Geometry Design Research Articles

Thermal and Mechanical Investigation of Friction Stir Welding with Disparate Materials AA6061 and AA7075

Background:: The primary objective of this study is to assess the impact of welding conditions on the mechanical properties of friction stir-welded butt joints created from two distinct aluminium alloys, namely, AA6061 and AA7075. Friction stir welding (FSW), known for its innovation and low-energy solid-state bonding technique, was employed in this research. Methods:: FSW experiments were carried out on both AA6061 and AA7075 alloys using a computer numerical control (CNC) machine. The selection and design of the tool geometry were meticulous, with an emphasis on new pin profiles that are nearly flat at the weld contact point. Precisely, four distinct tool geometries were machined from HC-HCr (High carbon, high chromium steel): Circular, Square, Tapered third, and Triangular. Critical process variables that significantly influence weld quality include rotation speed (800 rpm-1400 rpm) and traverse speed (12 to 25 mm/min). These variables were carefully optimized to achieve flawless welds. During the friction stir welding process, the nugget zone undergoes significant deformation, leading to the formation of a new microstructure that substantially impacts the mechanical properties of the joint. Results:: This study comprehensively investigates the thermal and mechanical properties of friction stir welding using aluminium alloys AA6061 and AA7075, considering various tool shapes. Among the four tool shapes employed, two were found to yield higher hardness values (referred to as BH). Notably, the square-shaped tool produced the highest temperature, reaching up to 690ºC, as determined by thermocouple readings. Based on the findings, the optimal FSW parameters for enhancing hardness involve an axial feed and spindle speed of 800 rpm combined with a feed rate of 15 mm/min. These parameters were identified as crucial for achieving the desired mechanical properties in the friction stir-welded joints. Conclusion:: This study presents new developments in FSW technology, which may have patent implications.

A Near Fourier-Limited Pulse-Preserving Monochromator for Extreme-Ultraviolet Pulses in the Few-Fs Regime

We present a pulse-preserving multilayer-based extreme-ultraviolet (XUV) monochromator providing ultra-narrow bandwidth (ΔE<0.6eV, Ec=92eV) and compact footprint (28×10cm2) for easy integration into high-harmonic generation (HHG) or free-electron laser (FEL) sources. The temporal resolution of the novel design supports pulse durations of typical pump–probe setups in the femtosecond and attosecond regime, depending on the mirror design and focusing geometries over the tuning range of the monochromator. The theoretical design is analyzed and experimentally characterized in a laser-driven HHG setup.

Modeling thermocapillary microgear rotation and transferring the concept of asymmetric shape to translational particle propulsion

In this study, we investigate the thermocapillary rotation of microgears at fluid interfaces and extend the concept of geometric asymmetry to the translational propulsion of micrometer-sized particles. We introduce a transient numerical model that couples the Navier–Stokes equations with heat transfer, displaying particle motion through a moving mesh interface. The model incorporates absorbed light illumination as a heat source and predicts both rotational and translational speeds of particles. Our simulations explore the influence of microgear design geometry and determine the scale at which thermocapillary Marangoni motion could serve as a viable propulsion method. A clear correlation between Reynolds number and rotation efficiency can be recognized. To transfer the asymmetry-based propulsion principle from rotational to directed translational motion, various particle geometries are considered. We demonstrate that, under illumination from above, geometrically asymmetric “Christmas tree”-shaped particles move forward. The exploration of breaking geometric symmetry for translational propulsion is mostly ignored in the existing literature, thus warranting further discussion. Therefore, we analyze expected translational speeds in comparison to corresponding microgears to provide insight into this promising propulsion method. Our simulations indicate that translational propulsion speeds of several particle lengths per second can be expected on the micrometer scale.

Evaluation of electric field in polymeric electrodes geometries for liquid biosensing applications using COMSOL multiphysics

This work investigates the electrical field distribution in polymeric electrodes, materials composed of polymers and nanoparticles that leverage the physicochemical interactions between constituents to modify mechanical and electrical properties. Polymeric matrices often incorporate carbon nanoparticles to impart specific conductive properties while simultaneously enhancing mechanical stability through a protective polymer layer. The morphology, dielectric properties, and geometric configuration of these materials influence the electric field distribution, which is critical to their functionality. Utilizing finite element modeling, this study not yet explored aims to predict these effects and guide the design of material compositions and structural geometries to optimize functionalities like catalytic activity, adhesion enhancement, and interface energy reduction. Simulations were conducted using COMSOL 6.0 across eight similar geometric configurations, assessing polarization, and electric potential distribution. Results underscore the importance of surface polarization in controlling roughness and optimizing biosensor performance for liquid samples. Notably, controlled surface roughness induces asymmetric electric field distortions at biosensor edges, influencing dipole moments in polarizable nanoparticles. Each tested geometry demonstrated unique characteristics pertinent to its application in 3D-printed biosensors, influenced by surface roughness and wettability. Additionally, modifications in the electrical double layer due to controlled roughness alter charge distributions at the electrode-electrolyte interface, affecting electric field configurations.

Optimization of Flywheel Design for the Engine CT-195 to Reduce Weight & Minimized Cost

Abstract: A flywheel stores energy in the form of kinetic (rotational) energy. Whereas each energy storage system has its inherent advantages and disadvantages compared to the others, it is the overall system performance and simplicity of flywheels that make them especially attractive for a variety of applications. Flywheel is mechanical device which is used to store the kinetic energy. There are many causes of flywheel failure. But maximum tensile and bending stresses induced in the web and rim under the action of centrifugal forces are the main causes of flywheel Failure. By changing the dimensions and shape and the materials and use such materials which increases stored energy and maintain minimum stresses with reduce mass of flywheel. It shows that smart design of flywheel geometry could both have a significant effect on the Specific Energy performance and reduce the operational loads exerted on the shaft/bearings due to reduced mass at high rotational speeds. we will compare the theoretical values of moment of Inertia with the Creo-Mechanic values so that the clear objective of the project can be seen. Our Main object is to optimise the flywheel weight without changing other important parameter like moment of inertia and its kinetic energy storage capacity.

Performance Enhancement in Submersible Pump Impellers: Design and Optimization Approaches

Abstract: Submersible pumps are essential components in various industries, including water supply, wastewater management, and oil extraction. Their efficiency and reliability are crucial for ensuring consistent fluid transport. At the core of submersible pumps lies the impeller, which directly influences pump performance. This paper examines advanced design and optimization approaches to enhance the performance of submersible pump impellers. By analyzing key factors such as blade geometry, material selection, and impeller design parameters, we explore methods to improve hydraulic performance, energy efficiency, and operational stability. Experimental validation confirms the effectiveness of these approaches in achieving superior pump efficiency and longevity. This study contributes to the advancement of submersible pump technology and sets a foundation for future research in the field.

The effect of rail crown film hole injection angle and blowing ratio on the flow and cooling performance of the squealer tip in a turbine blade

Squealer tip is considered as an efficient and reliable tip geometry design in leakage loss control and thermal load reduction in heavy-duty gas turbine blade. The cooling and aerodynamic characteristics of a squealer tip with different film hole parameters are investigated after validating the numerical approach. Firstly, superior aerodynamic and cooling performance of the rail crown film hole (RCFH) scheme is proved by comparing three squealer tip structures. Subsequently, two kinds of injection angles (streamwise injection α and normal injection β) and three angle values (35°, 90°, and 145°) are studied in RCFH schemes. Finally, a compound angle scheme consisting of optimal α and β is investigated at blowing ratios (M) varying from 0.5 to 2.0. In varied α hole schemes, the velocity of the coolant can be divided into the radial and streamwise components, the effects of which on leakage control are complementary, leading to minimal sensitivity of total leakage flow rate (LFR) to α. Increasing and decreasing α can both enhance the coolant attachment on the rail crown surface compared with the radial injected scheme. In varied β hole schemes, more coolant momentum is used to resist the leakage flow as β increases, which results in remarkable LFR reduction. Moreover, the back-press effect of leakage flow on the coolant is markedly enhanced, improving the utilization of coolant. In compound angle scheme, increasing M leads to enhanced impingement on clearance flow, and the maximum values of average film cooling efficiency (η) on the rail crown and cavity floor appear at M = 1.0 and M = 1.5, respectively.

Design and Optimization of Geometry of Liquid Feed Conveyor Pipes

The promotion and use of liquid feeding face the challenge of insufficiently stable delivery. This issue can be resolved, in part, by using the spiral flow produced by a spiral pipe (SPP). The aim of this study is to investigate how the structural characteristics of the spiral pipe affect the flow state of the liquid feed, and for this purpose, the computational fluid dynamics (CFD) technique has been employed and the liquid feed delivery process has been simulated by means of an Eulerian two-fluid model The results reveal a significant improvement in the slurry’s homogeneity as it traveled through a spiral pipe compared with a straight pipe (STP). The swirl number normally increased with the number, length, height, and angle of the spiral pipe’s guide vanes. The solid-phase distribution was more homogeneous when values of N = 1, L = 1D, H = 3/8R, and θ = 20° were used, respectively, and the COV within 10D downstream of the outlet of the spiral pipe was 3.902% smaller than that of the straight pipe. The results of this study can be used as a reference for the design of liquid feed-conveying pipes.

An optimization approach for geometry design of multi-axis wave energy converter

The current global energy crisis necessitates a shift to renewable energy sources to mitigate climate change impacts. Wave energy emerges as a promising renewable resource to fulfill increasing energy demands. This energy can be extracted using wave energy converters (WECs), with multi-axis WECs (MA-WECs) being more effective than single-axis versions due to their capacity to harness energy from waves in various directions. The challenge lies in determining the ideal geometric design for MA-WECs, that can be tackled through multi-objective optimization (MOO) techniques. This research focuses on evaluating different MOO algorithms for the optimal geometric design of MA-WECs. To assess the structural response of different geometries and sizes, the study utilized the NEMOH boundary element method solver, aiming to maximize power output, lower the levelized cost of energy (LCOE), and optimize the geometry configuration. Findings indicate that the choice of optimization algorithm considerably influences the MA-WEC's optimal design, enhancing power efficiency, reducing device volume, and cutting costs more effectively than the initial design.

Potential Impacts of Connected and Autonomous Vehicles on Controlling Criteria for Road Geometric Design: A Review

The development of connected and autonomous vehicles (CAVs) has progressed rapidly with advancements in intelligent transportation systems, automated driving technologies, and regulatory reforms worldwide. As the efficiency and safety of surface transportation heavily rely on highway geometric design, understanding the impact of CAVs on design control elements is essential to fully capitalize the benefits CAVs may offer. The objective of this study is to conduct a comprehensive review of existing literature to synthesize how CAVs can influence the controlling criteria for highway geometric design. Over 30 articles were thoroughly reviewed to gain insights into the impacts of CAVs on highway design and potential explanations for them. As CAVs could potentially reduce the minimum required stopping sight distance, they create opportunities to decrease other geometric dimensions, such as horizontal curve radius, length of vertical curves, horizontal sight offset, extra widening, and so on. However, this optimization is more feasible in an environment with fewer human-driven vehicles. Moreover, further related research needs to be done in mixed traffic streams and complex driving conditions. The critical discussions of this study can offer valuable insights, shedding light on the potential benefits and implications that an automated transportation sector may bring to future road geometry design.

Hypersonic inlet flow field reconstruction dominated by shock wave and boundary layer based on small sample physics-informed neural networks

High Mach number inlets face complex challenges such as shock wave/boundary layer interference, adversely impacting the aerodynamic characteristics and stable operating boundaries. Traditional computational fluid dynamics (CFD) simulations for performance and flow field analysis are slow, and data-driven deep learning technologies struggle with predicting flow fields in complex aerodynamic phenomena like shock wave/boundary layer interactions, boundary layer separation, and Mach disks. This study introduces a rapid, robust method for reconstructing hypersonic viscous inlet flow fields using inlet geometry design parameters. This method is called shock wave and boundary layer dominated two-dimensional multiphysical field reconstruction model based on multi-scale sensory field fusion residual physical information neural network (PIMSRF_ResNet), ensuring high-precision training data. Using the optimal Pareto solution set from multi-objective optimization with a small sample intelligence method, 150 sets of multi-physics fields under Ma10 conditions with varying geometric design parameters are calculated. Compared to traditional pure data-driven models, PIMSRF_ResNet's structural similarity in the test set reaches 0.9773, with a peak signal-to-noise ratio close to 30 dB and a correlation coefficient exceeding 98%. These experimental results demonstrated that the proposed method is a promising tool for real-time prediction of complex internal flow fields dominated by high Mach number shock waves and boundary layers.

Numerical Study of Fluid Flow in a Gyroid-Shaped Heat Transfer Element

This paper deals with the design of porous geometry of a heat transfer element. The proposed geometry combines a gyroid triply periodic minimal surface with the recursive principle of geometric body creation. The designed geometry is based on an attempt to increase the heat transfer surface while eliminating negative impacts on the fluid characteristics in the form of pressure loss or increase of the friction coefficient. The proposed geometry of the heat transfer element was compared with a pair of geometries based on the basic gyroid shape but with different channel size parameters. A numerical simulation was performed in Ansys Fluent 2020 R1 using the SST k-omega turbulence model for flow velocities in the range of 0.01 m.s−1 to 0.5 m.s−1, which covered a wide range of the Reynolds number and thus also flow forms in terms of the turbulence intensity. The presented results clearly show lower values of pressure loss and friction coefficient of the proposed geometry compared to the evaluated porous structures. Also, at the same time, they describe the factors positively influencing the mixing process of the liquid in the proposed element, which leads to an increase in the efficiency of the heat transfer process.

Embodied carbon optimisation of concrete pile foundations and comparison of the performance of different pile geometries

Concrete production and construction are responsible for a considerable share of the total carbon emissions annually. With the emerging need to cut carbon emissions from the construction sector, there has been a big interest in optimising the embodied carbon of superstructures. However, limited attention is given to optimising the embodied carbon of foundations as most designers are more interested in addressing the optimal foundations cost instead. For the first time in the open literature, this paper presents a generic genetic-algorithm-based tool to optimise the design of reinforced concrete piles. The algorithm is capable of allocating the optimal design parameters and geometry for reinforced concrete piles at any given soil conditions and required pile capacities. The algorithm is used to compare the environmental impact of different concrete pile types; solid cylindrical piles, hollow cylindrical piles, solid tapered piles and hollow tapered piles at different load capacities, the optimisation results are then compared to common industrial pile designs to quantify the possible carbon and material savings. Results show that a significant cut of more than 70% of the embodied carbon values can be achieved if the optimal pile type is used compared to common industrial design. Moreover, a finite element model built and validated over ABAQUS is used to compare the geotechnical performance of the different pile geometries. Finite element analysis results show a negligible difference between the stiffness of the different pile types when tested in the same soil conditions highlighting an outstanding optimisation efficiency of the proposed optimisation tool.

The Effect of Insulation Thickness on Heat Transfer Characteristics and Flammability in Tube Mesoscale Combustors

Micropower generator is a micro-scale energy source that has two main components, namely a micro/mesoscale combustor and thermophotovoltaics (TPV). The micro-scale combustor is one part that functions as a combustion chamber that produces heat in micropower plants. Heptane is used as fuel, while the combustor combustion chamber with a diameter of 3.5 mm is made from duraluminium-quart glass tube. Combustion stability in the combustion chamber is influenced by several factors, such as temperature, geometry, and combustion chamber design. In order to maintain flame stability, mesh is added to the combustion chamber. One way to minimize heat loss in the combustion chamber is to add an insulating layer to the combustion chamber. This research aims to prove the role of adding an insulating layer in flame stability in mesoscale burners. It is necessary to add an appropriate insulating layer to minimize heat loss so that it remains stable in the mesoscale burner. This experimental test shows that the temperature distribution when adding an insulation layer with a thickness of 3 mm has a higher temperature on the outside compared to a thickness of 6 mm. Meanwhile, the temperature inside the combustor chamber with a thickness of 6 mm is superior to that with a thickness of 3 mm. The flame limit of the combustor with a mesh distance of 5 mm for liquid heptane fuel was successfully stable at an equivalent ratio of ɸ0.97 – 1.5 with a maximum speed of 31.7.

Application of cold spray technology in design and manufacturing of complex geometries

Application of cold spray technology in design and manufacturing of complex geometries

A monolithic numerical model to predict the EMI shielding performance of lossy dielectric polymer nanocomposite shields in a rectangular waveguide: Design of an absorption-based sawtooth-shaped layer

A three-dimensional numerical model is constructed to predict the EMI shielding performance of a polymer nanocomposite shield in a rectangular waveguide. The Helmholtz wave equation for the electric field is implemented in component form and the set of coupled equations is solved via the finite element approach. Mesh convergence and model verification is performed by comparing free space model predictions for a flat, uniform layer to benchmark solutions calculated via transfer matrix theory. The capability of the model is showcased by exploring the role of geometry on the shielding performance of a sawtooth-shaped composite layer in a rectangular waveguide. Increasing the inclusion angle of the sawtooth, which is proportional to the ratio of the sawtooth amplitude and repeat unit width, reduces the transmitted power through the shield and increases the ratio of absorption to reflection of wave power by the shield. Thus, a rational design of this sawtooth geometry allows to overcome the typical trade-off between total shielding effectiveness and wave absorption contribution, thereby resulting in highly performant absorption-dominated shields.

3D printing for energy optimization of building envelope – Experimental results

The building sector is a major contributor to the world's energy consumption, exhibiting an ever-increasing trend. Heat losses through the building envelope constitute the most significant factor. Furthermore, the construction process has seen limited technological advancements in recent years, remaining heavily reliant on manual labor. Additive manufacturing emerges as a promising approach, with applications in the building sector on the rise. However, research on the thermal performance of 3D-printed components remains limited. Despite its recent introduction in the construction industry, 3D printing has yet to attain a level of maturity commensurate with other established methods.This paper aims to reduce this gap by analyzing 3D-printed blocks from a heat transfer perspective. The article introduces two key innovations. Firstly, it explores the design of various internal geometries and air gaps aimed at minimizing heat flux exchange between block surfaces. Secondly, it presents an experimental study conducted with a custom-designed setup tailored for testing 3D printed blocks. The blocks are constructed using recyclable plastic material and feature different internal geometries based on hexagonal cells. While the plan size of the cells remains consistent, their vertical structures vary as follows: 1) Block 1: Hexagonal air cavities without horizontal partitions. 2) Block 2: Hexagonal air cavities with three horizontal partitions, dividing the cells vertically into four parts. 3) Block 3: Honeycomb structure characterized by three horizontal partitions and staggering along the vertical axis.Their performance was experimentally evaluated using the Hot Box method, heat flow meter sensors, and infrared thermography. The results demonstrated reductions of up to 11.5 % in terms of thermal transmittance (U-value) with the inclusion of horizontal partitions. Starting from a U-value of 1.22 ± 0.04 W/m2K (Block 1), a transmittance of 1.08 ± 0.04 W/m2K was achieved for the honeycomb structure with horizontal partitions (Block 3).

The LHCb VELO Upgrade II: design and development of the readout electronics

The LHCb collaboration proposes a Phase-II Upgrade of the detector, to be installed during the LHC Long Shutdown 4 (2032–2034). Operating in the HL-LHC environment poses significant challenges to the design of the upgraded detector, and in particular to its tracking system. The primary and secondary vertices reconstruction will become more difficult due to the increase, by a factor of 7.5, of the average number of interactions per bunch crossing. The performance of the VErtex LOcator (VELO), which is the tracking detector surrounding the interaction region, is essential to the success of this Phase-II Upgrade. Data rates are especially critical for the LHCb full software trigger, and with the expected higher particle flux, the VELO Upgrade-II detector will have to tolerate a dramatically increased data rate: assuming the same hybrid pixel design and detector geometry, the front-end electronics (ASICs) of the VELO Upgrade-II will have to cope with rates as high as 8 Ghits/s, with the hottest pixels reaching up to 500 khits/s. With this input rate, the data output from the VELO will exceed 30 Tbit/s, with potentially a further increase if more information is added to the read-out. This paper outlines the challenges being addressed and the solutions under investigation for reading out the VELO sub-detector.

Failure investigation of fractured crane crawler track plate

A repetitive failure of crawler track plate made of G22NiMoCr5-6 of heavy-duty crane is observed to be occurring with an average rate of one track plate fractured every 100 working hours, presenting a great problem that may impose hazard on personnel and raising direct and indirect costs required for maintenance, spare parts, and downtime costs. The objective of this research is to investigate the cause of track plate failure. An experimental investigation is carried out including chemical composition, tensile test, impact toughness, hardness test, and metallographic observation along with fractography analysis. Also, working stresses are defined by applying the finite element method. Based on the results of the experimental and computational analysis, the fracture of track plate made of G22NiMoCr5-6 predominantly resulted from deficiency in the track plate geometry design which increases stress concentration within the fracture region, in addition, slight deviation of material properties compared to those prescribed by the standard may have played a role in exacerbating the problem.

Effect of Elevated Acetabular Cup on Contact and Failure Analysis in Hip Implants for Different Microseparations and Cup Inclinations Under Routine Gait Activities Using In Silico Approach.

The acetabular cup design plays a critical role in reducing contact stress between femur head acetabular cup. Many studies used ellipsoidal and spheroidal geometry in acetabular cup design to effectively reduce contact stress. The present study focuses on elevated acetabular cup rim with round corner design to reduce contact stress with round corner geometry. The cobalt chromium femur head and cup are considered for finite element (FE) model of hip resurfacing. The gait loads of routine activities of humans like normal walking, stair ascending and descending and sitting down and getting up gait activities are applied to the developed 3D FE model. Five microseparations of 0.5, 1, 1.5, 2 and 2.5mm are considered in the present study. The acetabular cup inclination angle considered for this study are 35°, 45°, 55°, 65° and 75°. The contact stress and von Mises stress plot for each gait activities under these microseparations are analyzed for betterment of longevity of implants. Overall elevated cup rim design helped in reducing contact stress to a greater extent than conventional cup with different geometries. Also, the predicted von Mises stress for all the parameters considered in the current study are well within the yield strength of CoCr material. Therefore, elevated cup rim could be used as a better alternative to spline and, ellipsoidal and circular geometries of cup.