检索结果-南通市图书馆

Chinese Journal of Aeronautics 2024年第2期37卷 482-500页

作者： Xiaohe WANG zengqiang cao Yuehaoxuan WANG Yingjiang GUO School of Mechanical Engineering Northwestern Polytechnical UniversityXi’an 710072China NPU Xuhang Electromagnetic Technology Co. Ltd.Xi’an 710100China

As the controlled research of Dynamic Installation(DI)and Static Installation(SI),a new interference installation method was developed based on electromagnetic loading to enhance the mechanical properties of composite *** different interference-fit sizes were considered,ranging from a net fit to 2.0%.The experiments were conducted to evaluate the installation resistance and the mechanical behavior of the joint under external ***,an FFA model to model the stress distribution and damage behavior of the bolt-hole contact interface was *** load-displacement curve and damage modes of experiments were used to verify the FEA *** results show that the installation resistance during DI process was remarkably lower than that of SI process corresponding to all interference-fit sizes,and the stress amplitudes induced by interference were larger and widely *** damage of the hole wall was positively correlated with interference fit size,but DI can significantly reduce the damage compared to *** performance tests,DI enhanced the static bearing capacity and extended longer fatigue life of the joints than *** methods can be an effective way to achieve highly reliable interference joints in composite structures.

关键词： Carbon Fiber-Reinforced Polymer(CFRP) Bolted joints Interference-fit Electromagnetic installation Finite Element Analysis(FEA) Damage mechanics Bearing behavior

Thermal transport in composition graded silicene/germanene heterostructures

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2024年第4期33卷 49-54页

作者：曹增强王超宇张宏岗游波倪宇翔 School of Physical Science and Technology Southwest Jiaotong UniversityChengdu 610031China Department of Materials Science and the Advanced Coatings Research Center of the China Educational Ministry Fudan UniversityShanghai 200433China Key Laboratory of High Performance Scientific Computation School of ScienceXihua UniversityChengdu 610039China

Through equilibrium and non-equilibrium molecular dynamics simulations,we have demonstrated the inhibitory effect of composition graded interface on thermal transport behavior in lateral ***,we investigated the influence of composition gradient length and heterogeneous particles at the silicene/germanene(SIL/GER)heterostructure interface on heat *** results indicate that composition graded interface at the interface diminishes the thermal conductivity of the heterostructure,with a further reduction observed as the length increases,while the effect of the heterogeneous particles can be considered *** unveil the influence of composition graded interface on thermal transport,we conducted phonon analysis and identified the presence of phonon localization within the interface composition graded *** these analyses,we have determined that the decrease in thermal conductivity is correlated with phonon localization within the heterostructure,where a stronger degree of phonon localization signifies poorer thermal conductivity in the *** research findings not only contribute to understanding the impact of interface gradient-induced phonon localization on thermal transport but also offer insights into the modulation of thermal conductivity in heterostructures.

关键词： composition graded interface thermal transport phonon localization molecular dynamics

Electromagnetic riveting technique and its applications

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2020年第1期33卷 5-15页

作者： zengqiang cao Yangjie ZUO School of Mechanical Engineering Northwestern Polytechnical UniversityXi’an 710072China School of Aeronautics and Astronautics Sichuan UniversityChengdu 610065China

With the increasing applications of novel materials and structures in new-generation aircraft,conventional joining techniques in aircraft component assembly are greatly *** meet those challenges,the electromagnetic riveting(EMR)technique was developed as an advanced joining tool,which exhibits obvious advantages in the assembly of new-generation *** this paper,the riveting principle of EMR was analyzed,and its development history and status were presented in ***,equipment features of three typical EMR systems were ***,three important applications of EMR were covered,i.e.,composite structure riveting,titanium rivet and large-size aluminum rivet riveting,and interference fit bolt ***,a novel strengthening method for mechanical linking holes based on EMR was also presented,which can significantly improve the fatigue behaviors of mechanical ***,open questions in the EMR field were discussed,and some recommendations for future work were also *** paper can be useful for optimizing the joint designs of aircraft components and improving the level of aircraft maintenance.

关键词： Composite Electromagnetic riveting Hole strengthening Interference fit Titanium alloys

在线全文

学校读者我要写书评

暂无评论

基于电磁加载的冲击测试方法及应用

航空制造技术 2024年第7期67卷 112-124页

作者：王晓荷曹增强郭映江郭程翔王玥浩轩西北工业大学西安710072 陕西大工旭航有限公司西安710072

针对国防军工和航空航天对材料、结构或产品进行冲击试验的广泛需求,以及现有冲击测试技术在加载速度、加载力、安全隐患及模式单一等方面存在的问题,提出了基于电磁加载的冲击测试方法,开发了电磁加载的冲击测试系统。电磁力驱动的冲... 详细信息

针对国防军工和航空航天对材料、结构或产品进行冲击试验的广泛需求,以及现有冲击测试技术在加载速度、加载力、安全隐患及模式单一等方面存在的问题,提出了基于电磁加载的冲击测试方法,开发了电磁加载的冲击测试系统。电磁力驱动的冲击测试方法可针对不同的试验对象和不同试验要求,通过调整电源控制参数(主要是电容值和充电电压值)实现加载脉宽、载荷幅值及加载速度的精确调整和控制;通过改变电磁加载头方向便可实现拉伸-压缩试验的快速转换。此外,针对结构受复杂冲击加载的动态测试需求,基于电磁驱动的多轴多向加载可通过控制程序精准控制多驱动头同时放电,从而实现多轴多向同步加载,保证了作用于试件材料上的各向冲击载荷的同步性。因此,基于电磁加载的测试技术具有可控性好、重复性高、测试精度和试验效率高等优势,基于电磁加载的冲击测试解决了传统测试方法加载速度范围小、测试应变率范围有限、大加载力冲击测试难等难题,实现了冲击测试试验安全、稳定、可靠及更加精确的控制和测量。

关键词：电磁加载动态冲击电磁霍普金森杆低速冲击应变率

Bolt insertion damage and mechanical behaviors investigation of CFRP/CFRP interference fit bolted joints

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2022年第9期35卷 354-365页

作者： Yangjie ZUO Ting YUE Ruisong JIANG zengqiang cao Liu YANG School of Aeronautics and Astronautics Sichuan UniversityChengdu 610065China Xi’an Space Engine Co.Ltd Xi'an 710100China School of Mechanical Engineering Northwestern Polytechnical UniversityXi'an 710072China Xi’an ASN Technology Group Co.Ltd Xi'an 710072China

Interference fit has advantages in improving fatigue behaviors of composite bolted joints,however, interference fit bolt insertion tends to cause damages in laminates weakening joint mechanical properties. Therefore, an experimental study was conducted to investigate bolt insertion damages of Carbon Fiber Reinforced Polymer(CFRP)/CFRP interference fit bolted *** behaviors of joints were also evaluated experimentally under both quasi-static loads and cyclic loads. Scanning Electron Microscope(SEM) and high-resolution X-ray micro-CT scan were used to examine micro damages in laminates. Damage and failure behaviors of joints were characterized. The results demonstrated that the hole entrance in upper laminate and the laminate boundary near the hole wall were the most critical regions for damages during bolt insertions. However, the influence of those damages on quasi-static failure loads and fatigue failure modes of joints was minimal. Delamination and matrix cracking occurred first in laminates following fiber and matrix fracture in quasi-static tensile tests. Interference fit could improve the fatigue resistance of the laminate hole, however, the bolt seemed to suffer a more critical local fatigue loading *** paper can contribute to composite structure designs, especially in understanding damage and failure behaviors of composite bolted joints.

关键词： Bolted joints Composite Damage Failure Fatigue life Interference fit

在线全文

学校读者我要写书评

暂无评论

喷施新型腐植酸对谷子籽粒产量和品质的影响

中国农业大学学报 2024年第6期29卷 68-76页

作者：李香宇张星星夏杜菲赵磊曹增强陈向阳陈阜文新亚中国农业大学农学院/农业农村部农作制度重点实验室北京100193 永定河流域投资有限公司北京100193 永定河流域(大同市云州区)农业发展有限公司山西大同037000

为探究灌浆初期喷施新型腐植酸对谷子产量和品质的影响,以清水喷施为对照(NC),设置腐植酸低(0.75 L/hm^(2),600×,LC),中(3.75 L/hm^(2),120×,MC),高(7.50 L/hm^(2),60×,HC)3个浓度梯度,在谷子灌浆初期喷施于叶面,测定产量、穗部性状... 详细信息

为探究灌浆初期喷施新型腐植酸对谷子产量和品质的影响,以清水喷施为对照(NC),设置腐植酸低(0.75 L/hm^(2),600×,LC),中(3.75 L/hm^(2),120×,MC),高(7.50 L/hm^(2),60×,HC)3个浓度梯度,在谷子灌浆初期喷施于叶面,测定产量、穗部性状以及籽粒蛋白质、氨基酸、脂肪、碳水化合物、直链淀粉、黄色素、总黄酮、多酚等多个指标,分析谷子产量及营养品质的变化。结果表明:1)灌浆初期叶面喷施新型腐植酸可以通过增加千粒重来增加产量,各处理的谷子产量增加幅度由高到低为HC>MC>LC>NC,MC和HC处理分别比NC增产18.5%和19.4%,谷子增产的最适新型腐植酸浓度介于60~120×。2)灌浆期喷施新型腐植酸可改善谷子籽粒品质,显著提高蛋白质、氨基酸、黄色素、多酚含量(PLC>HC>NC,中浓度(3.75 L/hm^(2),120×,MC)处理对品质提升效果最好。综上,叶面喷施新型腐植酸可以提升谷子产量,改善籽粒品质,中浓度处理综合表现最好。

关键词：生物腐植酸谷子品质产量

在线全文

学校读者我要写书评

暂无评论

电磁铆接技术在大飞机制造中的应用初探

航空学报 2008年第3期29卷 716-720页

作者：曹增强西北工业大学现代设计与集成制造技术教育部重点实验室陕西西安710072

电磁铆接是一种新型连接工艺,本文介绍了电磁铆接技术的特点及其发展。针对大飞机制造的技术需求,分析了电磁铆接技术在大飞机研制中的作用,重点介绍了电磁铆接技术在干涉配合铆接、复合材料结构铆接、干涉配合紧固件安装等方面的应用... 详细信息

电磁铆接是一种新型连接工艺,本文介绍了电磁铆接技术的特点及其发展。针对大飞机制造的技术需求,分析了电磁铆接技术在大飞机研制中的作用,重点介绍了电磁铆接技术在干涉配合铆接、复合材料结构铆接、干涉配合紧固件安装等方面的应用。实验研究表明电磁铆接形成的干涉量均匀,能够提高结构疲劳寿命,可以安装大干涉量干涉配合紧固件,对复合材料结构铆接可以减少安装损伤。分析了为满足大飞机研制的需要,中国下一阶段在电磁铆接技术方面要进行的工作。

关键词：电磁铆接飞机制造干涉配合疲劳寿命复合材料

气候变化背景下冀西北半干旱区玉米水分盈亏变化特征

在线全文

学校读者我要写书评

暂无评论

现代农业科技 2024年第7期 124-128页

作者：宋天媛雷振东张星星鲁少华曹增强永定河流域投资有限公司北京100194

为研究气候变化条件下冀西北半干旱区玉米水分盈亏情况,本文基于1991—2020年气象数据,分析玉米需水量的主要影响因素和变化特征,通过水分盈亏指数研究玉米生育期内各月份的水分供应情况。结果表明:玉米全生育期多年平均相对湿度、日照... 详细信息

为研究气候变化条件下冀西北半干旱区玉米水分盈亏情况,本文基于1991—2020年气象数据,分析玉米需水量的主要影响因素和变化特征,通过水分盈亏指数研究玉米生育期内各月份的水分供应情况。结果表明:玉米全生育期多年平均相对湿度、日照时数和平均风速呈不断降低趋势,平均温度则呈上升趋势,其中日照时数变化尤为显著。生育期内玉米需水量呈先增后减的抛物线趋势,玉米需水量与日照时数、平均温度成极显著正相关,与平均相对湿度成极显著负相关。多年降雨量呈先降后升的变化趋势,仅存在1个突变点,未出现反复振荡的变化趋势。玉米全生育期不同月份均有发生干旱的可能性,其中7—8月正值灌浆期,应及时监测玉米水分情况,防止水分亏缺造成减产。本研究结果可为冀西北半干旱区玉米科学灌溉提供参考。

关键词：气候变化玉米作物需水量气象因子冀西北半干旱区

Tool Wear of Various Materials of Drills in Drilling CFRP Composite and Its Impacts on Drilling Quality

在线全文

学校读者我要写书评

暂无评论

Transactions of Nanjing University of Aeronautics and Astronautics 2020年第S1期37卷 41-48页

作者： ZHENG Guo cao zengqiang School of Mechanical Engineering Northwestern Polytechnical UniversityXi’an 710072P.R.China

Drilling carbon fiber reinforced polymer(CFRP)composites is liable to generate serious defects including burrs,delamination,fiber pullouts and matrix cracking because of their inherent anisotropy in mechanical ***,studies on drilling quality during composites processing is necessary. The thrust force of different material drill bits in composites drilling process was measured by the dynamometer and the surface quality of the hole wall was observed by scanning electron microscope(SEM),moreover,the tool wear and its effects on the hole wall quality were also taken into account.

关键词： composites thrust force hole quality tool wear

在线全文

学校读者我要写书评

暂无评论

复合材料螺接性能的影响因素研究

航空学报 2012年第4期33卷 755-762页

作者：张岐良曹增强西北工业大学机电学院陕西西安710072

利用有限元软件ANSYS建立了单钉双剪复合材料单拉接头的1/2模型,研究了钉孔配合、螺栓预紧力和接触面间摩擦对接头的强度等性能的影响。设计了若干实验,证明有限元模型是有效的,其计算误差控制在10%以内。有限元计算结果表明:小干涉量... 详细信息

利用有限元软件ANSYS建立了单钉双剪复合材料单拉接头的1/2模型,研究了钉孔配合、螺栓预紧力和接触面间摩擦对接头的强度等性能的影响。设计了若干实验,证明有限元模型是有效的,其计算误差控制在10%以内。有限元计算结果表明:小干涉量的过盈配合能极大地提高接头的强度,与3%间隙量相比,最优干涉量下接头强度可提高36.5%;适当的螺栓拧紧力矩也可提高接头的强度;接头中被连接板间的摩擦对接头强度也是有利的,但在一定接头尺寸条件下,摩擦力的增大有可能会改变接头的破坏模式。以上研究成果为复合材料多钉连接钉载分配均匀化的参数化分析提供了一个突破口,这也是本文后续研究的一个内容。

关键词：复合材料螺栓连接有限元法干涉配合预紧力失效模式