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micro-CT和有限元分析技术在手舟骨研究中的应用进展
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作者 吕远 张德洲 +11 位作者 钱海龙 王思敏 王超群 李琨 陈杰 白雪 赵海龙 张少杰 马渊 李志军 史君 王星 《局解手术学杂志》 2025年第2期168-173,共6页
手舟骨是手部的重要骨骼之一,在临床上损伤频发且治疗具有一定难度。因此,深入研究手舟骨的微观结构和生物力学特征对了解其损伤机制和优化治疗方案至关重要。微计算机断层扫描(micro-CT)技术提供了高分辨率的骨组织成像,而有限元分析... 手舟骨是手部的重要骨骼之一,在临床上损伤频发且治疗具有一定难度。因此,深入研究手舟骨的微观结构和生物力学特征对了解其损伤机制和优化治疗方案至关重要。微计算机断层扫描(micro-CT)技术提供了高分辨率的骨组织成像,而有限元分析则能帮助模拟手舟骨在不同生理和病理状态下的应力分布和行为模式。通过micro-CT技术获取手舟骨的高分辨率三维图像,能够用于构建手舟骨真实解剖结构的有限元模型,从而实现对手舟骨力学性能的精确模拟。这两种先进技术的融合为揭示手舟骨的结构功能关系及其损伤机制提供了新视角。因此,本文回顾了手舟骨的解剖学特征及其在不同状态下的生物力学行为,并重点讨论了micro-CT和有限元分析技术在手舟骨研究中的具体应用及其优势,通过综述近几年来的研究成果,为手舟骨相关疾病的诊断、治疗及预防提供新的科学依据和方法。 展开更多
关键词 手舟骨 微观结构 生物力学 micro-CT 有限元分析 基础研究 临床研究 研究进展
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APPLICATION OF SUB-ELEMENT AND MICRO-ELEMENT IN BEM WITH ROLLER BEARING LOAD 被引量:5
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作者 ShuXuedao XingXidong 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2004年第3期423-426,共4页
Aiming at the discontinuous traction on contact elements of roller bearing,new concepts of sub- and micro-element are put forward. In the sub-element and micro-element,traction influence coefficient has been modified,... Aiming at the discontinuous traction on contact elements of roller bearing,new concepts of sub- and micro-element are put forward. In the sub-element and micro-element,traction influence coefficient has been modified, which is calculated by the former boundary elementmethod (BEM) with roller bearing load. Hence, three-dimensional distribution of load on rollerbearing is calculated accurately. In practice, it has been proved that this method has highercalculation accuracy. An effective numerical method is offered for analyzing load characteristics ofroller bearing to improve service longevity of roller bearing and operation efficiency of rollingmill. 展开更多
关键词 Sub-element micro-element BEM
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Three-dimensional Finite Element Modeling of a Maxillary Premolar Tooth Based on the Micro-CT Scanning: A Detailed Description 被引量:5
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作者 黄政 陈智 《Journal of Huazhong University of Science and Technology(Medical Sciences)》 SCIE CAS 2013年第5期775-779,共5页
This study describes the details of how to construct a three-dimensional (3D) finite element model of a maxillary first premolar tooth based on micro-CT data acquisition technique, MIMICS soft- ware and ANSYS softwa... This study describes the details of how to construct a three-dimensional (3D) finite element model of a maxillary first premolar tooth based on micro-CT data acquisition technique, MIMICS soft- ware and ANSYS software. The tooth was scanned by micro-CT, in which 1295 slices were obtained and then 648 slices were selected for modeling. The 3D surface mesh models of enamel and dentin were created by MIMICS (STL file). The solid mesh model was constructed by ANSYS. After the material properties and boundary conditions were set, a loading analysis was performed to demonstrate the ap- plicableness of the resulting model. The first and third principal stresses were then evaluated. The re- suits showed that the number of nodes and elements of the finite element model were 56 618 and 311801, respectively. The geometric form of the model was highly consistent with that of the true tooth, and the deviation between them was ~).28%. The loading analysis revealed the typical stress patterns in the contour map. The maximum compressive stress existed in the contact points and the maximum tensile stress existed in the deep fissure between the two cusps. It is concluded that by using the micro-CT and highly integrated software, construction of the 3D finite element model with high quality will not be difficult for clinical researchers. 展开更多
关键词 three-dimensional finite element micro-CT PREMOLAR MIMICS ANSYS
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Finite element analysis of the effect of micro-pore defect on linear friction welding of medium carbon steel 被引量:3
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作者 杨夏炜 李文亚 马铁军 《China Welding》 EI CAS 2014年第1期1-5,共5页
Micro-pore is a very common material defect. In the present paper, the temperature fields of medium carbon steel joints with and without micro-pore defect during linear friction welding (LFW) were investigated by us... Micro-pore is a very common material defect. In the present paper, the temperature fields of medium carbon steel joints with and without micro-pore defect during linear friction welding (LFW) were investigated by using finite element method. The effect of micro-pore defect on the axial shortening of joints during LFW was examined. The x- and y-direction displacements of micro-pore during the LFW process were also studied. In addition, the shape of micro-pore after LFW was observed. The heat conducted from the weld inteace to the specimen interior. The fluctuation range of the temperature curves for the joint with micro-pore is larger than that without micro-pore. Position of micro-pore changes with the change of the friction time. The circular shape of micro-pore becomes oval after welding. 展开更多
关键词 linear friction welding finite element method micro-pore temperature field
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Microanalysis of Multi-Element in Juncus effusus L. by LIBS Technique 被引量:3
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作者 刘晓娜 黄建梅 +5 位作者 吴志生 张乔 史新元 赵娜 贾帅芸 乔延江 《Plasma Science and Technology》 SCIE EI CAS CSCD 2015年第11期904-908,共5页
Laser-induced breakdown spectroscopy (LIBS) was used to decipher the unique multi-elemental characteristics of Juncus effusus L. The spectral fingerprints of Juncus effusus L. were established based on elemental mic... Laser-induced breakdown spectroscopy (LIBS) was used to decipher the unique multi-elemental characteristics of Juncus effusus L. The spectral fingerprints of Juncus effusus L. were established based on elemental microanalysis via LIBS. Microanalysis and multimode sampling methodologies were designed in this study. The relative standard deviation (RSD) approach was performed to optimize the multi-shot measurements. Taking advantage of the capability with no or minimal sample pre-treatment of LIBS, a thermodynamic chart of four elements (Mg, Ca, Ba, and Na) was created from twelve collection regions. The diagram of elemental distribution on a micro-scale was generated to explore the nature of Juncus effusus L. by LIBS. The results demon- strated that LIBS is a promising technique for rapid elemental microanalysis of heterogeneous samples. 展开更多
关键词 LIBS Juncus effusus L. RSD approach thermodynamic chart elemental microanalysis micro-SCALE
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Characterizing the influence of stress-induced microcracks on the laboratory strength and fracture development in brittle rocks using a finite-discrete element method-micro discrete fracture network FDEM-μDFN approach 被引量:6
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作者 Pooya Hamdi Doug Stead Davide Elmo 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2015年第6期609-625,共17页
Heterogeneity is an inherent component of rock and may be present in different forms including mineralheterogeneity, geometrical heterogeneity, weak grain boundaries and micro-defects. Microcracks areusually observed ... Heterogeneity is an inherent component of rock and may be present in different forms including mineralheterogeneity, geometrical heterogeneity, weak grain boundaries and micro-defects. Microcracks areusually observed in crystalline rocks in two forms: natural and stress-induced; the amount of stressinducedmicrocracking increases with depth and in-situ stress. Laboratory results indicate that thephysical properties of rocks such as strength, deformability, P-wave velocity and permeability areinfluenced by increase in microcrack intensity. In this study, the finite-discrete element method (FDEM)is used to model microcrack heterogeneity by introducing into a model sample sets of microcracks usingthe proposed micro discrete fracture network (mDFN) approach. The characteristics of the microcracksrequired to create mDFN models are obtained through image analyses of thin sections of Lac du Bonnetgranite adopted from published literature. A suite of two-dimensional laboratory tests including uniaxial,triaxial compression and Brazilian tests is simulated and the results are compared with laboratory data.The FDEM-mDFN models indicate that micro-heterogeneity has a profound influence on both the mechanicalbehavior and resultant fracture pattern. An increase in the microcrack intensity leads to areduction in the strength of the sample and changes the character of the rock strength envelope. Spallingand axial splitting dominate the failure mode at low confinement while shear failure is the dominantfailure mode at high confinement. Numerical results from simulated compression tests show thatmicrocracking reduces the cohesive component of strength alone, and the frictional strength componentremains unaffected. Results from simulated Brazilian tests show that the tensile strength is influenced bythe presence of microcracks, with a reduction in tensile strength as microcrack intensity increases. Theimportance of microcrack heterogeneity in reproducing a bi-linear or S-shape failure envelope and itseffects on the mechanisms leading to spalling damage near an underground opening are also discussed. 展开更多
关键词 Finite-discrete element method(FDEM) micro discrete fracture network(μDFN) Brittle fracture
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Recasting theory of elasticity with micro-finite elements
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作者 Wennan Zou 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2015年第5期679-684,共6页
In the classical theory of elasticity,a body is initially modeled as a homogeneous and dense assemblage of constituent "material particles".The kernel concept of elastic deformation is the displacement of the partic... In the classical theory of elasticity,a body is initially modeled as a homogeneous and dense assemblage of constituent "material particles".The kernel concept of elastic deformation is the displacement of the particle that associates the current configuration with the reference one.In this paper,we exploit an alternative constituent "micro-finite element",and use the stretch of the element as the essential quality to recast the theory of elasticity.It should be realized that such a treatment means that the elastic body can be modeled as a finite covering of elements and consequently characterized by a manifold.The recasting of the elasticity theory becomes more feasible for dealing with defects and topological evolution. 展开更多
关键词 micro-finite element STRETCH DISPLACEMENT Relative rotation Compatibility condition
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Transport patterns of micro nutrient elements from the continental shelf of the East China Sea to the Kuroshio area
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作者 Lu Saiying, Yao Qiao’er and Chen Zhen 《Acta Oceanologica Sinica》 SCIE CAS CSCD 1992年第2期219-230,共12页
On the basis of the in situ data of DO2, pH, SiO2. PO4-P, NO3-N and NO2-N collected in the north of the East China Sea during 1987-1988, the following points are mainly expounded.1.The inorgonic nutrients are obviousl... On the basis of the in situ data of DO2, pH, SiO2. PO4-P, NO3-N and NO2-N collected in the north of the East China Sea during 1987-1988, the following points are mainly expounded.1.The inorgonic nutrients are obviously affected by continent runoff in the north of the East China Sea. Their distributions are characteristic of its distribution of terrigenous materials.2.There are three transport paths of nutrients from the shelf to the Kuroshio area. The first is mixing-diffusing-advec-tion and upwelling process, the process of biology and biochemistry belongs to the second, and the sinking process is the last one.3.The swing of the Kuroshio axis affectes both the range of the migration of substances through mixing-diffusing-advec-tion process and the upwelling degree of the subsurface Kuroshio water to the shelf.4.Most part of the substances sink as macroparticles to the deep layer before reaching the Kuroshio area. 展开更多
关键词 Transport patterns of micro nutrient elements from the continental shelf of the East China Sea to the Kuroshio area
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Biomechanical assessment of new surgical method instead of kyphoplasty to improve the mechanical behavior of the vertebra:Micro finite element study
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作者 Seyed Aref Hosseini Faradonbeh Nima Jamshidi 《World Journal of Orthopedics》 2017年第11期829-835,共7页
AIM To reduce post treatments of kyphoplasty, as a common treatment for osteoporotic vertebrae.METHODS This study suggests a new method for treating vertebrae by setting the hexagonal porous structure instead of the r... AIM To reduce post treatments of kyphoplasty, as a common treatment for osteoporotic vertebrae.METHODS This study suggests a new method for treating vertebrae by setting the hexagonal porous structure instead of the rigid bone cement mass in the kyphoplasty(KP). The KP procedure was performed on the fresh ovine vertebra of the level L1. Micro finite element modeling was performed based on micro computed tomography of ovine trabecular cube. The hexagonal porous structure was set on one cube instead of the bone cement mass. For the implant designing, two geometrical parameters were considered: Spacing diameter and thickness.RESULTS The results of micro finite element analyses indicated the improvement in the mechanical behavior of the vertebra treated by the hexagonal porous structures, as compared to those treated by vertebroplasty(VP) and KP under static loading. The improvement in the mechanical behavior of the vertebra, was observed as 54% decrease in the amount of maximum Von Misses stress(improvement of stress distribution), in trabecular cube with embedded hexagonal structure, as compared to VP and KP. This is comparable to the results of the experimental study already performed; it was shown that the improvement of mechanical behavior of the vertebra was observed as: 83% increase in the range of displacements before getting to the ultimate strength(increasing the toughness) after setting hexagonal pearls inside vertebrae. Both the material and geometry of implant influenced the amount of Von Mises stress in the structure.CONCLUSION The new proposed method can be offered as a substitute for the KP. The implant geometry had a more obvious effect on the amount of Von Mises stress, as compared to the implant material. 展开更多
关键词 VERTEBROPLASTY KYPHOPLASTY micro finite element modeling Hexagonal porous structure Von MISES stress
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Method Investigation for Fabricating Micro-Optical Elements by Use of Half Tone Masks
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作者 Tong-Kai Zhao Qin Feng 《Journal of Electronic Science and Technology》 CAS 2010年第2期131-134,共4页
Several approaches to fabricate micro optical elements by use of half tone masks are studied and compared. It is shown that half tone masks employed in filtering image systems can obtain gray patterns with considerabl... Several approaches to fabricate micro optical elements by use of half tone masks are studied and compared. It is shown that half tone masks employed in filtering image systems can obtain gray patterns with considerably high precision, but it is hard to operate from the viewpoint of operation. The method using contacting lithography technology or laser ablation can be easily operated with the cost of reducing fabrication precision and the trouble of choosing appropriate materials. For all of these methods, the coding of half tone masks with corrections for the nonlinear characteristics of coding, imaging and photoresist is recommended. 展开更多
关键词 Index Terms --Contacting lithography half tone masks micro-optical elements optical filtering systems.
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Investigation of Micro-mechanical Response of Asphalt Mixtures by a Three-dimensional Discrete Element Model 被引量:1
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作者 侯曙光 ZHANG Dong +1 位作者 HUANG Xiaoming ZHAO Yongli 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2015年第2期338-343,共6页
The micro-mechanical response of asphalt mixtures was studied using the discrete element method. The discrete element sample of stone mastic asphalt was generated first and the vehicle load was applied to the sample. ... The micro-mechanical response of asphalt mixtures was studied using the discrete element method. The discrete element sample of stone mastic asphalt was generated first and the vehicle load was applied to the sample. A user-written program was coded with the FISH language in PFC3 D to extract the contact forces within the sample and the displacements of the particles. Then, the contact forces within the whole sample, in asphalt mastic, in coarse aggregates and between asphalt mastic and coarse aggregates were investigated. Finally, the movement of the particles in the sample was analyzed. The sample was divided into 15 areas and a figure was drawn to show how the balls move in each area according to the displacements of the balls in each area. The displacements of asphalt mastic balls and coarse aggregates were also analyzed. The experimental results explain how the asphalt mixture bears vehicle load and the potential reasons why the rutting forms from a micro-mechanical view. 展开更多
关键词 asphalt mixture discrete element method micro-mechanical response vehicle load contact force displacement
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Using Finite Element Analysis and Experimental Analysis on Vibration of a Piezoelectric Micro Pump
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作者 Bo-Wun Huang Jung-Ge Tseng +1 位作者 Chien-Hua Chang Chen-Yuan Li 《Journal of Applied Mathematics and Physics》 2015年第8期1038-1043,共6页
Due to the rise of biological and MEMS technology in recent years, some micro flow system components have drawn attention and been developed by many investigators. The importance of micro-pumps manufactured is higher ... Due to the rise of biological and MEMS technology in recent years, some micro flow system components have drawn attention and been developed by many investigators. The importance of micro-pumps manufactured is higher than the other part of micro flow system since it is the power source of the entire micro-flow system and responsible for driving working fluid in the microfluidic system. In actual operation, the instability and bad dynamic characteristics of the micro-pump will cause larger fluid flow mobility error, such as transport behavior and response procedures failure, etc., and even damage the microfluidic system. Therefore, to investigate the stability and dynamic characteristics of a micro pump is necessary. The Finite element analysis (FEA), ANSYS Workbench, is employed to analyze the dynamic characteristics of this micro pump, and experiment is also considered in this study. 展开更多
关键词 COMPONENT micro PUMP FINITE element Analysis PIEZOELECTRIC
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COUPLED THERMO-MECHANICAL ANALYSIS OF FUNCTIONALLY GRADIENT WEAK/MICRO-DISCONTINUOUS INTERFACE WITH GRADED FINITE ELEMENT METHOD 被引量:1
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作者 Zhiwen Gao Kang Yong Lee Youhe Zhou 《Acta Mechanica Solida Sinica》 SCIE EI 2012年第4期331-341,共11页
Coupled thermo-mechanical analysis of two bonded functionally graded materials subjected to thermal loads is conducted in this study with the graded finite element method. The thermal-mechanical properties of the bi-m... Coupled thermo-mechanical analysis of two bonded functionally graded materials subjected to thermal loads is conducted in this study with the graded finite element method. The thermal-mechanical properties of the bi-material interfaces are classified based on discontinuity degrees of their material properties and their derivatives at the interfaces. Numerical results indicate that discontinuity exerts remarkable effect on the temperature profile and stress value at the interface of two bonded functionally-graded materials. Under the thermal flux loading conditions, the stronger the interface discontinuity is, the smaller the heat flux is. 展开更多
关键词 functionally graded material thermo-mechanical analysis weak/micro discontin-uous graded finite element method
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Micro-PIXE analysis of trace element composition and their distribution in minerals of mantle peridotite 被引量:1
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作者 陈友红 朱节清 +4 位作者 邬显慷 谷英梅 张旗 徐平 李秀云 《Nuclear Science and Techniques》 SCIE CAS CSCD 1996年第1期28-31,共4页
Micro-PIXEanalysisoftraceelementcompositionandtheirdistributionin mineralsofmantleperidotiteChenYou-Hong(陈友红... Micro-PIXEanalysisoftraceelementcompositionandtheirdistributionin mineralsofmantleperidotiteChenYou-Hong(陈友红),ZhuJie-Qing(朱节清... 展开更多
关键词 地质学 示踪元素组成 地幔橄榄岩矿石 分布
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基于微元-分层法的受硫酸盐侵蚀隧道衬砌有效强度预测模型 被引量:1
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作者 刘新荣 庄炀 +2 位作者 周小涵 梁宁慧 陈海 《材料导报》 北大核心 2025年第13期165-173,共9页
隧道衬砌受硫酸盐侵蚀后的有效强度是评价运营隧道安全性的重要依据,但现有硫酸盐侵蚀试验为缩短试验周期而提高了侵蚀溶液中硫酸盐浓度,导致试验结果无法预测实际运营时间下受硫酸盐侵蚀隧道衬砌的有效强度。针对隧道衬砌的单面腐蚀特... 隧道衬砌受硫酸盐侵蚀后的有效强度是评价运营隧道安全性的重要依据,但现有硫酸盐侵蚀试验为缩短试验周期而提高了侵蚀溶液中硫酸盐浓度,导致试验结果无法预测实际运营时间下受硫酸盐侵蚀隧道衬砌的有效强度。针对隧道衬砌的单面腐蚀特点,本工作提出微元-分层法,并以此建立了考虑时间效应的隧道衬砌有效强度预测模型。选取重庆某受硫酸盐侵蚀隧道进行了工程案例分析,通过420 d的室内侵蚀试验和数值模拟,对有效强度预测模型的关键参数进行了求解,并与试验结果进行对比验证。进一步研究了该隧道在整体腐蚀和拱脚局部腐蚀情况下衬砌有效强度的变化规律。研究结果表明:提出的有效强度预测模型能够避免尺寸效应计算腐蚀衬砌的有效强度,其计算结果与试验结果吻合良好;在隧道衬砌有效强度损失阶段,损失速度随运营时间呈先慢后快的特点;在相同情况下,拱脚局部腐蚀时隧道衬砌的有效强度损失小于整体腐蚀。 展开更多
关键词 隧道工程 有效强度预测 微元-分层法 腐蚀衬砌 硫酸盐单面侵蚀
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Analysis and Design of Thermally Actuated Micro-Cantilevers for High Frequency Vibrations Using Finite Element Method
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作者 Mojtaba Komeili Carlo Menon 《World Journal of Mechanics》 2016年第3期94-107,共14页
Vibrational behavior of thermally actuated cantilever micro-beams and their mechanical response at moderately high frequency under a non-harmonic periodic loading is studied in this paper. Two different configurations... Vibrational behavior of thermally actuated cantilever micro-beams and their mechanical response at moderately high frequency under a non-harmonic periodic loading is studied in this paper. Two different configurations are considered: 1) a straight beam with two actuation layers on top and bottom which utilizes the bimorph effect to induce bending;2) a uniform beam with base excitation, where the beam is mounted on an actuator which moves it periodically at its base perpendicular to its axis. Generally, vibrating micro-cantilevers are required to oscillate at a specified frequency. In order to increase the efficiency of the system, and achieve deflections with low power consumption, geometrical features of the beams can be quantified so that the required vibrating frequency matches the natural frequencies of the beam. A parametric modal analysis is conducted on two configurations of micro-cantilever and the first natural frequency of the cantilevers as a function of geometrical parameters is extracted. To evaluate vibrational behavior and thermo-mechanical efficiency of micro-cantilevers as a function of their geometrical parameters and input power, a case study with a specified vibrating frequency is considered. Due to significant complexities in the loading conditions and thermo-mechanical behavior, this task can only be tackled via numerical methods. Selecting the geometrical parameters in order to induce resonance at the nominal frequency, non-linear time-history (transient) thermo-mechanical finite element analysis (using ANSYS) is run on each configuration to study its response to the periodic heating input. Approaches to improve the effectiveness of actuators in each configuration based on their implementation are investigated. 展开更多
关键词 micro-Electro-Mechanical Systems Finite element Thermal Actuations micro-CANTILEVER Dynamic Thermo-Mechanical Analysis
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空间目标光学散射特性计算方法研究
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作者 张玉双 谢晓钢 +2 位作者 苏华 张飞舟 李果 《强激光与粒子束》 北大核心 2025年第9期182-190,共9页
光学散射特性是空间目标的重要特征,在目标识别和探测系统中起着非常重要的作用。针对空间目标仿真渲染需求,以及传统目标光学散射特性方法仅给出目标光学散射截面(OCS)、散射特性或模拟目标图像等不足,对空间目标光学散射特性计算进行... 光学散射特性是空间目标的重要特征,在目标识别和探测系统中起着非常重要的作用。针对空间目标仿真渲染需求,以及传统目标光学散射特性方法仅给出目标光学散射截面(OCS)、散射特性或模拟目标图像等不足,对空间目标光学散射特性计算进行了较全面研究,给出了空间目标光学散射特性计算流程,给出了目标OCS、目标辐照度、天光背景亮度、目标星等、信噪比和探测概率等计算公式,根据太阳辐射特性、相对于站址位置、天地背景球辐射特性等,利用图形处理单元(GPU)和着色语言实现任意时刻目标光学散射特性计算(目标OCS、探测器接收到的目标反射光功率和背景光功率、目标星等、信噪比和探测概率、模拟目标亮度图像等)。通过球体和圆柱体实验验证了目标OCS计算正确性。通过光学散射特性仿真实验,给出了空间目标在不同站址、不同反射特性和不同探测窗口下目标光学散射特性计算结果,结果表明,目标光学散射特性计算结果合理。给出了全套计算公式、计算参数和计算结果,对空间目标光学散射特性计算、目标图像识别等研究提供了参考。 展开更多
关键词 光学散射特性 空间目标 微元划分 着色语言 快速计算
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基于微CT建模的小麦籽粒力学特性有限元分析 被引量:1
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作者 任广跃 张帅 +5 位作者 李琳琳 刘文超 曹伟伟 卫新雨 吴向天 段续 《农业工程学报》 北大核心 2025年第10期80-89,共10页
为探究不同粒型小麦在挤压破碎过程中的力学行为,探索粒型对小麦力学特性、应力、应变及总变形规律的影响,该研究以含水率为16%的小麦籽粒为研究对象,采用微CT(X-ray micro-computed tomography)扫描建模与有限元分析相结合的方法,精确... 为探究不同粒型小麦在挤压破碎过程中的力学行为,探索粒型对小麦力学特性、应力、应变及总变形规律的影响,该研究以含水率为16%的小麦籽粒为研究对象,采用微CT(X-ray micro-computed tomography)扫描建模与有限元分析相结合的方法,精确构建小麦籽粒的三维模型,系统分析了不同粒型小麦在挤压破碎过程中的力学特性、应力、应变及总变形分布规律。结果表明,小麦粒型与力学响应行为密切相关,较大小麦籽粒具有更高的抗压强度和弹性模量,且应力集中主要发生在籽粒腹沟区域。整体挤压分析表明,不同粒型的小麦裂纹生成规律相似;在腹式和侧式压缩下,裂纹均沿腹沟处产生,并延腹沟向内部延伸,这一结果通过微CT扫描模型的精确建模与有限元模拟得到了验证,同时将小麦颗粒受挤压时的应力应变及总变形分布情况可视化,以表征小麦颗粒在挤压过程中的力学行为。通过微CT扫描小麦压缩后的裂纹与有限元模拟后腹沟处应力集中的现象进行对比,从试验与仿真双重角度验证了腹沟区域其特有的结构特征。本研究通过微CT扫描与有限元分析的结合,揭示了小麦腹沟作为力学薄弱区域的结构特性,构建了精准的挤压模型,为优化制粉工艺参数、实现小麦精准低损加工提供了理论模型与设计依据。 展开更多
关键词 小麦籽粒 力学特性 抗压强度 微CT扫描 有限元
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疲劳裂纹萌生与短裂纹扩展仿真方法
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作者 赵秋 唐琨 +3 位作者 吴维青 李英豪 邓俊逸 陈鹏 《机械科学与技术》 北大核心 2025年第2期361-372,共12页
为建立适用于多晶金属钢疲劳裂纹萌生与短裂纹扩展的数值分析方法,基于Roe-Siegmund循环内聚力本构及Voronoi图法生成具有疲劳累计损伤特性的微观晶粒组织模型,同时考虑晶粒微观层面的力学特性,赋予各晶粒随机局部坐标系及各向异性线弹... 为建立适用于多晶金属钢疲劳裂纹萌生与短裂纹扩展的数值分析方法,基于Roe-Siegmund循环内聚力本构及Voronoi图法生成具有疲劳累计损伤特性的微观晶粒组织模型,同时考虑晶粒微观层面的力学特性,赋予各晶粒随机局部坐标系及各向异性线弹性常数,最后研究了气孔、夹杂等微观缺陷对裂纹萌生路径及寿命的影响。结果表明:上述方法在裂纹萌生路径上符合实际情况,存在穿晶及沿晶两种断裂模式并以后者为主,能够获取符合正态分布的裂纹萌生寿命范围值,并与文献试验结果相吻合;气孔及夹杂附件萌生出裂纹并与主裂纹汇合,影响裂纹萌生路径并改变裂纹萌生寿命。 展开更多
关键词 金属疲劳断裂 循环内聚力模型 微观缺陷 Voronoi图法 Cohesive单元
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基于声发射和离散元理论煤体宏细观损伤力学行为研究
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作者 张琪 李祥春 +1 位作者 刘耀儒 聂百胜 《中南大学学报(自然科学版)》 北大核心 2025年第1期173-188,共16页
研究煤体在加载过程中的宏细观尺度损伤力学行为对于从本质上探寻连续-非连续型材料的损伤破坏机理至关重要。本文基于声发射监测实验并结合PFC2D离散元软件,从本质上阐述煤体材料复杂宏观力学行为的细观损伤破坏机理。研究结果表明:当... 研究煤体在加载过程中的宏细观尺度损伤力学行为对于从本质上探寻连续-非连续型材料的损伤破坏机理至关重要。本文基于声发射监测实验并结合PFC2D离散元软件,从本质上阐述煤体材料复杂宏观力学行为的细观损伤破坏机理。研究结果表明:当煤体进入屈服阶段后,微裂隙结构彼此相互贯通并形成随意的漫射分布,声发射(AE)定位信号表现出明显的激增现象,这一现象可以作为煤体失稳破坏前的预警信息;围压的作用改变了煤体在宏观尺度下的纵向劈裂破坏模式,导致次生裂纹数量增加,并形成多个共轭剪切面,使煤体由纵向劈裂模式和剪切破裂模式向“Y”形剪切破坏模式和多剪切破坏模式转变;煤体宏观主破裂面与轴向应力方向形成的破裂夹角随围压变化呈正相关递增关系。在应力-应变全过程不同阶段中,煤体轴向应力与轴向应变对应微裂纹扩展演化的敏感性阈值指标,可为煤体宏细观损伤破坏机理研究提供借鉴。 展开更多
关键词 煤体 声发射 离散元 宏细观 损伤破坏
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