- 标题
- 摘要
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- 实验方案
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Differences in Simulated Refractive Outcomes of Photorefractive Keratectomy (PRK) and Laser In-Situ Keratomileusis (LASIK) for Myopia in Same-Eye Virtual Trials
摘要： The use of computational mechanics for assessing the structural and optical consequences of corneal refractive procedures is increasing. In practice, surgeons who elect to perform PRK rather than LASIK must often reduce the programmed refractive treatment magnitude to avoid overcorrection of myopia. Building on a recent clinical validation study of finite element analysis (FEA)-based predictions of LASIK outcomes, this study compares predicted responses in the validated LASIK cases to theoretical PRK treatments for the same refractive error. Simulations in 20 eyes demonstrated that PRK resulted in a mean overcorrection of 0.17 ± 0.10 D relative to LASIK and that the magnitude of overcorrection increased as a function of attempted correction. This difference in correction closely matched (within 0.06 ± 0.03 D) observed differences in PRK and LASIK from a historical nomogram incorporating thousands of cases. The surgically induced corneal strain was higher in LASIK than PRK and resulted in more forward displacement of the central stroma and, consequently, less relative flattening in LASIK. This FE model provides structural confirmation of a mechanism of action for the difference in refractive outcomes of these two keratorefractive techniques, and the results were in agreement with empirical clinical data.
关键词： laser in situ keratomileusis (LASIK),refractive surgery,cornea,photorefractive keratectomy (PRK),finite element analysis
更新于2025-09-16 10:30:52
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[IEEE 2019 IEEE SENSORS - Montreal, QC, Canada (2019.10.27-2019.10.30)] 2019 IEEE SENSORS - Optical Fiber Bragg Grating Based Pressure Sensor Using a Composite Diaphragm For Pressure Measurements
摘要： The development of an optical fiber based pressure sensor, created using a Fiber Bragg Grating (FBG) and a glass fiber reinforced polymer membrane for use in aerodynamic applications, is reported. The FBG was co-bonded on the surface of the membrane to measure the strain induced by the deflection of the diaphragm with applied pressure. The sensor exhibited high sensitivities of 56.7 pm/kPa, with a minimum resolution of 21 Pa over a 0 to 35 kPa range. The outputs from a mathematical model, Finite Element analysis and the experimental results are compared and discussed.
关键词： Glass Fiber Reinforced Polymer,Finite Element Analysis,Fiber Bragg Grating,optical pressure sensor
更新于2025-09-16 10:30:52
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Thermomechanical Stress Distribution Analysis of Junction Box on Silicon Photovoltaic Modules Based on Finite Element Analysis
摘要： The electrical failure associated with concentration of heat and thermomechanical stress inside junction boxes is one of the main failure modes of photovoltaic (PV) modules. Three types of potting junction boxes with partial 72 Si cells PV panel are modeled under a constant current steady-state condition. The temperature distribution results are veri?ed through thermal dissipation tests. It is found that when one diode is in the ON-state, the split kind of junction box shows the highest temperature distribution on the surface, which is nearly 15 ?C higher than the other two types under 25 ?C with 11 A current applied. When three diodes are working, the other two types of junction box with three diodes inside will be intensely heated. The internal temperature distribution shows that bigger size and more copper coverage can help improve the thermal dissipation. Thermomechanical stress analysis based on the steady-state conditions is then carried out. The results show stress concentration on the side wall of the type I junction box while the other two types having conspicuous impact to the backsheet.
关键词： thermomechanical stress,temperature distribution,junction box,photovoltaic (PV),Finite element analysis
更新于2025-09-12 10:27:22
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[IEEE 2019 25th International Conference on Automation and Computing (ICAC) - Lancaster, United Kingdom (2019.9.5-2019.9.7)] 2019 25th International Conference on Automation and Computing (ICAC) - Temperature Field Simulation and Experimental Analysis of Laser Cladding 45 Steel
摘要： In order to explore the influence in temperature field change on the cladding quality and substrate deformation during laser cladding, adopt the APDL parametrization design language in ANSYS finite element analysis software to establish the laser cladding process model and the cladding process. The dynamic simulation and the temperature field distribution during the simulation cooling process were carried out, and the experimental verification and comparison were carried out under the same process parameters. The results showed that the single-pass cladding layer has the best shape under the process parameters that laser power of 1800w, powder feeding capacity of 20g/min and scanning speed of 8mm/s. During the cladding simulation process, the temperature of the molten pool and the peak temperature of the time-course curve are basically constant, and the temperature field distribution takes on a steady-state distribution. After the cladding,the temperature of cladding layer diffuses to the both ends, the temperature field changes gradually decrease during the cooling process, and the temperature is in an unsteady state. As the cooling time increases, the temperature drop gradient gradually decreases. The temperature field cooling analysis is carried out under the same process parameters. The error between the experimental results and the simulation results is less than 10%, which is very consistent and has guiding significance for practical experiments.
关键词： temperature field,finite element analysis,laser cladding
更新于2025-09-12 10:27:22
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Multi-physical analysis of thermo-optical effects for different Selective Laser Melting (SLM) scanning strategies
摘要： In this paper, transient thermo-optical effects in protective windows for selective laser melting are analyzed by means of a multi-physical analysis. The temperature distribution of the window is simulated for different scanning strategies and orders of exposure. Therefore, cubic test specimens are virtually built and the resulting axial and lateral focus shift is analyzed. Furthermore, the impact of the distance between the laser scanner and the protective window is analyzed. The simulations predict that spreading the thermal load on the window both spatially and temporally reduces the focus shift. Consequently, the focus shift is reduced if the window is placed further away from the laser scanner.
关键词： thermal lensing,Selective laser melting,protective window,finite element analysis,laser-powder bed fusion,additive manufacturing
更新于2025-09-12 10:27:22
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Laser treatment surface: An innovative method to increase the adhesive bonding of ENF joints in CFRP
摘要： Recently, many studies showed the opportunity to use a CO2 laser for treating the surfaces for structural bonding. In this work, a study on the effectiveness of a laser texturing on ENF bonded joints made with CFRP and epoxy adhesive has been developed. The experimental results showed that the use of this technology allows obtaining mechanical resistances of the bonded joints higher than 80% compared to untreated ones. Furthermore, a numerical model is proposed to forecast the response of the ENF specimens, and the numerical results are in good agreement with the experimental ones. This work represents a basis for the development of an innovative approach to design the laser texturing as a function of the applied stress.
关键词： A. Adhesive joints,C. Finite element analysis (FEA),A. Polymer-matrix composites (PMCs),B. Surface treatments,B. Debonding
更新于2025-09-12 10:27:22
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Effects of Structural Parameters on the Poisson's Ratio and Compressive Modulus of 2D Pentamode Structures Fabricated by Selective Laser Melting
摘要： Metamaterials have been receiving an increasing amount of interest in recent years. As a type of metamaterial, pentamode materials (PMs) approximate the elastic properties of liquids. In this study, a finite-element analysis was conducted to predict the mechanical properties of PM structures by altering the thin wall thicknesses and layer numbers to obtain an outstanding load-bearing capacity. It was found that as the thin wall thickness increased from 0.15 mm to 0.45 mm, the compressive modulus of the PM structures increased and the Poisson’s ratio decreased. As the layer number increased, the Poisson’s ratio of the PM structures increased rapidly and reaches a stable value ranging from 0.50 to 0.55. Simulation results of the stress distribution in the PM structures confirmed that stress concentrations exist at the junctions of the thin walls and weights. For validation, Ti–6Al–4V specimens were fabricated by selective laser melting (SLM), and the mechanical properties of these specimens (i.e., Poisson’s ratio and elastic modulus) were experimentally studied. Good consistency was achieved between the numerical and experimental results. This work is beneficial for the design and development of PM structures with simultaneous load-bearing capacity and pentamodal properties.
关键词： Selective laser melting,Pentamode materials,Metamaterials,Finite-element analysis
更新于2025-09-12 10:27:22
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Finite Element Simulation and Experimental Validation of Laser Assisted Machining of Inconel 718
摘要： Laser assisted machining (LAM) is a promising technology for machining of difficult to cut materials with reduced cutting forces, improved surface finish and tool life. This paper is mainly focused on study of cutting forces during laser assisted machining of Inconel 718 superalloy using finite element (FE) approach. An iterative procedure was adopted in this work to determine the coefficient of friction at tool chip interface to obtain rational values of cutting force for the identified cutting range. Arbitrary Lagrangian Eulerian (ALE) formulation was included to simulate the chip formation process. Johnson-cook material model for flow stress behaviour of workpiece material was incorporated during simulation. To validate the FE model, LAM experimentations were done under orthogonal cutting condition. The experiments were conducted according to Taguchi’s design of experiments. The cutting force results obtained through experimentation and simulation were compared and presented here. The FE prediction of cutting forces agrees with the experimental conditions for most of the cases within 15% deviation.
关键词： Cutting force,Finite Element Analysis,Inconel 718,Taguchi method,Orthogonal machining,Laser assisted machining
更新于2025-09-12 10:27:22
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Luminescence Image Analysis Using Finite-Element Models: Finished Solar Cell Analysis
摘要： A general computational routine which seeks cell parameters that best explain a set of luminescence imaging data is presented in this article. The routine combines Griddler, a finite-element simulator for solar cells, and tailored multivariate regression techniques. It is applied to a dataset of luminescence images from about 80 monocrystalline silicon Al back surface field solar cells with varying front metal grid contact resistance and recombination. The fitted cell parameters including contact resistance spatial distribution, saturation current densities of the wafer’s passivated regions, and under the metal contacts lead to simulated I–V characteristics that are in agreement with experimental data. The extracted contact resistance also correlates well with transmission line method measurements. In a separate study of luminescence imaging data from a multicrystalline passivated emitter rear local contacted cell (PERC) cell, this analysis routine is also compared with an alternative high spatial resolution method, yielding comparable results.
关键词： Finite element analysis,luminescence,photovoltaic cells
更新于2025-09-11 14:15:04
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Rectangular and sinusoidal Au-Grating as plasmonic sensor: A comparative study
摘要： Sensitivity of surface plasmon resonance sensor (SPRS) is mainly associated to efficient excitation of surface plasmon polaritons (SPPs) waves. In this work, effect of 50 nm thick Au film designed as rectangular and sinusoidal grating structure on glass substrate has been explored by finite element analysis (FEA) using COMSOL Multiphysics 5.3a. The comparison between the rectangular and sinusoidal gratings for efficient sensing has been presented here. Slit width (SW) for grating device has been optimized by applying far-field and near-field analysis while periodicity of grating structure is kept constant. Far field transmission spectra for both devices have been analyzed by illuminating the grating device through excitation port from the substrate side. Resonance wavelength (RW) dips for plasmonic grating device has been examined in each transmission spectrum for different values of refractive indices (RI). The sensitivity of plasmonic grating device has been calculated by measuring the shift in resonance wavelength by varying refractive index of analyte. The sinusoidal grating supporting fundamental plasmonic mode is found to be more sensitive (717 nm/RIU) as compared to simple rectangular grating (693 nm/RIU). Being highly sensitive to minute change in refractive index, such devices are efficiently applicable in real life.
关键词： Plasmonic sensor,Sinusoidal grating,Finite element analysis,Refractive index sensing,Sensitivity,Rectangular grating
更新于2025-09-11 14:15:04