Material Design Parameters Research Articles

Modular design for optimized acoustic properties of multilayer system

It has been demonstrated that multilayer systems have the potential for excellent sound absorption, effectively attenuating sound across a wide range of frequencies and offering a versatile solution for addressing acoustic challenges in various environments. A key consideration is the design of a multi-layer structure and the parameters of each layer to achieve optimal sound absorption performance. Modular design is a crucial aspect of this work, involving the creation of smaller, units that can be customized and combined to achieve specific sound absorption properties. This study applies numerical optimization, inversion, and matrix methods to multilayer sound absorber systems, aiming to provide customized parameters for the modular design of fibrous materials with exceptional sound absorption properties. The effectiveness of the modular design will be validated and improved through impedance tube measurements of the manufactured multilayer systems, ensuring that the resulting sound absorbers meet the desired acoustic performance across diverse real-world scenarios.

An In-Depth Review on the Eccentric Compression Performance of Engineered Bamboo Columns

This review paper delves into the eccentric compression performance of engineered bamboo columns, focusing on objectives like evaluating methodologies, influential parameters, and testing techniques for eccentric compression behavior. It employs a systematic literature review adhering to PRISMA 2020 guidelines to synthesize data from various studies on material properties, design parameters, and construction methods. The findings reveal challenges in predicting failure modes under eccentric compression and the need for a unified model to assess the impact of eccentricity and slenderness ratios on performance. It introduces novel insights into the standardization and testing of engineered bamboo for structural applications. It addresses a significant gap in current research by offering a comprehensive predictive framework for eccentrically loaded, engineered bamboo columns. Doi: 10.28991/CEJ-2024-010-03-020 Full Text: PDF

An ingestible self-propelling device for intestinal reanimation.

Postoperative ileus (POI) is the leading cause of prolonged hospital stay after abdominal surgery and is characterized by a functional paralysis of the digestive tract, leading to symptoms such as constipation, vomiting, and functional obstruction. Current treatments are mainly supportive and inefficacious and yield acute side effects. Although electrical stimulation studies have demonstrated encouraging pacing and entraining of the intestinal slow waves, no devices exist today to enable targeted intestinal reanimation. Here, we developed an ingestible self-propelling device for intestinal reanimation (INSPIRE) capable of restoring peristalsis through luminal electrical stimulation. Optimizing mechanical, material, and electrical design parameters, we validated optimal deployment, intestinal electrical luminal contact, self-propelling capability, safety, and degradation of the device in ex vivo and in vivo swine models. We compared the INSPIRE's effect on motility in models of normal and depressed motility and chemically induced ileus. Intestinal contraction improved by 44% in anesthetized animals and up to 140% in chemically induced ileus cases. In addition, passage time decreased from, on average, 8.6 days in controls to 2.5 days with the INSPIRE device, demonstrating significant improvement in motility. Luminal electrical stimulation of the intestine via the INSPIRE efficaciously restored peristaltic activity. This noninvasive option offers a promising solution for the treatment of ileus and other motility disorders.

Organic Photovoltaic Materials for Solar Fuel Applications: A Perfect Match?

This work discusses the use of donor and acceptor materials from organic photovoltaics in solar fuel applications. These two routes to solar energy conversion have many shared materials design parameters, and in recent years there has been increasing overlap of the molecules and polymers used in each. Here, we examine whether this is a good approach, where knowledge can be translated, and where further consideration to molecular design is required.

Selective photoelectrocatalytic CO2 reduction to ethanol using nanotubular oxides grown on metastable Ti-Cu alloy

The photoelectrochemical conversion of CO2 to C2 products such as ethanol is a topic of much current interest and relevance for decreasing the amount of greenhouse gases in the atmosphere. Here, the photoelectrocatalytic selectivity for the CO2 reduction reaction on Ti-O-Cu nanotubes grown on bimetallic alloys (Ti-xCu; x = 0.5, 5.5 and 10 at. %) was investigated. The product selectivity in the CO2 reduction reaction was found to depend on the effects of composition and distribution of the oxidant species along the nanotubes. This behavior was coordinated by the substrate phases obtained from Ti-Cu alloys subjected to different heat treatments (annealed followed by rapid cooling – quenched (Q) or annealed with controlled cooling (A)). A nanotubular (Nt) oxide layer was grown on these substrates and the influence of metastable (quenched) or equilibrium (annealed) phases was related to the diffusion of the copper species. The two types of electrodes were compared in terms of their relative proclivity toward CO2 photoreduction. Methanol was produced as the dominant reduction product on Nt/Ti-10Cu (A). On the other hand, Nt/Ti-10Cu (Q) produced a respectable yield and selectivity for ethanol, reaching 2.32 mmol/L of ethanol. In a broader vein, this study demonstrates the importance of surface defects in an active heterogeneous photocatalyst and provides insights into the key parameters for the precursor design, selection, and optimal performance of materials for the CO2 reduction reaction leading to C2 compounds.

Pioneering sustainable power: Harnessing material innovations in double stage segmented thermoelectric generators for optimal 4E performance

This study presents groundbreaking advancements in sustainable power through a comprehensive exploration of double-stage segmented thermoelectric generators (DSSTEGs) optimized for efficient solar energy conversion. Specifically comparing DSSTEGs with other solar thermoelectric generator (STEG) configurations through geometry parametric optimization, we elucidate the intricate interplay between material properties and design parameters using a finite element method-driven numerical approach. The focus is on achieving 4E optimization (energy, exergy, environmental, and economic factors). Our results demonstrate that a skutterudite content of 6.17% maximizes DSSTEG performance, showcasing its superiority over conventional STEGs. The optimized DSSTEG excels with remarkable CO2 savings of 23.78 kgyr−1 and an impressive high output power of 50.08 W at the optimal skutterudite content. Moreover, the DSSTEG design demonstrates a balanced cost-effectiveness with an outstanding $0.05 per watt output, surpassing conventional STEGs' cost-efficiency. These findings offer a pragmatic framework for integrating innovative materials and optimized designs in concentrated solar energy applications, signifying a significant stride in the field of thermoelectric generators. The pivotal role of materials and design in defining and optimizing performance for enhanced solar energy conversion is highlighted, propelling the path towards a more sustainable and efficient energy future.

The effect of tread patterns on slip resistance of footwear outsoles based on composite materials in icy conditions

Introduction: Falls on icy surfaces are the leading cause of injuries for outdoor workers. Footwear outsole material and geometrical design parameters are the most significant factors affecting slips-and-falls. Recently, composite materials have been incorporated into outsoles to improve traction, yet the best design parameters are not fully understood. Method: In this effort, based on Taguchi orthogonal array design, 27 outsole prototypes were fabricated with different tread pattern features using our patented composites and tested in a simulated winter condition. Results: An analysis of variance (ANOVA) showed that surface area (p = 0.041, Contribution = 15.63%) was the only factor significantly affecting the slip-resistance of our prototypes. The best performance was observed for the maximized surface area covered by our composite material with circular and half circular plugs laid obliquely, mostly in the forefoot area. Practical Applications: These findings suggest that some tread design features of composite-based footwear have a great role in affecting slip-resistance properties of composite-based footwear.

Optimization Design and Mechanical Performances of Plant-Mix Hot Recycled Asphalt Using Response Surface Methodology.

This study aimed to explore the influence of material design parameters on the physical and mechanical properties of recycled asphalt. A Box-Behnken design was employed to determine the optimal preparation scheme for 17 groups of recycled asphalt. The effects of styreneic methyl copolymer (SMC) regenerant content, styrene-butadiene-styrene (SBS)-modified asphalt content, and shear temperature on the mechanical properties of recycled asphalt were analyzed using conventional and high/low-temperature rheological tests. The optimal processing parameters were determined by a response surface model based on multiple response indexes. The results revealed that the SBS-modified asphalt content had the most significant effect on the penetration of recycled asphalt. An increase in SMC regenerant content led to a gradual decrease in the rutting factor, while SBS-modified asphalt content had the opposite effect. The usage of SMC regenerant helped to reduce non-recoverable creep compliance by adjusting the proportion of viscoelastic-plastic components in recycled asphalt. Furthermore, the stiffness modulus results indicated that the addition of SMC regenerant improved the recovery performance of recycled asphalt at a low temperature. The recommended contents of SMC regenerant and SBS-modified asphalt are 7.88% and 150%, respectively, with a shear temperature of 157.7 °C.

Optical-Fiber-Embedded Beam for Subgrade Distributed Settlement Monitoring: Experiments and Numerical Modeling

In this study, Brillouin optical time domain analysis (BOTDA) sensing technology was utilized for monitoring settlement in a similarity model of a highway subgrade. As contact winding cannot be used for an optical fiber that is buried directly in the soil, uncoupling between the fiber and the soil can occur. Thus, an optical-fiber-embedded beam (OFEB) was developed, and a method for measuring and calculating the beam’s deformation was proposed. A calibration test and a test on a similarity model of a subgrade were carried out to investigate the applicability and monitoring accuracy of the OFEB. It was concluded that the OFEB can accurately measure beam deflection, and the maximum relative error between measurements by the optical fiber and a displacement transducer was approximately 5%. The OFEB was embedded directly into a similarity model of a subgrade to monitor settlement. The deflection deformation of the OFEB was found to be close to the subgrade settlement over a certain settlement range, with a relative error below 8.1%. Thus, the OFEB can be used to measure large-range distributed settlement in a subgrade. A numerical simulation was performed to identify appropriate beam dimensions and material design parameters, thereby extending the measurement range before decoupling of the OFEB and the soil occurs. The enhancement of the measurement range and the accuracy of the OFEB based on the preliminary experiments carried out in this study enables further investigation of settlement monitoring.

Demiryolu Havai Hatlarında Pantograf Kuvveti ve Seyir Teli Gerilimi İlişkisinin Sonlu Elemanlar Yöntemi ile İncelenmesi

Railway overhead line electrification (OLE) is used for providing continuous power to the trains throughout catenary wires and the current collector device of the pantograph. The interaction of contact force exerted by the pantograph and contact wire is an important topic in regulating OLE dynamics. OLE components are subjected to fluctuating contact forces due to the trains running with high speed, therefore, it is important to estimate service life of contact wires and pantograph carbon collectors by considering contact wire/pantograph interference. This study performs a number of contact force and stress/strain analysis of standard OLE designs used in Europe, Series 1, Sicat S1.0, Sicat H1.0, Re250 and EAC 350, with finite element method. The results establish a link between stress levels and contact force in the contact lines depending on the design parameters of contact wire type, pretension, span-length, and contact wire material. Understanding the bending of the contact wire due to the contact force will help to predict potential failures in mainlines and extend our knowledge of safety and reliability of various OLE design parameters.

Uncertainty propagation, entropy, and relative entropy in the homogenization of some particulate composites

AbstractThe main idea of this work is an application of probabilistic entropy and also relative entropy in the numerical analysis of uncertainty propagation in the homogenization of some composite materials. The homogenization method is based on the determination of deformation energy for the representative volume elements computed with the use of some specific finite element method experiments. Uncertainty propagation concerns material and geometrical design parameters of particulate composites and is performed thanks to an application of polynomial responses; probabilistic moments of the effective tensor are computed via the iterative generalized stochastic perturbation technique and the semi‐analytical probabilistic method. Probabilistic entropy is determined according to Shannon theory, while relative entropies equations employed here follow mathematical models created by Kullback & Leibler, Jeffreys, Hellinger, and Bhattacharyya. Deterministic analyses have been performed with the use of the system ABAQUS, while all the remaining procedures have been programmed in the computer algebra system MAPLE.

Explainable machine learning models for probabilistic buckling stress prediction of steel shear panel dampers

Steel shear panel dampers are widely used as passive energy-dissipation devices in earthquake-resistant structures. The out-of-plane buckling stress of the core plate included in the steel shear panel damper is critical for obtaining the desired lateral force-resistant and hysteretic energy-absorbing capacities. However, the existing calculation method of buckling stress of the steel shear panel damper cannot well address the effects of the steel material’s and geometries’ inherent uncertainties. This paper intends to develop the probabilistic buckling stress prediction models of steel shear panel dampers using machine learning methods considering the steel material’s and geometries’ uncertainties. To this end, the nominal buckling stress prediction models are first developed using different machine learning algorithms based on finite element analysis results where the efficiency of the finite element models has been validated through test results. The analysis results confirm the highest accuracy of the artificial neural network (ANN) model. The SHapley Additive exPlanations (SHAP) and feature importance analysis methods are adopted for interpreting the developed prediction models. The analysis results indicate that the yielding stress of steel (fy), the height-to-width ratio (α), the width-to-thickness ratio (β), and the initial imperfection (δ) show significant influences on the nominal buckling stress of the steel panel damper while the thickness of the core plate (t) shows negligible effects. The probabilistic buckling stress prediction models are further developed based on the trained ANN model considering the combined uncertainties of steel materials and geometries by the Latin hypercube sampling method. The efficiency of the developed probabilistic buckling stress prediction models is confirmed by capturing the probability density of the numerical simulation results. The global sensitivity analysis (GSA) method is introduced for investigating the influence of the design parameters on the discreteness of the probabilistic buckling stress. It has been found from the analysis results that the uncertainties of the yielding stress of steel (fy) and the initial imperfection (δ) have significant influence, that of the height-to-width ratio (α) have limited influence, and that of the width-to-thickness ratio (β) and the thickness of the core plate (t) have negligible influence on the buckling stress of the steel panel damper. For practical application, the interactive software named “PBSSD” is developed and provided for predicting the probabilistic buckling stress by inputting the nominal design parameters of steel material and geometries.

Mechanical properties of PLA based closed porous structures manufactured using FDM process

PurposeThe purpose of this article covers the design and manufacture of porous materials that can be used in different engineering applications by additive manufacturing.Design/methodology/approachThe most important design parameters of the porous materials are the cell structure and wall thickness. These two design criteria are difficult to control in porous materials produced by conventional production methods. In the study, two different wall thicknesses and four different pore diameters of the porous structure were determined as design parameters.FindingsA compression test was applied to the produced samples. Also, the densities of the produced samples were compared. As a result of the study, changes in mechanical properties were observed according to the cell wall thickness and pore size.Originality/valueThe originality of the study is that, unlike traditional porous structure production, the pore structure and cell wall thicknesses can be produced in desired dimensions. In addition, a closed pore structure was tried to be produced in the study. Studies in the literature generally have a tube-type pore structure.

Multi-objective crashworthiness optimization of square aluminum tubes with functionally graded BCC lattice structure filler

The objective of this study is to find the optimum design configurations for the crashworthiness of functionally graded lattice structure filled aluminum tubes under multiple impact loading conditions. Base strut diameter, draft angle and aspect ratio are considered as filler material design parameters, and the optimal design configurations are sought for maximizing the specific energy absorption and minimizing the peak crush force. The finite element simulations are performed to establish the sample design space; linear and non-linear least square regression meta-models are developed to estimate the objective function values; the weighted superposition attraction-repulsion algorithm is employed to create design alternatives and seek their optimum combinations. The compromise programming technique is also adapted for combining multiple objectives and generating different optimum design options. The results revealed that the proper selection of design parameters can effectively enhance the crashworthiness performance of hybrid structures under multiple impact loading conditions. In particular, the results showed that the specific energy absorption value of square tubes can be improved up to 76% with the selection of appropriate lattice filler parameters. The present study provides a guideline for the optimum design of functionally graded lattice structure filled thin-walled structures under multiple impact loading conditions.

Radiation shielding optimization design research based on bare-bones particle swarm optimization algorithm

In order to further meet the requirements of weight, volume, and dose minimization for new nuclear energy devices, the bare-bones multi-objective particle swarm optimization algorithm is used to automatically and iteratively optimize the design parameters of radiation shielding system material, thickness, and structure. The radiation shielding optimization program based on the bare-bones particle swarm optimization algorithm is developed and coupled into the reactor radiation shielding multi-objective intelligent optimization platform, and the code is verified by using the Savannah benchmark model. The material type and thickness of Savannah model were optimized by using the BBMOPSO algorithm to call the dose calculation code, the integrated optimized data showed that the weight decreased by 78.77%, the volume decreased by 23.10% and the dose rate decreased by 72.41% compared with the initial solution. The results show that the method can get the best radiation shielding solution that meets a lot of different goals. This shows that the method is both effective and feasible, and it makes up for the lack of manual optimization.

Design for Manufacturing of Cemented Carbide Coated Components Toward High Wear and Impact Resistance Performance

Abstract Wear- yet impact-resistant demand is a big challenge for coated components under heavy-load service condition. To solve this high-performance manufacturing problem, a new strategy of design for manufacturing (DFM) with integrated design and processing is developed to incorporate processing effect on final performance via the pivot role of surface integrity. An impact performance model and the impact tester are constructed for a component with coated flat block/bulk cylinder mates for potential application in hydraulic machinery. A WC-12Ni/Ni60A two-layer coating on 17-4PH martensitic steel substrate is designed with thermal spray process. Impact crater depth, surface hardening, and residual stresses are identified as major surface integrity parameters determining wear/impact performance by the modeling with testing. The design parameters of geometry, material, and structure are quantitatively linked to the final performance by a process signature (PS) correlative analysis on the identified surface integrity to internal material loading of plastic/elastic strain energies. The PS correlation posts coating thickness as a high-sensitivity parameter for design, facilitating a buffering effect of reduced peak stresses among the coating-substrate system. The DFM optimization is understood by irreversible thermodynamics as reducing energy dissipation of the internal material loading from the external impact loads. The manufacturing inverse problem is thus solved by material-oriented regularization (MOR) on the homologous PS correlations integrating the design and processing phases. The manufactured component, with optimal Ni60A interlayer thickness of 75–100 µm at a top WC-12Ni coating of 200 µm, achieves a desired performance of up to 6000 impacts under a nominal load of 15 kN.

Influence of material uncertainties on thermo-elastic vibration characteristics of graphene reinforced functionally graded porous beams

This paper aims to study the influence of material uncertainties on thermo-elastic vibration response of functionally graded porous (FGP) beams reinforced with graphene platelets (GPLs) using the perturbation-based stochastic finite element method. The influence of material uncertainty on the vibration behavior of FGP-GPL reinforced beams subjected to thermal loading conditions have been discussed for low variability (randomness) in material design parameters (porosity content, amount of nanofillers) and material properties (Young’s modulus, density of metal matrix, and nanofillers) respectively. A C0 continuous stochastic finite element formulation based on higher-order shear deformation theory has been formulated. The convergence and validation of the present formulation have been compared with a traditional Monte-Carlo simulation to establish the accuracy of the present methodology. The homogenized effective material properties are estimated using the Halpin-Tsai micromechanics model and Voigt’s rule of mixture and are typically assumed to be varying along the thickness direction. The results highlighting the effect of uncertainty in material properties on the thermo-elastic vibration response of FGP-GPL reinforced beams have been discussed thoroughly.

Effective medium theory for the low-temperature heat capacity of a metasolid plate

Nanopatterning can be used to strongly control the thermal properties of solids, but theoretical understanding relies often on complex numerical simulations. Here, an analytical theory is derived for the low temperature heat capacity of a nanopatterned phononic crystal plate, focusing on the geometry of a square lattice of cylindrical holes in an isotropic matrix material. Its quasistatic elastic properties were studied using an anisotropic effective medium theory, that is, considering it as a homogenized metasolid. The effective elastic parameters can then be used as an input for an anisotropic plate theory, yielding analytical expressions for the dispersion relations of the three lowest phonon modes that are dominant in the low temperature limit below 1K. Those results were then used to derive a simple analytical formula for the heat capacity, which was compared numerically with the exact results for an example material. The effects of material and geometric design parameters in the formula are also discussed, giving simple guidelines how to tune the heat capacity up to an order of magnitude or more.

Numerical investigation to assess the output performance of concentrated solar parabolic dish system

In this study, a standalone solar parabolic dish Stirling system is mathematically modeled and simulated using MATLAB to investigate the effects of material design and opt-geometrical parameters on output performance of the system. The concentrator diameter, rim angle, dispersion angle, incidence angle, solar angle, receiver emissivity, receiver absorbance, receiver thermal conductivity, and concentrator reflectance are the major parameters considered for investigation. The effects of the aforementioned parameters have been rigorously observed on Geometrical Concentration Ratio (G.C.R), receiver temperature, receiver thermal loss, output power, and overall efficiency of the system. In addition, the optimized values of the studied parameters have also been identified to establish the optimal geometrical configuration of the system. The results revealed that the maximum output power and the overall efficiency of the system have been calculated at 45° rim angle, 0.4° dispersion angle, 0° incidence angle, and 0.3° solar angle. At these optimal angles, receiver thermal loss may be significantly minimized while maintaining the desired G.C.R. The results, for the purpose of validation, have also been compared with theoretical and experimental dataset from the contemporary literature and found in good agreement.

Side chain engineering and film uniformity: two key parameters for the rational design of dopant-free polymeric hole transport materials for efficient and stable perovskite solar cells

Herein, we introduce a series of new (X–DADAD)n-type conjugated polymers comprised of benzo[1,2-b:4,5-b′]dithiophene (X), benzo[c] [1,2,5]thiadiazole (acceptor, A), and thiophene (donor, D) units as highly promising hole transport materials for perovskite solar cells (PSCs). The rational engineering of the backbone structure and the side chains enabled high power conversion efficiencies of up to 20% in n-i-p perovskite solar cells in combination with impressive operational stability: the devices preserved initial performance after >2500 h of continuous illumination at open-circuit conditions. The origins of the observed long-term perovskite solar cells stability enabled by the newly designed polymeric hole transport materials have been revealed through the use of infrared scattering-type scanning near-field optical microscopy and further elucidated by density functional theory calculations. The presented findings point to novel strategies of designing advanced charge transport materials to simultaneously endow the PSCs with high performance and durability.