Scholarly Publications - Mechanical Engineering
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Item Embargo On a canonical interface model with application to micro-heterogeneous elastic solids(Elsevier BV, 2025-03-22) Javili, Ali; Larsson, Fredrik; Runesson, Kenneth; Steinmann, PaulFinite-thickness interphases between different constituents in heterogeneous materials are often replaced by a zero-thickness interface model. Due to increasing area-to-volume ratio with decreasing size of microstructures, interfaces introduce a physical length into the effective response at the macroscale. The most commonly studied interface models are the cohesive interface model and the elastic interface model. The cohesive interface model allows for a displacement jump across the interface, in contrast to the elastic interface model that requires displacement continuity across the interface. The classical general interface model assumes that the interface displacement itself must coincide with the displacement average across the interface. The recently proposed extended general interface model defines the interface displacement kinematically via the weighted average of displacement across the interface. Here, we propose a canonical interface model based on a variationally consistent approach, which encompasses all previous interface models. We implement our model with the finite element method and illustrate its consequences through a series of numerical examples. Moreover, variationally consistent homogenization is employed to upscale an elastic composite with particles surrounded by a canonical interface and embedded in a matrix. The numerical results highlight the significance of the canonical interface model on the overall response of composites, at times leading to counter-intuitive behavior at the macroscale.Item Open Access A geometrically nonlinear correspondence model for continuum-kinematics-inspired peridynamics(Springer International Publishing, 2025-03-19) Javili, Ali; Ekiz, Ekim; Steinmann, PaulPeridynamics (PD) has proven to be a promising theory to describe the behavior of materials allowing for singularities and fracture. The classical PD theory restricts the Poisson ratio. To address this issue, Continuum-kinematics-inspired Peridynamics (CPD) has been proposed as a variationally consistent formulation that can capture the Poisson effect exactly. Due to its geometrically exact nature, CPD does not suffer from zero-energy modes and displacement oscillations, making it an ideal nonlocal elasticity framework for large deformations. In a two-dimensional setting, CPD builds upon one-neighbor and two-neighbor interactions. One-neighbor interactions capture length-associated elasticity between pairs of points, equivalent to the original PD formalism. The two-neighbor interactions of CPD recover area-associated elasticity between triplet of points. This contribution provides for the first time a correspondence material model for CPD in a two-dimensional setting such that it recovers a well-established compressible neo-Hookean energy density of nonlinear elasticity at large deformations. At small deformations, the proposed model reduces to classical isotropic linear elasticity. The theory is illustrated via a series of numerical examples. © The Author(s), under exclusive licence to Springer Nature Switzerland AG 2025.Item Open Access Monitoring and control of cyber-physical-human systems(Elsevier, 2025-09-12) İnanç, Emirhan; Uzun, Muhammed Yusuf; Yıldız, Yıldıray; Ding, ZhengtaoCyber-physical-human systems (CPHS) refer to systems involving humans, cyber technologies, and physical components that interact with each other and evolve together. The expanding presence of these systems in various aspects of our lives highlights the growing significance of ensuring their efficiency, dependability, and safety. This chapter aims to offer insights into the monitoring and control aspects of CPHS, the roles of its elements, and the interactions between them, supported by relevant examples from recent literature.Item Embargo Microfluidic rapid isolation and electrochemical detection of S. pneumonia via aptamer-decorated surfaces(Elsevier BV, 2025-04-01) Babaie, Zahra; Kibar, Güneş; Yeşilkaya, Hasan; Amrani, Yassine; Doğan, Soner; Tuna, Bilge G.; Özalp, Veli C.; Çetin, BarbarosBackground: S. pneumoniae is widely recognized as a leading cause of respiratory infections worldwide, often resulting in high mortality rates. However, the advent of microfluidic technologies has brought significant advancements, including the simplified, sensitive, cost-effective, and rapid approach to pneumococcal bacteremia detection. In this study, a microfluidic magnetic platform is presented for rapid isolation, and an electrode array is utilized for the electrochemical detection of S. pneumoniae. Aptamer-decorated surfaces were employed for both isolation and detection. For isolation, silica magnetic microparticles were synthesized and decorated with aptamer. Results: Isolation performance was assessed for phosphate-buffered saline (PBS) and blood samples for different concentrations of S. pneumoniae. Electrical impedance spectroscopy (EIS) with fabricated gold interdigitated electrodes (IDEs) decorated with aptamer was implemented for the detection of S. Pneumoniae at different bacteria concentrations. The microfluidic platform performed bacteria isolation at comparable isolation efficiency with batch systems but at a much faster rate (isolation took about a minute, and the aptamer-decorated electrode array exhibited a limit of detection (LOD) at 962 CFU/mL and linear range between 10⁴, and 10⁷ CFU/mL. Significance: Our method represents a significant advancement compared to previous reports. Our microfluidic platform can efficiently isolate 60 μL of the bacteria sample within about one minute. The entire process takes about two minutes including the detection step. Furthermore, our method achieves a notable improvement in the detection limit for S. pneumoniae compared to conventional ELISA and magnetic microfluidics ELISA.Item Open Access Lightly loaded vibro-impacts of lubricated gear contacts: model and experiments(SAGE Publications Ltd., 2025-11-11) Dönmez, Ata; O'Toole, Michael; Kahraman, AhmetLow-frequency external excitations in drivetrains are known to cause vibro-impact motions characterized by tooth separations and sequences of impacts along the drive and coast-side backlash boundaries. Such vibro-impact motions are called gear rattling under completely unloaded conditions and gear hammering under lightly loaded conditions, both causing adverse noise and durability concerns. Recent experimental and theoretical studies under dry contact condition revealed that gears transmitting event light loads can exhibit sequences of periodic and non-periodic vibro-impact motions. This study aims at complementing those earlier studies both theoretically and experimentally by including lubrication effects. On the experimental side, tightly controlled vibro-impact measurements under dry and lubricated conditions are presented. A discrete dynamic model of the same set-up is proposed with two different gear mesh interface formulations: a piecewise-linear (PL) formulation to represent dry contact conditions and a hydrodynamic (HD) lubrication formulation intended to capture lubricant effects. Results indicate that the measured sound pressure levels and predict impact severity levels are reduced by lubrication. While the lubrication does not change angular displacements at all, its influence on impact accelerations and velocities is significant, describing the mechanisms of how lubricant reduces rattle noise. The PL and HD versions of the model are shown to correlate well with the corresponding dry and lubricated gear rattle experiments, suggesting that they can be effective in quantifying lubricant effects on gear vibro-impacts.Item Open Access Isogeometric boundary element formulation to simulate droplets in microchannel confinement(Emerald Publishing, 2025-02-20) Gümüş, Özgür Can; Kabacaoğlu, Gökberk; Çetin, BarbarosPurpose: This study aims to present an isogeometric boundary element formulation that stably and accurately models the motion of a droplet with arbitrary viscosity in free flows and microchannel confinements. Design/methodology/approach: Like other numerical methods, isogeometric boundary element formulation also suffers from mesh distortion; therefore, volume correction and mesh relaxation are also required for efficient and stable simulations of deformable particles in Stokes flow with high accuracy. To improve the stability and accuracy of the proposed formulation, (i) volume correction and (ii) mesh relaxation algorithms to prevent mesh distortion are implemented. Findings: Several test cases for a droplet in free-space shear flow are demonstrated for different Ca and viscosity ratio values which determine the deformability of a droplet. The results reveal that the drift of the enclosed volume inside a droplet and the mesh distortion becomes severe at low viscosity ratios and high Ca values, i.e. in the high deformability regime. The proposed numerical method integrating the stabilization algorithm enables the simulations at low spatiotemporal resolutions, even in extreme cases. The proposed method provides more than 10× speed-up compared to high-fidelity simulations without mesh relaxation. Efficient and accurate 3D simulations of droplets are also presented for simulations in microfluidic confinement. Practical implications: The current formulation can be applied for many different microfluidic applications, and can be extended to tackle multiphysics simulations of multiple droplets in microchannel confinement. Originality/value: The paper presents an isogeometric boundary element formulation with volume correction and mesh relaxation to model the motion of a droplet with arbitrary viscosity in free flows and microchannel confinements.Item Open Access Upscaling elastic interphases to canonical interface models(Elsevier BV, 2025-12-31) Javili, Ali; Larsson, Fredrik; Runesson, Kenneth; Steinmann, PaulFinite-thickness interphases in heterogeneous materials are often idealized as zero-thickness interfaces in computational models. The interphase may be for instance the transition zone between inclusion and matrix in composites or the grain boundaries in polycrystalline solids. A more advanced application arises in the context of batteries, where the solid electrolyte interphase forms an electro-chemo-mechanically active layer surrounding the electrodes. For geometrically equivalent macro samples, due to increasing area-to-volume ratio with decreasing size, including interfaces introduces a length-scale into the effective response of heterogeneous materials. Recently, a canonical interface model was proposed by the authors that permits both displacement and stress discontinuities across the interface. Unlike the general interface model, this framework treats the interface displacement as an independent field with its own constitutive behavior. However, the associated interface parameters remain phenomenological to date. In this paper, we account for the microstructural features in a thin interphase zone and employ out-of-plane geometrical reduction together with variationally consistent InterPhase Homogenization (IPH) in order to derive the interface properties. In other words, phenomenological parameter values are replaced by “physics-based” values. In particular, it is possible to account for any complex micro-design within the interphase to bring about metamaterial characteristics upon upscaling. Numerical results showcase the upscaled response and highlight the significance of the microstructural design and constitutive relations of the interphase pertinent to a multiphase elastic solid.Item Open Access Identification of tangential and normal forces in micro end milling through machine learning analysis of force signals(Inderscience Publishers, 2025-11-25) Karpat, YiğitDeveloping digital twins of manufacturing processes, like computer numerical control (CNC) machining, is vital due to their importance for creating high value-added parts. Tool condition monitoring has been an important research topic within this context where a major focus is on analysing machining force signals. Micro-milling is a complex process due to contributing factors like tool runout, deflection, edge radius, elastic recovery of materials, microstructure effects, and machining dynamics. This paper focuses on machine learning analysis of force signals to identify normal and tangential forces acting on the micro end mill. A machine learning algorithm based on Gaussian Process Regression (GPR) has been used to identify normal and tangential forces as a function of uncut chip thickness. The novelty of this approach is that identified normal force variation as a function of uncut chip thickness reveals information on minimum uncut chip thickness and edge radius. Monitoring the variation of these characteristic points on the force curves can be used to identify tool wear and predict remaining useful tool life.Item Open Access Analytical estimates for elastic properties of composites accounting for canonical interfaces(Wiley-VCH Verlag GmbH & Co. KGaA, 2025-07-15) Javili, AliThe objective of this contribution is to provide novel analytical estimates for the effective properties of micro-heterogeneous elastic solids accounting for interfacial effects, and to compare the results with computational simulations using the finite element method. The interphase transition zone between different constituents in the microstructure here is replaced by the recently proposed canonical interface model. The canonical interface model encompasses all previous interface models such as the general interface model, the cohesive interface model, and the elastic interface model. This manuscript presents a comprehensive study covering a broad range of interface parameters and stiffness ratios, demonstrating the utility of the proposed solutions in understanding and fine-tuning composites behavior.Item Open Access Continuum-kinematics-inspired peridynamics for transverse isotropy(Elsevier B.V., 2025-03-15) de Villiers, A.M.; Stadler, J.; Limbert, G.; McBride, A.T.; Javili, Ali; Steinmann, P.Accounting for the combined effects of mechanical anisotropy and nonlocality is critical for capturing a wide range of material behaviour. Continuum-kinematics-inspired peridynamics (CPD) provides the essential underpinning theoretical and numerical framework to realise this objective. The formalism of rational mechanics is employed here to rigorously extend CPD to the important case of transverse isotropy at finite deformations while retaining the fundamental deformation measures of length, area and volume intrinsic to classical continuum mechanics. Details of the anisotropic contribution to the potential energy density due to length, area and volume elements are given. A series of numerical examples serve to elucidate the theory presented.Item Open Access A novel energy-fitted hexagonal quadrature scheme enables low-cost and high-fidelity peridynamic computations(Elsevier B.V., 2025-05-15) Schaller, Emely; Javili, Ali; Steinmann, PaulIn this contribution, we propose a novel hexagonal quadrature scheme for one-neighbor interactions in continuum-kinematics-inspired peridynamics equivalent to bond-based peridynamics. The hexagonal quadrature scheme is fitted to correctly integrate the stored energy density within the nonlocal finite-sized neighborhood of a continuum point subject to affine expansion. Our proposed hexagonal quadrature scheme is grid-independent by relying on appropriate interpolation of pertinent quantities from collocation to quadrature points. In this contribution, we discuss linear and quadratic interpolations and compare our novel hexagonal quadrature scheme to common grid-dependent quadrature schemes. For this, we consider both, tetragonal and hexagonal discretizations of the domain. The accuracy of the presented quadrature schemes is first evaluated and compared by computing the stored energy density of various prescribed affine deformations within the nonlocal neighborhood. Furthermore, we perform three different boundary value problems, where we measure the effective Poisson's ratio resulting from each quadrature scheme and evaluate the deformation of a unit square under extension and beam bending. Key findings of our studies are: The Poisson's test is a good indicator for the convergence behavior of quadrature schemes with respect to the grid density. The accuracy of quadrature schemes depends, as expected, on their ability to appropriately capture the deformation within the nonlocal neighborhood. Our novel hexagonal quadrature scheme, rendering the correct effective Poisson's ratio of 1/3 for small deformations, together with quadratic interpolation consequently yields the most accurate results for the studies presented in this contribution, thereby effectively reducing the computational cost.Item Open Access Quantum mechanical moduli field(Elsevier Ltd, 2025-05-01) Gengor, G; Çelebi, Orçun Koray; Mohammed, A.S.K.; Sehitoglu, H.To understand the role of defects in materials science, ranging from mechanical to physical properties, determining the spatial variation of elastic moduli is of paramount importance. Using electron wavefunctions, we derive novel expressions for local elastic moduli in the lattice scale, Quantum Mechanical Moduli Field (QMMF). The QMMF provides insight into the interplay between elastic properties and defects. To derive QMMF, we differentiate the local stress density against strain. The QMMF has contributions from kinetic, exchangecorrelation, and electrostatic interactions. We provide novel expressions and numerical schemes to calculate QMMF. In atomistic calculations, the atoms are modeled as point-like entities, which only allows the macroscopic elastic properties to be calculated. Since the QMMF represents the local elastic properties, it provides a significant advancement from previous studies, especially in the presence of multi-elements. Four example applications of QMMF are provided. Firstly, the macroscopic elastic moduli of Ni and B2NiTi are calculated using QMMF in agreement with experiments. Secondly, a H interstitial in Ni is considered. The effect of H concentration on H softening is evaluated. Thirdly, the effect of dilatation on moduli is calculated, revealing the nonlinearity of moduli. Finally, the local elastic properties around W solute in the Ni matrix are calculated. The W solute increases the macroscopic moduli of Ni in a non-linear fashion. It is found that the macroscopic hardening is due to the hardening of the Ni matrix rather than W solutes forming hard-spots. The QMMF uses electron densities to unveil such surprising effects that are otherwise unobservable.Item Open Access Multistability and noise-induced transitions in dispersively coupled nonlinear nanomechanical modes(American Physical Society, 2025-08-06) Allemeier, David; Kaya, Ismet I.; Hanay, Mehmet Selim; Ekinci, Kamil L.We study the noisy dynamics of two coupled bistable modes of a nanomechanical beam. When decoupled, each driven mode obeys the Duffing equation of motion, with a well-defined bistable region in the frequency domain. When both modes are driven, intermodal dispersive coupling emerges due to the amplitude dependence of the modal frequencies and leads to coupled states of the two modes. We map out the dynamics of the system by sweeping the drive frequencies of both modes in the presence of added noise. The system then samples all accessible states at each combination of frequencies, with the probability of each stable state being proportional to its occupancy time at steady state. In the frequency domain, the system exhibits four stable regions—one for each coupled state—which are separated by five curves. These curves are reminiscent of coexistence curves in an equilibrium phase diagram: each curve is defined by robust interstate transitions, with equal probabilities of finding the system in the two contiguous states. Remarkably, the curves intersect in two triple points, where the system now transitions between three distinct contiguous states. A physical analogy can be made between this nonequilibrium system and a multiphase thermodynamic system, with possible applications in computing, precision sensing, and signal processing.Item Open Access Multilayer integrated acoustofluidic device for multistage particle manipulation(Institute of Physics Publishing Ltd., 2025-07-31) Açıkgöz, Hande Nur; Atay, Atakan; Karaman, Alara; Özer, M. Bülent; Çetin, BarbarosIn this study, we present a multilayer integrated acoustofluidic device for multistage microparticle manipulation, which combines acoustic size-based separation and enrichment within a compact architecture. The device is composed of two layers, each equipped with independent piezoelectric actuators operating at distinct resonance frequencies. The top layer enables the separation of 2 µm and 12 µm fluorescent particles, while the bottom layer enhances the concentration of 2 µm particles. A thin polymer layer is used to acoustically isolate the units, allowing concurrent manipulation without any acoustic interference. The performance of the isolated units as well as the integrated device was experimentally assessed under varying flow conditions, demonstrating high-efficiency separation and tunable enrichment ratios. This multilayer platform provides a scalable and efficient solution for complex bioanalytical applications requiring sequential acoustofluidic operations in a miniaturized format.Item Open Access ReLMBot: a reconfigurable, legged, miniature, modular robot with compliant or rigid, magnetic connection mechanisms(Institute of Electrical and Electronics Engineers, 2025-09-24) Uğur, Mustafa; Yaman, Yiğit; Arslan, Burak; Ergin, Ömer Çağrı; Özcan, OnurThis letter presents ReLMBot, a reconfigurable, legged, miniature, modular robot with magnetic and passive mechanisms. The robot comprises multiple modules, each equipped with backbones featuring permanent magnets, which offer reconfigurability without requiring additional power or actuation while enhancing the robot’s compliance. Moreover, by choosing the geometry of the magnets differently, the connections can be made rigid (square-shaped) or compliant (cylindrical). A dynamic model incorporating the robot’s magnetic connections is developed to simulate and verify its climbing performance and docking/undocking behavior. The results demonstrated that cylindrical magnets achieve a higher success rate in climbing obstacles and provide significantly higher additional climbing height compared to square-shaped magnets as the number of modules increases. Furthermore, the robot’s starting position relative to the obstacle has a major impact on its climbing success. Modules with square shaped magnets maintain near 100% success until just below their climbable limit, then drop sharply, especially with fewer modules. Cylindrical magnets show a gradual decline, turning abruptly 5 mm before failure. The modules weigh 29.43 grams and have palm-sized dimensions, allowing them to dock and undock to perform various tasks, including climbing obstacles higher than a single module. The modules possess soft c-shaped legs, enabling operation in diverse terrains like gravel, sand, or grass. The modules’ miniature structure, ease of manufacture, and affordability make them a suitable option for multiple use cases. The robot’s wireless communication capability makes it a strong contender for surveillance in confined spaces like collapsed buildings and nuclear sites, large areas like farmlands, and even planetary exploration missions.Item Open Access A hybrid model to analyze stress distributions at the tool and workpiece interface during drilling of thick cfrp laminates considering thermal effects(Springer UK, 2025-06-18) Shariar, Fahim; Karagüzel, Umut; Karpat, YiğitDrilling is employed as a machining method to meet the demands for producing functional CFRP structures without compromising their unique and desirable material properties. Because of its intrinsic material properties and drill-induced damages, drilling CFRP remains an ambitious task. This study investigates the stress distributions at the tool-workpiece interface during the CFRP dry drilling process. A better understanding of contact pressure and tangential stress distribution on the cutting edge of drills is necessary for a better selection of process parameters. The drill margin region, which directly affects the hole wall quality, has been included in the analysis. Drilling experiments were conducted to measure thrust force, torque, and temperature for different cutting parameter configurations. Finite element-based thermal models have been utilized to estimate the hole wall surface temperature during drilling. The analytical cutting force model is coupled with the temperature distribution from the FE model to analyze the variation of contact pressure and tangential stress distributions along the tip of the drill, together with the thermal effects on contact pressure during drilling.Item Open Access The Kirsch problem in second strain gradient elasticity(The Royal Society Publishing, 2025-08-13) Xie, Jinchen; Javili, Ali; Linder, ChristianThe Kirsch problem, namely the problem of an infinite plane with a circular hole under uniaxial tension, is one of the cornerstone problems in elasticity. The Kirsch problem is rooted in classical elasticity theory, which cannot explain the size effects. We investigate the Kirsch problem for the first time in the framework of Mindlin’s second strain gradient elasticity theory. By presenting the fundamental equations in polar coordinates, we use the stress function to derive the closed-form solution of the Kirsch problem. Then, we compare the solution to its counterparts associated with first strain gradient elasticity and classical elasticity. Our results indicate that the strain gradient effects can increase stiffness and reduce the stress concentration around the hole. Under the second strain gradient elasticity theory, a larger circular hole radius results in higher stress concentration, exhibiting a significant size effect. Furthermore, we establish a mixed finite-element method for second strain gradient elasticity. The results of computational simulations are in close agreement with the solution proposed in this contribution. This work extends the Kirsch problem to second strain gradient elasticity providing a benchmark solution highlighting the importance of higher gradient effects in predicting the elastic behaviour of materials at smaller scales.Item Open Access Cr₂O₃-graphene nanocomposites for high-performance supercapacitors and methylene blue degradation: synthesis and electrochemical analysis(Elsevier BV, 2025-07-25) Asim, Muhammad; Iqbal, Javed; Islam, Bilal; Bashir, Javaria; Maqsood, Nabeel; Skotnicová, Kateřina; Nawaz, AhmadThis study aims to enhance the photocatalytic performance of chromium oxide (Cr₂O₃) by incorporating graphene nanoplatelets (GNPs) to form Cr2O3/GNPs nanocomposites. Pristine Cr₂O₃, GNPs, and Cr₂O₃/GNPs nanocomposites were synthesized using a cost-effective ex-situ co-precipitation method at different stoichiometric ratios (7:3), (2:3), and (1:9). Structural characterization via X-ray diffraction and Raman spectroscopy confirmed that Cr₂O₃ retained its rhombohedral phase across all compositions, with no evidence of phase transformation. A significant reduction in crystallite size by 50.0 %, 58.4 %, and 72.45 % was observed for the 7:3, 2:3, and 1:9 compositions, respectively, relative to pristine Cr₂O₃. Photocatalytic experiments revealed that the Cr₂O₃/GNPs (1:9) nanocomposite exhibited the highest methylene blue dye degradation efficiency, attributed to defect-induced charge separation and enhanced interfacial electron transport. The rate constant (k$_a$pp) and C/C$_0$ ratio further validated this optimal composition, as UV–Vis spectroscopy demonstrated a substantial decrease in MB absorption intensity, signifying efficient dye removal. Electrochemical investigations using cyclic voltammetry, galvanostatic charge-discharge (GCD), and electrochemical impedance spectroscopy confirmed the superior energy storage properties of the Cr₂O₃/GNPs (1:9) nanocomposite, which exhibited the highest specific capacitance (462.2 F/g) and the lowest equivalent series resistance (6Ω). The synergistic 2D interfacial interactions between Cr₂O₃ and GNPs facilitated rapid charge transport, efficient electron-hole separation, and enhanced ionic conductivity, making this nanocomposite a promising candidate for both environmental remediation (wastewater treatment) and energy storage (supercapacitor) applications.Item Open Access Arbitration with control barrier functions for safe shared control(Institute of Electrical and Electronics Engineers Inc., 2025-12-10) Uzun, Muhammed Yusuf; Yıldız, YıldırayBy combining automation accuracy with human adaptability, shared control provides enhanced performance and safety in dynamic, complex environments. Traditional arbitration methods for integrating automation and human inputs often rely on system-specific, parameter-dependent functions that are based on shared control metrics such as trust, workload, or attention. Meanwhile, Control Barrier Functions (CBFs) enforce safety constraints on automated systems but are typically limited to safeguarding plant states. This letter introduces a novel arbitration method based on Control Barrier Functions (CBFs), where shared control metrics such as workload, attention, and trust are expressed as real-time inequality constraints. The resulting quadratic-programming formulation determines the automation assistance input that enforces these constraints while preserving feasibility and safety. This CBF-based arbitration provides a systematic, interpretable, and scalable foundation for safe human–autonomy integration.Item Embargo Optimizing slot design in pin-fin heat sinks: a numerical approach to lower entropy and pressure drop(Elsevier Inc., 2026-01-07) Hossain, Md Ishtiaque; Chowdhury, Md Samiul Haider; Durjoy, Md. Shahjahan; Ahmed, Syed Shaheer Uddin; Siddique, Istiaq JamilMinimizing the entropy generation and pressure drop penalty during heat transfer has been a prime concern in the design of heat sinks. One way to mitigate this is to include slots in the pin fin heat sink design, which not only improves the overall heat transfer but also reduces these penalties. Present study numerically investigates the impact of six different slot designs on the conventional pin fin structure, which are venturi, circular cavity, sudden expansion, sudden contraction, linear divergence, and linear convergence. A three-dimensional computational fluid dynamics (CFD) model is used to validate the experimental investigation of a cylindrical pin–fin heat sink, considering four Reynolds numbers ranging from 8,547 to 21,367. Later, the model is utilized to examine different slot-inserted square-shaped fin structures to study the overall performance based on Nusselt number, pressure drop across the heat sink, hydrothermal performance factor (HTPF), thermal resistance, and total entropy generation. Among the six different slots, the venturi slot (VS) outperformed the rest. This configuration reports a 33.6% increase and a 29.03% decrease in HTPF and total entropy generation, respectively. As a follow-up, the VS is applied in the cylindrical pin fin (CPF) to understand the influence of the principal fin design on effective heat transfer.