Geometric Design Research Articles

Impact of geometric design and mechanical strain on the electrocaloric effect of nanoscale BaTiO3/SrTiO3 composites

Impact of geometric design and mechanical strain on the electrocaloric effect of nanoscale BaTiO3/SrTiO3 composites

Induction Motor Geometric Parameter Optimization Using a Metaheuristic Optimization Method for High-Efficiency Motor Design

In this study, the optimum design for an induction motor (IM) was realized by providing details of its geometric design. The IM optimization was carried out using the Artificial Ecosystem-based Optimization (AEO) algorithm, a metaheuristic method. The AEO algorithm was used for the first time in IM optimization, and the design parameters were optimized. Ten motor design parameters were used as design variables. IM efficiency was improved, as the objective function. The genetic algorithm (GA) optimization method was used for comparison with the results obtained with the AEO method. The optimized and unoptimized results of the IM design generated with codes created in the Matlab program were verified with the Ansys RMxprt program, and it could be seen that the results are in good agreement. As a result of these studies, it was observed that the use of AEO in determining the geometric parameters of the IM had better convergence accuracy and reached the optimum result in a shorter time compared to the GA optimization method. It was observed that IM efficiency increased from 90.34% to 91.575% on average with the AEO method.

A parameterized model of center-symmetric space deployable arrays inspired by Miura and five-crease origami

Thick-panel origami has gained significant attention for its potential applications in the design of space deployable arrays. However, existing origami structures often fail to meet the stringent constraints imposed by various spacecraft in terms of connectivity and space efficiency, limiting the achievement of optimal folding ratios and compact transportation. To address these challenges, we propose a parameterized geometric model and design method for center-symmetric thick-panel space deployable arrays for varying scales and functions, integrating five-crease vertices with Miura origami. A planar four-bar linkage mechanism is applied to coordinate the motion between the five-crease vertices and Miura origami, ensuring one-degree-of-freedom (one-DOF) motion. The proposed model is validated through a case study on a space exposure experiment platform, with a scaled-down prototype fabricated for testing. The resulting space deployable arrays can be compactly placed within a rectangular prism, offering central symmetry, one-DOF motion, high volume efficiency and folding ratio, and enhanced design flexibility and adaptability.

Enhancing heat transfer efficiency in solar storage devices using eddy current structures and vibrations

This study introduces a novel phase change material (PCM)-based solar energy storage system integrating Tesla valve-inspired eddy current structures and mechanical vibrations to enhance thermal performance. By systematically optimizing the geometric design and vibration parameters, a 90°shunt angle was identified as the most effective configuration, achieving a significant 59.9% reduction in PCM melting time and completing the melting process in just 178 s. This superior performance was attributed to the generation of strong eddy currents, which disrupted the thermal boundary layer and enhanced heat transfer between the heat transfer fluid (HTF) and PCM. Mechanical vibrations (0.0003 m amplitude and 100 Hz frequency) further improved performance, particularly for shunt angles of 30°and 60°, where melting times were reduced by 13.4% and 13.36%, respectively, demonstrating the synergistic effects of geometry and vibration.The impact of natural convection was evaluated across a range of Rayleigh numbers (11,400 to 1,140,000), revealing that higher Rayleigh numbers enhanced heat transfer, especially for the 90°configuration. In contrast, shunt angles exceeding 90°showed reduced efficiency due to the thickening of boundary layers. Comparative analysis with existing heat transfer enhancement studies demonstrated the superior performance of the proposed system, which achieved greater reductions in melting time compared to designs using fin structures or optimized inclinations. This research provides valuable insights into the development of high-performance, scalable, and sustainable solar energy storage systems, bridging the gap between laboratory innovation and practical application.

Reduced order design space analysis and operational mapping for ramjet engines

Ramjet propulsion is often favored for powering supersonic vehicles cruising at speeds exceeding Mach 3. Despite the relatively simple geometric design of these engines compared to turbo-based alternatives, the complex flow physics involved makes their design and optimization challenging. Hence, the design and performance analysis of ramjet engines are crucial to ensure that the propulsion system meets the demands of the flight trajectory. To address this, a design and analysis methodology using zero-and-one dimensional models, Busemann intakes, and detailed chemistry approach is applied to explore the design space of ramjet engines. By investigating design parameters across a wide range of operational conditions, a multi-dimensional data matrix is generated. Employing a sensitivity analysis technique referred to as Shapley Additive Explanations (SHAP) framework, the propulsive performance characteristics under various operational and design conditions are discussed.

Bézier Curves and Surfaces with the Blending (α, λ, s)-Bernstein Basis

This study presents a generalized approach to Bézier curves and surfaces by utilizing the blending (α,λ,s)-Bernstein basis. The (α,λ,s)-Bernstein basis introduces shape parameters α, λ, and s, which allow for more flexibility and control over the curve’s shape compared to the classical Bernstein basis. The paper explores the properties of these generalized curves and surfaces, demonstrating their ability to maintain essential geometric characteristics, such as convex hull containment and endpoint interpolation, while providing enhanced control over the shape. This work aims to contribute to the fields of computer-aided geometric design and related applications by offering a robust tool for curve and surface modeling.

Outlet Configuration of a Reversed Circular Flow Jet Impingement Photovoltaic Thermal (PVT)

The utilization of the jet impingement technique is a prevalent approach in enhancing the efficiency of photovoltaic thermal (PVT) collector through the augmentation of heat transfer rate. The present work introduces a novel approach known as the reverse circular flow jet impingement (RCFJI) on a PVT collector. The performance analysis of the PVT collector was assessed through the utilization of CFD simulation. The RCFJI was installed to a jet plate which incorporates 36 holes. The holes were positioned at a spacing of 113.4 mm (x-axis) and 126 mm (y-axis). The air outlet channel of the jet plate has been configured into four different configurations: one hole (1h), three holes (3h), four holes (4h) and five holes (5h) to analyze the best outlet configuration leading to the highest energy performance. The simulation evaluation encompassed a range of solar irradiance spanning from 600 W/m<sup>2</sup> to 900 W/m<sup>2</sup>, while the mass flow rates varied from 0.01 kg/s to 0.14 kg/f for each geometrical design. Based on the research, the configuration that records the highest efficiency was 1h. The maximum photovoltaic efficiency recorded was 11.38% at 600 W/m<sup>2</sup> and mass fl ow rate of 0.14 kg/s. While the maximum thermal efficiency was 63.2% at solar irradiance 900 W/m<sup>2</sup> and mass flow rate of 0.14 kg/s.

Bezier Curves and Surfaces with the Generalized α-Bernstein Operator

In the field of Computer-Aided Geometric Design (CAGD), a proper model can be achieved depending on certain characteristics of the predefined blending basis functions. The presence of these characteristics ensures the geometric properties necessary for a decent design. The objective of this study, therefore, is to examine the generalized α-Bernstein operator in the context of its potential classification as a novel blending type basis for the construction of Bézier-like curves and surfaces. First, a recursive definition of this basis is provided, along with its unique representation in terms of that for the classical Bernstein operator. Next, following these representations, the characteristics of the basis are discussed, and one shape parameter for α-Bezier curves is defined. In addition, by utilizing the recursive definition of the basis, a de Casteljau-like algorithm is provided such that a subdivision schema can be applied to the construction of the new α-Bezier curves. The parametric continuity constraints for C0, C1, and C2 are also established to join two α-Bezier curves. Finally, a set of cross-sectional engineering surfaces is designed to indicate that the generalized α-Bernstein operator, as a basis, is efficient and easy to implement for forming shape-adjustable designs.

Building Contoured Pavements With Precast Concrete Pavement Slabs

When precast pavement slabs were first introduced for rapidly replacing and repairing concrete pavement in the early 2000’s, it was commonly believed by roadway engineers and precasters that flat, single-plane slabs could be used in most roadway locations. It has now become apparent that, while flat single-plane panels works in locations where the original roadway is straight and even slightly curved, contoured roadways require similarly-contoured (warped) precast replacement panels. This paper focuses on how highway geometrical features, such as horizontal and vertical curves, super-elevation transitions, vertical and horizontal departures of existing pavement from as-built locations and vertical and horizontal geometry of intersecting roadways, may significantly affect the geometric design, fabrication and installation of mildly-reinforced and precast prestressed pavement slabs. Particular reference will be made to the importance of including parameters for designing and installing non-planar precast pavements in contract plans and specifications.

Simulation model for tooth root crack growth in spur gears based on geometric design properties

Simulation model for tooth root crack growth in spur gears based on geometric design properties

Green spaces. A necessity for the health and well-being of hospitalized children ‒ Case CHU Batna, Algeria

This article tackles the topic of the health spaces and well-being of children hospitalized at the pediatric care in Chu Banta, Algeria, with a focus on the therapeutic garden based on the model of health architecture. In hospital therapeutic gardens, patient health and well-being are crucial, particularly in children’s hospitals because children are often more vulnerable than adults. The aim of this research was to examine the opinions and preferences of children and therapists on the components that should be considered when designing a therapeutic garden for children in hospitals, taking into account factors such as age, disease, and mental health. To do this, 50 hospital therapists employed by the hospital and 200 sick children looked at 100 simulated images and answered questions. The results showed that there was no discernible difference between the therapists’ and patients’ preferences for a children’s hospital environment. The children in the hospital preferred cartoon characters, animal motifs, and geometric designs. They also enjoyed crying trees and called for furniture in plant forms. The hospital garden has flower beds and water fountains installed. Outside the service, this study has demonstrated that therapists are capable of becoming experts in identifying children’s preferences for wellbeing in the therapy garden. These results can also be applied to studies on children’s preferences in situations where it is more difficult to assess the preferences of the subjects’ directly. Therefore, these results may aid architects and designers to create more child-friendly hospital environments.

Geometric Design and Safety Outcomes of Roundabouts in the Canadian Context: A Case Study in the Region of Waterloo

Road safety remains a critical concern in Canada and worldwide. In response, roundabouts have emerged as a safer intersection design under certain road, traffic and environmental conditions, with extensive research highlighting the critical role of geometric design in their safety effect. However, such geometric effects remain relatively unexplored in Canada, where roundabouts are a recent addition. Moreover, it is unknown whether the underlying relationship varies over time due to the evolution in driver behaviour. This study attempts to address these questions by utilizing data from the Region of Waterloo and constructing negative binomial models. Results indicate that geometric design significantly impacts collision frequency, with effects generally consistent but showing some temporal variability. The study also highlights unique relationships between geometries and safety in Canada, advocating for tailored roundabout designs and cautioning against direct application of findings from other regions.

Analysis of trajectory transection rate on four-lane divided rural highway curves

Objective The study aims to develop continuous trajectory profiles along curves with minimal error. It also focuses on formulating a percentage trajectory transection rate model as a function of geometric parameters (e.g., radius and curve length) for through and passing maneuvers on four-lane divided highways. Additionally, the study sought to identify the critical maneuver between through and passing on horizontal curves of four-lane divided highways. Methods A total of 15 horizontal curve sites on a four-lane divided rural highway in plain terrain were selected. An instrumented vehicle, equipped with a GPS data logger and cameras, was used for data collection. Naturalistic driving data from 34 drivers’ trips across the curves were collected for analysis, ensuring free-flow conditions. This dataset was used to develop continuous trajectory profiles, with GPS positioning errors minimized by calibrating the profiles at the Point of Curvature (PC) and Point of Tangency (PT) using the vanishing point method. Moreover, multiple linear regression technique was used to develop the mean percentage trajectory transection rate models i.e., for through (PTTR μC_T ) and passing (PTTR μC_P ) maneuvers. Results The trajectory profiles were effectively developed using the vanishing point method, which restricts the mean absolute error to 16 cm. The developed models revealed that curve length significantly influences PTTR in through maneuvers, while deflection angle, approach tangent length and curve length are the most critical factors in passing maneuvers. Notably, curve length emerged as a common predictor for both maneuvers. Additionally, a 15% higher trajectory transection rate was observed in passing maneuvers. Conclusions Combining geometric features such as curve length, deflection angle, and approach tangent length provides a more comprehensive understanding of drivers’ trajectory behavior, especially during passing maneuvers. The developed models can serve as a supplemental tool in geometric design to minimize lateral deviations and trajectory transitions across horizontal curves on four-lane divided highways. Passing maneuvers are riskier than through maneuvers, often involving lane changes and unpredictable paths. This highlights the need for roadway departure safety measures such as raised pavement markings, centerline rumble strips, and passing restrictions at specific curves.

A review of axial and radial ejectors: Geometric design, computational analysis, performance, and machine learning approaches

A review of axial and radial ejectors: Geometric design, computational analysis, performance, and machine learning approaches

4D-printed programmable sample-/eluent-actuated solid-phase extraction device for trace metal analysis.

To integrate valves, manifolds, and solid-phase extraction (SPE) columns into a compact device is technically difficult. Four-dimensional printing (4DP) technologies, employing stimuli-responsive materials in three-dimensional printing (3DP), are revolutionizing the fabrication, functionality, and applicability of stimuli-responsive analytical devices that can show time-dependent shape programming to enable more complex geometric designs and functions. However, 4D-printed stimuli-responsive actuators and valves utilized to control flowing streams in SPE applications remain rare. The tunable stimuli-responsive 4D-printed flow control actuators and valves with the capability of the programmable actuation can be used to manipulate flowing streams and simplify the automation of a conventional SPE scheme. We employed digital light processing three-dimensional printing (3DP), bisphenol A ethoxylate dimethacrylate-based photocurable resins, and 2-carboxyethyl acrylate (CEA)-incorporated flexible photocurable resins to fabricate an SPE column positioned between two [H+]-responsive flow-actuated needle valves. The two valves sequentially close after loading an alkaline sample (pH>pKa of CEA) due to swelling of the stem. Subsequently, they sequentially open upon loading an acidic eluent (pH<pKa of CEA; deswelling of the stem). The optimized device enabled a semi-automatic SPE scheme for Mn, Co, Ni, Cu, Zn, Cd, and Pb ions and showed competitive performance when coupled with inductively coupled plasma mass spectrometry-with the method detection limits ranging from 0.5 to 5.9ngL-1. We validated the reliability and applicability of this method by analyzing the metal ions in reference materials (CASS-4, SLRS-5, 1643f, and Trace Elements Urine L-2) and spike analyses of natural water and human urine samples. To the best of our knowledge, our device is the first demonstration of an SPE scheme performed by the programmable actuation of 4D-printed stimuli-responsive flow control valves, highlighting the analytical applicability of the tunable stimuli-responsive 4D-printed parts and the promising capability of 4DP technologies in advancing conventional sample pretreatment devices.

FRACTAL GEOMETRIES DESIGN FOR THREE-DIMENSIONAL PRINTING: ANALYSIS OF PERFORMANCE AND VIBRATION RESPONSE FOR PRODUCT DESIGN

Additive Manufacturing (AM) has enhanced the development of complex designs and geometries that are difficult or impossible to achieve with conventional manufacturing methods. Therefore, research focused on the analysis of the functional properties related to the behavior conferred by the filling material and the internal structure became especially relevant. In this sense, fractal geometry is one of the most established theories to characterize complex geometries based on repetitive self-similar patterns that allow complex shapes to be described and relate them to mechanical, rheological and morphological properties. The design of fractal microstructures promises the development of advanced materials with improved mechanical properties and multiple functions related to vibration absorption, weight reduction, among others. In relation to the compatibility of elastic materials with three-dimensional printing processes, the study of fractal geometries in terms of geometric design and its correlation with improved mechanical behavior is established as an objective. Several TPU-based fractal samples were designed and tested using compression processes to characterize the behavior of elastic fractal geometries as a function of fractal dimension. Specifically, Sierpinski pyramids-based specimens were designed to explore the influence of fractal dimensions and iterations on the elasticity of the samples. Additionally, a case study was carried out to by using Finite Element Method (FEA) in order to analyze the stress distribution and vibrational behavior based on fractal order. The results demonstrated a notable variation in compression behavior and vibrational behavior depending on the fractal order, highlighting the potential of fractal geometries to enhance mechanical performance in AM applications. Keywords: Fractal Geometries, Product Design, Three-Dimensional Printing, Performance, Thermoplastic Polyurethane.

Stretchable wrinkle-structured liquid metal sandwich films enable strain-insensitive electromagnetic shielding and Joule heating.

Stretchable electromagnetic interference (EMI) shields with strain-insensitive EMI shielding and Joule heating performances are highly desirable to be integrated with wearable electronics. To explore the possibility of applying geometric design in elastomeric liquid metal (LM) composites and fully investigate the influence of LM geometry on stretchable EMI shielding and Joule heating, multifunctional wrinkle-structured LM/Ecoflex sandwich films with excellent stretchability are developed. The denser LM wrinkle enables not only better electrical conduction, higher shielding effectiveness (SE) and steady-state temperature, but also enhanced strain-stable far-field/near-field shielding performance and Joule-heating capability. More strikingly, compared to most previously reported stretchable EMI shields or electric heaters, the densely wrinkled film could achieve multidirectional strain-insensitive shielding behavior with slightly strain-enhanced or strain-invariant EMI SE under stretching parallel or perpendicular to the electric field of EM waves, as well as show ideal strain-insensitive Joule-heating behavior over a larger strain range of 250%. The current findings suggest an effective strategy for developing stretchable LM-based composites with strain-insensitive properties.

Geometric design of two novel rotor profiles for Roots vacuum pumps with elliptical curve

Geometric design of two novel rotor profiles for Roots vacuum pumps with elliptical curve

Social-cultural Significance of Similar Motifs of The Raigarh District, Chhattisgarh: Tattoo Art Vs Ancient Rock Art

The Raigarh district is a home for various tribal groups, such as, Kanwars, Oraon, Gonds, Majhi and Birhors. The research paper focuses on traditional Tattoo art as practiced by various tribal groups of the region. The tribal perceive tattooing as a permanent identification mark which accompanies a person to next life. It is considered vital for the young tribal girls to have tattooing before their marriage. it is also believed to have healing effect. Diversified motifs of tribal art include human figures (dancing scenes, palms and soles), animal figures, plant figures, natural scenes along with non-geometric and geometric designs. Relatively greater concentration of motifs is observed on walls and floors of worshiping places. These motifs are expression of their cultural beliefs system related to their clan Gods, rituals, magic, mythology and folklores Some of tattoo motifs, such as, Symbolic human figures, animals figures (Scorpion, Centipedes, Sparrows), Plant figures (leaves, Creeper, Flowers) exhibit broad similarities to those of ancient rock art of the region. These ethnographic parallels provide useful clues for reconstructing life ways of ancient communities. Tribal groups, by and large, have been living in their homeland since remote past. While impact of interactions with non-tribal communities in recent past has brought some changes in their traditional occupation, food, dress etc., there is virtually no change in case of their magico religious practices, beliefs in clan Gods, mythology and folklore. Thus, it may be hypothesized that motifs observed in the tribal art have been playing cultural role related to their magico-religious practices, clan Gods, folklores and mythology, since the time their remote ancestors were occupying rock shelters.

Practical guide for assessing the need for conservation or modernization of roads in Mexico

Given the accelerated deterioration of the road network in Mexico, the proposed guide presents a rigorous methodological approach that facilitates decision-making between the conservation and modernization of road segments, ensuring their functionality and safety. Developed in response to the concerning state of the National Road Network (RNC), this guide combines documentary research with field evaluations, providing a robust technical tool for engineers and technicians to make informed decisions. It is based on key indicators such as signage, pavement condition, and geometric design. To validate its application, a case study was conducted on a road section in the Municipality of Valle de Bravo, State of Mexico, demonstrating the importance of implementing modernization work when conditions require it. This guide establishes itself as an indispensable tool for the strategic management of road infrastructure, optimizing resource allocation and ensuring that Mexican roads meet the demands of transportation, with a focus on safety and efficiency.