Simulation Of Bridge Research Articles

Influence of membrane hydrophilicity on water permeability: An experimental study bridging simulations

There has been an argument on the influence of membrane hydrophilicity on permeability between experimental and simulation works. Theoretical work finds that the membranes have a characteristic called a threshold pressure drop (ΔPT). Strongly hydrophobic membranes exhibit extremely high ΔPT, making membranes less wettable and consequently less permeable. In order to experimentally investigate the influence of wetting states of membranes, determined by membrane hydrophilicity, on permeability, we prepared a series of membranes with progressively changing hydrophilicities by atomic layer deposition (ALD) of TiO2 on polytetrafluoroethylene membranes while keeping the pore size unchanged. In addition, adding ethanol into the water and raising the operating pressure drops are also selected to improve the wetting degrees. The experimental results verify the presence of ΔPT for all membranes and the hydrophobic membranes having higher ΔPT. Since the hydrophilic membranes have better wetting degrees but higher transport resistance, there should be an optimized hydrophilicity, which is found to be determined by the feed solution and the operating ΔP. The optimized hydrophilic modification is the one when the membrane can be just adequately wetted by the feed solution at the target operating pressure drops. Highest water permeability is expected to be obtained at a moderate hydrophilicity, neither at the extreme hydrophilicity nor at the extreme hydrophobicity.

The behavior of reinforced concrete pylons in the static analysis of cable-stayed bridges

In this paper, we consider a linear static analysis of cable-stayed bridges with different pylon shapes under their own weight. The cable-stayed bridge is one of the modern bridges that are built to cover large spans. It is therefore necessary to study the behavior of the pylons before you can apply it in practice. For this study, different pylon shapes are compared with the size of the bridge span, while other parameters remain unchanged. The various forms of pylons considered for a cable-stayed bridge are diamond, small diamond, Y-inverted, A, H and U-shaped. The height of the pylon remains the same for all cable-stayed bridge models with different pylon shapes. The bridge simulation was prepared using the Midas/Civil software. For this study, the semi-fan type cable-stayed bridge was adopted. The study gives the deformed state of the pylons, i.e. bending moments, transverse and longitudinal forces, and deflections. This study will be useful for selecting the shape of the pylon for the bridge used in specific conditions.

Displacement shape measurement of continuous beam bridges based on long-gauge fiber optic sensing

Abstract Displacement shape is an important index for performance assessment of bridges. It is usually hard to find “reference point” for direct arrangement of displacement transducers on real bridges, and therefore indirect measurement methods using strain sensors attracts increasing attention. A reference-free method for monitoring displacement shape of continuous beam bridges using long-gauge fiber optic sensors is proposed in this article. Firstly, the method for calculating the displacement shape of continuous beam bridges using fiber optic strain sensors along the whole structure was theoretically established. Meanwhile, displacement shape determination of a certain span using fiber optic strain sensors along the corresponding span was also presented for the purpose of cost saving in practical engineering. The presented method is independent of external loads and could be applied to both static and dynamic loads. Results from numerical simulation of a three-span bridge show that both methods could obtain the displacement shape of each span with high precision. Furthermore, experimental results indicate that the presented method could perform online monitoring of time-displacement series at each cross section with high accuracy, and could achieve the displacement shape along the continuous beam bridge at a certain time. Therefore, it could be a convenient reference-free strategy for monitoring the displacement shape of continuous beam bridges in actual engineering.

Improved Continuous Wavelet Transform for Modal Parameter Identification of Long-Span Bridges

Accurate and timely identification of modal parameters of long-span bridges is important for bridge health monitoring and wind tunnel tests. Wavelet analysis is one of the most advantageous methods for identification because of its good localization characteristics in both time and frequency domain. In recent years, the wavelet method has been applied more frequently in parameter identification of linear and nonlinear systems. In this article, based on wavelet ridges and wavelet skeleton, the improved modal parameter identification method was studied. To find the appropriate time-frequency resolution, an optimal wavelet basis design principle based on minimum Shannon entropy was proposed. Aiming at endpoint effect in wavelet transform, a prediction continuation method based on support vector machine (SVM) was proposed, which can effectively suppress the endpoint effect of the extended samples. In view of the fact that the ridges of metric matrices obtained by the traditional crazy climber algorithm cannot fully reflect the distribution of ridges of modulus value matrices of wavelet coefficients, an improved high-precision crazy climber algorithm was put forward to accurately identify the position of the ridge of wavelet coefficients. Finally, taking a long-span cable-stayed bridge and a long-span suspension bridge as the engineering background, improved continuous wavelet transform (CWT) was applied to modal parameter identification of bridge under ambient excitation. The modal parameters such as modal frequency, damping ratio, and mode shape were obtained. Compared with the calculation value of the numerical simulation of long-span cable-stayed bridge and wind tunnel test of long-span suspension bridge, the reliability of CWT for modal parameter identification of long-span bridges under ambient excitation was verified.

Development of Evaluation Procedures for Watchkeeping Officers Using Bridge Simulator

Development of Evaluation Procedures for Watchkeeping Officers Using Bridge Simulator

Large-scale simulation of steel cable-stayed bridge under vehicle load and temperature change

Large-scale simulation of steel cable-stayed bridge under vehicle load and temperature change

Evaluation of Thermal Bridges Using Online Simulation Software

In order to reach nearly Zero Energy Buildings, a thorough design must be given in designing proper junctions, which will overall reduce the impact of the thermal bridges on the thermal performance of the building envelope. It is well-known that a thermal bridge is a weak thermal area of the building envelope through which increased heat losses occur. For the thermal bridges' evaluation, several numerical simulation software exist on the market, but their usage implies knowledge regarding the numerical modelling and simulation using various numerical methods (i.e. finite element method, finite difference methods, and others). Due to time constraint, designers use thermal bridges atlases that provide values for the linear heat transfer coefficient for several types of thermal bridges. Nevertheless, the multitude of existing thermal bridges requires more and more atlases which are not feasible in elaborating, due to time constraints. In order to respond to this demand, the authors developed a software for the modelling and simulation of thermal bridges that can be easily accessed by practitioners. The paper presents the software its components and the way that the user can interact with it.

Numerical simulation of steel bridge during earthquake using an elastic-plastic model combined with memory surface

Numerical simulation of steel bridge during earthquake using an elastic-plastic model combined with memory surface

The Evaluation of Thermal Comfort using a BIM-based Thermal Bridge Simulation

Global warming has become an important issue today, caused by the increasing demand for energy and humans lifestyle. To reduce the impact, more architects started to respond regarding environmental issues. The concept of green architecture promotes to solving this problem. Natural ventilation is the one of the concept green architecture. This research tends to look at the aspect of Thermal Comfort in naturally ventilated mosque buildings through the Thermal Bridges strategy. Naturally ventilated building tend to have better indoor air quality (IAQ), but worse thermal comfort. Therefore, this research investigates the range of acceptable temperature and calculate by BIM thermal bridge simulation to achieve thermal comfort for naturally ventilated mosque building. The method of analysis conducted is quantitative based on direct measurement of weather data and existing comfort conditions in the field, calculations, and simulations using Building Information Modeling (BIM). Data was collected through a field survey in Itenas Mosque Building and were used to develop and validate then using the BIM thermal bridge model for simulation. The data collected from field survey and in situ environmental measurement such as air temperature, relative humidity, and wind velocity. The thermal comfort prediction model was developed from statistical analysis of the field survey data. Based on the result of thermal Bridge simulation using BIM software required exchange material of the existing building to achieve thermal comfort. Keyword-Thermal comfort, Building Information Modelling, Thermal Bridge Simulation

The Use of a Full Mission Bridge Simulator Ensuring Navigational Safety during the Klaipeda Seaport Development

The Use of a Full Mission Bridge Simulator Ensuring Navigational Safety during the Klaipeda Seaport Development

Non-Stationary Turbulent Wind Field Simulation of Long-Span Bridges Using the Updated Non-Negative Matrix Factorization-Based Spectral Representation Method

Numerical simulation of the turbulent wind field on long-span bridges is an important task in structural buffeting analysis when it comes to the system non-linearity. As for non-stationary extreme wind events, some efforts have been paid to update the classic spectral representation method (SRM) and the fast Fourier transform (FFT) has been introduced to improve the computational efficiency. Here, the non-negative matrix factorization-based FFT-aided SRM has been updated to generate not only the horizontal non-stationary turbulent wind field, but also the vertical one. Specifically, the evolutionary power spectral density (EPSD) is estimated to characterize the non-stationary feature of the field-measured wind data during Typhoon Wipha at the Runyang Suspension Bridge (RSB) site. The coherence function considering the phase angles is utilized to generate the turbulent wind fields for towers. The simulation accuracy is validated by comparing the simulated and target auto-/cross-correlation functions. Results show that the updated method performs well in generating the non-stationary turbulent wind field. The obtained wind fields will provide the research basis for analyzing the non-stationary buffeting behavior of the RSB and other wind-sensitive structures in adjacent regions.

Study on decoupling control method of vehicle wheel bridge simulation loading system

There are mechanical coupling interference and hydraulic coupling interference in the vehicle wheel bridge simulation loading system based on secondary regulation, which can cause the control accuracy of the system to decrease obviously and seriously affect the control performance of the system. In order to eliminate the coupling interference between systems, two decoupling methods are proposed, one way to do this is to join the decoupling element, and the other is to join the robust compensator. The simulation results show that the decoupling control of decoupling element has a good decoupling effect on mechanical coupling, but it has no effect on hydraulic coupling. Robust decoupling control has a good decoupling effect on mechanical coupling and hydraulic coupling.

Oscillatory Thermosolutal Capillary Convection of High Prandtl Number Fluid for Liquid Bridge under Gravity Environment

An investigation on the oscillating characteristic of temperature and transverse velocity in a half-floating zone liquid bridge for the mixture solution of toluene/n-hexane with the ratio of 0.24/0.76 under gravity has been conducted numerically. In this paper, the free surface is treated as a deformable interface in the direct numerical simulation of liquid bridge by using a mass conserving level set method for the first time. The results show the onset of temperature oscillation is earlier than that of transverse velocity oscillation at the hot corner. The velocity oscillation presents a certain pulsation characteristic compared with the temperature oscillation characteristic. In the transforming process from the stable stage to the oscillatory stage, the coupling effects of the temperature, velocity, free surface and concentration oscillations constitute complete oscillation mechanism of thermosolutal capillary convection. When the concentration difference is ΔCcr=0.1 and temperature difference is ΔTcr=0.5℃, the oscillatory thermosolutal capillary convection is caused by temperature difference, the oscillation form of velocity on the monitoring points near the free surface is a sine curve. In addition, when the temperature difference is ΔTcr=1.0℃, the temperature at hot corner occurs irregular oscillation. At the hot corner, the average oscillating periods of transversal velocity at three monitoring points are T0.04s, and the onset times of transversal velocity is basically the same, t5.53s, which have a lag (t0.01s) compare with onset time of temperature oscillation.

Pedestrian Bridge Simulation Using Wasted Tire Rubber with Two Boundary Systems

The development of pedestrian bridge construction, ranging as it does, from a simple tree trunk, laid a cross a stream, through to today's spectacular three-dimensional support structures. Limited resources, environmental concerns, economic feasibility as well as the cost; are very important factors. These factors in addition to safety, durability and aesthetics should be considered in the design and construction processes for Pedestrian bridges. Therefore, it’s important to look for alternative construction materials that verify most of these factors. Waste rubber tire is a material that can be used to develop new forms of Pedestrian bridges. In this research, a simple experiment was conducted to simulate the real pedestrian bridge using waste rubber tire. The use of waste rubber tire showed positive results as a structural member in carrying loads. Consequently, it can sustain the safe passing of pedestrians. In addition, the use of fixed boundary conditions has reduced the central deflection of the bridge span to about fifty percent.

The Impact of Bridge Alerts on Navigating Officers

New navigation-related technologies and complex ships' systems are associated with a considerable amount of information and alerts on navigational bridges. Each alert triggers a process conducted by the Officer Of the Watch (OOW), which includes data collection and interpretation, decision making, as well as appropriate actions. In the case of too many alerts or poorly managed alerts, the workload of the OOW may significantly increase, and situational awareness may be compromised, increasing the risk of errors. The main goal of this research is to analyse OOW actions triggered by the alerts. The research methods included an experiment on a bridge simulator with experienced officers, a questionnaire survey and a series of interviews. The main outcomes encompass the frequency of the alerts and the number and the processing times of single actions conducted upon an alert. The results indicate that, on average, during one watch, an OOW spends 22·4 minutes conducting 64 actions triggered by 16 alerts. However, officers consider 45% of the alerts as over-prioritised and distracting at the moment of their notification.

Optimization of LNG terminal parameters for a wide range of gas tanker sizes: the case of the port of Świnoujście

LNG terminals are built to handle tankers of specific size, with cargo capacities within a narrow scope. This is related to the differences in cargo, fender and mooring systems used for LNG tanker handling of various sizes. The research problem solved in the article is the development of the method for optimal design of a universal LNG cargo handling facility that enables safe operations of LNG tankers in a wide range of cargo capacity that covers almost entire spectrum of global fleet tanker sizes. The article presents a methodology of optimizing the parameters of LNG cargo terminals to accommodate both small bunker ships with cargo capacity of 500 m3 (50 metres in length) to Q-flex type tankers capable of carrying up to 220 000 m3 (320 m in length). The authors have determined conditions for the safe operation of these tankers in sea LNG terminals and described differences in the construction of cargo, fendering and mooring systems. The optimization of both location and terminal parameters for a wide range of gas tanker sizes as well as approach channels leading to the LNG berths was performed using a specially designed two-stage simulation method of optimization. In the first stage the best location of a universal LNG terminal and its berths in the existing port basin is determined. The second stage defines optimal parameters of approach waterways to the berths of a universal LNG terminal. The optimization criterion at both stages was the minimization of the costs to build and to operate a universal LNG terminal. The developed optimization methodology was actually used in the design of the universal LNG terminal in the outer port of Świnoujście. The tests made use of real time simulation (RTS) and non-autonomous models of ships, in which ship movement is controlled by a human (pilot, captain). Simulation tests were performed on a multi-bridge ship handling Polaris simulator with a 3D projection, from Kongsberg Maritime AS. This full-mission bridge simulator (FMBS) is located at the Marine Traffic Engineering Centre, Maritime University of Szczecin. Two simulation ship movement models were built and verified for testing the manoeuvres of port entry and berthing. These are: Q-flex type tanker (length: 320 m) and an LNG bunker ship, 6,000 m3 capacity, 104 m in length. The test results were used in the design of the universal LNG terminal in the outer port of Świnoujście and approach waterways leading to the berths (now this investment project is in progress).

Experimental research on adjacent pounding effect of midspan curved bridge with longitudinal slope

Seismic pounding between adjacent girders has a significant effect on the seismic performance of midspan bridges, and connection parameters, such as gap size and longitudinal slope, influence adjacent pounding (AP). However, at present, such influence of the aforementioned parameters on pounding between adjacent girders is unclear, and relevant experimental tests remain insufficient. For these reasons, a 1/10-scale curved bridge model with a small radius and a longitudinal slope is designed and fabricated; moreover, an adjustable simulation method of the pounding between adjacent girders is proposed. A series of shake table tests is conducted to analyse the influence law of the AP parameters, including the excitation direction and gap size; the AP effects on the dynamic response of the bridge model with a longitudinal slope and the simulation of adjacent bridges are also analysed. The experimental results show that pounding responses between adjacent girders are significantly influenced by the state of excitation waves, and the peak pounding forces under bidirectional excitation are significantly greater than those under the unidirectional excitation. The outside peak pounding force is greater than that on the inside because of the bending–torsion coupling of the curved bridge model; this aggravates the rotational response of the model. The pounding frequency decreases with the increase in gap size, whereas the peak pounding force is inconsistent with the change in gap size; large gaps may also induce large pounding forces. The pounding force near the short pier can be greater than that near the tall pier because of the influence of longitudinal slope. The foregoing is also the major reason for the significant vertical dynamic response of the girder; the pounding causes large horizontal and vertical acceleration pulses at the ends of the main girder. The displacement response of the pier top will significantly increase after the AP, and the pounding effect will increase the damage probability of piers; hence, these should be considered in the seismic design of adjacent midspan curved bridges. The proposed AP simulation method between adjacent midspan curved bridges can be used to investigate the AP effect on adjacent midspan bridges.

Rational Design of Packaging: Toward Safer and Ecodesigned Food Packaging Systems.

It is necessary and urgent to reduce the impact of single-use plastics and in particular those used for beverages and similar products. Fewer plastics or reduced shelf-life need to be explored simultaneously while keeping open the possibilities of bringing on the innovative market designs and consumer experiences. This work details a general computational framework bridging simulation of coupled mass transfer and non-linear thermodynamics with 3D geometry optimization, ecodesign and other mass transfer-related risks (collapse, migration of chemicals). The three-dimensions (impacts, design, shelf-life) of the storage of alcoholic beverages in plastic containers are presented as a representative case-study of the multi-objective ecodesign problem and as an illustration of new trends to accelerate prototyping and innovation. The capacity to evaluate, maximize product shelf-life and minimize packaging waste was tested on 450 miniatures served usually in plane and train. Four alcoholic strengths (including pure water) and four storage conditions were considered. Several alternatives (900 different 3D designs) were explored by simulation and constrained optimization to reach the targeted shelf-life. The large set was used to establish the Pareto optimal design enabling to minimize weights while maximizing shelf-life. The approach is sufficiently versatile and flexible to adapt arbitrary designs and additional phenomena controlling shelf-life (aroma scalping, oxidation, migration of non-intentionally added substances).

A multidisciplinary approach to calibrating advanced numerical simulations of masonry arch bridges

Abstract This paper proposes a robust multidisciplinary method that combines geomatic procedures (terrestrial laser scanning and reverse engineering), geophysical methods (ground-penetrating radar and multichannel analysis of surface waves), sonic and impact echo tests, and ambient vibration approaches to generate accurate numerical simulations of masonry arch bridges. These methods are complemented by a robust finite element model updating method based on metamodeling global sensitivity analysis and a robust calibration strategy. The results obtained corroborate the feasibility of the proposed methodology with an average relative error in frequencies of 1.21% and an average modal assurance criterion of 0.93.

A Multiobjective Optimization Approach for COLREGs-Compliant Path Planning of Autonomous Surface Vehicles Verified on Networked Bridge Simulators

This paper presents a multiobjective optimization approach for path planning of autonomous surface vehicles (ASVs). A unique feature of the technique is the unification of the Convention on the International Regulations for Preventing Collisions at Sea (COLREGs) with good seamanship’s practice along with hierarchical (rather than simultaneous) inclusion of objectives. The requirements of collision avoidance are formulated as mathematical inequalities and constraints in the optimization framework and thus collision-free manoeuvres and COLREGs-compliant behaviours are provided in a seafarer-like way. Specific expert knowledge is also taken into account when designing the multiobjective optimization algorithm. For example, good seamanship reveals that if allowed, an evasive manoeuvre with course changes is always preferred over one with speed changes in practical maritime navigation. As a result, a hierarchical sorting rule is designed to prioritize the objective of course/speed change preference over other objectives such as path length and path smoothness, and then incorporated into a specific evolutionary algorithm called hierarchical multiobjective particle swarm optimization (H-MOPSO) algorithm. The H-MOPSO algorithm solves the real-time path planning problem through finding solutions of the formulated optimization problem. The effectiveness of the proposed H-MOPSO algorithm is demonstrated through both desktop and high-fidelity networked bridge simulations.