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[IEEE 2018 31st International Vacuum Nanoelectronics Conference (IVNC) - Kyoto, Japan (2018.7.9-2018.7.13)] 2018 31st International Vacuum Nanoelectronics Conference (IVNC) - Recent progress in development of radiation tolerant image sensor with field emitter array
摘要： A prototype image sensor is developed using cadmium telluride-based photodiode and a volcano-structured FEA. Radiation tolerance of each component was tested by irradiating gamma-ray using cobalt-60 source. Gamma-ray tolerance of up to 1.2 MGy was confirmed for both FEA and photodiode.
关键词： Radiation tolerant,Image sensor,Cadmium telluride (CdTe),Field emitter array (FEA)
更新于2025-09-23 15:21:21
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[ASME ASME 2018 International Technical Conference and Exhibition on Packaging and Integration of Electronic and Photonic Microsystems - San Francisco, California, USA (Monday 27 August 2018)] ASME 2018 International Technical Conference and Exhibition on Packaging and Integration of Electronic and Photonic Microsystems - The Effects of Temperature, Strain Rate, and Aging on the Poisson’s Ratio of SAC Lead Free Solders
摘要： In this study, we have conducted a combined numerical and experimental study on the Poisson’s ratio of SAC lead free solders. The Poisson’s ratio (PR) is one of the basic mechanical properties used in many material constitutive models. Although often not measured, it is important property in many finite element method (FEM) calculations. The value of the Poisson’s ratio of SAC lead free solders is relatively unexplored compared to other material properties, and for FEA simulations it is typically assumed to be ? = 0.3. In the current work, we have shown the effects of the chosen value of the solder joint Poisson’s ratio on the finite element results for BGA components subjected to thermal cycling. In the finite element models, the reliability predictions were based on the Morrow-Darveaux energy-based fatigue model. Several sizes (5, 10, 15 mm) of PBGA components with SAC305 solder joints with 0.4 and 0.8 mm spacing were modeled. The packages were subjected to a time dependent cyclic temperature distribution from -40 to 125 oC. The package assemblies were assumed to be in a stress-free state at 25 oC (room temperature), with no residual stresses induced in the manufacturing process. The simulation results have demonstrated that for specified range of Poisson’s ratio values of 0.15 < ??< 0.40, the solder Plastic Work varied over 20% and the Predicted Reliability Varied over 50%. To determine the actual Poisson’s ratio experimentally, uniaxial tensile stress-strain tests were carried out on SAC305 (96.5Sn3.0Ag0.5Cu) specimens using a micro tension/torsion testing machine with two strain rates (0.0001, and 0.00001 (sec-1)), four testing temperatures (T = 25, 50, 75, 100 oC), and several durations of prior aging at T = 125 oC. Deformations and strains in axial and transverse directions were measured using strain gages with automatic data acquisition from LabVIEW software. The recorded transverse strain vs. axial strain data were then fit with a linear regression analysis to determine the Poisson’s ratio values. A test matrix of experiments was developed to study the effects of temperature, strain rate, alloy composition, and solidification cooling profile on the value of solder Poisson’s ratio. The Poisson’s ratio was found to increase with increasing temperature, and decrease with increasing strain rate. Using a slower solidification cooling profile led to an increase in the solder Poisson’s ratio value. Finally, the microstructural coarsening that occurs during isothermal aging lead to an increase in the Poisson’s ratio.
关键词： FEA,Lead Free Solder,Reliability,DAQ,PBGA Packaging
更新于2025-09-23 15:21:21
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Reference Module in Biomedical Sciences || X-Ray Based Imaging Methods to Assess Bone Quality
摘要： Dual X-ray absorptiometry (DXA) is one of the best-researched quantitative imaging modalities in medicine. Its physical basis, technical features and limitations have been addressed in hundreds of papers and summarized in a report on bone densitometry of the International Commission on Radiation Units (ICRU) that also covers quantitative computed tomography (QCT) and describes performance measures used in densitometry (Kalender et al., 2009). The primary output of DXA is areal bone mineral density (aBMD). Its clinical relevance for the diagnosis of osteoporosis, fracture prediction, and monitoring of treatment and age related changes has been investigated in multiple very large epidemiological and pharmaceutical studies of more than 2,00,000 subjects worldwide. aBMD is the basis of the WHO working definition of osteoporosis (Kanis and WHO Study Group, 1994). It is a strong predictor of fracture risk, but even in combination with other risk factors it cannot predict whether an individual subject eventually will fracture or not. Today, about 50–100 patients with osteoporosis must be treated to prevent one fracture (Albert and Reddy, 2017); vice versa, about 50% subjects who fracture do not have osteoporosis (Schuit et al., 2004; Siris et al., 2004).
关键词： TBS,QCT,FEA,Bone Quality,Imaging Methods,X-Ray,HSA,DXA,HR-pQCT
更新于2025-09-23 15:21:01
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Modeling of 1D Au plasmonic grating as efficient gas sensor
摘要： Gas-sensor reported here consist of a sensingchip of a metallic grating designed on gold (Au) film over a glass substrate which has been modelled using finite element analysis (FEA). The Au is layered in the form of horizontal nano-strips with a periodic nano-sized gap known as slit-width. The transverse magnetic (TM) light illuminates the metallic films from substrate side at normal incidence. The transmission loss spectrums have been extracted for 0th order diffraction for different physical interpretations. The several combinations of periodicity and slit width have been optimized by taking slit width as half of periodicity. The refractive index sensitivity achieved at optimal geometrical parameters is noteworthy and it is reported to be 599 (nm/RIU) at a spatial period of 660 nm. The novel theoretical results has been supported by far field and near field analysis. The design suggested in this report is important becuase of the wavelength range that lie in the visible region where most of the real life spectrometers works. Such sensors can be applicable in industries for detection of toxic gases and harmful metallic pieces in atmosphere.
关键词： Resonance,Gas Sensor,Surface Plasmons resonance,Finite Elemental Analysis (FEA),Sensitivity
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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The generation and validation of a CUF-based FEA model with laser-based experiments
摘要： Architectural structures today are increasingly complex and structural health monitoring plays an important role in guaranteeing their safety. How to improve the reliability of deformation analysis is, thus, one of the key problems. This article combines laser-based measurement technology and the Carrera unified formulation (CUF) method to investigate the deformation of engineering structures. Within this article, we simulate architectural structures using the CUF geometric model, which is consistent with the results of the laser tracker experiment. We aimed at constructing an intelligent and efficient CUF model which can be applied extensively in the monitoring of various constructs, such as tunnels and bridges. The innovation of this article is that high-accuracy laser tracker technology is integrated with an effective CUF model to investigate the load-displacement relationship considering lateral displacement.
关键词： multi-sensor,laser tracker,SHM,FEA,terrestrial laser scanning
更新于2025-09-12 10:27:22
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[Laser Institute of America ICALEO? 2015: 34th International Congress on Laser Materials Processing, Laser Microprocessing and Nanomanufacturing - Atlanta, Georgia, USA (October 18–22, 2015)] International Congress on Applications of Lasers & Electro-Optics - Prediction of weld bead for fiber laser keyhole welding based on FEA
摘要： Fiber laser keyhole welding as a popular metal joining process has been widely used in a variety of applications especially automotive, shipbuilding and aerospace industries. Although process parameters determination based on experiments is the frequently used in the practical welding, it is often a very costly and time consuming. Accurately predicting the weld bead without expensive trial experiments has great theoretical significance and engineering value for welding process parameters pre-selection. An innovative volume heat source model was proposed for weld bead geometry prediction through finite element analysis (FEA) in fiber laser keyhole welding. The hybrid heat source model consists of a double ellipsoid heat source and a 3D Gaussian heat distribution model. To validate the effectiveness of the proposed heat source model, the fiber laser keyhole welding of the stainless steel SUS301L-HT has been carried out in this paper. The main three parameters, laser power (LP), welding speed (WS) and focal position (FP) have been taken into consideration as the design variables. Both of the predicted values from the FEA and back propagation neural network (BPNN) are compared with the experimental results. The FEA predicted results achieve good agreement with experimental results of weld bead shape and dimension and are better than BPNN predicted results. The objective variation trend is also analyzed by two prediction methods. From the discussion, it is revealed that the proposed prediction method of weld bead is effective for fiber laser keyhole welding process and replacing the expensive experiments.
关键词： Weld bead prediction,Keyhole welding,Fiber laser,FEA,BPNN
更新于2025-09-12 10:27:22
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AIP Conference Proceedings [Author(s) SolarPACES 2017: International Conference on Concentrating Solar Power and Chemical Energy Systems - Santiago, Chile (26–29 September 2017)] - A multiphysics approach to an automotive headlamp low beam cut-off line
摘要： In this study, cumulative effect of warpage due to injection molding process and thermal expansion of plastic parts because of heat generated by the light functions on headlamp low beam cut-off line has been inspected by virtual methods. Firstly, deformed mesh generated by mold flow analysis for light module bracket and headlamp housing have been converted to solid computer aided design (CAD) models by the help of commercially available CAD software. Thermal finite element analysis (FEA) has been performed at ambient temperature of 22°C with the light functions all on and stabilized temperature map has been exported for use as load input for structural FEA. After structural FEA, directional displacements and angular rotations of focal point of the light module have been extracted as inputs for optical analysis. Optical analysis results have been inspected to understand the effects on low beam cut-off line of the Headlamp.
关键词： automotive headlamp,low beam cut-off line,multiphysics,thermal expansion,FEA,warpage,optical analysis
更新于2025-09-09 09:28:46
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[ASME ASME 2015 Conference on Smart Materials, Adaptive Structures and Intelligent Systems - Colorado Springs, Colorado, USA (Monday 21 September 2015)] Volume 2: Integrated System Design and Implementation; Structural Health Monitoring; Bioinspired Smart Materials and Systems; Energy Harvesting - Traveling Wave Phenomenon Through Piezoelectric Actuation of a Free-Free Cylindrical Tube
摘要： Previous work has demonstrated that piezoceramics are capable of generating net wave propagation without reflections in one‐dimensional structures. The investigation into cylindrical traveling waves provides insight into unique dynamics (i.e., symmetric and non-symmetric modes) that have yet to be fully defined for two and three dimensional systems. The work herein will focus on the generation and characterization of traveling waves that propagate along the circumferential direction. The coupled system, given by a free‐free cylinder with multiple piezoelectric actuator (PZT) patches, is used to evaluate several traveling wave modes in the cylinder. The use of structurally integrated piezoelectric patches as actuators has many advantages over the conventional shakers. Apart from the small, low weight, low cost and the size of these ceramic plates, PZTs can also generate waves over a wide frequency range. The use of multiple PZTs can be leveraged to excite the systems at a given frequency with a defined phase difference between them in order to generate highly controlled directional traveling waves in the cylindrical structure without reflections. Finite Element Modeling (FEM), in conjunction with experiments, were conducted to provide a comprehensive understanding of the generation and propagation behavior of the traveling wave modes in a thin walled cylinder.
关键词： 2D,piezoelectric,dynamics,FEA,Traveling waves,vibration
更新于2025-09-09 09:28:46