Current Design Methods Research Articles

The design and performance evaluation of low-noise rubber-fibre micro-surfacing pavement

ABSTRACT Owing to its good performance and quick construction, micro-surfacing is frequently employed in the prevention and treatment of pavement diseases. However, the shortcomings of the current design methods and the noise problems have not been resolved. Two ways of optimising gradation and adding additives were used to reduce the noise and enhance the performance of micro-surfacing. The gradation of the micro-surfacing was investigated based on fractal theory and the optimum gradation range was determined. The results showed that adding more fibre to micro-surfacing improves its resistance to rutting, wear, water damage and cracking. The anti-skid performance of rubber powder-fibre micro-surfacing (RFMS) falls as the asphalt aggregate ratio rises, but wear resistance and water damage resistance rise and rutting resistance and fracture resistance increase initially before declining. The best mix proportion of RFMS is determined based on the overall mass of aggregate and each component is as follows: 1.5% cement (PO42.5), 3% rubber powder (40 mesh) and 0.2–0.25% polypropylene monofilament fibre (6 mm). RFMS can reduce pavement noise while maintaining good anti-skid performance. The study is an important supplement to the research on micro-surfacing and its noise reduction.

A Novel Hull Girder Design Methodology for Prediction of the Longitudinal Structural Strength of Ships

The ship hull girder model has been widely adopted in ship mechanics research such as small-scale and large-scale hydroelastic ship model experiments. Current design methods cannot seriously meet the structural rigidity requirement, and the distinction between the ship structural masses and the cargo masses is rather vague. This research proposes a simple and novel ship hull girder design methodology. The main novelties are that (1) the structural rigidity design requirement for the ship hull girder corresponding to any targeted real ship with arbitrary structural complexity is precisely satisfied by the proposed strategy of adopting a composite hull girder system, and that (2) the mass density per unit length of the proposed hull girder is solely related to the mass density distribution of the targeted ship structures by considering the hull girder system as a complete finite element (FE) model, and thus (3) a better ship hull girder model for prediction of the total structural responses can be consequently established. A real ship is adopted as the design target, and the structural responses of the real ship and the proposed ship hull girder model are compared and analyzed. The proposed model is compared to the currently widely accepted ship hull girder models through numerical experiments. The proposed hull girder design methodology possesses the potential for upgrading the classical structural design approach to match the growing trend of adopting FEM-based approaches for ship structure research.

Designing microplastic-binding peptides with a variational quantum circuit-based hybrid quantum-classical approach.

De novo peptide design exhibits great potential in materials engineering, particularly for the use of plastic-binding peptides to help remediate microplastic pollution. There are no known peptide binders for many plastics-a gap that can be filled with de novo design. Current computational methods for peptide design exhibit limitations in sampling and scaling that could be addressed with quantum computing. Hybrid quantum-classical methods can leverage complementary strengths of near-term quantum algorithms and classical techniques for complex tasks like peptide design. This work introduces a hybrid quantum-classical generative framework for designing plastic-binding peptides combining variational quantum circuits with a variational autoencoder network. We demonstrate the framework's effectiveness in generating peptide candidates, evaluate its efficiency for property-oriented design, and validate the candidates with molecular dynamics simulations. This quantum computing-based approach could accelerate the development of biomolecular tools for environmental and biomedical applications while advancing the study of biomolecular systems through quantum technologies.

Failure rate analysis of loitering munition fuze safety system

Abstract The projection environment and operational characteristics of new types of munitions, such as loitering munitions and drones, differ significantly from those of conventional munitions. These new munitions are characterized by a weaker projection environment, longer cruise times, and secondary strike capabilities. Current fuze safety system design methods no longer meet these requirements. Therefore, it is necessary to propose new methods for calculating fuze failure rates to ensure the reliability of the fuze safety system. In this paper, aiming at the recoverable safety system of the loitering munition fuze, combined with the operational requirements and environmental characteristics of the loitering munition, and at the same time, based on the Markov chain, the failure rate analysis of the recoverable safety system of the loitering munition fuze was carried out. Also obtain the change of the failure rate of the fuze safety system under different states.

Modulation strategy design method for single-inductor multi-port converter based on reinforcement learning

Single-inductor multi-port converters have the characteristics of "more silicon and less magnetism" and have great application potential in many fields. However, single-inductor multi-port converters have many switching modes and the modulation strategy design is complex. The current design method is to manually select the switching mode sequence and perform modal analysis. The design process requires power electronics expertise and experience. This paper proposes a modulation strategy design method for single-inductor multi-port converters based on reinforcement learning. This method uses a neural network to generate the modulation strategy and adopts a set of simple rules to provide rewards for training the neural network. Through reinforcement learning, the neural network can summarize experience in trial and error without human intervention and finally generate the optimal modulation strategy. This method has many advantages: (1) It only requires known conditions such as port voltage and converter structure as input, and some simple constraints as rewards, avoiding complicated manual design; (2) It can use a neural network to generate the optimal modulation strategy under different operating conditions, and has strong adaptability. Based on this method, a modulation strategy design for a single-inductor multi-port converter is carried out, and the effectiveness of the method is verified by experiments.

Research on the Design Method of Camellia oleifera Fruit Picking Machine

Camellia oleifera fruit pickers are essential for improving picking efficiency and promoting the Camellia oleifera industry. However, it is challenging to develop pickers that meet user needs. Current design tools and methods have limitations, such as a single model, poor synergy between integrated models, and subjective bias when analysing user requirements and translating them into product attributes. To solve these problems, this study proposes a new design decision model based on the Fuzzy Analytic Hierarchy Process (FAHP), Function Analysis System Technique (FAST), Theory of Inventive Problem Solving (TRIZ Theory), and extension transformation theory. The model was developed and applied to design an Camellia oleifera fruit picker. In this paper, an empirical investigation of an Camellia oleifera base in Wuhan was carried out, and multi-level demand analysis was used to identify the design demands in the behavioural process; FAHP was used to calculate the demand weights to clarify the design focus; expert knowledge was used to convert the demands into specific product functional features, and FAST was used to decompose these features to find the contradictory conflicts; TRIZ theory was used to determine the principles of resolving the contradictions, and the extension transformation theory were used to generate the creative design solutions for the products. By integrating FAHP, FAST, TRIZ theory and the extension transformation theory, the subjective bias in product design is eliminated, the design decision-making process is improved, and new methods and ideas are provided for the design of oleaginous tea fruit pickers and similar products. Finally, the conceptual design of an Camellia oleifera fruit picking machine was produced. However, the conceptual design has yet to be subjected to exhaustive simulation experiments and prototype testing. Future research will focus on conducting the necessary simulations, prototypes, and field tests to fully assess the feasibility and effectiveness of the design and make the required iterative improvements accordingly to commercialize the product eventually.

Performance of plant-produced asphalt mixtures for balanced mix design implementation

ABSTRACT Several transportation agencies in Canada are currently relying on volumetric properties of asphalt mixtures to accept or reject the final mix design. The existence of various pavement defects on Canadian roads indicates that volumetric mix design procedure alone does not guarantee adequate long-term pavement performance. Therefore, transportation agencies are finding ways to increase durability of their asphalt mixtures to accomplish a road network that is more sustainable, safer and more economical. The balanced mix design (BMD) approach integrates two or more performance test criteria into mix design and acceptance to produce asphalt mixtures that are resistant to cracking and permanent deformation. The main objective of this study is to assess cracking and rutting performance of plant-produced asphalt mixtures to validate current volumetric mix design methods and investigate ways to optimise mix performance for moving towards an efficient BMD framework. Six plant-produced mixtures were collected from different pavement construction projects to prepare specimens for cracking and rutting evaluation. Cracking performance was determined using the Illinois flexibility index test and rutting performance was determined using the Hamburg wheel-tracking test. Results showed that polymer-modified binders, recycled materials and reduction of nominal maximum aggregate size contributed to better rutting performance. Nevertheless, limestone aggregates, recycled asphalt shingles and low asphalt content reduced cracking resistance and did not lead to an efficient BMD framework.

A Modular Biosensor Design for Quantitative Measurement of Free Nedd8.

The objective of our study was to develop a genetically encoded biosensor for quantification of Nedd8, a post-translational modifier that regulates cellular signals through conjugation to other proteins. Perturbations in the balance of free (i.e., unconjugated) and conjugated Nedd8 caused by defects in Nedd8 enzymes or cellular stress are implicated in various diseases. Despite the biological and biomedical importance of Nedd8 dynamics, no method exists for direct quantification of free Nedd8, hindering the study of Nedd8 and activities of its associated enzymes. Genetically encoded biosensors are established as tools to study other dynamic systems, but limitations of current biosensor design methods make them poorly suited for free Nedd8 quantification. We have developed a modular method to design genetically encoded biosensors that employs a target binding domain and two reporter domains positioned on opposite sides of the target binding site. Target quantification is based on competition between target binding and the interaction of the reporter domains. We applied our design strategy to free Nedd8 quantification by developing a selective binder for free Nedd8 and combining it with fluorescent or split nanoluciferase reporters. Our sensors produced quantifiable and specific signals for free Nedd8 and enabled real-time monitoring of deneddylation by DEN1 with a physiological substrate. Our sensor design will be useful for high-throughput screening for deneddylation inhibitors, which have potential in treatment of cancers such as acute lymphoblastic leukemia. The modular design strategy can be extended to develop genetically encoded quantitative biosensors for other proteins of interest.

Performance and behaviour of prebored and precast pile with floating pile tip based on A full-scale field static axial load test

This study investigates the load transfer mechanism of a Prebored and Precast pile (PP pile), constructed installed in accordance with the rules applicable to the Hyper-Straight pile method (HS pile), in clay soils. While the HS pile method, developed in Japan, typically results in high bearing capacity piles in various soil types, its performance in clay soils remains understudied. Our research focuses on a unique configuration where the pile tip “floats” within a soil–cement mixing (SCM) column near the bottom of the borehole, a condition that significantly influences the system’s performance.We conducted a full-scale axial static load test on a 500 mm diameter and 140 mm thickness straight shaft precast prestressed concrete spun pile. The pile was instrumented with vibrating wire strain gauges (VWSG) and displacement measuring devices (tell-tales), embedded 15 m deep in a 750 mm diameter SCM column (15.75 m long). The pile tip was positioned 75 cm above the bottom of the borehole, creating a floating condition within the SCM material. Both the pile and the surrounding SCM were instrumented to provide comprehensive data on the system’s behavior.The test involved two loading–unloading cycles. The 1st Cycle reached a maximum load of 3627 kN, resulting in a 75.52 mm pile head settlement. The 2nd Cycle achieved a maximum load of 4181 kN, leading to a 118.04 mm pile head settlement. In the 1st Cycle, we observed upward movement of the SCM material around the shaft after the pile skin friction reached its maximum capacity. Stress at the pile tip exceeded the unconfined compressive strength of the SCM material, indicating potential local shear failure.Contrary to expectations based on HS pile performance in other soil types, the ultimate bearing capacity of our pile was determined to be 2000 kN, comprising 545 kN from skin friction and 1455 kN from end bearing. This result aligns more closely with the behavior of conventional bored pile rather than the “hyper” capacity typically associated with HS pile. Consequently, we classify our pile as a “prebored and precast pile,” like systems used in China and Korea.Our study concludes that the strength of the SCM material and the pile tip location significantly influence the pile’s bearing capacity in clay soils. These findings highlight the critical impact of soil type on the performance of piles constructed using the HS method. The observed behavior suggests that current design methods for HS pile may overestimate capacity in clay conditions, emphasizing the importance of soil-specific analysis and testing.This research contributes to the understanding of PP pile behavior in clay soils, providing valuable insights for geotechnical engineers. It underscores the need for refined prediction models and design methods specific to these soil conditions, paving the way for more accurate and reliable foundation designs in regions with predominant clay soils.

Surface Facets Reconstruction in Copper-Based Materials for Enhanced Electrochemical CO2 Reduction.

The unavoidable and unpredictable surface reconstruction of metallic copper (Cu) during the electrocatalytic carbon dioxide (CO2) reduction process is a double-edged sword affecting the production of high-value-added hydrocarbon products. It is crucial to control the surface facet reconstruction and regulate the targeted facets/facet interfaces, and further understand the mechanism between activity/selectivity and the reconstructed structure of Cu for CO2 reduction. Based on the current catalyst design methods, a facile strategy combining chemical reduction and electro-reduction is proposed to achieve specified Cu(111) facets and the Cu(110)/(111) interfaces in reconstructed Cu derived from cuprous oxide (Cu2O). The surface facet reconstruction significantly boosted the electrocatalytic conversion of CO2 into multi-carbon (C2+) products comparing to the unmodified catalyst. Theoretical and experimental analyses show that the Cu(110)/(111)s interface between Cu(110) and a small amount of Cu(111) can tailor the reaction routes and lower the reaction energy barrier of C-C coupling to ethylene (C2H4). The work will guide the surface facets reconstruction strategy for Cu-based CO2 electrocatalysts, providing a promising paradigm to understand the structural variation in catalysts.

Numerical study on concentrated load capacity of chosen HC floors

Precast prestressed hollow core floors are able to distribute concentrated loads due to the presence of cast on site joints and torsional stiffness of individual units. By considering this phenomenon in design, the directly loaded element is able to withstand loads much higher than in case of a single element analysis. The current design method provided by European Standard EN 1168 as well as different analytical methods can provide results that do not fully represent the actual performance of the floor. Due to that fact that a sparse amount of experimental data on full scale floor exists, out of which just a handful is documented well, the results of code provisions and analytical models are difficult to evaluate. Based on previous numerical analyses, validated by existing experimental data, numerical models of three hollow core floors were prepared which were used to design new experiments on full scale hollow core floors. Analysis focuses on the Ultimate Limit State of the HC floors, obtained failure loads are compared to single element results and with the results of the EN 1168 standard calculations.

Experimental and numerical studies on corrugated steel retrofitted damaged reinforced concrete arches

The corrugated steel (CS) reinforcement method has been adopted for strengthening dilapidated bridges and culverts owing to its advantages of convenient construction, good corrosion resistance, and high deformability. However, the current design method for corrugated steel retrofitted damaged reinforced concrete (CSRDRC) arches is excessively conservative as it only considers the bearing capacity of the CS, neglecting the contributions of the original reinforced concrete (RC) structure and the infill layer. This paper studied the behaviour of CSRDRC arches under three-point loading experimentally and numerically. The experimental results demonstrate that the bearing capacity and initial stiffness of the arches are significantly enhanced after CS reinforcement. The increase in damage degree of the original structure has a slight effect on the bearing capacity and initial stiffness, but an obvious adverse effect on the ductility of the CSRDRC arches. A finite element model (FEM) was developed and verified against test results and then utilized to conduct parametric analysis. Finally, a simplified formula was proposed for predicting the axial compressive bearing capacity of CSRDRC arches.

Explicit consideration of geomaterial uncertainties in the load resistance factor design of piles driven into rock-based intermediate geomaterials

The study presents a method for estimating the end bearing of piles driven into rock-based intermediate geomaterials (IGMs). Existing design methods, rooted in soil mechanics, often fall short when applied to IGMs. Moreover, the geomaterial (geological and ground properties) uncertainties are neglected and the piles are designed based on subsurface information from distant boreholes. To address this gap, the study introduces an approach that explicitly considers geomaterial uncertainties by combining empirical models and geostatistical simulation to predict end bearing. Using data from 87 piles driven into various rock-based IGMs with dynamic load testing as the construction control technique, this study introduces the Proposed Design Method (PDM) for the prediction of end bearing. PDM is compared to the Current Design Method (CDM), which is based on traditional soil-mechanics methods. Predictions from these methods are subsequently evaluated against the measured end bearings. The results demonstrate that while the PDM yields comparable predictions to the CDM, it offers a more robust consideration of geomaterial uncertainties. The PDM leads to an approximate 13.60% to 19.35% increase in uncertainties compared to CDM across various IGMs. These findings advance the understanding of pile behavior in the presence of geomaterial uncertainties and inherent variability.

Effect of the building orientation on additively manufactured copper alloy: Hydraulic performance of different surface roughness channels

The additive manufacturing capabilities open new frontiers in the design of complex geometries in many different application fields, especially thermal science, in which multi-functional, efficient, compact components with internal cooling or heating channels are becoming more and more requested. Among the possible additive manufacturing technologies, the laser powder bed fusion process has recently been proven to manufacture high-conductivity metals, with good mechanical and thermal properties (i.e. pure copper and copper alloys), attracting the attention of the heat transfer community. However, depending on the material, design, and process parameters, the surface roughness of the components can remarkably change and become a critical issue in cooling applications. Currently, the surface texture characteristics and the final channel size cannot be accurately estimated a priori, and thus the initial hypothesis of the current design methods may lead to unpredictable and undesired results. This work experimentally and numerically explores the effects of the building orientation on the fluid dynamic behaviour in CuCrZr alloy channels, which is considered one of the most promising additive manufacturing materials for thermal applications. By coupling the experimental hydraulic results with surface characterization and X-ray computer tomography dimensional measurements of the channels, a novel simplified methodology to properly correlate the pressure drop to the surface texture of a single wall is proposed and numerically validated.

Design of cold-formed high strength steel irregular octagonal hollow section columns

This paper presents experimental numerical investigations on the structural behaviour of cold-formed high strength steel irregular octagonal hollow section (OctHS) columns with both non-slender and slender cross-sections. An experimental programme, including material tests, measurements of initial global geometric imperfection, and pin-ended column tests, was first conducted. The key findings from the experimental programme are presented and discussed. Following the validation against the experimental results, the proposed finite element modelling methodology was established to replicate the test observations, and then was adopted to generate a boarder range of numerical results through parametric studies. The collected experimental and numerical data were used to evaluate the applicability of current structural steel design methods on the column buckling strength for irregular OctHS columns. Assessment results demonstrate that the design method adopted in Chinese code can provide accurate prediction, whilst modified design method adopted in Eurocode 3, considering the effect of steel grade on the column strength, has been proposed and shown to greatly enhance the prediction accuracy with improved consistency. The corresponding assessments on the design approaches adopted in American and Australian codes were also discussed.

Exploring the effects of volumetrics and binder properties on the performance of asphalt mixtures

Current design methods rely mainly on the volumetric properties of asphalt mixtures. More comprehensive mixture analyses facilitate a broader understanding of the pavement performance as a function of factors such as traffic, climate, and mixture properties. Recently, performance-based mix designs have been developed to overcome shortcomings of the volumetric-based designs. Nevertheless, these new approaches may be time-consuming and expensive, and establishing a comprehensive understanding of the interplay between binder characteristics, volumetric properties, and performance outcomes becomes crucial. This work aims to explore relationships among these three aspects of asphalt mixtures regarding fatigue cracking and rutting performance. A database from different Brazilian studies and tests were collected. Data exploration analysis was conducted to evaluate the effect of the binder and volumetric properties on the fatigue and rutting results. The statistical analyses conducted in this study highlight that most properties within the database significantly impact asphalt mixture performance. Additionally, clear relationships were identified between various performance parameters. Lastly, multivariate analyses pinpointed key volumetric and binder variables that predominantly influence the mixture performance, particularly in relation to fatigue and rutting results.

The STAGE method for simultaneous design of the stress and geometry of flexure mechanisms

Current design methods for flexure (or compliant) mechanisms regard stress as a secondary, limiting factor. This is remarkable because stress is also known as a useful design parameter. In this paper we propose the Stress And Geometry (STAGE) method, to design the geometry of a flexure mechanism together with a desired stress field. From this design, the stress-free to-be-fabricated geometry is computed using the inverse finite element method. To demonstrate the potential of the method, the geometry of the well-known crossed-flexure pivot is taken as example. We first show how this mechanism can be redesigned for the same functional geometry with various internal stresses. This results for a specific choice of stress field in a design of a crossed-flexure pivot with 23% lower peak stresses during motion as compared to the known designs, for a ±45° rotation. We then present a second example, of a Folded Leaf Spring (FLS). With a parameter sweep the optimal stress field is calculated, showing a peak stress reduction of 28% during motion. This result was validated with an experiment, showing a normalized mean absolute error of 5.5% between experiment and theory. With a second experiment it was verified that the functional geometry of the FLS with internal stresses was equal to the one without internal stresses, with geometric deviations smaller than half the thickness of the flexures.

Using intrusive approaches as a step towards accounting for stochasticity in wind turbine design

Current wind turbine design methods require tens of thousands of time-domain simulations and use different random seeds to account for the stochasticity of the environmental conditions. The account of stochasticity is nonintrusive because the sampling method calls a deterministic model multiple times without changing its underlying equations. In this work, we investigate and demonstrate using simple proof of concepts how intrusive approaches can be used to directly account for stochasticity in the equations representing a mechanical system. Our long term goal is to apply such methodology to the design of wind turbines without requiring an excessive number of simulations. Intrusive methods manipulate stochastic variables directly to provide the probability density functions (PDFs) of the states and outputs at any time as functions of the PDFs of the inputs. We illustrate how different methods can be used with a reduced-order model of a wind turbine with one degree of freedom and for linear and nonlinear models. We discuss how the methods can be extended and what it will take to apply them to a level of fidelity similar to current state-of-the-art wind turbine design tools.

Ultimate torsional moment of dry horizontal joint for prefabricated concrete tower

SummaryMore and more prefabricated steel–concrete hybrid wind turbine towers have been built because of their better lateral stiffness than those of the full steel towers, in which epoxy resin joints are commonly adopted at the horizontal joint between two ring units for improving the erection speed. In fact, epoxy resin joints are designed in the same way as dry joints due to the very thin thickness of epoxy resin layer, in which epoxy resin only acts as a leveling blanket and sealer for jointing and compensates for the unevenness of the contact surface between two ring units. The current design method for the resistance to torsional moment at the horizontal joint is not reasonable because of the unreasonable assumption of Saint‐Venant's torsional theory. The integral expressions of the ultimate torsional moment at the horizontal joint with and without shear force are derived, respectively. The solution of the integral expressions for the ultimate torsional moment is realized by Python programming. The refined finite element analyses of two cases are compared with the existing small‐scale tests with segmental aluminum tubes, which verifies the calculation accuracy of the proposed integral method. In the modified integral model of the ultimate torsional moment, a correction term of the resistance to torsional moment and a more suitable distribution of shear stress under the action of horizontal shear force are proposed to obtain a more accurate ultimate torsional moment. Finally, 36 sets of cases with typical dimensions and axial forces in practical engineering are analyzed by the proposed integral model in the absence of horizontal shear force. One six‐parameter model for calculating the ultimate torsional moment is fitted by the least square method. A discount factor is proposed to consider the influence of the horizontal shear force on the ultimate torsional moment.

Mechanical properties of multi-bolted Glulam connection with slotted-in steel plates

The Bolted Glulam Connection with Slotted-in Steel Plates (BGCSSP) is widely employed in modern timber structures due to its advantages of convenient installation and reliable force transmission. However, the current design methods lack rigorous mechanical derivation and fail to consider various influencing factors comprehensively. Furthermore, designing multiple dowel connections based on the behavior of individual dowels impedes optimization and limits the applicability of design rules. To systematically investigate the failure modes and mechanical characteristics of Multi-bolted Glulam Connection with Slotted-in Steel Plates (MGCSSP), specimens from 12 groups (6 specimens per group) were subjected to parallel grain tensile tests, considering four key influencing factors: bolt quantity, bolt arrangement, bolt diameter, and base material thickness. The experimental results indicate that as the number of bolts increases, the failure transitions from double-hinge failure to single-hinge failure. Additionally, there is an observable upward trend in both initial stiffness and peak load for the same type of specimen as the quantity of bolts increases, accompanied by a decreasing trend in the ductility coefficient. The analysis of experimental results reveals that both the quantity and diameter of bolts impact the initial stiffness and peak load of MGCSSP specimens. Based on experimental observations, dual-parameter calculation models for the initial stiffness and peak load of MGCSSP are proposed. The calculated results of the models align well with experimental data, providing references and convenience for the design of MGCSSP.