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Principal Face-based Recognition Approach for Machining Features of Aircraft Integral Panels 被引量:1
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作者 YU Fangfang ZHENG Guolei +2 位作者 RAO Youfu DU Baorui CHU Hongzhen 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2011年第6期976-982,共7页
Feature recognition aims at extracting manufacturing features with geometrical information from solid model and is considered to be an efficient way of changing the interactive NC machining programming mode.Existing r... Feature recognition aims at extracting manufacturing features with geometrical information from solid model and is considered to be an efficient way of changing the interactive NC machining programming mode.Existing recognition methods have some disadvantages in practical applications.They can essentially handle prismatic components with regular shapes and are difficult to recognize the intersecting features and curved surfaces.Besides,the robustness of them is not strong enough.A new feature recognition approach is proposed based on the analysis of aircraft integral panels' geometry and machining characteristics.In this approach,the aircraft integral panel is divided into a number of local machining domains.The machining domains are extracted and recognized first by finding the principal face of machining domain and extracting the sides around the principal face.Then the machining domains are divided into various features in terms of the face type.The main sections of the proposed method are presented including the definition,classification and structure of machining domain,the relationship between machining domain and principal face loop,the rules of machining domains recognition,and the algorithm of machining feature recognition.In addition,a robotic feature recognition module is developed for aircraft integral panels and tested with several panels.Test results show that the strategy presented is robust and valid.Features extracted can be post processed and linked to various downstream applications.The approach is able to solve the difficulties in recognizing the aircraft integral panel's features and automatic obtaining the machining zone in NC programming,and can be used to further develop the automatic programming of NC machining. 展开更多
关键词 numerical control aircraft integral panel computer aided manufacturing feature extraction
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A Novel Deep Learning Representation for Industrial Control System Data
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作者 Bowen Zhang Yanbo Shi +2 位作者 Jianming Zhao Tianyu Wang Kaidi Wang 《Intelligent Automation & Soft Computing》 SCIE 2023年第6期2703-2717,共15页
Feature extraction plays an important role in constructing artificial intel-ligence(AI)models of industrial control systems(ICSs).Three challenges in this field are learning effective representation from high-dimensio... Feature extraction plays an important role in constructing artificial intel-ligence(AI)models of industrial control systems(ICSs).Three challenges in this field are learning effective representation from high-dimensional features,data heterogeneity,and data noise due to the diversity of data dimensions,formats and noise of sensors,controllers and actuators.Hence,a novel unsupervised learn-ing autoencoder model is proposed for ICS data in this paper.Although traditional methods only capture the linear correlations of ICS features,our deep industrial representation learning model(DIRL)based on a convolutional neural network can mine high-order features,thus solving the problem of high-dimensional and heterogeneous ICS data.In addition,an unsupervised denoising autoencoder is introduced for noisy ICS data in DIRL.Training the denoising autoencoder allows the model to better mitigate the sensor noise problem.In this way,the represen-tative features learned by DIRL could help to evaluate the safety state of ICSs more effectively.We tested our model with absolute and relative accuracy experi-ments on two large-scale ICS datasets.Compared with other popular methods,DIRL showed advantages in four common indicators of AI algorithms:accuracy,precision,recall,and F1-score.This study contributes to the effective analysis of large-scale ICS data,which promotes the stable operation of ICSs. 展开更多
关键词 Industrialcontrolsystem MACHINELEARNING deeplearning autoencoder
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航空液压管路轴向挤压式接头组件连接强度的数值分析
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作者 赵天章 张铁森 +3 位作者 白雪山 张帅 韩颖杰 戴群 《塑性工程学报》 CAS CSCD 北大核心 2024年第1期142-148,共7页
针对目前航空液压管接头无法满足高工作压力要求的问题,以Φ12 mm的钛合金轴向挤压式接头为研究对象,利用Abaqus平台建立了轴向挤压连接成形与拉脱试验过程的有限元模型,通过同参数条件下的拉脱试验验证了有限元模型的准确性。结果表明... 针对目前航空液压管接头无法满足高工作压力要求的问题,以Φ12 mm的钛合金轴向挤压式接头为研究对象,利用Abaqus平台建立了轴向挤压连接成形与拉脱试验过程的有限元模型,通过同参数条件下的拉脱试验验证了有限元模型的准确性。结果表明,有限元模型计算误差仅为3.4%,接头组件连接强度是由导管与管套凹槽的轴向对抗阻力和导管与管套径向接触力共同决定的。系统研究了管套材料力学性能、凹槽结构、摩擦因数对接头组件连接强度的影响规律,管套材料屈服强度越高,连接强度越强;管套凹槽宽度每增长0.2 mm,连接强度提高约2.4%;摩擦因数每增加0.01,接头连接强度平均提升18%左右。 展开更多
关键词 轴向挤压 钛合金 导管 连接强度 有限元
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整体化“E”形复合材料框成型工艺设计
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作者 孟庆杰 张旺 +1 位作者 顾雪琳 张仁旺 《纤维复合材料》 CAS 2024年第3期39-42,共4页
随着航空先进复合材料应用愈发广泛,复合材料零件的形式逐渐增多,应用也愈发广泛,框是飞机的重要组成部分,常用作机身隔框或其他骨架零件,其直接影响着飞机的外形准确度和结构承载能力,“E”形复合材料框的巧妙设计和尝试提高了复合材... 随着航空先进复合材料应用愈发广泛,复合材料零件的形式逐渐增多,应用也愈发广泛,框是飞机的重要组成部分,常用作机身隔框或其他骨架零件,其直接影响着飞机的外形准确度和结构承载能力,“E”形复合材料框的巧妙设计和尝试提高了复合材料框的整体化水平,避免了金属框类零件难加工、疲劳性差等缺点,分析此“E”形复合材料框零件的结构特点,基于真空袋-热压罐成型方法,阐述了该类零件成型的工艺难点和关键控制点,巧妙设计成型工装方案,严格控制工艺操作流程,制造出内部质量好、外形尺寸精准、外观良好的复合材料“E”形框零件。 展开更多
关键词 复合材料 E形 真空袋-热压罐成型
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大型厚板曲面件的多点成形仿真
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作者 刘宝明 刘璐 +1 位作者 宋国秋 韩志仁 《沈阳航空航天大学学报》 2024年第1期9-17,共9页
传统的厚板曲面件制造方法存在着成本高、效率低等问题,多点成形技术为这一问题提供了解决方法。但多点成形技术又因为回弹导致工艺参数难以确定使实验操作次数增加,降低成形效率。为了提高成形效率,采用ABAQUS有限元软件模拟与实验相... 传统的厚板曲面件制造方法存在着成本高、效率低等问题,多点成形技术为这一问题提供了解决方法。但多点成形技术又因为回弹导致工艺参数难以确定使实验操作次数增加,降低成形效率。为了提高成形效率,采用ABAQUS有限元软件模拟与实验相结合的方法进行板料成形的研究与分析。首先,利用有限元软件进行三维建模并模拟板料的成形过程;然后,通过对模拟结果的分析进行模具型面的补偿修正;最后,利用修正后的模具型面进行实验操作,获得了符合要求的零件。对修正后的型面进行成形实验可以减少操作次数,提高实验的成形效率,为后续的研究提供参考。 展开更多
关键词 厚板曲面件 多点成形 ABAQUS 模拟成形 三维建模
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Adaptive PI Control Based Stability Margin Configuration of Aircraft Control Systems with Unknown System Parameters and Time Delay
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作者 ZHANG Zhibing ZHOU Dapeng +2 位作者 WANG Yeguang GAO Wanxin ZHANG Yanjun 《Journal of Systems Science & Complexity》 SCIE EI CSCD 2024年第4期1507-1525,共19页
The stability margin is a vital indicator for assessing the safety level of aircraft control systems.It should maintain sufficient stability margin to ensure safety during flight,especially in the process of large man... The stability margin is a vital indicator for assessing the safety level of aircraft control systems.It should maintain sufficient stability margin to ensure safety during flight,especially in the process of large maneuver operations.The stability margin is generally quantified by the Bode diagram,which strictly depends on the system parameters and the open-loop transfer function.However,due to the uncertain flight environments,transmission delays of sensors and mode switchings,etc.,there exist large parameter and structure uncertainties in the aircraft control systems,which make it difficult to precisely configure the stability margin to the desired value by the usual control methods.To address this problem,an indirect adaptive control strategy is proposed in this paper,where an adaptive PI control law with the capability of self-configuration of stability margin is developed.The developed control law not only achieves stable time-varying command tracking in the time domain,but also is able to automatically configure the phase margin and gain margin in the frequency domain.Finally,the simulation of the one-degree-of-freedom roll rate control model of the air vehicle verifies the validity of the proposed control method. 展开更多
关键词 Adaptive control aircraft control parameter uncertainty stability margin configuration
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Special Vehicle Target Detection and Tracking Based on Virtual Simulation Environment and YOLOv5-Block+DeepSort Algorithm
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作者 Mingyuan Zhai Hanquan Zhang +3 位作者 Le Wang Dong Xiao Zhengmin Gu Zhenni Li 《Computers, Materials & Continua》 SCIE EI 2024年第11期3241-3260,共20页
In the process of dense vehicles traveling fast,there will be mutual occlusion between vehicles,which will lead to the problem of deterioration of the tracking effect of different vehicles,so this paper proposes a res... In the process of dense vehicles traveling fast,there will be mutual occlusion between vehicles,which will lead to the problem of deterioration of the tracking effect of different vehicles,so this paper proposes a research method of virtual simulation video vehicle target tracking based on you only look once(YOLO)v5s and deep simple online and realtime tracking(DeepSort).Given that the DeepSort algorithm is currently the most effective tracking method,this paper merges the YOLOv5 algorithm with the DeepSort algorithm.Then it adds the efficient channel attention networks(ECA-Net)focusing mechanism at the back for the cross-stage partial bottleneck with 3 convolutions(C3)modules about the YOLOv5 backbone network and before the up-sampling of the Neck feature pyramid.The YOLOv5 algorithm adopts expected intersection over union(EIOU)instead of complete intersection over union(CIOU)as the loss function of the target frame regression.The improved YOLOv5 algorithm is named YOLOv5-Block.The experimental results show that in the special vehicle target detection(TD)and tracking in the virtual simulation environment,The YOLOv5-Block algorithm has an average accuracy(AP)of 99.5%,which significantly improves the target recognition correctness for typical occlusion cases,and is 1.48 times better than the baseline algorithm.After the virtual simulation video sequence test,multiple objects tracking accuracy(MOTA)and various objects tracking precision(MOTP)improved by 10.7 and 1.75 percentage points,respectively,and the number of vehicle target identity document(ID)switches decreased.Compared with recent mainstream vehicle detection and tracking models,the YOLOv5-Block+Deepsort algorithm can accurately and continuously complete the detection and tracking tasks of special vehicle targets in different scenes. 展开更多
关键词 YOLOv5 DeepSort virtual simulation attention mechanism
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高性能Pt/g-C_(3)N_(4)的制备及其光催化产氢的研究
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作者 韩忠昊 姜丰祥 +6 位作者 常峻华 谢英鹏 常越伦 陈龙飞 梁松青 温远光 王志煜 《辽宁化工》 CAS 2024年第7期977-983,共7页
采用热分解法制备了层状g-C_(3)N_(4)催化剂,并通过超声处理初步提高g-C_(3)N_(4)的光催化性能,后通过浸渍法引入Pt助剂以进一步提高其催化性能,并对样品进行XRD、低温N_(2)吸附、EDS、XPS、UV-vis和EIS等表征及光催化分解水制氢性能研... 采用热分解法制备了层状g-C_(3)N_(4)催化剂,并通过超声处理初步提高g-C_(3)N_(4)的光催化性能,后通过浸渍法引入Pt助剂以进一步提高其催化性能,并对样品进行XRD、低温N_(2)吸附、EDS、XPS、UV-vis和EIS等表征及光催化分解水制氢性能研究。结果表明:适宜的超声时间能够提高催化剂的结晶度,且催化剂的比表面积和孔体积均有所增加,这为光催化制氢反应提供了更多的活性位点。适量Pt助剂的引入拓展了g-C_(3)N_(4)的光吸收带边,降低了催化剂的禁带宽度,降低了催化剂的电阻,促进了光生载流子的产生和迁移,提高了催化剂对光的利用率,其产氢速率可提高超过600倍。 展开更多
关键词 光催化制氢 g-C_(3)N_(4)光催化剂 Pt助剂
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UAV cooperative air combat maneuver decision based on multi-agent reinforcement learning 被引量:17
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作者 ZHANG Jiandong YANG Qiming +2 位作者 SHI Guoqing LU Yi WU Yong 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2021年第6期1421-1438,共18页
In order to improve the autonomous ability of unmanned aerial vehicles(UAV)to implement air combat mission,many artificial intelligence-based autonomous air combat maneuver decision-making studies have been carried ou... In order to improve the autonomous ability of unmanned aerial vehicles(UAV)to implement air combat mission,many artificial intelligence-based autonomous air combat maneuver decision-making studies have been carried out,but these studies are often aimed at individual decision-making in 1 v1 scenarios which rarely happen in actual air combat.Based on the research of the 1 v1 autonomous air combat maneuver decision,this paper builds a multi-UAV cooperative air combat maneuver decision model based on multi-agent reinforcement learning.Firstly,a bidirectional recurrent neural network(BRNN)is used to achieve communication between UAV individuals,and the multi-UAV cooperative air combat maneuver decision model under the actor-critic architecture is established.Secondly,through combining with target allocation and air combat situation assessment,the tactical goal of the formation is merged with the reinforcement learning goal of every UAV,and a cooperative tactical maneuver policy is generated.The simulation results prove that the multi-UAV cooperative air combat maneuver decision model established in this paper can obtain the cooperative maneuver policy through reinforcement learning,the cooperative maneuver policy can guide UAVs to obtain the overall situational advantage and defeat the opponents under tactical cooperation. 展开更多
关键词 DECISION-MAKING air combat maneuver cooperative air combat reinforcement learning recurrent neural network
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Corrosion behavior of an Al-6Mg-Sc-Zr alloy 被引量:8
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作者 XU Guangxin TAO Binwu +1 位作者 LIU Jianhua LI Songmei 《Rare Metals》 SCIE EI CAS CSCD 2005年第3期246-251,共6页
The corrosion behavior of an Al-6Mg-Sc-Zr alloy was studied and compared with that of an Al-6Mg-Zr alloy. The addition of scandium into the Al-6Mg-Zr alloy reduced the susceptibility to exfoliation corrosion. By using... The corrosion behavior of an Al-6Mg-Sc-Zr alloy was studied and compared with that of an Al-6Mg-Zr alloy. The addition of scandium into the Al-6Mg-Zr alloy reduced the susceptibility to exfoliation corrosion. By using the constant load tensile method in a 3.5 wt.% NaCl solution, the resistance to SCC of the Al-6Mg-Sc-Zr alloy was higher than that of the Al-6Mg-Zr alloy. When the specimens were not applied with an anodic current, the Al-6Mg-Sc-Zr alloy was resistance to SCC and no brittle cracking was found on the fracture surface. When an anodic current was applied, the Al-6Mg-Sc-Zr alloy specimens failed as a result of accelerated corrosion rather than SCC. It was believed that the addition of scandium re- sulted in (Al3Sc, Zr) particles that greatly refined grains and promoted the formation of homogeneous discontinuous distribution of β-phase in the alloy base, which much contributed to good corrosion resistance of the Al-6Mg-Sc-Zr alloy. 展开更多
关键词 CORROSION Al-Mg-Sc-Zr alloy SCC test exfoliation corrosion SCANDIUM
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New Methodology for Evaluating Toughness of Composite Laminates-Investigation of Damage Resistance 被引量:12
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作者 杨旭 沈真 +1 位作者 燕瑛 刘兵山 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2003年第2期73-79,共7页
The existing problems in toughened resin evaluation technology, particularly the disadvantage of the toughened resin identification method by CAI, is pointed out based on the point of view of composite structure desi... The existing problems in toughened resin evaluation technology, particularly the disadvantage of the toughened resin identification method by CAI, is pointed out based on the point of view of composite structure design. It is proposed to evaluate the toughness of composites by both damage resistance and damage tolerance. Seven different toughness composites are investigated by impact and quasi\|static indentation tests. Based on experimental data analysis, the parameter that is most sensitive to the damage resistance is determined as the damage parameter. The parameter to evaluate the damage resistance and its measuring method are proposed. 展开更多
关键词 composite materials design limit damage resistance damage parameter impact dent
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Microstructure and mechanical property of additively manufactured NiTi alloys:A comparison between selective laser melting and directed energy deposition 被引量:11
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作者 ZHENG Dan LI Rui-di +4 位作者 YUAN Tie-chui XIONG Yi SONG Bo WANG Jia-xing SU Ya-dong 《Journal of Central South University》 SCIE EI CAS CSCD 2021年第4期1028-1042,共15页
NiTi shape memory alloy(SMA)with nominal composition of Ni 50.8 at%and Ti 49.2 at%was additively manufactured(AM)by selective laser melting(SLM)and laser directed energy deposition(DED)for a comparison study,with emph... NiTi shape memory alloy(SMA)with nominal composition of Ni 50.8 at%and Ti 49.2 at%was additively manufactured(AM)by selective laser melting(SLM)and laser directed energy deposition(DED)for a comparison study,with emphasis on its phase composition,microstructure,mechanical property and deformation mechanism.The results show that the yield strength and ductility obtained by SLM are 100 MPa and 8%,respectively,which are remarkably different from DED result with 700 MPa and 2%.The load path of SLM sample presents shape memory effect,corresponding to martensite phase detected by XRD;while the load path of DED presents pseudo-elasticity with austenite phase.In SLM sample,fine grain and hole provide a uniform deformation during tensile test,resulting in a better elongation.Furthermore,the nonequilibrium solidification was studied by a temperature field simulation to understand the difference of the two 3D printing methods.Both temperature gradient G and growth rate R determine the microstructure and phase in the SLM sample and DED sample,which leads to similar grain morphologies because of similar G/R.While higher G×R of SLM leads to a finer grain size in SLM sample,providing enough driving force for martensite transition and subsequently changing texture compared to DED sample. 展开更多
关键词 Ni50.8Ti49.2 shape memory alloy additive manufacturing selective laser melting laser directed energy deposition mechanical properties
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A combined airfoil with secondary feather inspired by the golden eagle and its influences on the aerodynamics 被引量:5
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作者 Di Tang Zhongyong Fan +3 位作者 Mingxia Lei Binbin Lv Li Yu Hao Cui 《Chinese Physics B》 SCIE EI CAS CSCD 2019年第3期246-255,共10页
Bird flight is a remarkable adaption that has allowed thousands of species to colonize all terrestrial habitats. A golden eagle has impressive flying abilities, such as hovering, perching, preying and attacking. To re... Bird flight is a remarkable adaption that has allowed thousands of species to colonize all terrestrial habitats. A golden eagle has impressive flying abilities, such as hovering, perching, preying and attacking. To reveal the flying abilities, avian geometry of a golden eagle was extracted based on noncontact surface measurements using a ROMBER three-dimensional laser scanner. Distributions of a camber line, thickness and a secondary feather line of the extracted point cloud were fitted using convenient analytical expressions. A traditional airfoil was established with the camber line and thickness, then a combined airfoil was constructed by combining the traditional airfoil with a secondary feather. Oscillations of an airfoil as well as rapid pitch up were simplified as a sine wave around the quarter chord axis. Thereafter, both steady and unsteady aerodynamic performances of the airfoil are computed, the influences of the secondary feather on the steady and unsteady aerodynamics were further studied. 展开更多
关键词 AERODYNAMICS large PREY SECONDARY FEATHER three-dimensional scanning
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Influence of viscous medium temperature distribution on sheet fracture in viscous pressure forming at warm temperature 被引量:2
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作者 刘建光 王忠金 +1 位作者 张鑫 李毅 《中国有色金属学会会刊:英文版》 CSCD 2007年第A01期223-227,共5页
Viscous pressure forming(VPF) of aluminum alloy AA3003 sheet metal at warm temperature was investigated by using coupled thermo-elastoplastic-viscoplastic finite element method. The influence of viscous medium tempera... Viscous pressure forming(VPF) of aluminum alloy AA3003 sheet metal at warm temperature was investigated by using coupled thermo-elastoplastic-viscoplastic finite element method. The influence of viscous medium temperature distribution on sheet fracture location was studied and the distributions of fracture factor at different temperatures were obtained by using ductile fracture criterion. The results show that the failure of sheet metal varies with increasing initial temperature of viscous medium. When the initial temperature of viscous medium is near that of sheet metal,the failure location occurs at dome center,and when the initial temperature of viscous medium is too low,however,the failure location occurs at die corner. The occurrence of fracture can be postponed and even prevented through controlling the temperature distribution in viscous medium. 展开更多
关键词 温度 分布情况 铝合金 测试方法
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Volume Diffuse Dielectric Barrier Discharge Plasma Produced by Nanosecond High Voltage Pulse in Airflow 被引量:2
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作者 齐海成 高巍 +2 位作者 樊智慧 刘一荻 任春生 《Plasma Science and Technology》 SCIE EI CAS CSCD 2016年第5期520-524,共5页
Volume diffuse dielectric barrier discharge (DBD) plasma is produced in subsonic airflow by nanosecond high-voltage pulse power supply with a plate-to-plate discharge cell at 6 mm air gap length. The discharge image... Volume diffuse dielectric barrier discharge (DBD) plasma is produced in subsonic airflow by nanosecond high-voltage pulse power supply with a plate-to-plate discharge cell at 6 mm air gap length. The discharge images, optical emission spectra (OES), the applied voltage and current waveforms of the discharge at the changed airflow rates are obtained. When airflow rate is increased, the transition of the discharge mode and the variations of discharge intensity, breakdown characteristics and the temperature of the discharge plasma are investigated. The results show that the discharge becomes more diffuse, discharge intensity is decreased accompanied by the increased breakdown voltage and time lag, and the temperature of the discharge plasma reduces when airflow of small velocity is introduced into the discharge gap. These phenomena are because that the airflow changes the spatial distribution of the heat and the space charge in the discharge gap. 展开更多
关键词 diffuse DBD OES AIRFLOW atmospheric pressure nanosecond pulse
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Corrosion evolution of high-temperature formed oxide film on pure Sn solder substrate 被引量:2
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作者 Hui ZHAO Xu SUN +2 位作者 Long HAO Jian-qiu WANG Jing-mei YANG 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2022年第12期3998-4013,共16页
The evolution of morphology, composition, thickness and corrosion resistance of the oxide film on pure Sn solder substrate submitted to high-temperature aging in 150 °C dry atmosphere was investigated. The result... The evolution of morphology, composition, thickness and corrosion resistance of the oxide film on pure Sn solder substrate submitted to high-temperature aging in 150 °C dry atmosphere was investigated. The results indicate that high-temperature aging accelerates the dehydration of Sn(OH)_(4)in the pre-existing native oxide film to form SnO_(2)and facilitates the oxidation of fresh Sn substrate, resulting in the gradual increase in oxide film thickness and surface roughness with prolonging aging time. However, the corrosion resistance of the film initially is enhanced and then deteriorated with an extending aging time. Besides, the formation and evolution mechanisms of the oxide film with aging time were discussed. 展开更多
关键词 pure Sn solder oxide film high-temperature aging corrosion resistance
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Ultra-Broadband Infrared Metamaterial Absorber for Passive Radiative Cooling 被引量:1
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作者 Yan-Ning Liu Xiao-Long Weng +6 位作者 Peng Zhang Wen-Xin Li Yu Gong Li Zhang Tian-Cheng Han Pei-Heng Zhou Long-Jiang Deng 《Chinese Physics Letters》 SCIE CAS CSCD 2021年第3期44-49,共6页
Infrared metamaterial absorber(MMA) based on metal-insulator-metal(MIM) configuration with flexible design,perfect and selective absorption,has attracted much attention recently for passive radiative cooling applicati... Infrared metamaterial absorber(MMA) based on metal-insulator-metal(MIM) configuration with flexible design,perfect and selective absorption,has attracted much attention recently for passive radiative cooling applications.To cool objects passively,broadband infrared absorption(i.e.8-14 μm) is desirable to emit thermal energy through atmosphere window.We present a novel MMA composed of multilayer MIM resonators periodically arranged on a PbTe/MgF_(2) bilayer substrate.Verified by the rigorous coup led-wave analysis method,the proposed MMA shows a relative bandwidth of about 45%(from 8.3 to 13.1 μm with the absorption intensity over 0.8).The broadband absorption performs stably over a wide incident angle range(below 50°) and predicts 12 K cooling below ambient temperature at nighttime.Compared with the previous passive radiative coolers,our design gets rid of the continuous metal substrate and provides an almost ideal transparency window(close to 100%)for millimeter waves over 1 mm.The structure is expected to have potential applications in thermal control of integrated devices,where millimeter wave signal compatibility is also required. 展开更多
关键词 MILLIMETER PASSIVE INFRARED
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CFD-Based Load Calculation Method for Monopile Support Configuration of Offshore Wind Turbine
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作者 Guo Tongqing Tong Xiaolong Lu Zhiliang 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI CSCD 2016年第1期88-94,共7页
An unsteady load calculation method for the support configuration of a monopile-supported offshore wind turbine is developed based on the Fluent software platform.Firstly,the water wave is generated by imposing the in... An unsteady load calculation method for the support configuration of a monopile-supported offshore wind turbine is developed based on the Fluent software platform.Firstly,the water wave is generated by imposing the inlet boundary conditions according to the exact potential flow solution.Then the wave evolution is simulated by solving the unsteady incompressible Navier-Stokes(N-S)equations coupled with the volume of fluid method.For the small amplitude wave with reasonable wave parameters,the numerical wave result agrees well with that of the given wave model.Finally,a monopile support configuration is introduced and a CFD-based load calculation method is established to accurately calculate the unsteady load under the combined action of wave and wind.The computed unsteady wave load on a small-size monopile support located in the small amplitude wave flow coincides with that of the Morison formula.The load calculations are also performed on a large-size monopile support and a monopile-supported offshore wind turbine under the combined action of small amplitude wave and wind. 展开更多
关键词 monopile-supported offshore wind turbine Navier-Stokes(N-S)equations volume of fluid(VOF) method small amplitude wave unsteady load
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轴压载荷下蒙皮参数对复合材料加筋壁板屈曲及后屈曲行为的影响 被引量:2
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作者 许良 边钰博 +2 位作者 宋万万 周松 邢本东 《复合材料科学与工程》 CAS 北大核心 2023年第4期100-106,共7页
飞机中有大量加筋壁板结构,利用复合材料取代传统金属材料制造加筋壁板结构可减轻重量,提升性能。为研究轴压载荷下不同蒙皮参数对复合材料加筋壁板结构的屈曲与后屈曲行为的影响,通过ABAQUS建立了有限元模型。首先采用特征值法进行屈... 飞机中有大量加筋壁板结构,利用复合材料取代传统金属材料制造加筋壁板结构可减轻重量,提升性能。为研究轴压载荷下不同蒙皮参数对复合材料加筋壁板结构的屈曲与后屈曲行为的影响,通过ABAQUS建立了有限元模型。首先采用特征值法进行屈曲分析,然后采用ABAQUS中动力显式(dynamic explicit)建立模型模拟,最后进行轴压试验验证。结果表明:有限元仿真值与试验值相差不大,即该模型求解方法可以准确预测其后屈曲载荷;蒙皮参数的不同使得加筋壁板结构的屈曲模态发生改变,并且对后屈曲行为有明显影响,显著改变了加强筋结构的承载能力。研究结果对优化复合材料加筋壁板的承载能力与提高飞机结构设计效率具有重大意义。 展开更多
关键词 复合材料加筋壁板 有限元 准静态分析 屈曲 后屈曲
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Design of high-performance and sustainable Co-free Ni-rich cathodes for next-generation lithium-ion batteries 被引量:1
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作者 Hao Ge Zhiwen Shen +8 位作者 Yanhong Wang Zhijia Sun Xiaoman Cao Chaoyue Wang Xinyue Fan Jinsong Bai Rundong Li Tianhua Yang Gang Wu 《SusMat》 SCIE EI 2024年第1期48-71,共24页
Great attention has been given to high-performance and inexpensive lithiumion batteries(LIBs)in response to the ever-increasing demand for the explosive growth of electric vehicles(EVs).High-performance and low-cost C... Great attention has been given to high-performance and inexpensive lithiumion batteries(LIBs)in response to the ever-increasing demand for the explosive growth of electric vehicles(EVs).High-performance and low-cost Co-freeNi-rich layered cathodes are considered one of the most favorable candidates for nextgeneration LIBs because the current supply chain of EVs relies heavily on scarce and expensive Co.Herein,we review the recent research progress on Co-free Nirich layered cathodes,emphasizing on analyzing the necessity of replacing Co and the popular improvment methods.The current advancements in the design strategies of Co-free Ni-rich layered cathodes are summarized in detail.Despite considerable improvements achieved so far,the main technical challenges contributing to the deterioration of Co-free Ni-rich cathodes such as detrimental phase transitions,crack formation,and severe interfacial side reactions,are difficult to resolve by a single technique.The cooperation of multiple modification strategies is expected to accelerate the industrialization of Co-free Ni-rich layered cathodes,and the corresponding synergistic mechanisms urgently need to be studied.More effects will be aroused to explore high-performance Co-free Ni-rich layered cathodes to promote the sustainable development of LIBs. 展开更多
关键词 Co-free cathodes electrochemical performance lithium-ion batteries modification strategies Ni-rich layered cathodes
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