Numerical Investigation of a Ship Collision With Waterway Embankments

2010 ◽  
Author(s):  
Gang Qiu ◽  
Ju¨rgen Grabe
Keyword(s):  
Reaction Force ◽  
Fe Model ◽  
Test Results ◽  
Bridge Abutments ◽  
Inland Waterways ◽  
Existing Structures ◽  
Stopping Distance ◽  
Parametric Studies ◽  
Collision Force ◽  
The Impact

During the last century there has been an increase in frequency of ships colliding with waterway embankments of inland waterways. The increasing occurrence of shipping accidents threatens the safety of freights and the serviceability of existing structures, such as tunnel and bridge abutments which are located near embankments. It is necessary to develop a method enabling prediction of the collision force and the stopping distance of a collision ship. In the related project “Hochdonn” of BAW (Federal Waterways Engineering and Research Institute, Germany) collision experiments were performed to analyze the impact mechanisms in grounding problems. A 3D FE model using a Coupled Eulerian Lagrangian approach is used to recalculate the collision experiment of BAW with the test ship “Gerda”. The stopping distance and the reaction force that are indicated by the numerical simulation match the field test results very closely. In addition two parametric studies are undertaken to quantify the influences on the collision process from the initial velocity as well as the bow type of the ship.

Compressive Behavior of a Polyurea Elastomer

2014 ◽  
Vol 900 ◽  
pp. 7-10
Author(s):  
Fabrizia Ghezzo ◽  
Xi Geng Miao ◽  
Chun Lin Ji ◽  
Ruo Peng Liu
Keyword(s):  
Material Behavior ◽  
Loading Conditions ◽  
Test Results ◽  
Metallic Structures ◽  
Compression Load ◽  
Existing Structures ◽  
The Past ◽  
Severe Shock ◽  
The Impact ◽  
Impact Events

The application of elastomeric coatings for improving the ability of already existing structures to dissipate the energy released by impact events has been investigated by many researchers in the past decade and is today an area of considerable interest. In recent years, polyurea has been successfully applied as a coating material for enhancing the impact protection of buildings and it has also demonstrated a considerable improvement of the survivability of metallic and non-metallic structures subjected to severe shock and impact loading conditions. Given its remarkable properties in terms of impact energy mitigation, life endurance and corrosion resistance, this material is currently of interest for its application in many fields of engineering. This paper presents and discusses the results of the mechanical characterization conducted on a polyurea elastomer fabricated following two different procedures and subjected to varying strain rates of compression load. The tests were conducted to verify the sensitivity of the material behavior to the varying loading conditions and to verify how the fabrication of the material in the laboratory can influence the test results.

DYNAMIC RESPONSE OF METALLIC SANDWICH PANELS UNDER BLAST LOADINGS

2012 ◽  
Vol 12 (03) ◽  
pp. 1250017 ◽  
Author(s):  
HONGXIN WANG ◽  
XIAOXIONG ZHA ◽  
JIANQIAO YE
Keyword(s):  
Finite Element ◽  
Energy Balance ◽  
Dynamic Response ◽  
Analytical Method ◽  
Sandwich Panels ◽  
Fe Model ◽  
Test Results ◽  
Fluid Structure Interactions ◽  
Parametric Studies ◽  
Blast Loadings

An energy-balance-based analytical method and finite element (FE) simulations were developed in this paper to study the dynamic response of metallic sandwich panels subject to blast loadings. The analytical model can be used to predict approximately the deflection of the panels, while the FE model can take into account fluid–structure interactions and the effect of strain rate. Both models were validated by comparing their predictions with the test results available in the literature. Parametric studies were then carried out to assess various factors that are influential in characterizing the dynamic behavior of sandwich panels subject to blast loads.

scholarly journals Behavior of innovative T-shaped multi-partition steel-concrete composite columns under concentric and eccentric compressive loadings

2018 ◽  
Author(s):  
Sumei Zhang ◽  
Jie Chen ◽  
Zhenfeng Huang ◽  
Xiongxiong Zhang ◽  
Lanhui Guo
Keyword(s):  
Fe Analysis ◽  
Fe Model ◽  
Test Results ◽  
Analysis Model ◽  
Concrete Compressive Strength ◽  
Working Mechanism ◽  
Steel Tubes ◽  
Composite Columns ◽  
Parametric Studies ◽  
Strain Responses

T-shaped multi-partition steel-concrete composite column, composed of several concrete-filled rectangular steel hollow sections, is considered as an innovative composite member with the ability to accommodate neighboring wall thickness with great easiness. This paper intends to study the behavior of this innovative composite member under concentric and eccentric compressive loadings. A finite element (FE) analysis model accounting for the influences of confinement effects, geometric and material nonlinearities is developed using the program ABAQUS. The ultimate strength and load-strain responses predicted from the analysis are validated against the test results in the experiments conducted by the authors. The comparisons indicate that the FE model reasonably estimates the responses of the concentrically and eccentrically loaded T-shaped multi-partition steel-concrete composite columns. The verified model is then utilized to numerically investigate the working mechanism of the columns. The load distribution between the infilled concrete and the steel tubes and the stress distribution of the concrete during the loading process are analyzed. Moreover, parametric studies are performed to investigate the behavior of T-shaped multi-partition steel-concrete composite columns under different loadings. The studied parameters include steel to concrete area ratio, concrete compressive strength, steel yield strength and load eccentricity. Combined with the experimental results, FE analysis and parametric studies, the design recommendations for T-shaped multi-partition steel-concrete composite columns under different loadings are proposed.

Modeling of a Mainframe Server Frame Subjected to Seismic Loadings

2013 ◽  
Author(s):  
Budy Notohardjono ◽  
Shawn Canfield ◽  
Richard Ecker
Keyword(s):  
Finite Element ◽  
Material Properties ◽  
Structural Damage ◽  
Structural Integrity ◽  
Reaction Force ◽  
Functional System ◽  
Fe Model ◽  
Test Results ◽  
Linear Material ◽  
Explicit Dynamic

This paper describes the finite element modeling of a mainframe server frame. The frame consists of a server rack or frame with its add-on stiffening brackets. The frame is anchored directly to the floor with bolts at each of the four corners. The Telcordia Zone 4 earthquake test profile represents a severe dynamic load input and will be used herein to analyze the mainframe server frame. The main objective of this modeling is to validate the frame design prior to actual seismic testing, which ultimately ensures the structural integrity of a functional mainframe system during a seismic event. The server frame finite element (FE) model is derived from a three dimensional CAD model of a standard sheet metal frame weldment assembly which is then simplified and meshed with finite elements. This FE model represents the server frame, welded connections, and stiffening brackets, which are specifically designed to withstand seismic test profiles. To represent the components that populate the server frame, point masses are tied to the frame at the same attachment points that exist in the real assembly. The validation of the FE model involves the use of a horizontal shaker test to assess the server frame’s stiffness. The goal of this paper is to show a good correlation between FE model and test results using two separate FE solver technologies: implicit and explicit. For an implicit solver, linear material properties were used to obtain modal behavior that approximates the actual server frame’s behavior. Once these outputs were achieved, further response refinement was attempted by porting the model to an explicit dynamic solver. An explicit solver allowed non-linear material properties and body to body contact behavior to be included in the FE model while applying the seismic test profile to the server frame using a time domain input. The explicit dynamic model outputs used to correlate to actual test results were the modal dynamics, the displacement of the top of the server frame, and the maximum reaction force at the anchored corners. Finally, a functional system was subjected to the Telcordia Zone 4 seismic test profile. The system was functional during and after the seismic test with no significant structural damage having occurred.

A Simple Performance Test for Evaluating End Hose Support Straps for Railroad Freight Cars

2011 ◽  
Author(s):  
Z. Liu ◽  
L. Hua
Keyword(s):  
Mechanical Properties ◽  
Performance Test ◽  
Reaction Force ◽  
Performance Testing ◽  
Drop Test ◽  
Test Results ◽  
The Real ◽  
Current Requirement ◽  
The Impact ◽  
Railroad Freight

A study has been performed to simulate the impact experienced on hose support straps during end hose separations on railroad freight cars. Analysis and comparison of test results of different hose straps show that the elasticity of the hose strap determines the reaction force generated by a certain impact. Under the same impact, a stiffer hose strap sustains a larger reaction force. Unlike the current requirement of AAR S-4006, the relation between the elasticity of the hose strap and its reaction force is not linear. Additionally, for a certain impact, the reaction force of the hose strap is only related to its mechanical properties, which reflects the real application. This study concludes that a simple drop test is adequate as an alternative method for performance testing of hose straps.

A Comprehensive Model for Assessing the Impact of Steel Cleanliness on Bearing Performance

2014 ◽  
Vol 137 (1) ◽  
Author(s):  
Xiaolan Ai
Keyword(s):  
Inclusion Size ◽  
Reduction Factor ◽  
Test Model ◽  
Test Results ◽  
Stressed Volume ◽  
Bearing Life ◽  
Steel Cleanliness ◽  
Parametric Studies ◽  
Inclusion Length ◽  
The Impact

Steel cleanliness as measured by nonmetallic inclusion content in steel plays a major role in affecting bearing durability. A high-fidelity virtual bearing life test model was developed to predict the impact of inclusions on bearing fatigue life. This model analyzes distributions of inclusion size, shape, orientation, and location, and computes stress alterations to bearing material due to inclusions and the resulting life reduction. Comparisons between model predictions and experimental test results were made, confirming the validity of the model. Parametric studies were conducted to explore the effects of inclusion counts, inclusion size distributions, and the effect of overall bearing size on bearing life. A regression equation was proposed based on simulation results, linking the bearing life reduction factor (LRF) to the accumulative inclusion length within the stressed volume under contact load.

Model estimates of the results of diabetes patients using modern glucometers with tri-color technology for displaying test results

2019 ◽  
pp. 81-89
Author(s):  
Larisa Dmitrievna Popovich ◽  
Svetlana Valentinovna Svetlichnaya ◽  
Aleksandr Alekseevich Moiseev
Keyword(s):  
Diabetes Mellitus ◽  
Type 2 Diabetes ◽  
Type 1 Diabetes ◽  
Economic Benefits ◽  
Test Results ◽  
Self Monitoring ◽  
Patients With Diabetes ◽  
The Impact

Diabetes – a disease in which the effect of the treatment substantially depends on the patient. Known a study showed that the use of glucometers with the technology of three-color display of test results facilitates self-monitoring of blood sugar and leads to a decrease in glycated hemoglobin (HbAlc). Purpose of the study: to modeling the impact of using of a glucometer with a color-coded display on the clinical outcomes of diabetes mellitus and calculating, the potential economic benefits of reducing the hospitalization rate of patients with diabetes. Material and methods. Based on data from two studies (O. Schnell et al. and M. Baxter et al.) simulation of the reduction in the number of complications with the use of a glucometer with a color indication. In a study by O. Schnell et al. a decrease of HbA1c by 0.69 percent is shown when using the considered type of glucometers, which was the basis of the model. Results. In the model, the use of a glucometer with a color-coded display for type 1 diabetes led to a decrease in the total number of complications by 9.2 thousand over 5 years per a cohort of 40 thousand patients with different initial levels of HbA1c. In a cohort of 40 thousand patients with type 2 diabetes, the simulated number of prevented complications was 1.7 thousand over 5 years. When extrapolating these data to all patients with diabetes included in the federal register of diabetes mellitus (FRD), the number of prevented complications was 55.4 thousand cases for type 1 diabetes and 67.1 thousand cases for type 2 diabetes. The possible economic effect from the use of the device by all patients with a diagnosis of diabetes, which are included in the FRD, estimated at 1.5 billion rubles for a cohort of patients with type 1 diabetes and 5.3 billion rubles for patients with type 2 diabetes. Conclusion. Improving the effectiveness of self-monitoring, which is the result of the use of glucometers with color indicators, can potentially significantly reduce the incidence of complications in diabetes and thereby provide significant economic benefits to society.

scholarly journals Theoretical analysis and experimental research on multi-layer elastic damping track structure

2021 ◽  
Vol 13 (2) ◽  
pp. 168781402199497
Author(s):  
Guanghui Xu ◽  
Shengkai Su ◽  
Anbin Wang ◽  
Ruolin Hu
Keyword(s):  
Finite Element ◽  
Analytical Solution ◽  
Finite Element Simulation ◽  
Reaction Force ◽  
Vibration Reduction ◽  
Vertical Direction ◽  
Propagation Path ◽  
Track Structure ◽  
Test Results ◽  
Element Simulation

The increase of axle load and train speed would cause intense wheelrail interactions, and lead to potential vibration related problems in train operation. For the low-frequency vibration reduction of a track system, a multi-layer track structure was proposed and analyzed theoretically and experimentally. Firstly, the analytical solution was derived theoretically, and followed by a parametric analysis to verify the vibration reduction performance. Then, a finite element simulation is carried out to highlight the influence of the tuned slab damper. Finally, the vibration and noise tests are performed to verify the results of the analytical solution and finite element simulation. As the finite element simulation indicates, after installation of the tuned slab damper, the peak reaction force of the foundation can be reduced by 60%, and the peak value of the vertical vibration acceleration would decrease by 50%. The vibration test results show that the insertion losses for the total vibration levels are 13.3 dB in the vertical direction and 21.7 dB in the transverse direction. The noise test results show that the data of each measurement point is smoother and smaller, and the noise in the generating position and propagation path can be reduced by 1.9 dB–5.5 dB.

scholarly journals Simulation of Energy Absorption Performance of the Couplers in Urban Railway Vehicles during a Heavy Collision

Machines ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 91
Author(s):  
Sunghyun Lim ◽  
Yong-hyeon Ji ◽  
Yeong-il Park
Keyword(s):  
Reaction Force ◽  
Crash Test ◽  
Railway Vehicle ◽  
Buffer System ◽  
Railway Vehicles ◽  
Hydraulic Shock Absorber ◽  
Coupling Buffer ◽  
Absorption Performance ◽  
Different Characteristics ◽  
The Impact

Railway vehicles are generally operated by connecting several vehicles in a row. Mechanisms connecting railway vehicles must also absorb front and rear shock loads that occur during a train’s operation. To minimize damage, rail car couplers are equipped with a buffer system that absorbs the impact of energy. It is difficult to perform a crash test and evaluate performance by applying a buffer to an actual railway vehicle. In this study, a simulation technique using a mathematical buffer model was introduced to overcome these difficulties. For this, a model of each element of the buffer was built based on the experimental data for each element of the coupling buffer system and a collision simulation program was developed. The buffering characteristics of a 10-car train colliding at 25 km/h were analyzed using a developed simulator. The results of the heavy collision simulation showed that the rubber buffer was directly connected to the hydraulic shock absorber in a solid contact state, and displacement of the hydraulic buffer hardly occurred despite the increase in reaction force due to the high impact speed. Since the impact force is concentrated on the vehicle to which the collision is applied, it may be appropriate to apply a deformation tube with different characteristics depending on the vehicle location.

scholarly journals Deep Neural Network and Polynomial Chaos Expansion-Based Surrogate Models for Sensitivity and Uncertainty Propagation: An Application to a Rockfill Dam

Water ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 1830
Author(s):  
Gullnaz Shahzadi ◽  
Azzeddine Soulaïmani
Keyword(s):  
Polynomial Chaos ◽  
Complex Structure ◽  
Uncertainty Propagation ◽  
Surrogate Models ◽  
Polynomial Chaos Expansion ◽  
Soil Parameters ◽  
Chaos Expansion ◽  
Rockfill Dam ◽  
Parametric Studies ◽  
The Impact

Computational modeling plays a significant role in the design of rockfill dams. Various constitutive soil parameters are used to design such models, which often involve high uncertainties due to the complex structure of rockfill dams comprising various zones of different soil parameters. This study performs an uncertainty analysis and a global sensitivity analysis to assess the effect of constitutive soil parameters on the behavior of a rockfill dam. A Finite Element code (Plaxis) is utilized for the structure analysis. A database of the computed displacements at inclinometers installed in the dam is generated and compared to in situ measurements. Surrogate models are significant tools for approximating the relationship between input soil parameters and displacements and thereby reducing the computational costs of parametric studies. Polynomial chaos expansion and deep neural networks are used to build surrogate models to compute the Sobol indices required to identify the impact of soil parameters on dam behavior.

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