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Investigation of stress distribution and damage behavior caused by forced installation of a composite bolted joint with a hole-location error

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Chinese Journal of Aeronautics 2024年第1期37卷 201-217页

作者： Chinan LIU Yuan LI Yi cheng An’an ZHAO Kunpeng DU Yue SHI Ximing LI Hui cheng School of Mechanical Engineering Northwestern Polytechnical UniversityXi’an 710072China AVIC Xi’an Aircraft Industry Group Company LTD Xi’an 710089China

In this paper,the influence of forced installation caused by a hole-location error on the 3D stress distribution and damage of a composite bolted joint is *** analytical model of stress distributed on composite holes is promoted,in view of non-uniform extrusion caused by forced *** first,non-uniform extrusion of the hole edge caused by forced installation is *** to the contact state,expression of hole deformation is ***,based on Hertz theory,the maximum extrusion load is obtained with help of deformation *** constructing an elastic foundation beam model,3D stress distributed on a hole could be analyzed according to the extrusion ***,stress distribution predicted by the above analytical method is compared with that provided by FE considering composite ***,a forced installation experiment is carried out to analyze the damage distribution of the *** show that a central-symmetrically distributed stress is introduced by the hole-location *** an increment of the error,strength of composite decreases due to extrusion ***,stress presents a concave distribution on the *** the hole-location error exceeding 3%,stress decreases gradually due to failure of *** of holes does not exhibit a centrosymmetric *** damage is mainly distributed on the entrance of the hole at the lower sheet.

关键词： Hole-location error Composite joint Forced installation Stress distribution Damage

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关于高校思政课实践教学的思考

中国教育技术装备 2011年第27期 89-90页

作者：程春艳潍坊科技学院

近年来,我国高校在加强和改进思想政治理论课教学方面投入大量的人力、财力和物力,做了大量的工作,但效果并不是很明显。究其原因,主要是高校思政课实践教学的缺失。主要从实践理念、教学方法手段的改革及办学模式方面进行阐述。

关键词：高校思政课实践教学

渐进性肌肉放松训练对缓解脑梗死病人焦虑状态的研究

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护理实践与研究 2005年第6期2卷 5-6页

作者：程春燕山东省菏泽市立医院

目的:探讨渐进性肌肉放松训练对缓解脑梗死病人焦虑状态的可行性。方法:选择96例脑梗死病人,随机分为治疗组和对照组,每组各48例。对照组给予常规护理,治疗组在常规护理基础上,进行渐进性肌肉放松训练。治疗前后,两组分别行焦虑评分。结... 详细信息

目的:探讨渐进性肌肉放松训练对缓解脑梗死病人焦虑状态的可行性。方法:选择96例脑梗死病人,随机分为治疗组和对照组,每组各48例。对照组给予常规护理,治疗组在常规护理基础上,进行渐进性肌肉放松训练。治疗前后,两组分别行焦虑评分。结果:焦虑水平比较,治疗前两组无统计学差异(P>0.05);治疗后,治疗组明显低于对照组(P<0.05)。结论:渐进性肌肉放松训练可以缓解脑梗死后焦虑水平,有利于神经功能康复。

关键词：渐进性肌肉放松训练脑梗死焦虑

The higher-order topological pumping explored in the 2D acoustic crystal

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Science China(Physics,Mechanics & Astronomy) 2024年第2期67卷 127-133页

作者： Yanqiu Wang Bin Liang Jianchun cheng Key Laboratory of Modern Acoustics Ministry of EducationInstitute of AcousticsDepartment of PhysicsNanjing UniversityNanjing 210093China Collaborative Innovation Center of Advanced Microstructures Nanjing UniversityNanjing 210093China

The topological pumping has been instrumental in advancing our understanding of topological phase transitions in various physical systems,which can be extended to uncover intriguing higher-order topological phases in the lower-dimensional ***,we propose a theoretical exploration of topological dipole pumping on an acoustic square superlattice by cyclically modulating intracell couplings,which shares the topological nature of an extended three-dimensional system with chiral hinge *** the multipole chiral numbers,we characterize the higher-order topological phases that arise during the *** evolution of topological phase transitions is verified by numerical simulations and shows corner states are transferred across the *** findings can inspire the construction of chiral hinge states in artificial crystals,opening up new possibilities for the design of devices allowing the unidirectional propagation of sound.

关键词： topological phases of matter Thouless pumping acoustic metamaterial

Factors Influencing Fracture Propagation in Collaborative Fracturing ofMultiple HorizontalWells

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Energy Engineering 2024年第2期121卷 425-437页

作者： Diguang Gong Junbin Chen cheng cheng Yuanyuan Kou Shanxi Key Laboratory of Well Stability and Fluid&RockMechanics inOil andGas Reservoirs Xi’an Shiyou UniversityXi’an710065China The Second Oil Production Plant Petro China Changqing Oilfield CompanyQingyang745100China

Horizontal well-stimulation is the key to unconventional resource exploration and *** development mode of the well plant helps increase the stimulated reservoir ***,fracture interference between wells reduces the fracturing ***,a 2D hydro-mechanical coupling model describing hydraulic fracture(HF)propagation is established with the extended finite element method,and the effects of several factors on HF propagation during multiple wells fracturing are *** results show that with an increase in elastic modulus,horizontal principal stress difference and injection fluid displacement,the total fracture area and the reservoir stimulation efficiency are both improved in all three fracturing *** a comparison of the three technologies,the method of improved zipper fracturing is proposed,which avoids mutual interference between HFs,and the reservoir stimulation effect is improved *** study provides guidance for optimizing the fracturing technology of multiple horizontal wells.

关键词： Multi-well fracturing inter-fracture interference hydraulic fracturing hydro-mechanical coupling extended finite element horizontal well

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急性脑出血的早期综合康复效果分析

基层医学论坛 2010年第33期14卷 976-977页

作者：程春燕揭阳市人民医院广东揭阳522000

目的探讨早期综合康复护理措施对急性脑出血患者的康复效果。方法将76例脑出血患者分成2组,在综合治疗的基础上,研究组40例患者在发病早期给予肢体康复锻炼、语言训练、吞咽功能锻炼等综合康复护理措施;对照组36例患者仅给予综合治疗。... 详细信息

目的探讨早期综合康复护理措施对急性脑出血患者的康复效果。方法将76例脑出血患者分成2组,在综合治疗的基础上,研究组40例患者在发病早期给予肢体康复锻炼、语言训练、吞咽功能锻炼等综合康复护理措施;对照组36例患者仅给予综合治疗。对比2组的康复效果。结果研究组治疗总有效率达89%,其中出院时能恢复独立生活的占33%,生活还需要他人协助的占56%.对照组总有效率达64%,其中出院时能恢复独立生活的占21%,生活还需要他人协助的占43%.2组总有效率比较,研究组明显高于对照组,差异有统计学意义。结论实施早期综合康复护理措施有利于脑出血患者的尽早康复。

关键词：脑出血综合康复护理早期疗效

Performance of double-arch tunnels under internal BLEVE

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Underground Space 2024年第6期19卷 6-25页

作者： Ruishan cheng Wensu Chen Hong Hao Center for Infrastructural Monitoring and Protection School of Civil and Mechanical EngineeringCurtin UniversityPerth 6000Australia Earthquake Engineering Research&Test Center Guangzhou UniversityGuangzhou 510000China

Double-arch tunnels,as one of the popular forms of tunnels,might be exposed to boiling liquid expanding vapour explosions(BLEVEs)associated with transported liquified petroleum gas(LPG),which could cause damage to the tunnel and even catastrophic collapse of the tunnel in extreme ***,very limited study has investigated the performance of double-arch tunnels when exposed to internal BLEVEs and in most analyses of tunnel responses to accidental *** TNT-equivalence method was used to approximate the explosion load,which may lead to inaccurate tunnel response *** study numerically investigates the response of typical double-arch tunnels to an internal BLEVE resulting from the instantaneous rupture of a 20 m^(3) LPG *** of various factors,including in-situ stresses,BLEVE locations,and lining configurations on tunnel responses are *** results show that the double-arch tunnels at their early-operation ages are more vulnerable to severe damage when exposed to the BLEVE due to the low action of in-situ stress of rock mass on the response of early-age *** is also found that directing the LPG tank to different driving lanes inside tunnels can affect the BLEVE-induced tunnel response more significantly than varying the configurations of tunnel ***,installing section-steel arches in the mid-wall can effectively improve the blast resistance of the double-arch tunnels against the internal *** addition,the prediction models based on multi-variate nonlinear regressions and machine learning methods are developed to predict the BLEVE-induced damage levels of the double-arch tunnels without and with section-steel arches.

关键词： Double-arch tunnel BLEVE Lining configuration Section-steel arch Damage prediction

Market Equilibrium Based on Cloud-edge Collaboration

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CSEE Journal of Power and Energy Systems 2024年第1期10卷 96-104页

作者： Tong cheng Haiwang Zhong Qing Xia the State Key Laboratory of Power Systems the Department of Electrical EngineeringTsinghua UniversityBeijing 100084China

Market participants can only bid with lagged information disclosure under the existing market mechanism,which can lead to information asymmetry and irrational market behavior,thus influencing market *** promote rational bidding behavior of market participants and improve market efficiency,a novel electricity market mechanism based on cloudedge collaboration is proposed in this *** market information,called residual demand curve,is published to market participants in real-time on the cloud side,while participants on the edge side are allowed to adjust their bids according to the information disclosure prior to closure *** proposed mechanism can encourage rational bids in an incentive-compatible way through the process of dynamic equilibrium while protecting participants’*** paper further formulates the mathematical model of market equilibrium to simulate the process of each market participant’s strategic bidding behavior towards equilibrium.A case study based on the IEEE 30-bus system shows the proposed market mechanism can effectively guide bidding behavior of market participants,while condensing exchanged information and protecting privacy of participants.

关键词： Cloud-edge collaboration market mechanism residual demand curve strategic bidding

Machine learning and numerical investigation on drag coefficient of arbitrary polygonal particles

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International Journal of Mechanical System Dynamics 2024年第3期4卷 317-330页

作者： Haonan Xiang cheng cheng Pei Zhang Genghui Jiang School of Energy and Power Engineering Nanjing University of Science and TechnologyNanjingChina School of Engineering Westlake UniversityHangzhouChina

The drag coefficient,as the most important parameter that characterizes particle dynamics in flows,has been the focus of a large number of *** good predictability is achieved for simple shapes,it is still challenging to accurately predict drag coefficient of complex-shaped particles even under moderate Reynolds number(Re).The problem is that the small-scale shape details of particles can still have considerable impact on the drag coefficient,but these geometrical details cannot be described by single shape *** address this challenge,we leverage modern deep-learning method's ability for pattern recognition,take multiple shape factors as input to better characterize particle-shape details,and use the drag coefficient as *** obtain a high-precision data set,the discrete element method coupled with an improved velocity interpolation scheme of the lattice Boltzmann method is used to simulate and analyze the sedimentation dynamics of polygonal *** different machine-learning models for predicting the drag coefficient are developed and *** results show that our model can well predict the drag coefficient with an average error of less than 5%for *** findings suggest that data-driven models can be an attractive option for the drag-coefficient prediction for particles with complex shapes.

关键词： drag coefficient arbitrary polygonal particle shape factor DEM–LBM machine Learning