstration; CFD: Computation Fluid Dynamics; EDC: Eddy Dissipation Concept; FAA: Federal Aviation Administration; FDS: Fire Dynamic Simulator; FVDOM: Finite Volume Discrete Ordinate Method; GAMG: Geometric Algebraic Multi-Grid; HRR: Heat Release Rate; IAEA: International Atomic Energy Agency; NIST: National Institute of Standards and Technology; NPP: Nuclear Power Plant; NTSB: National Transport Safety Board; OpenFOAM: Open Field Operation And Manipulation; PBiCG: Preconditioned Bi-Conjugated Gradient; PISO: Pressure Implicit with Splitting of Operator; SMD: Sauter Mean Diameter; TNO: The Netherlands Organization of applied scientific research; VTT: Technical Research Centre of Finland; WTC: World Trade Centre [ABSTRACT FROM AUTHOR]

Nuclear energy presently contributes more than 17% of global energy demand. In order to avoid the nuclear disasters, safety concern in nuclear structures is always of high concern. In the present study, response analysis of the outer containment of a typical Nuclear Power Plant (NPP) has been carried out against aircraft impact using finite element code ABAQUS. To maximise the effect of collision, the wall is considered as flat in the present study. Moreover, to maintain computational economy, only a quarter of the wall has been modelled. A 1.2 m thick doubly reinforced concrete wall has been simulated in the present study. Behaviour of concrete has been incorporated using Concrete Damaged Plasticity model while the Johnson Cook elastic-viscoplastic model has been used for reinforcement. Material parameters at elevated temperature have been taken from Eurocode 2. Reaction time response curve of Boeing 707-320 has been employed to find the response of containment against aircraft crash. Thermal stress analysis has been performed by combining the impact and heat effect together. It has been assumed that fire starts at 0.16 s after the application of impact load. A maximum deformation of 48 mm has been noticed. Maximum temperature was found to be 974 °C. [ABSTRACT FROM AUTHOR]

An aircraft crashing into a nuclear containment may induce a series of disasters related to containment capacity, including local penetration and perforation of the containment, intensive vibrations, and fire ignited after jet fuel leakage. In this study, structural safety of a reinforced concrete containment vessel (RCCV) has been studied against the direct hit of Airbus A320, Boeing 707-320 and Phantom F4 aircrafts. ABAQUS/explicit finite element code has been used to carry out the three-dimensional numerical simulations. The impact locations identified on the nuclear containment structure are mid height of containment, center of the cylindrical portion, junction of dome and cylinder, and over the cylindrical portion close to the foundation level. The loading of the aircraft has been assigned through the corresponding reaction-time response curve. The concrete damaged plasticity model was predicted to simulate the behavior of concrete while the behavior of steel reinforcement was incorporated using elastoplastic material model. Dynamic loading conditions were considered using dynamic increase factor. The mid height of containment and center of cylindrical portion have been found to experience most severe deformation against each aircraft crash. It has also been found that compression damage in concrete is not critical at none of the impact locations. [ABSTRACT FROM AUTHOR]

An aircraft crashing into a nuclear containment vessel may induce a series of disasters related to containment capacity, including local penetration and perforation of the containment, intensive vibrations, and fire ignited after jet fuel leakage. A procedure was presented for investigation of structural capacity of the containment of the newly developed Generation III + nuclear power plants ( NPPs) in accidental scenarios. A containment vessel-soil model was developed and verified to investigate the transient response of the containment and subsequently induced vibrations on the ground surface. Ground vibrations can be used as input data to obtain the vibration of equipment inside the containment or inside buildings adjacent to the containment. Impact action was represented using a force-time history function imposed on the crash area of the containment surface. Then, a thermal analysis was conducted to predict the temperature fields following a mechanical-thermal stress analysis for fire resistance assessment. Results found the containment vessel-soil model was capable of predicting the transient and vibration responses of the structure. For the effect of impact positions on ground vibration outside the containment, impact positions in the mid-height and bottom portions of the containment induced slightly intensive ground vibration compared to impact in the upper portion of the containment. Thus, appropriate impact position should be considered when ground vibration response is a concern. Structural safety associated with fire effect was generally ensured mainly due to the low thermal inertia of concrete. [ABSTRACT FROM AUTHOR]

Three-dimensional computational fluid dynamics (CFD) simulations of hydrocarbon fireballs have been performed for their detailed characterization, including diameter, lifetime, flame, and internal fireball structure. The diameter and duration of a fireball obtained by CFD simulations and available empirical models have been compared with experiments and video footage data. CFD simulations are essential as empirical models have inherent assumptions and limitation in describing internal fireball structures. The fireball resulting from the loss of a fuel tank exposed to fire (experiment conducted by the German Bundesanstalt für Materialforschung in 1999) and a fireball from an aircraft crash (aircraft ambulance crash in Iceland in 2013) are considered for the CFD analysis. Influence of initial momentum, turbulence, and radiation on fireball structure has been analyzed for both of the cases. To illustrate transient behavior, developed pressure and flame structures are studied during the evolution of a fireball. Fireball diameter and lifting height computed from numerical analysis is found to be in good agreement with available video footage data. The incident radiations on the ground are calculated using a numerical method along the radial position from the center of the fireball, to predict the thermal hazards from the fireball. [ABSTRACT FROM PUBLISHER]

The Internet not only has changed the dynamics of our collective attention but also through the transactional log of online activities, provides us with the opportunity to study attention dynamics at scale. In this paper, we particularly study attention to aircraft incidents and accidents using Wikipedia transactional data in two different language editions, English and Spanish. We study both the editorial activities on and the viewership of the articles about airline crashes. We analyse how the level of attention is influenced by different parameters such as number of deaths, airline region, and event locale and date. We find evidence that the attention given by Wikipedia editors to pre-Wikipedia aircraft incidents and accidents depends on the region of the airline for both English and Spanish editions. North American airline companies receive more prompt coverage in English Wikipedia. We also observe that the attention given by Wikipedia visitors is influenced by the airline region but only for events with a high number of deaths. Finally we show that the rate and time span of the decay of attention is independent of the number of deaths and a fast decay within about a week seems to be universal. We discuss the implications of these findings in the context of attention bias.

Background Aeromedical transport (AMT) is a reliable and well-established life-saving option for rapid patient transfers to health care delivery hubs. However, owing to the very nature of AMT, fatal and nonfatal events may occur. This study reviews aeromedical incidents reported since the publication of the last definitive review in 2003, aiming to provide additional insight into a wide range of factors potentially associated with fatal and nonfatal AMT incidents (AMTIs). We hypothesized that weather and/or visual conditions, postcrash fire, aircraft make and/or type, and time of day all correlate with the risk of AMTI with injury or fatality. Methods Specialty databases were queried for AMTI between January 1, 2003 and July 31, 2015. Additional Internet-based resources were also used to find any additional AMTI (including non-US occurrences) to augment the event sample size available for analysis. Univariate analyses of the collected sample were then performed for association between “fatal crash or injury” (FCOI) and weather/visual conditions, aircraft type and/or make, pilot error, equipment failure, post-incident fire, time of day (6 am-7 pm versus 7 pm-6 am), weekend (Friday-Sunday) versus weekday (Monday-Thursday), season of the year, and presence of patient on board. Variables reaching significance level of P < 0.20 were included in multivariate analysis. Results A total of 59 AMTIs were identified. Helicopters were involved in 52 of 59 AMTIs, with 7 of 59 fixed-wing incidents. Comparing pre-2003 data with post-2003 data, we noted a significant decrease in AMTIs per month (0.70 versus 0.39, respectively, P = 0.048), whereas the number of fatalities per year increased slightly (7.20 versus 8.26, p = n/s). In univariate analyses, abnormal weather conditions, impaired visibility, time of incident (7 pm-6 am), aircraft model/make, and post-incident fire all reached statistical significance sufficient for inclusion in multivariate analysis ( P < 0.20). Factors independently associated with FCOI included post-incident fire (odds ratio, 19.0; 95% confidence interval, 1.41-255.5) and time of incident between 7 pm and 6 am (odds ratio, 11.2; 95% confidence interval, 1.29-97.2). Weather conditions, impaired visibility, and aircraft model/make were not independently associated with FCOI. Conclusions The present study supports previous observation that post-crash fire is independently associated with FCOI. However, our data do not support previous observations that weather conditions, impaired visibility, or aircraft model/make are independently predictive of fatal AMTI. In addition, this report demonstrates that flights between the hours of 7 pm-6 am may be associated with greater odds of FCOI. Efforts directed at identification, remediation, and active prevention of factors associated with AMTI and FCOI are warranted given the global increase in aeromedical transport. [ABSTRACT FROM AUTHOR]

Weather conditions at night on March 19, 2016, when Boeing 737-800 crashed in Rostov-on-Don, are analyzed using the data of aerodrome observations and radiosounding, satellite data on cloudiness and cloud top temperature, and the data of synoptic and calculated charts of maximum wind. [ABSTRACT FROM AUTHOR]

Transportation networks constitute a critical infrastructure enabling the transfers of passengers and goods, with a significant impact on the economy at different scales. Transportation modes, whether air, road, or rail, are intrinsically coupled through passenger transfers and are interdependent. The frequent occurrence of perturbations on one or several modes disrupts passengers' entire journeys, directly and through ripple effects. This paper provides a case report of the Asiana crash in San Francisco International Airport (SFO) on July 6, 2013, and its repercussions on the multimodal transportation network. It studies the resulting propagation of disturbances on the transportation infrastructure in the USA, particularly on the U.S. air transport network and the ground transportation in the Bay Area. The perturbation takes different forms and varies in scale and time frame: cancelations and delays snowball in the airspace, with up to 86% of cancelations in the U.S. due to the SFO crash; highway traffic near the airport is impacted by congestion in previously not congested locations, with low speed and high delays on US 101; and transit passenger demand exhibits unusual traffic peaks in between airports in the Bay Area, with up to 180 passengers more per hour between SFO and Oakland International Airport Bay Area Rapid Transit stations. This paper also investigated the effect of the crash on the social media Twitter. This paper, through a case study, aims at stressing the importance of further data-driven research on interdependent infrastructure networks. The end goal is to form the basis for optimization models behind providing more reliable passenger door-to-door journeys and improved transport network resilience. [ABSTRACT FROM PUBLISHER]

Previously, a pair of aircraft crash fatalities was reported by Byard and Tsokos involving extreme trauma to the lower legs with avulsion of the musculature and extrusion of the distal tibial shaft through the inferior aspect of the feet and shoes. This report was important to both the forensics and the injury prevention fields because it demonstrates a finding that may help to indicate not only the severity and nature/direction of an impact but also the position of the extremities at the time of collision with the terrain. Thus, here are reported an additional nine cases out of a larger series of 1182 aircraft fatalities (0.7%) with similar findings and discuss the biomechanical origins of such injuries. [ABSTRACT FROM AUTHOR]

External hazards of nuclear facilities include high-energetic missile impact on external protective barriers made of reinforced concrete (RC). Potential sources of such impulsive loading are e.g. accidental as well as malevolent aircraft impact. Despite its low probability, accidental aircraft impact is a relevant loading case for the design of safety relevant building structures of nuclear facilities, while load assumptions have been different in different countries. Since 11.09.2001, also malevolent crashes of larger commercial airplanes are considered. Nowadays, complex analysis codes are frequently used for the assessment of such events. Their accuracy is validated based on impact tests. This paper focuses on impact tests carried out by the Technical Research Centre of Finland (VTT) in the framework of an international project called IMPACT. Among other partners, GRS participates in IMPACT in order to validate its analysis technique based on the software ANSYS AUTODYN. The test facility and results from tests carried out so far are described. Impacts of “soft” and “hard” missiles on RC structures are considered in this paper. In this context, “soft” implies that the missile is deformable relative to the target, while “hard” stands for almost rigid impactor behaviour. Failure mechanisms of RC structures include global effects such as bending vibrations and global cracking. Furthermore, local effects like punching (cone shaped cracking of target below missile), penetration (tunnelling of missile into the target) and perforation of the missile with finite residual velocity are possible. This paper presents results of selected tests and their simulations, each dealing with these different failure mechanisms. Specifications of liquid impact might be of relevance in aircraft crash scenarios. Therefore, some remarks regarding tests with liquid filled missiles are given. Some VTT tests were subject of broad benchmark simulations in the frame of the international activity IRIS (“Improving Robustness Assessment Methodologies for Structures Impacted by Missiles”). The paper gives an overview about the IRIS activity, including comparisons of numerical results obtained from blind and post-test simulations. Finally, the application of the simulation methodology to a generic RC containment structure is outlined. It is concluded, that the relevant mechanical phenomena occurring at high-energetic missile impact on RC structures can be simulated satisfyingly. In simulations of severely loaded concrete dependencies on modelling parameters may emerge. Therefore, parametric numerical studies as well as extended experimental test series are beneficial in order to specify the range of scattering of results. [ABSTRACT FROM AUTHOR]

Nuclear power plants with RBMK reactors were designed in late sixties - early seventies and were built entirely in the European part of the Russian Federation, the Lithuanian Republic and the Ukrainian Republic. The plants in the Lithuanian and the Ukrainian Republics are in various stages of decommissioning. As currently planned, the most of RBMK reactors still operating in the Russian Federation will end their operation in this decade. The reactor building, spent nuclear fuel and radioactive waste storage facilities, built at the time of construction of RBMK plants are not specially designed to withstand the direct impact of an aircraft crash. There were no such regulatory requirements at the time the plants were designed and, no such requirements were introduced by regulatory bodies later on. But for now, in the aftermath of the September 11, 2001 terrorist attack on the United States, the event of an aircraft crash on a nuclear facility can no longer be considered as extremely unlikely. This paper considers the state of a nuclear power plant with the RBMK type reactor(s) during certain decommissioning and dismantling stages and discusses the approach for the evaluation of radiological consequences to the public in the event of a large aircraft crash on potentially hazardous objects of the plant. The damage to spent nuclear storage facilities, the reactor graphite stack and storage facilities for the combustible waste may cause a significant release of radionuclides to the environment. Key components of the approach include the evaluation of a structural damage to the facilities, the evaluation of a fire propagation and impact, the evaluation of a spent nuclear fuel cooling capability in storage pools, the evaluation of an airborne radionuclide release, the evaluation of a radionuclide dispersion in the environment and the evaluation of the public exposure. A set of widely used software and methods for the performance of the specific tasks is discussed. The paper also describes how the proposed approach was applied for the evaluation of radiological consequences from a Boeing 767-400 type aircraft crash at the Ignalina NPP site where a plant with two RBMK-1500 type reactors is decommissioned. The paper does not address modern radioactive waste and spent nuclear fuel management and storage facilities that might be built at RBMK sites as well. As a rule, assessment and mitigation of an aircraft crash accident consequences is an integral part of design of these new facilities. • NPPs with RBMK reactors are not specially designed against an aircraft crash. • Vulnerable objects are spent nuclear fuel and combustible waste storage facilities. • The assessment approach consists of a set of specific assessment tasks. • Methods for the performance of specific assessment tasks are discussed. • The example of implementation of the proposed approach is described. [ABSTRACT FROM AUTHOR]

Abstract: The safety assessment of infrastructures, such as a nuclear power plant, for the crash of a large commercial aircraft has been performed worldwide after the terrorism that occurred in the U.S. on September 11, 2001. The assessment, however, has mainly focused on the techniques of impact analysis. In this study, a systematic procedure to assess the fire resistance of containment and auxiliary buildings subjected to such an aircraft crash is proposed. The intensity, duration and distribution of the fire are determined based on aircraft crash analyses and characteristics of jet fuel. A three-dimensional detailed finite element model of the containment and auxiliary buildings is established and used for heat transfer and thermal stress analyses, taking into account the material properties at an elevated temperature. Section forces can then be obtained that are based on a nonlinear stress–strain relationship. The fire resistance of the structure is assessed by comparing the fire-induced section forces with the section resistance which is evaluated using the load–moment strength interaction diagram. The study addresses the problem whereby the conventional assessment that only considers the flexural behaviour is less accurate. The assessment results support the general conclusion that the nuclear power plant structures can maintain structural integrity against external fire due to their relatively thick sections. The proposed procedure can be extensively applied to evaluate the fire endurance time of any type of structure subjected to an arbitrary fire. [Copyright &y& Elsevier]

In order to ensure that nuclear power plant buildings are reliable and safe in case of external loading, it is very important to evaluate uncertainties associated with loads, material properties, geometrical parameters, boundaries and other parameters. Therefore, a probability-based analysis was developed as the integration of deterministic and probabilistic methods using existing state-of-the-art software. The subject of this paper is the integrated analysis of building failure due to impact by a commercial aircraft. The Monte Carlo Simulation, First-Order Reliability and the combined Monte Carlo Simulation and Response Surface methods were used for the probabilistic analyses. During an aircraft crash, the dynamic impact loading is uncertain. Therefore a relation expressed by the probability of failure of impacted wall and loading function was determined. With failure defined as concrete cracking and rebar rupture, the failure probabilities of the impacted wall were calculated as a function of the peak impact load. The integrated deterministic and probabilistic analysis approach was applied to the Ignalina Nuclear Power Plant in Lithuania. The conclusions from this analysis was that a through-the-wall crack in the concrete element of a plant wall may occur with a probability of 0.0266, but the failure probability of the reinforcement bars is very small, that is, near zero. Thus, no perforation of the impacted wall by structures of the aircraft should occur. The importance of performing a probabilistic analysis of crash events is shown by comparing results to those obtained by a mean value deterministic approach. [ABSTRACT FROM AUTHOR]

• A commercial aircraft model was developed and validated through FTHA and MTIA. • Postulated aircraft crash to tokamak building was evaluated by SPH-FE coupling method. • Damage of concrete and embedded rebar was quantified under comprehensive conditions. • Sensitivity analyses were performed to rank significance of four independent variables. Nuclear structures, systems and components important to safety should be adequately protected against diverse internal and external hazards. As part of the effort, a few comprehensive guidelines to deal with human-induced events were established and individual researches to assess fissile plant containment buildings under plausible aircraft colliding conditions were carried out. In relation to developing fusion plants, soundness of major structures as a barrier should also be ensured to prevent disaster due to potential external hazards as well as internal hazards like the leakage of radioactive material and electromagnetic waves. The objective of this study is to examine structural integrity of postulated tokamak building taking into account dynamic loading derived from aircraft collision process. The numerical models of aircraft and reinforced concrete structure were made in use of smoothed-particle hydrodynamics and finite element methods. Appropriateness of time-dependent impact force and impulse histories was verified through comparison between preliminary analysis data for a rigid wall and those obtained from Riera method. Systematic analyses of aircraft crash onto the tokamak building were performed under hypothetical scenarios with different variables such as impact velocities, angles and rebar diameters. As results, basic engineering parameters such as stresses and strains of the rebar were calculated, and damage of the concrete was estimated. Further sensitivity analyses were performed and effects of each numerical input were discussed in terms of the significant. [ABSTRACT FROM AUTHOR]

• Analytical approaches for predicting the load-bearing capacity of rc-structures. • Efficient methods for estimating the load-bearing capacity. • Different calculation rules are implemented as an extension of the original CEB model. • Results of the extended CEB models are validated with impact tests and FE-Simulations. Protective Reinforced Concrete (RC) barrier walls of nuclear or industrial facilities are required to withstand accidental or intentional missile impact. The missiles (projectiles) can be classified as hard, semi-hard or soft. In particular, an airplane crash on a reinforced concrete structure causes local and global damage to the structure. Local damage mechanisms are usually associated with the impact of hard aircraft components such as engine shafts and wing boxes. In the event of a hard impact, the contact actions and target reactions are strongly coupled and therefore the calculation of capacity and damage effects is very sophisticated. There are various analysis methods for modelling both, hard and soft impacts. In this regard, empirical and semi-empirical models can be considered to calculate the load-bearing capacity in a simplified way with a few input parameters. However, validated numerical Finite Element (FE) simulation models allow further investigation on damage mechanism as well as detailed evaluation of stresses and strains in concrete and reinforcement. Hence, this paper investigates the efficiency of the existing analytical approaches as well as numerical simulation methods in predicting the load-bearing capacity of rc structures under hard and soft impact loads. Moreover, a novel simplified mechanical analytical method is proposed concerning hard impact loads. The mechanical principles are based on a nonlinear two degree of freedom (TDOF) system by Schlüter (Schlüter, 1987), which was extended for applications on hard impact scenarios considering the interaction between the impacting projectile and the rc target as well as penetration process of the projectile. FE-simulations and experimental test results of recent and ongoing research projects are presented and have been used for validation purposes and investigations. [ABSTRACT FROM AUTHOR]

LNG storage tanks are specified to be designed to withstand the impact of large commercial aircraft, while the existing studies refer to the safety assessment of the base-isolated LNG storage tank are quite limited. At present firstly, the detailed finite element (FE) models of LNG storage tanks are established. Based on the scaled tests of RC slabs under the impact of deformable and non-deformable projectiles, the numerical algorithm, constitutive model and the corresponding parameters of concrete are validated, which can both reproduce the behaviors of bending and punching shear failure potential induced by the aircraft impact. Then, the energy dissipation capacities and relative constitutive model of isolation systems are evaluated and validated. The reliable FE models of base-isolated LNG storage tanks with three typical isolation systems are established Furthermore, by adopting the missile–target coupled method, the dynamic responses and damage failure of tanks under aircraft impact are assessed, it derives that, (i) the fuselage and engines impact regions of tank wall are locally perforated and penetrated, the connection between the inner steel wall and deck is torn, and the safety of tanks is hard to be guaranteed; (ii) the selection isolation systems have sufficient lateral stiffness to resist the excessive global deformation of the base-isolated LNG storage tanks under aircraft impact, different types of isolation systems and boundary conditions of tanks have slight influence on the local damage of tank wall. The present work could provide beneficial guidances for the design and safety assessment of the base-isolated large-scale LNG storage tanks under aircraft collisions. • Refined FE models of LNG storage tanks against aircraft collisions are established. • Numerical algorithm, constitutive model and parameters of concrete are validated. • Energy dissipation capacities and isolator are evaluated and validated. • Dynamic response and damage failure of tanks under A380 aircraft impact are assessed. [ABSTRACT FROM AUTHOR]

• Consequence of gas explosion in the vicinity of nuclear power plant is analysed. • Butane explosion show a maximum overpressure of 0.27 bar and hydrogen shows a 0.37 bar pressure. • Building obstacles have influence on the evolution of fireball and overpressure propagation. • Predicted overpressure loadings could damage safety components needed to execute reactor shutdown. • The work is useful in designing the layout of the plant and placement of items important to safety. The International Atomic Energy Agency emphasizes on the safety assessment of fires involved by the crash of a large commercial aircraft into a nuclear power plant. In the guideline, it requires that a total load of aviation fuel that causes damage to exterior plants' components should be included when performing the initial stages of the nuclear plant site evaluation process and over the entire lifetime of the plant operation. In this study, the effects of jet fuel and hydrogen-induced external explosion on a nuclear power plant was investigated and analyzed. A turbulence model based on Reynolds-averaged Navier-Stokes CFD solver, called FLACS, was used to determine the explosion parameters within the plant vicinity. The simulation results of key explosion parameters for butane explosion show a deflagrative overpressure of 0.27 bar and impulse load of 0.015 bar·s at some preselected position. An elevated local temperature of about 2030 K is recorded for this fuel. Hydrogen explosion causes a maximum overpressure of 0.37 bar, and a maximum positive pressure impulse load of 0.022 bar·s at the exterior walls of building structures. From the findings, it showed that building obstacles have a substantial influence on the evolution of fireball and overpressure propagation. The computed overpressure and impulsive loadings observed are capable of causing substantial structural damages and vulnerabilities. A significantly elevated flame temperature recorded would have a harmful effect on the safety function of structures, systems and components (SSCs) that are needed to execute reactor shutdown. The findings of this study may be used to revisit the safety evaluation of a nuclear power plant (NPP) site with regards to the risks and consequences associated with external explosion due to aircraft impact. It is also useful in designing the layout of the NPP and site placement of relevant items important to safety. [ABSTRACT FROM AUTHOR]

Summary: Since the 9/11 attacks, whether nuclear power plants (NPPs) can withstand the malicious impact of large commercial aircraft has become a question that must be considered in the design phase. Refined model and fine‐scale element reflect more accurately the failure procedure and behaviour. However, due to the exceedingly complex structure of NPP, the traditional meshing method requires a substantial number of geometric operations involving point, line, area, and volume, leading to a tedious modelling process and very high computational costs, as well as making it difficult to modify and optimize the model. This paper combines the scaled boundary finite element method with the octree technique to refine nuclear engineering damage evolution analysis and establish a refined numerical model of the Generation III+ NPP, considering the detailed equipment hatch, air intake, and internal steel containment vessel structures. Subsequently, the refined damage evolution analysis of a large commercial aircraft crashing into an NPP was developed. The mesh size sensitivity, impact region shape comparison, and the influence of different impact heights were discussed. The results indicate that the cross‐scale refined meshing and analysis method provides a high‐quality discrete grid with fewer elements. Furthermore, this method is highly flexible, more accurately simulating the damage evolution and gradual destruction process. We recommend future structural optimization for the air intake and conducting detailed analyses at this location. The cross‐scale analysis method presented in this paper enables a rapid, refined simulation of a malicious impact by a large commercial aircraft. Additionally, it provides technical support for future studies of the responses of NPPs' internal structures, systems, and equipment under extreme earthquake and other disaster conditions. [ABSTRACT FROM AUTHOR]

This study examines patterns of skeletal trauma in propeller-driven aircraft crashes and blast-related ground loss incidents from WWII. Specifically, descriptions and criteria used to characterize aircraft deceleration- versus blast-related skeletal injuries are examined from 35 recently identified forensic anthropology cases to determine possible diagnostic traits and characterize skeletal trauma associated with these events. Among these cases, blast trauma is more localized within the skeleton and is associated with one or few primary directions of force. It is recommended that analysts differentiate between secondary and nonspecific blast trauma categories. Conversely, aircraft crash deceleration trauma is more widespread throughout the skeleton, with torsional fractures and injuries occurring from multiple or indeterminate directions. These traits reflect factors such as more complex loading environments than is seen in blast events. Two case studies are presented in detail to further illustrate differences in aircraft crash and blast-related incidents. Both studies emphasize consideration of the body as a whole unit to facilitate interpretations. While the cases presented herein result from historic war-related casualties that characterize the Defense POW/MIA Accounting Agency's (DPAA) casework, these skeletal cases provide guidelines more appropriate than clinically derived criteria developed through assessments of soft tissue injuries. These guidelines can be used by anthropologists and pathologists working with skeletal remain from mass disasters and other complex contexts, as well as provide avenues for future research., (© 2020 American Academy of Forensic Sciences.)

The Internet not only has changed the dynamics of our collective attention but also through the transactional log of online activities, provides us with the opportunity to study attention dynamics at scale. In this paper, we particularly study attention to aircraft incidents and accidents using Wikipedia transactional data in two different language editions, English and Spanish. We study both the editorial activities on and the viewership of the articles about airline crashes. We analyse how the level of attention is influenced by different parameters such as number of deaths, airline region, and event locale and date. We find evidence that the attention given by Wikipedia editors to pre-Wikipedia aircraft incidents and accidents depends on the region of the airline for both English and Spanish editions. North American airline companies receive more prompt coverage in English Wikipedia. We also observe that the attention given by Wikipedia visitors is influenced by the airline region but only for events with a high number of deaths. Finally we show that the rate and time span of the decay of attention is independent of the number of deaths and a fast decay within about a week seems to be universal. We discuss the implications of these findings in the context of attention bias.