Large-scale Engineering Research Articles

Real-time prediction of mooring tension for semi-submersible platforms

The harsh operating environment of deepwater semi-submersible production platforms poses severe challenges to the safe operation and maintenance of their production processes. Using artificial intelligence technology to improve the operation and maintenance level of large-scale offshore engineering equipment has become an inevitable trend. Accurate mooring tension prediction for semi-submersible production platforms can effectively identify potential damage and ensure the platform's safe and efficient production operation. Compared with traditional cyclic neural networks, transformer neural networks have faster calculation speeds, better generalization abilities and scalability, and better abilities to capture long-distance dependencies. In this study, the first deepwater semi-submersible production platform in the South China Sea, “DeepSea One,” was selected as the research object, and an improved novel transformer neural network architecture was proposed for the mooring tension prediction of semi-submersible production platforms using actual long-term mooring tension data obtained during the platform's production process. The proposed method was compared with the commonly used long short-term memory neural network model, and the comparison proved the effectiveness of the proposed method in predicting the dynamic tension of semi-submersible production platform mooring. In addition, the proposed method is also applicable for the prediction of other time series data in the field of shipbuilding and offshore engineering, which is of certain value for generalization.

High-order finite volume multi-resolution WENO schemes with adaptive linear weights on triangular meshes

This paper presents high-order finite volume multi-resolution weighted essentially non-oscillatory schemes with adaptive linear weights to solve hyperbolic conservation laws on triangular meshes. They are abbreviated as the ALW-MR-WENO schemes. The novel third-order, fourth-order, and fifth-order ALW-MR-WENO schemes are designed by applying two unequal-sized hierarchical central stencils in comparison to the classical WENO schemes which utilize many equal-sized upwind biased/central stencils. With the application of one simple condition, only two linear weights are automatically adjusted to be positive values on condition that their summation is one. The novel finite volume ALW-MR-WENO schemes could maintain the designed order of accuracy in smooth areas and reduce to the first-order accuracy so as to keep essentially non-oscillatory properties around strong discontinuities. So it is the first time that any high-order WENO schemes with the application of only two unequal-sized stencils are obtained on triangular meshes. And the major benefits are their efficiency, compactness, and simplicity in large scale engineering applications on unstructured meshes. Finally, several tests are used to indicate the effectiveness of these new finite volume WENO schemes.

Multi-Antenna Global Navigation Satellite System/Inertial Measurement Unit Tight Integration for Measuring Displacement and Vibration in Structural Health Monitoring

Large-scale engineering structures deform and vibrate under the influence of external forces. Obtaining displacement and vibration is crucial for structural health monitoring (SHM). Global navigation satellite system (GNSS) and inertial measurement unit (IMU) are complementary and widely used in SHM. In this paper, we propose an SHM scheme where IMU and multi-antenna GNSS are tightly integrated. The phase centers of multiple GNSS antennas are transformed into the IMU center, which increases the observation redundancy and strengthens the positioning model. To evaluate the performance of tight integration of IMU and multiple GNSS antennas, high-rate vibrational signals are simulated using a shaking table, and the errors of horizontal displacement of different positioning schemes are analyzed using recordings of a high-precision ranging laser as the reference. The results demonstrate that applying triple-antenna GNSS/IMU integration for measuring the displacement can achieve an accuracy of 2.6 mm, which is about 33.0% and 30.3% superior than the accuracy achieved by the conventional single-antenna GNSS-only and GNSS/IMU solutions, respectively.

Final physical design of engineering materials diffractometer at the China spallation neutron source

Neutron diffraction is a widely utilized technique in detecting microstructures and residual strains in large-scale engineering components. In this study, we present the final physical design of an upcoming neutron diffractometer for engineering materials at the China Spallation Neutron Source. Our primary objective is to minimize the experimental time required for precise diffraction peak determination. To achieve this, the design includes a neutron transport system, a neutron wavelength selection system, a diffracted neutron optical system, and a resolution and intensity regulation system. Notably, we optimized the wavelength bandwidth specifically for scientific experiments, while the neutron flux or integrated peak intensity were optimized through careful considerations of neutron transport. Additionally, we placed great emphasis on ensuring the uniformity of the neutron phase space to enhance measurement accuracy. Moreover, we optimized the combinations of resolution and integrated peak intensity based on the best figure of merit. Consequently, we successfully developed an advanced diffractometer that is poised to offer new capabilities for engineering material studies.

Evaluation of the Potential for CO2 Storage and Saline Water Displacement in Huaiyin Sag, Subei Basin, East China

CO2 geological storage combined with deep saline water recovery technology (CO2-EWR) is one of the most effective ways to reduce carbon emissions. Due to the complex structural features, it is difficult to use CO2-EWR technology in Huaiyin Sag, Subei basin, East China. In this study, the multi-source information superposition evaluation technology of GIS was utilized for the selection of CO2 storage sites and water displacement potential target areas in this area, which mainly focused on the sandstone reservoirs of Cretaceous Pukou Formation. Based on the results, a three-dimensional injection–extraction model was established. Various scenarios with different production/injection well ratios (PIR) were simulated. Research has shown that the suitability of the surrounding site of Huaiyin Power Plant can be divided into two levels: relatively suitable and generally suitable; the area in the generally suitable level accounts for more than 80%. At a PIR of 1, CO2 is distributed asymmetrically, whereas at PIRs of 2 or 4, CO2 is distributed symmetrically. When the number of production wells is constant, a higher injection rate results in a faster expansion rate of the CO2 plume. This means that the time taken for the CO2 plume to reach the production wells is shorter. Reservoir pressure increases rapidly after more than 60 years of CO2 injection at lower PIR values, while at higher PIRs, reservoir pressure eventually stabilizes. Higher PIR values correspond to higher gas saturation, indicating a greater capacity for CO2 sequestration with more producing wells. When PIR = 4, the total CO2 injection increased by 55.73% compared to PIR = 1. However, the extraction of saline decreases with an increase in the number of producing wells, resulting in a decrease in replacement efficiency. This study provides a theoretical basis and technical support for the implementation of large-scale CO2-EWR engineering and technology demonstration in this region.

Study on the influence of tool rotational speeds/welding traverse speeds on the quality and surface formation of 6mm copper friction stir welding

Abstract This paper describes a study on the formation and process parameters of friction stir welding joints on 6mm thick copper plates. Numerous experiments were conducted at lower rotational speeds and moderate welding traverse speeds to obtain optimal process parameters for high-quality friction stir welding joints with good surface formation and no internal defects. Simultaneously, considering the thickness tolerance fluctuations in the large-scale engineering application of Copper FSW, tests were conducted with pin lengths and shoulder plunge depths less than the plate thickness. Additionally, a unique modular stirring tool was designed by ourselves to reduce costs in large-scale engineering applications. The experimental results demonstrate that under the parameters of a rotational speed of 275r/min and a traverse speed of 120mm/min, welding joints with both surface and internal integrity can be achieved, with the joint strength level exceeding 80% of the base material. The mechanical weak point of the joint is located in the TMAZ region just below the pin as revealed by SEM testing, which shows both plastic and brittle fractures. EDS results indicate no inclusions or second-phase precipitates at the surface and port locations.

Heating aluminum dross: Harmless process and utilization as cement admixture

Phosphogypsum (PG) and aluminum dross (AD) with harmful impurities seriously hinder its large-scale engineering utilization. In this paper, the properties of AD and PG as cement admixture were investigated with the aim of reducing the environmental pollution and landfill stockpiling pressure. The migration and transformation rules under crucial factors were analyzed by different characterization methods while AD was heated at different temperature. Then, the compressive strength, soluble phosphorus and fluorine concentration, hydration heat and expansion rate of specimens prepared with AD, PG, and Portland cement (PC) were evaluated to illustrate the hydration mechanism. Compared to the other experiment sets, the results indicated that AD treated at 900°C not only had a higher nitrogen removal rate, but also maintained hydration activity at a relatively high level. Moreover, Heating AD at 900℃ effectively accelerated the dissolution of gypsum and calcium silicate, resulting in increased formation of ettringite (AFt), calcium silicate hydrates (C-S-H) and calcium aluminium hydrates (C-A-H). When the binder consisted of 14% heated aluminium dross (HAD), 6% PG, and 80% PC, the specimen reached the highest compressive strength value at 25.87 MPa. This work provided a new strategy for synergistic utilization of PG and AD, promoting the development of environment-friendly industrial wastes-based cementitious materials effectively.

Implementation of real-time hybrid simulation using a large shake table with onboard actuators

In recent decades, shake table real-time hybrid simulation (RTHS) has emerged as a promising seismic testing approach for complex engineering structures. However, the current shake table RTHS systems with actuators typically install the dynamic actuators on a reaction wall outside the table, which introduce interaction issues between the dynamic actuators and the shake table. This study proposes a potential improvement by developing a shake table RTHS platform with onboard actuators. The platform incorporates a 6 m × 9 m large-scale shake table where the physical substructure, two dynamic actuators, and the reaction frame are all positioned. To validate the effectiveness of the developed platform, a two-story steel frame is tested by both full structure shake table test and substructure shake table RTHS. In the shake table RTHS, the lower part of the frame serves as the physical substructure and is simultaneously loaded by the shake table and dynamic actuators, while the upper part is numerically analyzed in OpenSees, using OpenFresco and Simulink as intermediate softwares. The test results demonstrate that the developed shake table RTHS platform provides reasonable predictions to the structural seismic responses. In addition, time delay is optimized using both inner and outer loop compensators, highlighting the effectiveness of inverse compensation and adaptive time series (ATS) compensation schemes. This paper successfully develops a shake table RTHS platform using a large shake table with onboard dynamic actuators, providing a valuable seismic testing platform for RTHS of large-scale complex engineering structures.

Three-dimensional broadband simulation of near-fault seismic ground motion considering complete source-path-site effect: Modeled by fast multipole indirect boundary element method

Efficient and accurate numerical methods are essential for analyzing seismic wave propagation and amplification in near-fault complex sites. Understanding the complete process of ground motion simulation, including fault rupture, path propagation, and near-surface complex site response, is crucial for studying earthquake damage mechanisms, seismic zoning, and designing large-scale engineering structures. In this study, we propose a fast multipole indirect boundary element method (FMIBEM) to achieve broadband and high-efficiency simulation, enabling a comprehensive analysis of the complete process involving seismic ground motion. The FMIBEM significantly reduces the computational and storage costs associated with 3D near-fault complex site seismic wave scattering problems to O(N). We validate the accuracy of the method by comparing it with the analytical solution. Compared to the conventional indirect boundary element method (IBEM), our proposed method reduces computational time by over 95 % and storage costs by nearly 90 %. FMIBEM greatly enhances the efficiency of the boundary element method for simulating seismic wave scattering in near-fault complex sites. To demonstrate the effectiveness of our approach, we apply the FMIBEM method to two typical 3D near-fault complex site examples of seismic wave scattering. The simulation results successfully capture both the local site amplification effect and the characteristic near-fault seismic features, such as the hanging wall effect, permanent displacement effect, and large velocity pulse.

Investigating Environmental Efficiency Upgrading Path of Construction Waste Based on Configuration Analysis

The rapid development of urbanization and large-scale engineering projects have led to the output of a large quantity of construction waste, which also puts great pressure on the environment. Environmental efficiency, as one of the criteria for measuring sustainable development, can be used to measure the impact of enterprises, industries, or regions on the environment when creating economic value. This research takes 30 provinces in China as samples and uses configuration analysis and fuzzy-set qualitative comparative analysis (fsQCA) methods to analyze the combined effects of factors affecting the environmental efficiency of construction waste generation, to find upgrading paths to improve environmental efficiency. The results indicate that five configurations can promote provinces to achieve high environmental efficiency, which can be classified into three types: population density, technological innovation, and policy economy. These three configurations reveal the comprehensive impact of systematic correlations among population, technology, policy, and economic factors on environmental efficiency improvements. This research provides a certain theoretical reference for exploring the influencing factors of environmental efficiency and provides theoretical guidance for selecting different paths to improve the environmental efficiency of construction waste in regions with different social conditions.

Efficient computational homogenisation of 2D beams of heterogeneous elasticity using the patch scheme

Modern ‘smart’ materials have complex heterogeneous microscale structure, often with unknown macroscale closure but one we need to realise for large scale engineering and science. The multiscale Equation-Free Patch Scheme empowers us to non-intrusively, efficiently, and accurately predict large scale, system level, solutions through computations on only small sparse patches of the given detailed microscale system. Here the microscale system is that of a 2D beam of heterogeneous elasticity, with either fixed–fixed, fixed–free, or periodic boundary conditions. We demonstrate that the described multiscale Patch Scheme simply, efficiently, and stably predicts the beam’s macroscale, with a controllable accuracy, at finite scale separation. Dynamical systems theory supports the scheme. This article points the way for others to use this innovative systematic non-intrusive approach, via a developing toolbox of functions, to model and compute accurately macroscale system-levels of general complex physical and engineering systems.

An Interactive Knowledge-Based Multiobjective Evolutionary Algorithm Framework for Practical Optimization Problems

Experienced users often have useful knowledge and intuition in solving real-world optimization problems. User knowledge can be formulated as inter-variable relationships to assist an optimization algorithm in finding good solutions faster. Such inter-variable interactions can also be automatically learned from high-performing solutions discovered at intermediate iterations in an optimization run – a process called innovization. These relations, if vetted by the users, can be enforced among newly generated solutions to steer the optimization algorithm towards practically promising regions in the search space. Challenges arise for large-scale problems where the number of such variable relationships may be high. This paper proposes an interactive knowledge-based evolutionary multi-objective optimization () framework that extracts hidden variable-wise relationships as knowledge from evolving high-performing solutions, shares them with users to receive feedback, and applies them back to the optimization process to improve its effectiveness. The knowledge extraction process uses a systematic and elegant graph analysis method which scales well with number of variables. The working of the proposed is demonstrated on three large-scale real-world engineering design problems. The simplicity and elegance of the proposed knowledge extraction process and achievement of high-performing solutions quickly indicate the power of the proposed framework. The results presented should motivate further such interaction-based optimization studies for their routine use in practice.

Metal-Organic Framework-Based Composites for the Adsorption Removal of Per- and Polyfluoroalkyl Substances from Water.

The increasing health risks posed by per- and polyfluoroalkyl substances (PFASs) in the environment highlight the importance of implementing effective removal techniques. Conventional wastewater treatment processes are inadequate for removing persistent organic pollutants. Recent studies have increasingly demonstrated that metal-organic frameworks (MOFs) are capable of removing PFASs from water through adsorption techniques. However, there is still constructive discussion on the potential of MOFs in adsorbing and removing PFASs for large-scale engineering applications. This review systematically investigates the use of MOFs as adsorbents for the removal of PFAS in water treatment. This primarily involved a comprehensive analysis of existing literature to understand the adsorption mechanisms of MOFs and to identify factors that enhance their efficiency in removing PFASs. We also explore the critical aspects of regeneration and stability of MOFs, assessing their reusability and long-term performance, which are essential for large-scale water treatment applications. Finally, our study highlights the challenges of removing PFASs using MOFs. Especially, the efficient removal of short-chain PFASs with hydrophilicity is a major challenge, while medium- to long-chain PFASs are frequently susceptible to being captured from water by MOFs through multiple synergistic effects. The ion-exchange force may be the key to solving this difficulty, but its susceptibility to ion interference in water needs to be addressed in practical applications. We hope that this review can provide valuable insights into the effective removal and adsorption mechanisms of PFASs as well as advance the sustainable utilization of MOFs in the field of water treatment, thereby presenting a novel perspective.

Enhancing bonding behavior between basalt fiber-reinforced polymer sheets and concrete using resin pre-coating method and multi-wall carbon nanotubes

There is a crucial problem of premature debonding failure in fiber-reinforced polymer (FRP) sheet external bonding reinforcement for concrete structures. Using anhydrous ethanol as solvent instead of acetone, the effect of resin pre-coating (RPC) technique with neat resin-ethanol solution and multi-wall carbon nanotubes (MWCNTs)-resin-ethanol solution on the bonding behavior of the FRP-concrete joints was investigated by single-shear tests. Experimental results indicated that RPC technique significantly enhanced the bonding properties, especially when the pre-coating was MWCNTs-resin-ethanol solution. In the case of using neat epoxy resin as adhesive, compared with the control specimens without RPC treatment, the ultimate bearing capacity, ultimate global slip, maximum bond stress and interface fracture energy of the basalt fiber-reinforced polymer (BFRP)-concrete joints using RPC treatment with MWCNTs-resin-ethanol solution increased by 32.6 %, 48.4 %, 68.3 % and 88.8 %, respectively. MWCNTs could be seen in scanning electron microscopy (SEM) images of the fracture surface, which indicated that they could penetrate into the concrete and the crack bridging and pull-out of MWCNTs could enhance the interfacial adhesion of the FRP-concrete joints. Compared with the RPC treatment using the restricted acetone, the RPC treatment with MWCNTs-resin-ethanol solution can more significantly enhance the bond properties of the interface between concrete and FRP sheet, and it is suitable for large-scale practical engineering applications on site. This study demonstrated the great promise of the RPC technique with MWCNTs-resin-ethanol solution toward practical engineering application in reinforcement and repair of concrete structures.

A Two-Stage Registration Strategy for Thermal–Visible Images in Substations

The analysis of infrared video images is becoming one of the methods used to detect thermal hazards in many large-scale engineering sites. The fusion of infrared thermal imaging and visible image data in the target area can help people to identify and locate the fault points of thermal hazards. Among them, a very important step is the registration of thermally visible images. However, the direct registration of images with large-scale differences may lead to large registration errors or even failure. This paper presents a novel two-stage thermal–visible-image registration strategy specifically designed for exceptional scenes, such as a substation. Firstly, the original image pairs that occur after binarization are quickly and roughly registered. Secondly, the adaptive downsampling unit partial-intensity invariant feature descriptor (ADU-PIIFD) algorithm is proposed to correct the small-scale differences in details and achieve finer registration. Experiments are conducted on 30 data sets containing complex power station scenes and compared with several other methods. The results show that the proposed method exhibits an excellent and stable performance in thermal–visible-image registration, and the registration error on the entire data set is within five pixels. Especially for multimodal images with poor image quality and many detailed features, the robustness of the proposed method is far better than that of other methods, which provides a more reliable image registration scheme for the field of fire safety.

An experimental investigation into the effect two-phase flow induced vibrations have on a J-shaped flexible pipe

Multiphase flow inside of pipes occurs in a wide variety of engineering applications, including offshore deep-water oil and gas transport. Vibrations induced by the flow inside of the pipe can lead to its mechanical failure and thus lead to uncontrolled release of the fluids being transported. In subsea applications, flexible J-risers are often employed to deliver the produced fluids from the seafloor to the host platform. Despite the potentially significant liabilities associated with subsea hydrocarbon leaks, there has been a distinct lack of investigations into how flow induced vibrations in large scale, pressurised flexible J-risers can lead to system integrity loss. Previous investigations have generally focused on the response of rigid pipes or small scale, unpressurised flexible risers. This study presents an investigation into the response of a 10 m long, 50.8 mm internal diameter composite riser containing a tensile armour helical structure to a variety of two-phase, water-nitrogen flows at 10.8 barg of pressure and ambient temperature. High speed cameras were used to investigate the structure of the flow at either end of the flexible riser, whilst synchronised surface mounted strain gauges and accelerometers were used to investigate the response of the pipe. Time-averaged data were acquired to assess the general response of the pipe, whilst a statistical analysis of the fluctuations highlighted the movement of the pipe. One-dimensional and computational fluid dynamics simulations were used to define the experimental test matrix and provide further insight into the structure of the flow inside the J-riser. Single-phase gas flow was found not to cause the J-riser to move significantly, whilst multiphase flow led to significant in-plane movement of the pipe. Increasing the liquid flow rate (or decreasing the gas flow rate) increased the mean strain experienced by the pipe. At low gas flow rates, the pipe oscillated smoothly about its mean position, but at higher gas flow rates a violent intermittent whipping motion was observed. The latter produced large in-plane and out-of-plane movement of the pipe which could pose a threat to system integrity. This work offers new insights into fluid-structure interactions in large scale engineering applications, contributing to improved system design and control.

Enhanced Anti/De-Icing Performance on Rough Surfaces Based on The Synergistic Effect of Fluorinated Resin and Embedded Graphene.

Icing negatively impacts various industrial sectors and daily life, often leading to severe safety problems and substantial economic losses. In this work, a fluorinated resin coating with embedded graphene nanoflakes is prepared using a spin-coating curing process. The results shows that the ice adhesion strength is reduced by ≈97.0% compared to the mirrored aluminum plate, and the icing time is delayed by a factor of 46.3 under simulated solar radiation power of 96mWcm-2 (1 sun) at an ambient temperature of -15°C. The superior anti/de-icing properties of the coating are mainly attributed to the synergistic effect of the fluorinated resin with a low surface energy, the rough structure of the sandblasted aluminum plate, which reduces the contact area, and the embedded graphene nanoflakes with a superior photothermal effect. Furthermore, the hydrogen bonding competition effect between the exposed-edge oxygen-containing functional groups of the embedded graphene nanoflakes and water molecules further improves the anti-icing properties. This work proposes a facile preparation method to prepare coatings with excellent anti/de-icing properties, offering significant potential for large-scale engineering applications.

Low-cycle fatigue testing and microstructure of high strength-ductility structural steel materials

The well-known tradeoff between strength and ductility is a key issue in the large-scale engineering application of steel materials to resist fatigue due to earthquakes and other vibrational excitations. The steel production industry provides a vast range of technologies to achieve the desired performances. Through experimental research, it was found that FeCrNi-based high-ductility steel (HD-S) can demonstrate remarkable hysteresis behavior due to extensive deformation capacity of strain-hardening until the ultimate fracture, compared to industrially manufactured high-strength steel (HS-S) with the level of 1 GPa in yield strength. The balance between strength and ductility can be realized by slightly adding the percentage of Ni by 5% to achieve a ductile hysteresis behavior. Moreover, the HD-S specimens exhibit greater resistance to low-cycle fatigue with large plastic amplitude. By developing a new damage evolution law based on instantaneous damage differential during nonstationary fatigue history, the fatigue life of materials is extended into the inelastic hinges of flexural beams/origami components. The proposed approach enables the fatigue design of steel structural components with desirable disaster-prevention capacities for complex steel structures.

Covalent Organic Frameworks: Cutting-Edge Materials for Carbon Dioxide Capture and Water Harvesting from Air.

The implacable rise of carbon dioxide (CO2 ) concentration in the atmosphere and acute water stress are one of the central challenges of our time. Present-day chemistry is strongly inclined towards more sustainable solutions. Covalent organic frameworks (COFs), attributable to their structural designability with atomic precision, functionalizable chemical environment and robust extended architectures, have demonstrated promising performances in CO2 trapping and water harvesting from air. In this Review, we discuss the major developments in this field as well as sketch out the opportunities and shortcomings that remain over large-scale COF synthesis, device engineering, and long-term performance in real environments.

Edge Intelligence for Industrial IoT: Opportunities and Limitations

Industrial Internet of Things (IIoT) nowadays represents a fundamental technology for the Industry 4.0 initiatives for connecting devices, operators and processes so as to eventually fuel digital transformation. However, if based exclusively on Cloud Computing, the IIoT faces inevitable limitations and barriers. Therefore, in this paper we deal with the Edge Intelligence (EI), a novel paradigm at the confluence of Edge Computing and artificial Intelligence, and, particularly, we analyze its impact on the processing of the IIoT data in the proximity of the events of interest rather than on Cloud servers. Therefore, a general discussion on the most relevant benefits, limitations and open challenges of the IIoT-EI duo is proposed hereinafter and exemplified through an emblematic IIoT use case: this is related to safety-critical tasks based on video analytics and provides a full-fledged comparison between Cloud-and EI-based IIoT deployments (in terms of reliability, responsiveness, bandwidth usage, energy footprint and usability), finally outlining a general strategy for large-scale EI-aided IIoT systems engineering.