Impact Location Research Articles

Structural Health Monitoring Impact Classification Method Based on Bayesian Neural Network

This paper proposes a novel method for multi-class classification and uncertainty quantification of impact events on a flat composite plate with a structural health monitoring (SHM) system by using a Bayesian neural network (BNN). Most of the existing research in passive sensing has focused on deterministic approaches for impact detection and characterization. However, there are variability in impact location, angle and energy in real operational conditions which results in uncertainty in the diagnosis. Therefore, this paper proposes a reliability-based impact characterization method based on BNN for the first time. Impact data are acquired by a passive sensing system of piezoelectric (PZT) sensors. Features extracted from the sensor signals, such as their transferred energy, frequency at maximum amplitude and time interval of the largest peak, are used to develop a BNN for impact classification (i.e., energy level). To test the robustness and reliability of the proposed model to impact variability, it is trained with perpendicular impacts and tested by variable angle impacts. The same dataset is further applied in a method called multi-artificial neural network (multi-ANN) to compare its ability in uncertainty quantification and its computational efficiency against the BNN for validation of the developed meta-model. It is demonstrated that both the BNN and multi-ANN can measure the uncertainty and confidence of the diagnosis from the prediction results. Both have very high performance in classifying impact energies when the networks are trained and tested with perpendicular impacts of different energy and location, with 94% and 98% reliable predictions for BNN and multi-ANN, respectively. However, both metamodels struggled to detect new impact scenarios (angled impacts) when the data set was not used in the development stage and only used for testing. Including additional features improved the performance of the networks in regularization; however, not to the acceptable accuracy. The BNN significantly outperforms the multi-ANN in computational time and resources. For perpendicular impacts, both methods can reach a reliable accuracy, while for angled impacts, the accuracy decreases but the uncertainty provides additional information that can be further used to improve the classification.

Newly formed craters on Mars located using seismic and acoustic wave data from InSight

Meteoroid impacts shape planetary surfaces by forming new craters and alter atmospheric composition. During atmospheric entry and impact on the ground, meteoroids excite transient acoustic and seismic waves. However, new crater formation and the associated impact-induced mechanical waves have yet to be observed jointly beyond Earth. Here we report observations of seismic and acoustic waves from the NASA InSight lander’s seismometer that we link to four meteoroid impact events on Mars observed in spacecraft imagery. We analysed arrival times and polarization of seismic and acoustic waves to estimate impact locations, which were subsequently confirmed by orbital imaging of the associated craters. Crater dimensions and estimates of meteoroid trajectories are consistent with waveform modelling of the recorded seismograms. With identified seismic sources, the seismic waves can be used to constrain the structure of the Martian interior, corroborating previous crustal structure models, and constrain scaling relationships between the distance and amplitude of impact-generated seismic waves on Mars, supporting a link between the seismic moment of impacts and the vertical impactor momentum. Our findings demonstrate the capability of planetary seismology to identify impact-generated seismic sources and constrain both impact processes and planetary interiors. Impact-induced acoustic and seismic wave events on Mars recorded by the InSight lander’s seismometer have been traced to fresh craters observed in spacecraft imagery.

Climate and vegetation and their impact on stable C and N isotope ratios in bat guano

Cave guano deposits represent a relatively untapped paleoecological archive that can provide information about past vegetation, climate, and bat diet over several millennia. Recent research suggests that carbon isotope values (δ13C) measured in guano accumulations from insectivorous bats reflect the relative abundance of C3 and C4 plants on the landscape while nitrogen isotope values (δ15N) may reflect precipitation amount. Together, these proxies can provide useful information for restoration practitioners seeking to understand how plant species composition has changed over time in relation to climate and land use. To better calibrate these proxies for use in restoration, we compared instrumental records of precipitation and satellite imagery of vegetation with isotope values measured in modern bat guano from Mary Lawson Cave, a large limestone cavern located in central Missouri. Mary Lawson Cave hosts a maternity colony of insectivorous gray bats (Myotis grisescens), and as such, contains significant guano accumulations. In the fall of 2018, we collected a 60 cm long guano core that dates to 1999 cal AD at its base. Guano core δ13C values decrease from the base toward the surface (from ~-26 to -27‰) whereas δ15N values increase toward the surface even after accounting for ammonia volatilization (from ~3 to 5‰). Presently, the landscape around Mary Lawson Cave is dominated by a deciduous forest and pasture. Given that the land cover has changed very little over this period, the decline in δ13C values toward the present likely reflects a shift in land management on farms and/or increases in invasive C3 species. Rainfall amounts from nearby Lebanon, Missouri, are significantly positively correlated with guano δ15N values, a relationship that is notably opposite that observed previously in soil and plants. We argue that heavy fertilizer application and significant grazing intensity could lead to the accumulation of large pools of excess labile nitrogen which would be vulnerable to leaching during precipitation events. The relationship between guano δ15N values and precipitation may differ for materials from less agriculturally impacted locations or periods and should be extended into the past with caution.

Comparative study of immunological biomarkers in the carpet shell clams (Ruditapes decussatus) from metal-contaminated sites in the South Lagoon of Tunis (Tunisia)

The South Lagoon of Tunis (Tunisia) is a Mediterranean lagoon adversely affected by industrial contaminants, harbour activity and untreated urban sewage. In this lagoon, the clam Ruditapes decussatus has been widely used as a biomonitor of seawater pollution through measurements of parameters related to oxidative stress and neurotoxicity. However, few studies have considered parameters of the immune system of this species in the South Lagoon of Tunis. Therefore, the aim of the present work was to evaluate several immune-related parameters in the cell-free haemolymph of carpet shell clams sampled during August and February from three polluted sites in the South Lagoon of Tunis (S1, S2 and S3) and one less polluted site as a reference site (RS) in order to identify suitable biomarkers for environmental quality assessments of this ecosystem. Concerning the immune-related parameters, seasonal factors modulated phenoloxidase, lysozyme, protease and esterase activity, with lower values measured for samples collected in August than for samples collected in February. In fact, bactericidal activity against two of the pathogenic bacteria tested and the activity of most immune-related enzymes were reduced in the cell-free haemolymph of clams collected from the most sampling sites in August compared to February one. In addition, values of abiotic parameters (temperature, salinity and pH) and metal (cadmium, copper, iron, lead and zinc) concentrations in the clams’ soft tissues, previously obtained and published by the authors, as well as the values of immune-related parameters were integrated using principal component analyses. Results indicated that the values of all measured immune-related parameters were negatively correlated with the temperature values and the variations most of these parameters highlighted that the chemical industrial area (S3) was the most impacted location within the South Lagoon of Tunis. The present study illustrates that the immune-related parameters measured in carpet shell clam cell-free haemolymph represent suitable biomarkers for environmental quality assessments because they provide effective seasonal and spatial discrimination.

Oblique impact responses of Hybrid III and a new headform with more biofidelic coefficient of friction and moments of inertia.

New oblique impact methods for evaluating head injury mitigation effects of helmets are emerging, which mandate measuring both translational and rotational kinematics of the headform. These methods need headforms with biofidelic mass, moments of inertia (MoIs), and coefficient of friction (CoF). To fulfill this need, working group 11 of the European standardization head protection committee (CEN/TC158) has been working on the development of a new headform with realistic MoIs and CoF, based on recent biomechanics research on the human head. In this study, we used a version of this headform (Cellbond) to test a motorcycle helmet under the oblique impact at 8 m/s at five different locations. We also used the Hybrid III headform, which is commonly used in the helmet oblique impact. We tested whether there is a difference between the predictions of the headforms in terms of injury metrics based on head kinematics, including peak translational and rotational acceleration, peak rotational velocity, and BrIC (brain injury criterion). We also used the Imperial College finite element model of the human head to predict the strain and strain rate across the brain and tested whether there is a difference between the headforms in terms of the predicted strain and strain rate. We found that the Cellbond headform produced similar or higher peak translational accelerations depending on the impact location (−3.2% in the front-side impact to 24.3% in the rear impact). The Cellbond headform, however, produced significantly lower peak rotational acceleration (−41.8% in a rear impact to −62.7% in a side impact), peak rotational velocity (−29.5% in a side impact to −47.6% in a rear impact), and BrIC (−29% in a rear-side impact to −45.3% in a rear impact). The 90th percentile values of the maximum brain strain and strain rate were also significantly lower using this headform. Our results suggest that MoIs and CoF have significant effects on headform rotational kinematics, and consequently brain deformation, during the helmeted oblique impact. Future helmet standards and rating methods should use headforms with realistic MoIs and CoF (e.g., the Cellbond headform) to ensure more accurate representation of the head in laboratory impact tests.

Effects of pulsed magnetic field on the flight and impact of supersonic plasma spraying particles and the properties of coatings

In order to study the mechanism of pulsed magnetic field in supersonic plasma spraying process, the preparation of a Ni60 coating by pulsed magnetic field (PMF)-assisted supersonic plasma spraying was studied theoretically and experimentally to characterise the flight, impact, and spread behaviours of coating powder particles as well as stacking results and thus gain valuable mechanistic insights. PMF application made the particle flight paths converge inward, the flight speed decrease, decelerated the temperature drop, improved the particle melting state, promoted impact location concentration, afforded a more uniform particle morphology, and hindered breaking and splashing to increase the hardness, bonding strength, residual compressive stress, and compactness of the deposited coating. The obtained results provide a solid basis for the study of PMF–assisted supersonic plasma spraying.

Experimental analysis of dynamic behavior of elastic visco-plastic beam under repeated mass impacts

Repeated impact behaviors of an elastic visco-plastic steel beam struck by a hard sphere are experimentally examined in this paper. The interaction between impact bodies, behaviors of sub-impacts, wave propagations and dynamics of the beam are tested to get a better understanding into the mechanism of repeated impacts. At the four different impact locations on the beam, thirty repeated-mass-impact tests are conducted for each impact location under identical initial conditions except for the accumulated deformations. The effects of repeated impacts and impact location on the sub-impact behaviors, local contact deformations, wave propagations, high-frequency vibrations and long-term beam responses are analyzed. The sub-impact phenomenon is observed. The deterministic and random features of the influences of repeated impacts on the behaviors of sub-impacts are observed. The deterministic feature similar to the elastic shakedown phenomenon is found to occur for the first sub-impact behaviors, such as the kinetic coefficient of restitution, residual deformations and early wave propagations. The random feature is found to occur for the second sub-impact behaviors as well as the vibrational modes and long-term stress and displacement responses. The couplings of sub-impacts, wave propagation and high-frequency vibrations make the repeated impact behaviors of flexible structure much more complicated than single impact.

Rapid assessment of fire damage to reinforced concrete structures using the surface wave method with contact and non-contact receivers

The study developed a rapid on-site assessment method for fire damage of reinforced concrete structures by using surface wave dispersion characteristics. A reinforced concrete slab containing four kinds of arrangement of steel-reinforced bars was cast. The gas furnace produced the fire damage by heating on one surface of the slab with a maximum temperature of 600˚C. The surface wave tests were carried out using an impact source and a receiver 0.5 m away from the impact location before and after the fire damage. The impactor is a small hammer embedded with a piezoelectric element to record the initial time of the impact. Contact and non-contact receivers were applied. The former is a displacement receiver, and the latter is a microphone. The surface wave response in the waveform was filtered out, and then processed by the short-time Fourier transform and reassigned method to obtain the group velocity spectrogram. The wave velocity-wavelength diagram of the surface wave was used for analysis. This study compares the results obtained by the two types of receivers before and after the fire. The influence of the relative directions between the survey line and the steel bars is also discussed. The results show that the test results obtained from the two types of receivers are similar under room temperature and 600˚C. However, the signal noise of the microphone is relatively large, and the consistency of repeated tests after a fire is poorer. The oblique angle between the measuring line and the steel bar is the most suitable choice because it can better distinguish the severity of fire damage and estimate the depth of deterioration.

Analysis of the Vibration Modes of Impact Geoplates and Implications for Bedload Flux and Grain Size Measurements

AbstractSeismic geophones have been frequently used in combination with metal plates to indirectly estimate bedload flux in gravel bed mountain rivers. This indirect method has been calibrated with direct measurements in several conditions and proved effective to provide relevant information on spatial and temporal scales otherwise impossible to explore. Notwithstanding, a detailed description of the vibration modes of the plate is still lacking, limiting the possibility to interpret the signal. Here, we report on two sets of experiments where we explored the geoplate response in terms of frequency and amplitude of different vibrational modes. A first set of dry experiments was designed to investigate the variability of the signal as a function of the impact location on the plate. A second set reproduced standard flow conditions, with single pebbles transported by the flow. Results highlighted the occurrence of two main vibration modes, with a first rapid phase (about 5 ms) characterized by higher frequencies, and a second longer and more stable phase of vibration with a frequency in the range of 300–400 Hz. The signal of single impacts showed a good correlation with pebble mass, with only the number of impacts on the plate depending on the flow conditions. The evaluation of the grain size is a challenge given the variability of the signal generated by similar impacts. We propose a filtering strategy to improve grain size estimation. Our analysis shows that a more detailed understanding of the vibrational modes helps identifying best practices for an improved signal acquisition and elaboration.

Spatially explicit life cycle assessments reveal hotspots of environmental impacts from renewable electricity generation

Renewable energy generation has great potential to reduce greenhouse gas emissions, however, it may exacerbate other environmental impacts, such as water scarcity, elsewhere in the supply chain. Here, we reveal a wide range of global environmental impacts of concentrated solar power, run-of-river hydropower, and biomass burning compared to classical coal-fired power: Spatially explicit life cycle impact assessment is used to evaluate their supply chains with respect to demand for energy, land, material, and water, greenhouse gas emissions, and impacts on human health and ecosystem quality with a focus on mining. Hotspot analyses in terms of location and type of impact show that there is no clear preference for any of the technologies, mainly because water consumption is often critical on-site. The examined concentrated solar power plant is the least suitable for a sustainable energy transition: Its spatial hotspots are spreading the furthest globally and may exceed those of coal combustion in number and severity. The presented methodology is the basis to mitigate such environmental hotspots.

Vascular Complications in Children Following Button Battery Ingestions: A Systematic Review.

Children presenting to health care facilities with button battery (BB) impaction. To describe characteristics of children with vascular complications after BB impaction, as well as associated outcomes. National Capital Poison Center registry and PubMed database from inception to December 2021. All reports describing children aged <18 years with vascular, esophageal, or airway complications after BB ingestion. We extracted characteristics including date of publication, age and sex of child, battery type and size, duration and location of impaction, complications, subsequent interventions, and interval between battery removal and death. A total of 361 cases involved severe complications or death after BB ingestion (321 cases from the National Capital Poison Center registry database, 40 additional cases from PubMed). Nineteen percent (69 of 361) were fatal and 14% (51 of 361) involved vascular injuries. Three-quarters (75%) of vascular complications were aorto-esophageal fistulae and 82% of vascular injuries were not survivable. Fatal vascular cases had significantly longer median impaction time (96hours versus 144 hours, P <.05) and a wider range of presenting features than survivors. The total number of cases with vascular complications was small, data reported varied between cases, and no data were available on overall exposure. Long-term morbidity data were not available for the survivors. Prolonged BB impaction is a risk factor for vascular complications and death. A high index of suspicion is required for children representing with hematemesis after BB impaction, with prompt transfer to a tertiary center because vascular surgical intervention may offer a chance of survival.

Dynamics of polychaete communities in the intertidal soft bottom of Alexandria coast, Egypt

The species composition and abundance of polychaetes in the soft bottom intertidal zone of Alexandria coast were studied bi-monthly from August 2018 to June 2019. This study identified 42 species, including five newly recorded species for the Egyptian Mediterranean waters, which could be introduced either from the Western Mediterranean, Atlantic waters, or the Indo-Pacific Region. Furthermore, species diversity and numerical abundance of polychaetes showed significant temporal and spatial variations, which appeared to be related to environmental variability in the study area. The statistical analyses showed significant variations in polychaete assemblages and discriminated to some extent between locations that are subjected to anthropogenic impact and less impacted locations. Tolerant species contributed mainly to the abundance of the polychaete assemblages of impacted sites, in contrast with sensitive polychaetes species, which contributed mainly to the assemblages of less impacted sampling sites.

A fast simulation tool for ship grounding damage analysis

This paper presents a numerical tool based on analytical formulations for rapid assessment of damage in ship grounding accidents. Through a step-by-step solution, the ship resistant force is assessed by the super-element method and transferred to a 6-DoF external dynamics solver, which updates the global ship motion by taking into account the action of hydrodynamic forces. The two-way coupled solver is first confronted to finite element simulations considering a 34-kTons cruise ship in bottom and side grounding situations. It is then used to simulate thousands of scenarios, varying the rock shape, the ship impact location, initial penetration and velocity as well as rock/hull friction coefficient. In this way, the influence of ship structural properties (shell thickness, material grade, etc.) on the breach size is investigated. The highest breach reductions are obtained by increasing either the outer shell thickness or the material grade, while acting on transverse frames marginally affects the damage extent. It also appears that a bottom impact is systematically more damaging than a side impact, all else being equal. Likewise, a structural reinforcement is demonstrated to be more efficient in bottom grounding than in side grounding. This is because in side grounding situation, the ship is pushed away by rock and thus undergoes significant sway, yaw and sometimes roll motions that limit the damage extent. Finally, friction is shown to be of primary importance in bottom grounding, while its effect is rather limited in side grounding.

Ballistic impact response of flexible and rigid UHMWPE textile composites: Experiments and simulations

This study elaborates on the effects of matrix rigidity on the high-velocity impact behaviour of UHMWPE textile composites using experimental and numerical methods. Textile composite samples were manufactured of a plain-weave fabric (comprising Spectra® 1000 fibres) and four different matrix materials. High-velocity impact tests were conducted by launching a spherical steel projectile to strike on the prepared samples via a gas gun. The experimental results showed that the textile composites gradually changed from a membrane stretching mode to a plate bending mode as the matrix rigidity and thickness increased. The composites deformed in the membrane stretching mode had higher impact resistance and energy absorption capacity, and it was found that the average energy absorption per ply was much higher in this mode, although the number of broken yarns was smaller in the perforated samples. Moreover, the flexible matrix composites always had higher perforation resistance but larger deformation than the rigid matrix counterparts in the tested thickness and velocity range. A novel numerical modelling approach with enhanced computational efficiency was proposed to simulate textile composites in mesoscale resolution. The simulation results revealed that stress and strain development in the more rigid matrix composite was localised in the vicinity of the impact location, leading to larger local deformation and inferior perforation resistance.

Numerical Simulation of Viscosity Effects on Carbon Steel 90° Elbow Erosion due to Sand-Liquid Flow

Elbow pipes are important pipeline components in hydrocarbon transportation systems, and they were prone to erosive wear by the impact of abrasive particles. A discrete phase modeling (DPM) and numerical simulation of the liquid-sand transportation process was carried out focused on the investigation into the influence of carrier fluid viscosity on erosion distribution of carbon steel 90° elbows. The accuracy of the predicted results was validated by comparison with experimental data. CFD simulations have been carried out by combining DPM to predict the erosion rate and particle impaction regions in carbon steel 90° elbow with a diameter of 50.8 mm. The fluid viscosity is set for 1cP, 5cP, and 15 cP with an inlet velocity of 8 m/s, and the size of sand particles is 200 μm. While the maximum erosion rates enhance with an increase in fluid viscosity, the location of maximum particle impaction has been specified to be adjacent to the outlet for 1 cP and 5 cP carrier fluid viscosity. It is also found that increasing the viscosity does not considerably alter the average erosion rate. Moreover, the increase in carrier fluid viscosity with the same flow velocity influences maximum erosion rate and yields 1.45 times higher erosion rates at 15 cP compared to 5cP and 1cP. This is mainly due to severe sand impaction at the side of the elbow wall.

Does Increasing the Severity of Penalties Assessed in Association With the "Zero Tolerance for Head Contact" Policy Translate to a Reduction in Head Impact Rates in Youth Ice Hockey?

The risk of concussion is high in Canadian youth ice hockey. Aiming to reduce this burden, in 2011, Hockey Canada implemented a national "zero tolerance for head contact (HC)" policy mandating the penalization of any player HC. In 2018 to 2020, Hockey Canada further amended this HC policy including stricter enforcement of severe HCs. This study aimed to compare HC rates, head impact location, and HC enforcement prepolicy, postpolicy, and after policy amendments in elite U15 Canadian youth ice hockey. This is a prospective cohort study. A collection of events with the video camera located at the highest point near center ice in public ice hockey arenas in Calgary, Alberta. A convenience sample of 10 AA U15 games prepolicy (2008-2009), 8 games postpolicy (2013-2014), and 10 games after policy amendments (2020-2021). An analysis of 3 cohort years regarding the HC-policy implementation and amendments. Using Dartfish video-analysis software, all player contacts and HCs [direct (HC1), indirect (eg, boards, ice) (HC2)] were tagged using validated criteria. Univariate Poisson regression clustering by team-game offset by game length (minutes) was used to estimate incidence rates (IR) and incidence rate ratios (IRR) between cohorts. With additional rule modifications, a 30% reduction in HC1s emerged (IRR 2013-2020 = 0.70, 95% CI, 0.51-0.95). Since the HC-policy implementation, HC1s decreased by 24% (IRR 2008-2020 = 0.76, 95% CI, 0.58-0.99). The proportion of HC1s penalized was similar across cohorts (P 2008-2009 = 14.4%; P 2013-2014 = 15.5%; P 2020-2021 = 16.2%). The HC-policy amendments have led to decreased HC1 rates. However, referee enforcement can further boost the HC-policy effectiveness. These findings can help future referee training and potential rule modifications to increase player safety nationally.

Evaluation of the position of the impacted maxillary canine on CBCT

<h3>Objectives</h3> The aim of this study was to evaluate the position of the impacted maxillary canine on CBCT images. <h3>Study Design</h3> CBCT scans of 61 impacted canines in 43 patients were examined. The inclusion criteria were canine impaction, no artifacts that could compromise accurate localization of the impacted tooth, and no pathosis in the maxillae that could compromise evaluation of the tooth. The following canine-impacted related variables were evaluated: impaction side (unilateral, bilateral), impaction location (facial, center, palatal), impaction angulation (vertical, horizontal, oblique), relation to adjacent tooth (central and lateral incisors, first premolar), adjacent anatomical structures (nasal cavity, maxillary sinus, facial or palatal cortices). Patient demographic information was also collected. All variables were assessed by an oral and maxillofacial radiologist. <h3>Results</h3> Among the 43 CBCT scans, the subjects' ages ranged from 9 to 40 years old. Bilateral impacted canines were discovered in 18 subjects unilateral impactions were observed in 25. The impaction location of these canines was observed at the following frequencies: center 47.5%, facial 34.4%, and palatal 18%. Of the 61 impacted canines, the oblique angulation was the most frequent at 63.9%. In total, 78.7% of the impacted canines were in close relationship with the lateral incisor. The impacted teeth were most commonly related to the nasal cavity and maxillary sinus (62.3% and 57.4%, respectively). <h3>Conclusions</h3> CBCT allows the clinician to examine the impacted maxillary canine precisely and guide the surgeon for optimal treatment planning, which may reduce possible post-surgical complications. <b>Statement of Ethical Review</b> Human/Animal subjects were used and this study was approved by an institutional ethics panel

Effects of risk perception and perceived certainty on evacuate/stay decisions

In hurricane evacuation studies, the extant literature has extensively explored the effect of risk perception on evacuate/stay decisions. However, less attention has been paid to how perceived certainty affects households' evacuate/stay decisions. The objectives of this paper are to explore the effects of (1) perceived certainty about location of impact on both risk perception and perceived certainty about evacuation logistics; (2) risk perception on perceived certainty about evacuation logistics; and (3) perceived certainty about evacuation logistics on evacuate/stay decisions. Survey data gathered from households in the Jacksonville, Florida metropolitan area after Hurricane Matthew (2016) were analyzed using structural equation modeling (SEM). In addition, SEM allowed us to identify the factors that could be used to predict risk perception, perceived certainty about location of impact, and perceived certainty about evacuation logistics. The results showed that perceived certainty about location of impact had a non-significant effect on risk perception. Perceived certainty about location of impact had a positive effect on perceived certainty about evacuation logistics. However, the effect of risk perception on perceived certainty about evacuation logistics was non-significant. Both risk perception and perceived certainty about evacuation logistics had positive effects on households' evacuation decision while perceived certainty about location of impact had a negative effect on households' likelihood of evacuating. Overall, the findings can be used to improve on the prediction of households’ evacuation behavior.

Identification of floodwater source areas in Nepal using SCIMAP‐Flood

AbstractPractical approaches for managing flooding from fluvial sources are moving away from mitigation solely at the point of impact and towards integrated catchment management. This considers the source areas, flow pathways of floodwaters and the locations and exposure to the risk of communities. For a field site in southern Nepal, we analyse catchment response to a range of simulated rainfall events, which when evaluated collectively can help guide potential flood management solutions. This is achieved through the adoption of SCIMAP‐Flood, a decision support framework that works at the catchment‐scale to identify critical source areas for floodwaters. The SCIMAP‐Flood Fitted inverse modelling approach has been applied to the East Rapti catchment, Nepal. For multiple flood impact locations throughout the catchment, SCIMAP‐Flood effectively identifies locations where flood management measures would have the most positive effects on risk reduction. The results show that the spatial targeting of mitigation measures in areas of irrigated and rainfed agriculture and the prevention of deforestation or removal of shrubland would be the most effective approaches. If these actions were in the upper catchment above Hetauda or upstream of Manahari they would have the most effective reduction in the flood peak.

Mechanical model for the analysis of ship collisions against reinforced concrete floaters of offshore wind turbines

This paper presents a simplified mechanical model to study ship collisions against Reinforced Concrete (RC) floaters of Floating Offshore Wind Turbines (FOWTs). The model accounts for the deformability of both striking ships and struck RC structures, including a method to evaluate the elastic–plastic response of RC slabs with normal horizontal restraints, while considering contact area effects and punching shear failure. In the proposed model, the internal mechanics are coupled to the external body dynamics, whilst the hydro-mechanical effects acting on the collided bodies such as hydrostatic restoring, viscous, and wave damping forces are accounted for by the large rotations rigid-body dynamics solver MCOL. A parametric analysis is conducted on the model to study its sensitivity to changes in impact energy, impact location, reinforcement ratios, wall thicknesses, and striker rigidities, whose outcomes are compared with Non-Linear Finite Element (NLFE) simulations. The results show that the proposed model can accurately capture the penetrations in both structures, their body dynamics, and the contact force through the collision at a significantly lower computational cost than their NLFE counterpart.