Engineering Design Research Articles

Machine learning techniques for predicting the peak response of reinforced concrete beam subjected to impact loading

To meet the growing need for resilient structures in seismic and high-impact zones, accurate prediction of the response of reinforced concrete (RC) beams under impact loads is essential. Traditional methods, such as experimental testing and high fidelity finite element models, are often time consuming and resource intensive. To address these challenges, this study investigates various ensemble and non-ensemble machine learning techniques—including support vector machine, gaussian process regression (GPR), k-nearest neighbor (KNN), gene expression programming, random forest, decision tree, boosted tree, adaptive boosting tree, gradient boosting algorithm, stochastic gradient descent, and artificial neural network—for predicting the peak response of RC beams under impact loads. A set of 145 experimental data points from 12 different sources is used to train and evaluate these machine learning models. Key parameters in the data include beam width and depth, span, reinforcement ratios, concrete strength, steel yield strength, deflection, and impact characteristics. Except for KNN, all models showed satisfactory generalization capabilities with R2 values over 0.8. Statistical errors such as RMSE, a-10 index, MAE, and a-20 index are within acceptable limits. The GPR model is the most effective with R2 value of 0.95. Moreover, Shapely analysis identified beam depth, impact velocity, and beam breadth as critical factors. Overall, this study demonstrates the efficacy of machine learning in accurately predicting the behavior of RC structures under impact loads, providing valuable tools for civil engineers in design and analysis.

Matching analysis between the heating/cooling capacity of PVT heat pumps and the heating/cooling demand of residential buildings across various regions in China

PVT-HP (Photovoltaic-Thermal Heat Pump) is a novel type of energy saving technology. Existing researches on PVT-HP technology focuses only on its operating performance under some specific conditions, ignoring the matching of its energy supply capacity with the energy demand of buildings, which is very important for its engineering design and application. In this paper, the matching relationship between the heating/cooling capacity of the PVT-HP system and the heating/cooling demand of residential buildings in major cities of China has been analyzed. To achieve this goal, a novel prediction model used to calculate the heating/cooling performance of the PVT-HP system has been proposed. And the daily heating guarantee rate and daily cooling guarantee rate have been put forward to evaluate the matching relationship. Based on the evaluation indexes, the applicable matching relationship between the installed capacity of the PVT-HP system and the heating/cooling area of residential buildings has been analyzed. The result of case study shows that for the selected cities of Shenyang, Beijing and Wuhan, the heating/cooling area of residential building for PVT-HP system with installed capacity of 1hp should not exceed 17m2, 31m2 and 25m2, respectively. Further matching analysis of major cities in China shows that the PVT-HP system is more suitable for application in hot summer and cold winter zones of China, in where the suggested heating/cooling area for the PVT-HP system with installed capacity of one horse power is within the range of 30m2 to 37m2.

Use of Chitosan as a Precursor for Multiple Applications in Medicinal Chemistry: Recent Significant Contributions.

Chitosan (CS) is a polymer made up of mainly deacetylated β-1,4 D-glucosamine units, which is part of a large group of D-glucosamine oligomers known as chitooligosaccharides, which can be obtained from chitin, most abundant natural polymer after cellulose and central component of the shrimp exoskeleton. It is known that it can be used for the development of materials, among which its use stands out in wastewater treatment (removal of metal ions, dyes, and as a membrane in purification processes), food industry (anti-cholesterol and fat, packaging material, preservative, and food additive), agriculture (seed and fertilizer coating, controlled release agrochemicals), pulp and paper industry (surface treatment, adhesive paper), cosmetics (body creams, lotions, etc.), in the engineering of tissues, wound healing, as excipients for drug administration, gels, membranes, nanofibers, beads, microparticles, nanoparticles, scaffolds, sponges, and diverse biological ones, specifically antibacterial and antifungal activities. This article reviews the main contributions published in the last ten years regarding the use and application of CS in medical chemistry. The applications exposed here involve regenerative medicine in the design of bioprocesses and tissue engineering, Pharmaceutical sciences to obtain biomaterials, polymers, biomedicine, and the use of nanomaterials and nanotechnology, toxicology, and Clinical Pharmaceuticals, emphasizing the perspectives and the direction that can take research in this area.

The impact protection behavior of UHPC composite structure on RC columns

In order to prevent the reinforced concrete (RC) structures from being damaged under the overload impact, a new type of composite structure—ultra-high performance concrete (UHPC)–Bio-inspired honeycomb column thin-walled structure (BHTS) was designed in this paper. A scale model with a scaling factor of 1:10 was made. The experimental tests and numerical simulations of RC column and UHPC composite structure were carried out. By comparing the impact force, displacement, shear force, bending moment and energy absorption, the protective effect of the UHPC-BHTS composite structure on RC columns under lateral impact load was evaluated. Then, the failure process of RC column was analyzed, the UHPC-BHTS composite structure absorbed 76.42% of the impact kinetic energy under the higher energy input condition, the shear failure with large damage to the RC column can be converted into bending failure with small damage. At the same time, a new damage assessment method was used to evaluate the RC column. The results show that the RC column with UHPC-BHTS composite structure can effectively protects the RC column structural integrity under impact. The design and modeling methods in this research can provide a useful reference for anti-collision design in practical engineering.

Efficient and durable OER electrocatalysts through vacancy engineering and core-shell structure design in acidic environment

The electrocatalytic conversion of water into green hydrogen energy through overall water splitting advances sustainable energy goals. However, it is limited by the slow kinetics of the oxygen evolution reaction (OER) and durability challenges at high potentials. Here, we rationally develop a series of Mn-doped RuO2-coated Ru (Mn-Ru@RuO2) catalysts involving unique core-shell structures and abundant lattice distortions induced by oxygen defects. The optimal Mn-Ru@RuO2 sample demonstrated robust activity, achieving a low overpotential of 220 mV at 10 mA cm−2. Notably, this sample exhibited minimal degradation after 220 h and a 25.5-fold increase in mass activity (1.37 A mgRu−1) compared to commercial RuO2 at an overpotential of 300 mV. These results suggest that regulated oxygen deficiencies and optimal Ru3+/Ru4+ ratios facilitate the lattice oxygen oxidation (LOM) mechanism and the formation of a high concentration of ∗OH radicals, enhancing acidic OER performance. Additionally, the unique core-shell structures effectively prevent over-oxidation of the RuO2 shell, ensuring superior durability. This research not only breaks the trade-off of electrochemical activity and durability, but also provides valuable insights into the design of highly efficient and stable electrocatalysts.

Review of diver propulsion vehicle: A review

The ocean serves as a vital arena for resource exploitation, scientific inquiry, and strategic endeavors. Among the array of underwater propulsion technologies, diver propulsion vehicles (DPVs) stand out for their exceptional integration, concealability, and maneuverability. They hold a pivotal role in both marine scientific exploration and military operations beneath the waves, thus carrying significant research implications. However, the existing literature on DPVs remains limited, lacking comprehensive examinations of their design processes and parameters. This review systematically surveys and assesses the current landscape of DPV development and research. Three key facets—propeller design, performance assessment, and equipment engineering—are scrutinized and analyzed. By consolidating essential data from ongoing studies, this review offers valuable insights. Additionally, it forecasts potential directions and emerging focal points in the evolution of underwater propulsion for frogmen, drawing from current advancements. The objective is to furnish foundational data to support the design and study of frogman underwater propulsion systems, thereby advancing engineering applications in this domain.

Dynamic Condensation for Efficient Band-Structure Calculations of 2D Periodic Structures

Efficient band-structure calculations are essential for understanding the mechanical behaviors of periodic materials, with significant implications in material design and phononic engineering. This paper introduces the application of the improved reduced system (IRS) technique to expedite elastic band-structure calculations. The IRS, a dynamic condensation method, partitions the unit cell degrees of freedom (DOFs) into primary and secondary sets. A strategic selection of primary DOFs retains a subset of interior DOFs alongside all exterior DOFs while truncating the remaining interior DOFs. The integration of IRS with the Craig–Bampton method for additional reduction and the imposition of Bloch boundary conditions yields a notable decrease in computational overhead. Additionally, for structures with a high number of interior DOFs, a substructuring scheme can be implemented to further enhance efficiency. This approach offers a compelling combination of accuracy and expedited computation, making it applicable across diverse periodic materials.

Structure Analysis of Hybrid Marine Renewable Energy Platform

Abstract The Pilot Project Energy Laut Hybrid for coastal communities utilises a hybrid-based tripod pontoon structure. Hydrodynamic analysis was conducted using Computational Fluid Dynamic (CFD) simulations and Detail Engineering Design (DED) testing at the Hydrodynamics Laboratory of Indonesia (LHI). This research aims to conduct a structural analysis of the tripod pontoon frame, including redesigning and comparing the strength between the existing and modified designs. An analysis using the software SACS V15.1 was employed to obtain unity check values and stress distribution. The analysis revealed that the unity check values for the existing model, with airy wave01, airy wave02, stokes wave01, and stokes wave02, were 0.508, 0.498, 0.509, and 0.5, respectively. In contrast, the unity check values for the modified model, with airy wave01, airy wave02, stokes wave01 and stokes wave02, were 0.827, 0.81, 0.827, and 0.813, respectively, indicating a 63% increase in unity check for the modified model. The largest shear stress was observed on member A5-1-A5-2 in both models, which still complies with the API RP 2A-WSD standard. Additionally, the modified model was 21% lighter than the existing model, with Z shear stress increasing by 63% for both airy and stokes wave types.

Optimization design of composite cap-shape pillar structure based on gaussian process of combined kernel function

Abstract To quickly realize the optimal design of the cap-shaped structure, an optimization design method of composite cap-shaped pillar structure based on combined kernel function Gaussian process was proposed. First, the shortcomings of two kernel functions representing different linear characteristics of data in model construction were analyzed, on which a new combined kernel function was constructed. Based on the finite element numerical simulation results, a database with the web thickness, web height, fiber volume, and ultimate bearing capacity of the cap-shaped structure was constructed. Then, a Gaussian process model based on the combined kernel function was established and the model parameters were trained by the maximum likelihood method. Finally, taking the ultimate bearing capacity per unit volume as the optimization objective, the artificial fish swarm algorithm was used to quickly obtain the structure design parameters under the optimal objective function, and the simulation results were compared with the initial design parameters. The results showed that the method proposed in this paper can optimize the structure performance, improve the design efficiency, and meet the engineering design requirements.

Decoupling method of self-gravity compensation based on spherical multipole expansion for space gravitational wave detectors

In space gravitational wave detection missions, the gravity and its gradients produced by the spacecraft on the two Test Masses (TMs) are commonly referred to as the Self-Gravity(SG). It is an important source of TM disturbances in gravitational wave detection and other drag-free space missions and will affect the TM acceleration noise in many ways. The SG can be reduced by adding Balance Masses (BMs). But for typical space gravitational wave detectors, in which the sensitive axes of the two TMs are at an angle of 60°, the couplings of different SG components of two TMs make the gravity compensation process complicated in practice, which is normally an iterative process. This paper analyses the correspondence between the SG components of the two TMs and the spherical harmonics of different orders, and proposes a compensation method based on spherical multipole expansion. This method allows independent design of the BMs for most of the main SG components, without couplings and iterations. To verify this method, a self-gravity compensation simulation is carried out by using a demonstrating spacecraft structural model for TianQin gravitational wave detection mission. Three sets of BMs are designed on the outer surface of the inertial sensor vacuum chamber, to compensate for the two linear accelerations and one linear gradient that exceed the requirements. The results show that the SG components after compensation are two orders of magnitude lower than the initial level, and all the components meet the preliminary requirements of TianQin mission. This study could provide reference for the engineering design and development of the spacecraft and inertial sensor payload for space gravitational wave detection missions.

Avoiding Flood by Improving Cross-Sectional Capacity through River Normalization

Bekasi is one of the regions in Indonesia that often suffer from flooding. To overcome flooding problems in the Bekasi area, the Ciliwung Cisadane River Basin Center has begun a normalization project along the Bekasi River. This research aimed to evaluate the Bekasi River's cross-sectional capacity both before and after normalization. The analysis focused on the section where the Cileungsi and Cikeas rivers converge to the Bekasi weir. In this research, secondary data were employed, such as national digital elevation model data, detailed engineering designs of Bekasi River flood control activities, and rainfall data from the Cibinong Station that covers the period from 2006 to 2020. The result from planned flood discharge with the Nakayasu synthetic unit hydrograph method for a return period of 25 years on the Bekasi River was obtained at 665.81 m3/s. The results of hydraulic analysis before normalization with the HEC-RAS application show that flooding occurred at 102 out of 116 stations, with capacities of river cross-sections ranging from 453.49 m³/s to 665.71 m³/s at these overflow stations. Following the river normalization process, the cross-sectional capacity at all Bekasi River stations can accommodate flood discharge without any instances of overflow.Keywords: Flood, HEC-RAS, Nakayasu, Normalization, Rainfall.

Exploring the ring-opening metathesis polymerization process by kinetic Monte Carlo simulation

Investigating the kinetics of polymerization reactions is a powerful tool to obtain information for the engineering design of such processes. It provides insights into how the relative rates of elementary reactions which influence both the kinetics of the reactions and thus characteristics of the products as well, particularly when the reaction parameters of these reactions are unknown. Among polymerization processes, ring-opening metathesis polymerization (ROMP) has gained broad academic and industrial interest, due to its mild conditions to obtain a wide range of polymer products. In this study, kinetic Monte Carlo simulation was applied to reveal the effect of the elementary reactions of ROMP on the kinetics and product distribution. Both the propagation and the cross-metathesis reactions were considered, with the latter leading to the formation of various types of macrospecies whose population levels were also monitored. Relevant tendencies were observed regarding how the variations in the reaction parameters of the elementary reactions of this polymerization process, such as reaction probabilities, monomer addition method, catalyst-to-monomer ratio, and reaction time, affect the kinetics of the polymerization process and the product distributions. These variations also influence the key macromolecular parameters of the resulting polymeric materials, including chain length distribution (CLD), population levels, and polymer functionalities. The results of this study indicate that this simulation technique is a valuable tool for mapping the tailoring possibilities of modifying the reaction parameters of ROMP to achieve desired properties. These properties include number average molecular weight, polydispersity, chain end functionality, and macrocycle-free products.

InP-based strain engineered InAs(Sb)/InAsPSb multiple quantum wells with tunable emission and high internal quantum efficiency enabled by Sb incorporation

A type I InAs(Sb)/InAsPSb strain engineered multiple quantum wells light emitting diodes system has been demonstrated. Tensile InAsPSb quantum barriers with a high degree of band offset (∆EC = 116–123 meV, ∆EV = 193–250 meV) were used to compensate for the high compressive strain of the InAs(Sb) quantum wells. The structure was grown on the n+-InAsxP1−x metamorphic buffer with a high degree of relaxation (98%), low surface roughness (0.69 nm), and low dislocation density. Through careful strain engineering design, the compressive strain of InAs(Sb) reaches 0.57%–1.52% without strain relaxation. The incorporation of Sb into the multiple quantum wells not only reduces the bandgap but also improves the interface quality by acting as an effective surfactant. Structural analysis reveals superior quality in InAsSb/InAsPSb multiple quantum wells compared to InAs/InAsPSb multiple quantum wells, demonstrating significantly reduced interface roughness and suppression of the Stranski–Krastanov growth mode. Room temperature electroluminescence measurements show a tunable emission wavelength ranging from 2.7 to 3.3 μm, accompanied by a narrow full width at half maximum value of 45 meV. Photoluminescence analysis indicates that the internal quantum efficiency of InAsSb/InAsPSb multiple quantum wells is 5.5%, which is 7 times higher than that of InAs/InAsPSb.

Imperialist competition algorithm with quasi-opposition-based learning for function optimization and engineering design problems

Imperialist competition algorithm with quasi-opposition-based learning for function optimization and engineering design problems

A coupled machine-learning-individual-based model for migration dynamics simulation: A case study of migratory fish in fish passage facilities

The extensive development of hydropower projects has notably changed the ecohydrological conditions of fish habitats, affecting fish behavior, including habitat usage and migration, to varying extents. Understanding fish migration dynamics is essential for quantitatively assessing the impact of ecological restoration measures on migratory fish. However, no model has yet demonstrated sufficient accuracy to be considered valuable in ecological restoration engineering. To address this issue, in this article, a coupled machine-learning-individual-based model (ML-IBM) consisting of random forest (RF) and Eulerian–Lagrangian–agent method (ELAM) is constructed for predicting fish migration, aiming to find effective fish passage solutions before implementation. In this study, the passage data of ya-fish (Schizothorax prenanti) in vertical slot fishways (VSFs) is compiled to train ML-IBM to simulate fish migration in fish passage facilities. In movement prediction, the accuracy of swimming behavior classification reaches 83.4 %, and the R² for swimming speed regression exceeds 0.77. Compared with other state-of-the-art migration dynamic models, the proposed ML-IBM achieves the lowest root mean square error (RMSE) of 7.35 and a mean absolute error (MAE) of 6.26 in migration simulation results. Further, RF is used to quantitatively calculate the importance of input features. The contributions of each feature are analyzed and discussed from a hydrodynamic perspective, with the importance ranked as follows: flow velocity (FV) > turbulent kinetic energy (TKE) > total hydraulic strain (THS). This approach enhances the interpretability of the model and provides further insights into the mechanism of fish migration. The results presented in this study have significant implications for informing decision-making in the management of living resources and guiding engineering design processes.

On the imperfection sensitivity and design of buckling critical wind turbine towers

Wind turbine towers pose major challenges for design engineers due to their complex geometry, nonlinear material behavior and imperfection sensitivity. In service, these thin-walled shells are burdened by a combination of complex load cases and prone to buckling. In fact, one of the main design drivers of wind turbine towers is stability failure for which often the design recommendation of the EN-1993-1-6 are used.Recently an international shell buckling exercise was caried out by the team behind the EN-1993-1-6 design standard. Within this exercise 29 teams from academia and industry were asked to perform a series of linear and non-linear finite element simulations of an 8-MW multi-strake steel wind turbine support tower segment. In general, the linear and nonlinear analyzes posed no challenge for the shell buckling experts from around the world. However, the imperfection sensitivity analysis results scattered significantly among the participants. In addition, there was little consensus as to whether the given tower design is actually safe.The authors, whose background is aerospace engineering, participated in this exercise and show in this article how they overcome the challenges of this typical civil engineering problem. Among linear and non-linear analyzes the authors show the results of state-of-the-art shell buckling concepts which were developed for aerospace shells like interstage tanks and adapters but are also applicable to wind turbine towers.

Confined Element Distribution with Structure-Driven Energy Coupling for Enhanced Prussian Blue Analogue Cathode.

The structural failure of Na2Mn[Fe(CN)6] could not be alleviated with traditional modification strategies through the adjustable composition property of Prussian blue analogues (PBAs), considering that the accumulation and release of stress derived from the MnN6 octahedrons are unilaterally restrained. Herein, a novel application of adjustable composition property, through constructing a coordination competition relationship between chelators and [Fe(CN)6]4- to directionally tune the enrichment of elements, is proposed to restrain structural degradation and induce unconventional energy coupling phenomenon. The non-uniform distribution of elements at the M1 site of PBAs (NFM-PB) is manipulated by the sequentially precipitated Ni, Fe, and Mn according to the Irving-William order. Electrochemically active Fe is operated to accompany Mn, and zero-strain Ni is modulated to enrich at the surface, synergistically mitigating with the enrichment and release of stress and then significantly improving the structural stability. Furthermore, unconventional energy coupling effect, a fusion of the electrochemical behavior between FeLS and MnHS, is triggered by the confined element distribution, leading to the enhanced electrochemical stability and anti-polarization ability. Consequently, the NFM-PB demonstrates superior rate performance and cycling stability. These findings further exploit potentialities of the adjustable composition property and provide new insights into the component design engineering for advanced PBAs.

Structure regulation and performance optimization mechanism of Sr0.7Bi0.2TiO3-based energy storage ceramics based on charged defect design engineering

The linear-like relaxor ferroelectric Sr0.7Bi0.2TiO3 with regulable microstructure offers a new platform to reveal the essential mechanism of energy storage properties improvement and develop advanced pulse capacitors. Herein, Li with relatively weak volatility accompanied by Bi was introduced in Sr0.7Bi0.2TiO3 to form a charged defect and increase the maximum polarization (Pmax) while avoiding the deterioration of dielectric breakdown strength (BDS). The occupation of Li and the formation of Li-Bi defect dipole polar were analyzed using first principle calculations. A unique local superlattice induced by the lattice distortion was first observed in related systems. The Pmax was enhanced due to the increased size and number of polar structures. The breakdown behaviour and local electric field distribution were analyzed using numerical simulation. The BDS was improved due to the decreased oxygen vacancies, high thermal conductivity and enhanced electrical insulation. The excellent and stable energy storage performance was achieved in different temperatures, frequencies and cycles. Meanwhile, the optimized sample possesses excellent and stable charge–discharge properties, especially fatigue resistance (105 cycles under 25 °C and 150 °C). After the process optimization, the sample shows a higher energy storage density of 3.44 J/cm3 with a high efficiency of 93.74 % at 345 kV/cm due to the further enhanced BDS. In this work, the performance improvement mechanism was studied in-depth, providing a new strategy for optimizing linear-like lead-free relaxor ferroelectric energy storage properties.

The Effect of Engineering Design-Based Science Instruction on 6th-Grade Students’ Astronomy Understandings

Astronomy education is essential for STEM education in primary schools, and integrating engineering design-based science education enhances student engagement and achievement in the field of space science. Integrating engineering design into science education is essential for students to excel in astronomy and to meet the requirements of contemporary society. This study investigated the effect of engineering design-based instruction (EDBI) on the understanding of astronomy concepts among sixth-grade students. The study included a cohort of 37 sixth-grade students from a public school. It was carried out using a one-group pre-test, post-test experimental design. All participants received EDBI that was based on the objectives of the 6th grade “Solar System and Eclipses” unit. Statistical analyses were employed to ascertain the effect of astronomy instruction based on engineering design on students’ comprehension of astronomy concepts. The results indicated a significant difference in the average scores of students’ understanding of astronomical concepts before and after being taught using EDBI.

Synopsis on Experimental and Finite Element Analysis of Brake-Shoe

Design engineers always aim at improvement in each and every part of the automobile system. The automobile industry has continued improving for many years with the efforts conducted for the purpose of modification of the mechanical parts of vehicles in order to improve their performance and vibration response. These characteristics have a vital impact on the mechanical performance of the overall system balance. In addition, redesigning the mechanical models plays an important role in improving the sustainability of the system against the resultant stresses and strains; therefore, significant consideration should be taken for this when designed by engineers. A brake shoe is the part of a braking system that has brake lining used in automobiles. It is a device put on a track to slow down a bike; it is also called a brake shoe. When the brake is applied, the shoe moves and presses the lining against the inside of the drum. The friction between the lining and drum provides the braking effort. Energy is dissipated as heat