Selection Of Materials For Components Research Articles

Development of Rheology in the Area of High-Performance Concrete – A Review

Abstract The rheological or flow quality high-performance concrete (HPC) are significant as they affect several parameters, including ease of placing, compatibility, durability and strength. For the selection of component materials and prediction of the fresh and hardened characteristics of HPC, an adequate understanding of rheology is required. This literature review gives a gist of the works done in the field of rheological study of HPC. The flow models and equations to explain the flow behaviour of HPC mixes as proposed by the researchers are presented. Yield stress and plastic viscosity are the basic rheological parameters that are used in these equations. Various rheometers developed to measure and estimate these rheological parameters of HPC are also presented in this paper. This review provides a thorough analysis of the effects of various constituent materials on the rheological properties of HPC. This includes aggregates, cement, various supplementary cementitious materials like fly ash silica fume, slag etc. Also, the effect of mineral admixtures like superplasticizers and viscosity modifying agents along with the synergic effects is discussed. Finally, the prospects of the study on the unexplored areas and future challenges in the field of study are discussed.

The Use of SAW, RAM and PIV Decision Methods in Determining the Optimal Choice of Materials for the Manufacture of Screw Gearbox Acceleration Boxes

This article investigates material selection for components in worm gear reduction gearboxes, focusing on the worm shaft, gearbox casing, and worm gear body. The screw shaft’s and worm gear body’s material selection involved evaluating six criteria: hardness, tensile strength, yield strength, relative elongation, relative contraction, and impact strength. Gearbox casing materials were selected based on five parameters, including tensile strength, yield strength, relative elongation, impact strength, and hardness. The authors employed three Multi-Criteria Decision-Making (MCDM) methods, Simple Additive Weighting (SAW), Root Assessment Method (RAM), and Proximity Indexed Value (PIV) to assess material choices. Various methods, including Entropy, Logarithmic Percentage Change-driven Objective Weighting (LOPCOW), and Equal, determined weights for the criteria. Remarkably, consistent optimal material types emerged across all MCDM and weight determination methods, showcasing the robustness of the results. For screw shafts, C35 steel was identified as the optimal type. GC120- 04 stood out among nine materials for gearbox casing production. C35CrMo was determined as the best type among eight steel types for manufacturing the worm gear body. In summary, this study provides a comprehensive and objective approach to material selection for worm gear reduction gearbox components, offering valuable insights for decision-making in the mechanical engineering industry.

Application of Improved Process Neural Network Based on the Fireworks Algorithm in the Temperature-Rise Predictions of a Large Generator Rotor

Building an effective algorithm model for large key power equipment has very important research significance and application value. Aiming at the typical operating state characteristics of large generators and taking the temperature changes as the main research indicators, the improved fireworks algorithm was used to optimize the process neural network, and the key data characteristics were studied based on the machine experiment and actual operation data of a 300 MW generator so as to find the variation and development trends of the maximum temperature rise caused by negative-sequence current. Furthermore, the effectiveness of the neural network model suitable for large generators established in this paper was verified by test functions and experiments. On this basis, the calculation method was applied to different working conditions, component materials, and heating positions of the generator. Moreover, the temperature-rise prediction results of the structural components for the generator rotor were obtained, and the optimization scheme of the slot wedge material given, which provide a reference for temperature-rise research and the selection of component materials for large generators.

Integrated, reliable laser system for an 87Rb cold atom fountain clock

We designed, assembled, and tested a reliable laser system for 87Rb cold atom fountain clocks. The laser system is divided into four modules according to function, which are convenient for installing, adjusting, maintaining, and replacing of the modules. In each functional module, all optical components are fixed on a baseplate with glue and screws, ensuring the system’s structural stability. Mechanical stability was verified in a 6.11g RMS randomvibration test, where the change in output power before and after vibration was less than 5%. Thermal stability was realized by optimizing of the structure and appropriate selection of component materials of the modules through thermal simulation. In the laser splitting and output module, the change in laser power was less than 20% for each fiber in thermal cycles from 5 °C to 43 °C. Finally, the functionality of the laser system was verified for a rubidium fountain clock.

Material Selection Decision-Making Method for Multi-material Lightweight Automotive Body Driven by Performance

This work proposes a material selection decision-making method for multi-material lightweight body driven by performance to achieve that the right materials are used for the correct positions of the automotive body. The internal relationship between performance and mass, cross-sectional shape, wall thickness parameters, and material properties of a thin-walled structure is studied. The lightweight material indices driven by performance are then established. The lightweight material indices and material price are taken as the decision-making criteria for the material selection of automotive body components. A hybrid weighting method integrated with the analytic hierarchy process, fuzzy analytic hierarchy process, and quality function deployment is proposed. The difficulty of quantitatively evaluating the performance requirements of different components of the body is solved using the proposed weighting method combined with the numerical analytical results of the component performance under multiple operating conditions of the automotive body. Then, the weight of the decision-making criteria for material selection is calculated. Grey relational analysis is used to make multicriteria decision-making on a variety of candidate materials to select the best material for body components. After the lightweight material selection of the front longitudinal beam of the automotive body, the frontal collision safety performance of the body is effectively improved, and the mass of the front longitudinal beam is reduced by 45%. Material selection result of the front longitudinal beam indicates that the proposed material selection decision-making method can effectively achieve the fast material selection of components in different positions of the body.

Design, assembly and experimental tests of a Savonius type wind turbine

The present research project focuses on the development of a Savonius type wind turbine, where a literature review is initially carried out to recognize the appropriate parameters for its design such as turbulence, wind velocity, and air density, followed by a design methodology to achieve the dimensioning by means of resistance calculation and selection of component materials, after having the final concept defined. Using computational tools such as Solidworks, Inventor, Simulation Mechanical, the design stage was validated through simulation to study the dynamic fluid behavior and the components were modeled to evaluate their response to wind loads, verifying their resistance. Subsequently, according to the modeling, the detailed drawings of the components of the turbine were obtained, with which they were assembled. Finally, having the physical model of the Savonius wind turbine, experimental tests were carried out in the laboratory of Fluids and Hydraulic Machines of the Technological University of Pereira.

Evaluating the Intrinsic Material Stability at the Semiconductor/Electrolyte Interface for Solar Fuel Production

Stability is one of the most critical issues that determines the material selection for components used in integrated solar fuel generators. Although a variety of III-V semiconducting compounds with suitable band gaps can be used in tandem solar-cell devices, their material robustness in acidic/alkaline electrolyte under solar-driven water-splitting/solar-free dark conditions remains ambiguous. Thus, it is urgent and useful to evaluate whether these material have serious corrosion issues and whether their corrosion can be mitigated via mechanistic understanding. Herein, in a rigorous manner, we present a comprehensive study to understand the fundamental corrosion chemistry of these technologically-important semiconductors. Various characterization techniques including inductively coupled plasma mass spectroscopy (ICP-MS), X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM), and atomic-force microscopy (AFM) are combined to directly reveal the physical/chemical transformations occurring at the semiconductor/electrolyte interface. Combined with considerations of thermodynamic pourbaix diagrams, their sophisticated corrosion behaviors can be understood under varying conditions. Eventually, rational protection strategies are proposed to realize prolonged lifetime for sustained and practical solar fuel generation.

The Design of Flexible Rubber Tapping Tool with Settings the Depth and Thickness Control

Road map of land for agricultural commodities in West Aceh is prioritized for rubber plantations. This commodity is the main source of livelihood and employment for the commodity. Furthermore, it is very difficult for a novice tap to be able to control the depth, thickness, and slope of tapping angle. Therefore, rubber tapping is created to increase the productivity of rubber crops in this region. This research conducted using software where the selection of component materials and manufacturing are tested on 9 rubber trees. The treatment is carried out according to the design plan; controlling the depth between 1-1.5 mm of cambium, tapping the thickness 1.5-2 mm, and tilting the angles of 350-600. Thus, the result of the functional testing shows that rubber tapping can function properly and the test data at interval 09:00-10:00 WIB for slope 60°, 45°, 35° obtained the average latex amount of 1.83 grams, 1.11 grams, and 0.74 grams. In addition, the rubber tapping capacity of 5-6 seconds per tree is better when compared to conventional rubber tapping between 6-8 seconds with 5.32 cm3 rubber bark consumption.

Potentiostatic threshold potentials of stainless steels

Potentiodynamic measurements are used to determine key potentials to classify certain corrosion properties. The material selection for components (e.g. shafts) in corrosive environments is widely based upon these potentiodynamic measurements. Criticism for using these potentials for component design has been expressed in literature. Potentiostatic measurements are known to represent the long term corrosive impact experienced by components in a more realistic manner but are prone to scatter. Therefore a statistical approach called staircase method was adapted to the given electrochemical problem. With using this staircase method, a reliable value for the median potential (threshold potential) can be determined. This potential defines the threshold between anodic dissolution and cathodic protection. For the first time, this newly defined potentiostatic threshold potential is offering a validated median potential value for corrosion prediction in a given corrosion system based on potentiostatic measurements. Threshold potentials for the stainless steel grades 1.4057 and 1.4542 were investigated in aerated electrolytes at 25°C with different chloride ion concentrations.

Reliability study of fiber-coupled photodiode module for operation at 4 K

The reliability of a photodiode module intended for operation at 4K was investigated. Flip-chip bonded photodiodes and an adhesively bonded optical fiber attachment structure were considered. Finite element simulations of the thermomechanical stress were used to evaluate the stresses in different design configurations. Results showed that issues with chip cracking in silicon were eliminated by proper selection of component materials. Photodiode modules survived thermal cycling to 77K and extended operation in 4K.

Development of Micro-Capillary and Micro-Pouch Cells for in-Operando Observation of Dendrites and Electrodeposition Using Ultra High Resolution X-Ray Imaging

Lithium dendrite formation inside lithium-ion batteries with graphite anodes and beyond-lithium-ion batteries with metal anodes has shown to dramatically limit cycle life, restrict windows of operating conditions, and can result in catastrophic failures. Numerous research efforts have been and are still being dedicated to characterizing dendritic electrodeposition in batteries, yet the phenomenon remains to be fully understood. Our work aims to characterize the nucleation and growth of dendrites in batteries via in-operando observation using nanoscale x-ray radiography and computed tomography (nano-CT). Figure 1 shows our results using an in-house micro-capillary cell to observe in-operando the galvanostatic electrodeposition of copper in a symmetrical aqueous copper cell. In this cell, the electrode is coated on a metal micro-wire current collector and is immersed in a liquid bath of electrolyte. Such in-operando experiments allow for simultaneous observation of structure and voltage response as shown in Figure 1f, from which structural evolution can be correlated to cell voltage. In practical applications, an important aspect of dendritic failure is the interaction of electroplated Li with the electrolyte separator. To evaluate these interactions, we have developed a novel planar micro-pouch cell with commercial separator materials for in-operando observation at up to 50 nm resolution. Compared to the micro-capillary cell, which was used to produce the results shown in Figure 1, the new micro-pouch cell offers increased control of the active material loading and capacity, increased flexibility in component material selection, and easier assembly. Figure 1

Self-Healing of Precoated AISI 441 for Solid Oxide Fuel Cell Interconnects at Intermediate Temperatures

Sandvik Materials Technology develops nanocoatings for SOFC stainless steel interconnects. The properties of cerium cobalt coated AISI441 (EN 1.4509) have previously been studied extensively (1-4). However, the trend in SOFC have been to decrease working temperatures from above 800°C and today commercial systems are sold that operate below 650°C. The lower operating temperature opens up new possibilities in selection of component materials. In this study we have examined precoated AISI 441 used in solid oxide fuel cell interconnects at 650°C and compared to previous studies at 800°C. The coating characteristics after different oxidation times were studied by SEM. Also, the variation of cobalt coating thickness and the development of the surface oxides were examined by SEM. By using the double trench approach (3) samples with and without priming at 900°C for 5 hours followed by heat treatment at 650°C, were compared. These samples were also compared to the results from (3) with a sample prepared at 800°C for a total of 504 hours. Figure 1. Mass gain of pre-coated cerium cobalt AISI441 (EN 1.4509) from cyclic oxidation at 650°C and 800°C in ambient air. The mass gains are not corrected for Cr evaporation, which shows for the 650°C as it displays flat or negative mass gains. References J. Froitzheim, S. Canovic, M. Nikumaa, R. Sachitanand, L.G. Johansson and J. E. Svensson J. of Power Sources, 220, 217 (2012)J.G. Grolig, J. Froitzheim, J.E. Svensson, J. of Power Sources, 248 1007 (2014)R. Berger, M. W. Lundberg, J. Westlinder, H. Holmberg, ECS Trans. 68 1649 (2015)H. Falk-Windisch, J. Claquesin, M. Sattari, J.-E. Svensson, J. Froitzheim, J. of Power Sources, 343 1 (2017) Figure 1

Self-Healing of Precoated AISI 441 for Solid Oxide Fuel Cell Interconnects at Intermediate Temperatures

Sandvik Materials Technology develops nanocoatings for SOFC stainless steel interconnects. The properties of cerium cobalt coated AISI441 (EN 1.4509) have previously been studied extensively. However, the trend in SOFC have been to decrease working temperatures from above 800°C and today commercial systems are sold that operate below 650°C. The lower operating temperature opens up new possibilities in selection of component materials. In this study we have studied precoated AISI 441 used in solid oxide fuel cell interconnects at 650°C. The coating characteristics after different oxidation times were studied by SEM. Also, by using the double trench approach samples with and without pre-oxidizing at 900°C for 5 hours followed by heat treatment at 650°C, were compared.

Wave–current interaction effects on tidal stream turbine performance and loading characteristics

The transient interaction between tidal currents and the rotation of a horizontal axis turbine rotor have the potential to induce high asymmetric loadings, which are subsequently transmitted to the drive shaft and potentially high speed drive train components. To mitigate the potential for early component failure, analysis of asymmetric loading on marine turbines is fundamental to the design process. To investigate these loads a turbine mounted on a circular stanchion has been used to highlight the effects of introducing more realistic boundary conditions. Depending on their wavelength, waves can also have a significant effect on the overall design decisions and placement of devices. Thrust loading and bending moments applied to the drive shaft can be of the order of hundreds of kN and kNm respectively.Knowledge of the flow regime can allow designers to evaluate material selection for components and incorporate some deformation capability of the turbine blades to increase the power output and potentially alleviate some of the stress distribution through key structural points. The resulting data can then be used to estimate component life via fatigue prediction.This paper includes a multi-physics approach to modelling tidal energy devices and the potential for modelling to inform device condition monitoring.

3D Design and Performance Analysis of Weft Insertion Mechanism of Carbon Fiber Multi-Layer Loom

The design and research of weft insertion mechanism of carbon fiber multi-layer loom which has the great significance for the development of modern 3D weaving equipment. According to the special requirements of carbon fiber multi-layer weaving fabric, a multilayer weft insertion system incidental finding device is designed, which can be satisfied with multi-layer weft insertion according to the change of shedding position and different layers. In order to meet the sword belt and lifting gear running smooth, kinematic and dynamic analysis and static simulation have been done. Analysis results show that institutions satisfy all work requirements, and have important guiding significance for material selection of components.

Study on Megawatt-Class Wind Turbine Hydraulic System and its Materials

Compared with electric pitch, hydraulic pitch has the merits— fast response, stable pitch, safe , reliable, etc., and is generally used in the megawatt-class wind turbine. The problems faced by the localization process of the hydraulic system, considering most of our wind farms of the unique climatic conditions and use characteristics, the localization of technical parameters of the hydraulic system and component materials selection requirements and design methods are put forward. Wind turbine pitch hydraulic system with independent intellectual property rights is developed, and is passed the actual use of assessment of the wind farm

Development of an Aqueous Compatible Piezoelectric Drop-on-Demand Printhead Module for Textile Printing Applications

A novel 100 dpi 256 channel aqueous compatible piezoelectric drop-on-demand inkjet printhead module has been developed for scanning system textile printing. Both the use of water as a solvent and the high chemical reactivity of typical textile inks present challenges to the design of industrial inkjet printheads. Considerations for printhead component material selection and driver electronics protection will be reviewed. The changes made to the design in order to be compatible with typical aqueous based textile inks will be discussed. Next results from jetting performance testing of the new printhead will be compared to the baseline design using model fluid. Finally the adjustable binary mode and grayscale operation of the new printhead using VersaDropTM jetting technology will be examined.

Improved genetic algorithm based on family tree used for the material selection optimization of components made of multiphase materials

When the optimization of material selection for components made of multiphase materials is performed with the help of genetic algorithm,the prematurity of algorithm is easy to be produced and the global optimization solution cannot be obtained,be- cause the initial population is very few.An improved genetic algorithm based on family tree is put forward,in which family tree is used to evaluate the kinship of chromosomes and reduce the probability of chromosome inbreeding.Validation examples show that the problems mentioned previously are solved and the algorithm developed here is suitable for the optimization of material selection of components made of multiphase components.

Polymer tribology in safety medical devices: Retractable syringes

AbstractWe analyze an example of the application of polymer tribology to create a safety medical device, namely a retractable syringe. In service at various stages either low‐ or high‐dynamic friction is needed. Our work focuses on a VanishPoint® nonreusable safety syringe manufactured by Retractable Technologies, Inc., Little Elm, TX. Different medical‐grade materials strongly affect the performance of this product. Extant tribological testing methods developed for flat surfaces are of little use. A functionality test that provides static and dynamic friction between rounded and cylindrical parts moving one inside the other gives us data not obtainable from the earlier techniques. These results combined with the liquid blowout force results (also for cylindrical surfaces) tell us that a polyolefin elastomer imparts better properties to a polypropylene‐containing resin than does silica as an additive. Data‐based selection of appropriate polymeric materials for components of the syringe thus becomes possible. © 2007 Wiley Periodicals, Inc. Adv Polym Techn 26:56–64, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/adv.20084

Electrochemical Sensor for the Detection of SO2 in the Low-ppb Range

The development of an improved electrochemical sensor for the detection of concentrations of atmospheric sulfur dioxide in the low-ppb range is described. The sensor is based on a porous Au−solid polymer electrolyte sensing electrode which is in direct contact with the gas-containing atmosphere. Although the cell design is not new, it is demonstrated that, by careful selection of component materials and experimental conditions, the determination of trace concentrations of SO2 in air is possible with detection limits of approximately 1 ppb. The use of a strong anion exchange membrane as the solid polymer electrolyte is discussed and compared with the performance of Nafion. Cross sensitivities of the sensor to the major inorganic gaseous species found in the troposphere are also presented.