scholarly journals Simulation Analysis of Void Defect Detection in Sandwich-Structured Immersed Tunnel Using Elastic Wave

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Ruiqiang Liu ◽  
Songhui Li ◽  
Guoxin Zhang ◽  
Shenyou Song ◽  
Jianda Xin
Keyword(s):  
Influencing Factors ◽  
Steel Plate ◽  
Plate Thickness ◽  
Image Method ◽  
Detection Accuracy ◽  
Imaging Method ◽  
Waveform Data ◽  
Immersed Tunnel ◽  
Void Defects ◽  
The Impact

Void defects can be easily generated between a steel plate and concrete joint due to the complicated internal structure of a sandwich-structured immersed tunnel (SSIT), which affect the overall bearing capacity of the main structure of the immersed tube tunnel. A prototype experiment was conducted to study the application of impact imaging method in the nondestructive detection of void defects in SSITs. The detection criterion for the impact imaging method was established based on the features of the waveform data. Nevertheless, the influence of steel plate thickness, material properties, void location, and structure on the detection accuracy of the impact imaging method is unclear. Therefore, numerical simulation was applied to study the influencing factors by establishing a different condition model. Good agreement between the experimental and numerical results was observed for the response waveform collected from the inspection area. Using the calculation model and identified material parameters validated in the active prototype experiment, numerical simulations of several sets, which considered all influencing factors, were performed. The application scope and sensitivity of the impact image method were recommended to reduce misjudgement in practical applications and improve detection accuracy.

Optimisation of Ceramic/Steel Composite Armour of a Constant Thickness

Volume 1 ◽  
2004 ◽  
Author(s):  
Tanju Cakir ◽  
R. Orhan Yildirim ◽  
Bilgehan Ogel
Keyword(s):  
Ceramic Tile ◽  
Steel Plate ◽  
Plate Thickness ◽  
Impact Resistance ◽  
Thickness Ratio ◽  
Constant Thickness ◽  
Impact Behaviour ◽  
Back Plate ◽  
Steel Composite ◽  
The Impact

Impact resistance of ceramic/steel composite armour against 7.62 mm AP (armour piercing) projectile is examined analytically, numerically and experimentally. Total armour thickness is taken to be constant. Ceramic tile thickness and steel plate thickness are changed to observe the effect of the variation of the thickness ratio on the impact behaviour of ceramic/steel armour. Results show that the impact behaviour of ceramics is related to the ceramic tile thickness and back plate thickness. It is found that there is an optimum ceramic/steel thickness ratio which provides the best protection against a specified threat for a constant total armour thickness.

scholarly journals Sensitivity Analysis of Steel-Plate Concrete Containment against a Large Commercial Aircraft

Energies ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2829
Author(s):  
Xiuyun Zhu ◽  
Jianbo Li ◽  
Gao Lin ◽  
Rong Pan ◽  
Liang Li
Keyword(s):  
Sensitivity Analysis ◽  
Plastic Strain ◽  
Steel Plate ◽  
Concrete Strength ◽  
Plate Thickness ◽  
Time History ◽  
Commercial Aircraft ◽  
Strength Grade ◽  
Displacement Response ◽  
The Impact

Due to the excellent impact resistant performance of steel-plate concrete (SC) structure compared with the conventional reinforced concrete (RC) structure, SC structure is preferred to be used in the design of external walls of nuclear island buildings for new nuclear power plants (NPPs). This study aims at evaluating the effect of material and geometric parameters of SC containment on its impact resistant performance, thus the numerical simulation and sensitivity analysis of SC containment subjected to malicious large commercial aircraft attack are conducted based on the force time-history analysis method. The results show that: (1) the impact resistant performance of full SC containment is better than that of half SC containment; (2) for relatively thin full SC containment, the impact response and concrete damage can be significantly reduced by the enhancing of concrete strength grade or the increasing of steel plate thickness; (3) for the thicker full SC containment, concrete strength grade has only a slight influence on the impact displacement response, and the increasing of steel plate thickness has no significant effect on mitigating the impact displacement response. However, the increasing of steel plate thickness can effectively reduce its plastic strain, and the decreasing of strength grade of steel plate may obviously increase its plastic strain; and (4) concrete thickness plays a decisive role on the improvement of impact resistance, which is more effective than the enhancing of concrete strength grade. Resultantly, this paper provides a reference and guidance for the design of SC structure external walls of nuclear island buildings against a large commercial aircraft.

Bullet Impact on Steel and Kevlar®/Steel Armor: Computer Modeling and Experimental Data

2004 ◽  
Author(s):  
Dale S. Preece ◽  
Vanessa S. Berg
Keyword(s):  
Impact Crater ◽  
Steel Plate ◽  
Plate Thickness ◽  
Material Model ◽  
Impact Craters ◽  
Full Penetration ◽  
The World ◽  
Good Comparison ◽  
The Impact ◽  
Witness Plate

Computer hydrocode analyses and ballistic testing have been used to investigate the effectiveness of steel plate armor against lead/copper bullets commonly available in the U.S. and across the world. Hydrocode simulations accurately predict the steel plate thickness that will prevent full penetration as well as the impact crater geometry (depth and diameter) in that thickness of steel armor for a 338 caliber bullet. Using the hydrocode model developed for steel armor, studies were also done for an armor consisting of a combination of Kevlar® and steel. These analyses were used to design the experiments carried out in the ballistics lab at Sandia National Laboratories. Ballistics lab testing resulted in a very good comparison between the hydrocode computer predictions for bullet impact craters in the steel plate armor and those measured during testing. During the experiments with the combination armor (Kevlar®/steel), the steel became a witness plate for bullet impact craters following penetration of the Kevlar®. Using the bullet impact craters in the steel witness plate it was determined that hydrocode predictions for Kevlar® armor are less accurate than for metals. This discrepancy results from the inability of the hydrocode (Eulerian) material model to accurately represent the behavior of the fibrous Kevlar®. Thus, this paper will present the hydrocode predictions and ballistics lab data for the interaction between a lead/copper bullet and several armoring schemes: 1) steel, 2) Kevlar®, and 3) a Kevlar®/steel combination.

scholarly journals THE ROLE OF BACKFILL QUALITY ON CORRUGATED STEEL PLATE CULVERT BEHAVIOUR

2017 ◽  
Vol 12 (1) ◽  
pp. 1-11 ◽  
Author(s):  
Damian Beben
Keyword(s):  
Numerical Analysis ◽  
Internal Friction ◽  
Steel Plate ◽  
Plate Thickness ◽  
Numerical Calculations ◽  
Unit Weight ◽  
Steel Shell ◽  
Orthotropic Plates ◽  
Angle Of Internal Friction ◽  
The Impact

The subject of the article is a three-dimensional numerical analysis of the impact of backfill quality on the deformation of corrugated steel plate culvert. In the numerical analysis, the author took into consideration three different backfill types. The paper presents the calculations performed with the use of Abaqus program based on finite element method. A steel shell was modelled with the use of the theory of orthotropic plates, and backfill with the use of elastic-perfectly plastic Drucker-Prager model. The author made the numerical calculations under static live loads for the corrugated steel plate culvert with a span of 12.315 m and height of shell of 3.555 m. Soil cover over the shell crown was equal to 1.0 m. The steel shell consisted of the sheets of the corrugation of 0.14×0.38 m and plate thickness of 0.0071 m. The main aim of this paper is to present the impact of backfill quality (internal friction angle, unit weight, Young’s modulus) on the effort of the steel shell. The paper also shows the numerical calculations for the actual culvert, which previously had been studied experimentally. The author compared the obtained numerical results to the results of experiments. Parametric analysis showed that the angle of internal friction was a major factor in corrugated steel plate culverts. Considering the entire width of the corrugated steel plate culvert, the calculation model II was most favourable. The proposed method of modelling of the corrugated steel plate culvert allowed obtaining reasonable values of displacements and stresses in comparison to experimental results.

THE MODEL FOR MANAGING INVESTMENTS IN THE MOSCOW ENVIRONMENT BASED ON A POWER REGRESSION EQUATION

2020 ◽  
Vol 2 (7) ◽  
pp. 91-99
Author(s):  
E. V. KOSTYRIN ◽  
◽  
M. S. SINODSKAYA ◽  
Keyword(s):  
Solid Waste ◽  
Influencing Factors ◽  
Pair Correlation ◽  
Approximation Error ◽  
Regression Equation ◽  
Regression Equations ◽  
The Impact ◽  
The Relationship ◽  
Average Approximation ◽  
Average Approximation Error

The article analyzes the impact of certain factors on the volume of investments in the environment. Regression equations describing the relationship between the volume of investment in the environment and each of the influencing factors are constructed, the coefficients of the Pearson pair correlation between the dependent variable and the influencing factors, as well as pairwise between the influencing factors, are calculated. The average approximation error for each regression equation is determined. A correlation matrix is constructed and a conclusion is made. The developed econometric model is implemented in the program of separate collection of municipal solid waste (MSW) in Moscow. The efficiency of the model of investment management in the environment is evaluated on the example of the growth of planned investments in the activities of companies specializing in the export and processing of solid waste.

scholarly journals Aphid–Plant–Phytovirus Pathosystems: Influencing Factors from Vector Behaviour to Virus Spread

Agriculture ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 502
Author(s):  
Junior Corneille Fingu-Mabola ◽  
Frédéric Francis
Keyword(s):  
Influencing Factors ◽  
Virus Transmission ◽  
Physical Factors ◽  
Factors Affecting ◽  
Vector Borne Diseases ◽  
Vector Behaviour ◽  
Crop Fields ◽  
Host Seeking ◽  
The Impact ◽  
Vector Efficiency

Aphids are responsible for the spread of more than half of the known phytovirus species. Virus transmission within the plant–aphid–phytovirus pathosystem depends on vector mobility which allows the aphid to reach its host plant and on vector efficiency in terms of ability to transmit phytoviruses. However, several other factors can influence the phytoviruses transmission process and have significant epidemiological consequences. In this review, we aimed to analyse the aphid behaviours and influencing factors affecting phytovirus spread. We discussed the impact of vector host-seeking and dispersal behaviours mostly involved in aphid-born phytovirus spread but also the effect of feeding behaviours and life history traits involved in plant–aphid–phytovirus relationships on vector performances. We also noted that these behaviours are influenced by factors inherent to the interactions between pathosystem components (mode of transmission of phytoviruses, vector efficiency, plant resistance, …) and several biological, biochemical, chemical or physical factors related to the environment of these pathosystem components, most of them being manipulated as means to control vector-borne diseases in the crop fields.

scholarly journals Improved in vivo imaging method for individual islets across the mouse pancreas reveals a heterogeneous insulin secretion response to glucose

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Henriette Frikke-Schmidt ◽  
Peter Arvan ◽  
Randy J. Seeley ◽  
Corentin Cras-Méneur
Keyword(s):  
Insulin Secretion ◽  
In Vivo Imaging ◽  
Motion Blur ◽  
Isolated Islets ◽  
Imaging Method ◽  
Glucose Stimulation ◽  
Powerful Approach ◽  
Glucose Challenge ◽  
The Impact

AbstractWhile numerous techniques can be used to measure and analyze insulin secretion in isolated islets in culture, assessments of insulin secretion in vivo are typically indirect and only semiquantitative. The CpepSfGFP reporter mouse line allows the in vivo imaging of insulin secretion from individual islets after a glucose stimulation, in live, anesthetized mice. Imaging the whole pancreas at high resolution in live mice to track the response of each individual islet over time includes numerous technical challenges and previous reports were only limited in scope and non-quantitative. Elaborating on this previous model—through the development of an improved methodology addressing anesthesia, temperature control and motion blur—we were able to track and quantify longitudinally insulin content throughout a glucose challenge in up to two hundred individual islets simultaneously. Through this approach we demonstrate quantitatively for the first time that while isolated islets respond homogeneously to glucose in culture, their profiles differ significantly in vivo. Independent of size or location, some islets respond sharply to a glucose stimulation while others barely secrete at all. This platform therefore provides a powerful approach to study the impact of disease, diet, surgery or pharmacological treatments on insulin secretion in the intact pancreas in vivo.

scholarly journals Retrieving Forest Canopy Elements Clumping Index Using ICESat GLAS Lidar Data

2021 ◽  
Vol 13 (5) ◽  
pp. 948
Author(s):  
Lei Cui ◽  
Ziti Jiao ◽  
Kaiguang Zhao ◽  
Mei Sun ◽  
Yadong Dong ◽  
...  
Keyword(s):  
Large Scale ◽  
Forest Canopy ◽  
Remote Sensing Data ◽  
Alternative Methods ◽  
High Signal ◽  
Laser Altimeter ◽  
Waveform Data ◽  
Forest Park ◽  
Clumping Index ◽  
The Impact

Clumping index (CI) is a canopy structural variable important for modeling the terrestrial biosphere, but its retrieval from remote sensing data remains one of the least reliable. The majority of regional or global CI products available so far were generated from multiangle optical reflectance data. However, these reflectance-based estimates have well-known limitations, such as the mere use of a linear relationship between the normalized difference hotspot and darkspot (NDHD) and CI, uncertainties in bidirectional reflectance distribution function (BRDF) models used to calculate the NDHD, and coarse spatial resolutions (e.g., hundreds of meters to several kilometers). To remedy these limitations and develop alternative methods for large-scale CI mapping, here we explored the use of spaceborne lidar—the Geoscience Laser Altimeter System (GLAS)—and proposed a semi-physical algorithm to estimate CI at the footprint level. Our algorithm was formulated to leverage the full vertical canopy profile information of the GLAS full-waveform data; it converted raw waveforms to forest canopy gap distributions and gap fractions of random canopies, which was used to estimate CI based on the radiative transfer theory and a revised Beer–Lambert model. We tested our algorithm over two areas in China—the Saihanba National Forest Park and Heilongjiang Province—and assessed its relative accuracies against field-measured CI and MODIS CI products. We found that reliable estimation of CI was possible only for GLAS waveforms with high signal-to-noise ratios (e.g., >65) and at gentle slopes (e.g., <12°). Our GLAS-based CI estimates for high-quality waveforms compared well to field-based CI (i.e., R2 = 0.72, RMSE = 0.07, and bias = 0.02), but they showed less correlation to MODIS CI (e.g., R2 = 0.26, RMSE = 0.12, and bias = 0.04). The difference highlights the impact of the scale effect in conducting comparisons of products with huge differences resolution. Overall, our analyses represent the first attempt to use spaceborne lidar to retrieve high-resolution forest CI and our algorithm holds promise for mapping CI globally.

Flexural bearing capacity of RC hollow slab beam strengthened by steel plates of different thicknesses

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Long Liu ◽  
Lifeng Wang ◽  
Ziwang Xiao
Keyword(s):  
Finite Element ◽  
Bearing Capacity ◽  
Steel Plate ◽  
Plate Thickness ◽  
Research Field ◽  
Steel Plates ◽  
Nonlinear Material ◽  
Finite Element Models ◽  
Content Type ◽  
Flexural Bearing Capacity

PurposeThe flexural reinforcement of bridges in-service has been an important research field for a long time. Anchoring steel plate at the bottom of beam is a simple and effective method to improve its bearing capacity. The purpose of this paper is to explore the influence of anchoring steel plates of different thicknesses on the bearing capacity of hollow slab beam and to judge its working status.Design/methodology/approachFirst, static load experiments are carried out on two in-service RC hollow slab beams; meanwhile, nonlinear finite element models are built to study the bearing capacity of them. The nonlinear material and shear slip effect of studs are considered in the models. Second, the finite element models are verified, and the numerical simulation results are in good agreement with the experimental results. Finally, the finite element models are adopted to carry out the research on the influence of different steel plate thicknesses on the flexural bearing capacity and ductility.FindingsWhen steel plates of different thicknesses are adopted to reinforce RC hollow slab beams, the bearing capacity increases with the increase of the steel plate thickness in a certain range. But when the steel plate thickness reaches a certain level, bearing capacity is no longer influenced. The displacement ductility coefficient decreases with the increase of steel plate thickness.Originality/valueBased on experimental study, this paper makes an extrapolation analysis of the bearing capacity of hollow slab beams reinforced with steel plates of different thicknesses through finite element simulation and discusses the influence on ductility. This method not only ensures the accuracy of bearing capacity evaluation but also does not need many samples, which is economical to a certain extent. The research results provide a basis for the reinforcement design of similar bridges.

Computational predictions for predicting the performance of steel 1 panel shear wall under explosive loads

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Aydin Shishegaran ◽  
Behnam Karami ◽  
Elham Safari Danalou ◽  
Hesam Varaee ◽  
Timon Rabczuk
Keyword(s):  
Steel Plate ◽  
Plate Thickness ◽  
Ensemble Model ◽  
Maximum Deflection ◽  
Explosive Load ◽  
Statistical Parameters ◽  
Content Type ◽  
A Value ◽  
Error Terms ◽  
Better Than

Purpose The resistance of steel plate shear walls (SPSW) under explosive loads is evaluated using nonlinear FE analysis and surrogate methods. This study uses the conventional weapons effect program (CONWEP) model for the explosive load and the Johnson-Cook model for the steel plate. Based on the Taguchi method, 25 samples out of 100 samples are selected for a parametric study where we predict the damaged zones and the maximum deflection of SPSWs under explosive loads. Then, this study uses a multiple linear regression (MLR), multiple Ln equation regression (MLnER), gene expression programming (GEP), adaptive network-based fuzzy inference (ANFIS) and an ensemble model to predict the maximum detection of SPSWs. Several statistical parameters and error terms are used to evaluate the accuracy of the different surrogate models. The results show that the cross-section in the y-direction and the plate thickness have the most significant effects on the maximum deflection of SPSWs. The results also show that the maximum deflection is related to the scaled distance, i.e. for a value of 0.383. The ensemble model performs better than all other models for predicting the maximum deflection of SPSWs under explosive loads. Design/methodology/approach The SPSW under explosive loads is evaluated using nonlinear FE analysis and surrogate methods. This study uses the CONWEP model for the explosive load and the Johnson-Cook model for the steel plate. Based on the Taguchi method, 25 samples out of 100 samples are selected for a parametric study where we predict the damaged zones and the maximum deflection of SPSWs under explosive loads. Then, this study uses a MLR, MLnER, GEP, ANFIS and an ensemble model to predict the maximum detection of SPSWs. Several statistical parameters and error terms are used to evaluate the accuracy of the different surrogate models. The results show that the cross-section in the y-direction and the plate thickness have the most significant effects on the maximum deflection of SPSWs. The results also show that the maximum deflection is related to the scaled distance, i.e. for a value of 0.383. The ensemble model performs better than all other models for predicting the maximum deflection of SPSWs under explosive loads. Findings The resistance of SPSW under explosive loads is evaluated using nonlinear FE analysis and surrogate methods. This study uses the CONWEP model for the explosive load and the Johnson-Cook model for the steel plate. Based on the Taguchi method, 25 samples out of 100 samples are selected for a parametric study where we predict the damaged zones and the maximum deflection of SPSWs under explosive loads. Then, this study uses a MLR, MLnER, GEP, ANFIS and an ensemble model to predict the maximum detection of SPSWs. Several statistical parameters and error terms are used to evaluate the accuracy of the different surrogate models. The results show that the cross-section in the y-direction and the plate thickness have the most significant effects on the maximum deflection of SPSWs. The results also show that the maximum deflection is related to the scaled distance, i.e. for a value of 0.383. The ensemble model performs better than all other models for predicting the maximum deflection of SPSWs under explosive loads. Originality/value The resistance of SPSW under explosive loads is evaluated using nonlinear FE analysis and surrogate methods. This study uses the CONWEP model for the explosive load and the Johnson-Cook model for the steel plate. Based on the Taguchi method, 25 samples out of 100 samples are selected for a parametric study where we predict the damaged zones and the maximum deflection of SPSWs under explosive loads. Then, this study uses a MLR, MLnER, GEP, ANFIS and an ensemble model to predict the maximum detection of SPSWs. Several statistical parameters and error terms are used to evaluate the accuracy of the different surrogate models. The results show that the cross-section in the y-direction and the plate thickness have the most significant effects on the maximum deflection of SPSWs. The results also show that the maximum deflection is related to the scaled distance, i.e. for a value of 0.383. The ensemble model performs better than all other models for predicting the maximum deflection of SPSWs under explosive loads.

Sign in / Sign up

Export Citation Format

Share Document