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Optimization of Fixture Number in Large Thin-Walled Parts Assembly Based on IPSO

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Chinese Journal of Mechanical Engineering 2024年第2期37卷 213-227页

作者： Changhui liu Jing Wang Ying Zheng Ke Jin Jianbo Yu jianfeng liu School of Mechanical Engineering Tongji UniversityShanghai 201804China Shanghai Jiaotong University Shanghai 200240China Shanghai Waigaoqiao Shipbuilding Co. Ltd.Shanghai 200137China

There are lots of researches on fixture layout optimization for large thin-walled *** researches focus on the positioning problem,i.e.,optimizing the positions of a constant number of ***,how to determine the number of fixtures is *** most cases,the number of fixtures located on large thin-walled parts is determined based on engineering experience,which leads to huge fixture number and extra ***,this paper constructs an optimization model to minimize the number of *** constraints are set in the optimization model to ensure that the part deformation is within the surface profile *** addition,the assembly gap between two parts is also *** conduct the optimization,this paper develops an improved particle swarm optimization(IPSO)algorithm by integrating the shrinkage factor and adaptive inertia *** the algorithm,particles are encoded according to the fixture *** dimension of the particle is assigned to a sub-region by constraining the optional position range of each fixture to improve the optimization ***,a case study on ship curved panel assembly is provided to prove that our method can optimize the number of fixtures while meeting the assembly quality *** research proposes a method to optimize the number of fixtures,which can reduce the number of fixtures and achieve deformation control at the same time.

关键词： Assembly quality Large thin-walled parts Fixture layout PSO FEM

Development of Fixture Layout Optimization for Thin-Walled Parts:A Review

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Chinese Journal of Mechanical Engineering 2024年第1期37卷 15-39页

作者： Changhui liu Jing Wang Binghai Zhou Jianbo Yu Ying Zheng jianfeng liu School of Mechanical Engineering Tongji UniversityShanghai 201804China Shanghai Jiaotong University Shanghai 200240China Shanghai Waigaoqiao Shipbuilding Co. Ltd.Shanghai 200137China

An increasing number of researchers have researched fixture layout optimization for thin-walled part assembly during the past ***,few papers systematically review these *** analyzing existing literature,this paper summarizes the process of fixture layout optimization and the methods *** process of optimization is made up of optimization objective setting,assembly variation/deformation modeling,and fixture layout *** paper makes a review of the fixture layout for thin-walled parts according to these three ***,two different kinds of optimization objectives are *** usually consider in-plane variations or out-of-plane deformations when designing ***,modeling methods for assembly variation and deformation are divided into two categories:Mechanism-based and data-based *** common methods are discussed *** that,optimization algorithms are reviewed *** are two kinds of optimization algorithms:Traditional nonlinear programming and heuristic ***,discussions on the current situation are *** research direction of fixture layout optimization in the future is discussed from three aspects:Objective setting,improving modeling accuracy and optimization ***,a new research point for fixture layout optimization is *** paper systematically reviews the research on fixture layout optimization for thin-walled parts,and provides a reference for future research in this field.

关键词： Thin-walled parts Assembly quality Fixture layout optimization Modeling methods Optimization algorithms

Creep constitutive model considering nonlinear creep degradation of fractured rock

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International Journal of Mining Science and Technology 2024年第1期34卷 105-116页

作者： Wang Chunping liu jianfeng Chen Liang liu Jian Wang Lu Liao Yilin Beijing Research Institute of Uranium Geology Beijing 100029China CAEA Innovation Center for Geological Disposal of High-Level Radioactive Waste Beijing 100029China State Key Laboratory of Hydraulics and Mountain River Engineering Sichuan UniversityChengdu 610065China School of Architecture and Civil Engineering Xihua UniversityChengdu 610039China

Stability analysis of underground constructions requires a model study of rock masses’ long-term performance. Creep tests under different stress conditions was conducted on intact granite and granite samples fractured at 30° and 45° angles. The experimental results indicate that the steady creep strain rates of intact and fractured rock present an exponential increase trend with the increase of stress level. A nonlinear creep model is developed based on the experimental results, in which the initial damage caused by fracture together with the damage caused by constant load have been taken into consideration. The fitting analysis results indicated that the model proposed is more accurate at identifying the full creep regions in fractured granite, especially the accelerated stage of creep deformation. The least-square fit error of the proposed creep model is significantly lower than that of Nishihara model by almost an order of magnitude. An analysis of the effects of elastic modulus, viscosity coefficient, and damage factors on fractured rock strain rate and creep strain is conducted. If no consideration is given to the effects of the damage, the proposed nonlinear creep model can degenerate into to the classical Nishihara model.

关键词： Fractured rock Damage Creep Beishan granite Geological disposal

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Multiscale modeling of gas-induced fracturing in anisotropic clayey rocks

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第6期16卷 2091-2110页

作者： Jianxiong Yang jianfeng liu Zhengyuan Qin Xuhai Tang Houquan Zhang State Key Laboratory of Hydraulics and Mountain River Engineering College of Water Resource and HydropowerSichuan UniversityChengdu610042China School of Resources and Safety Engineering Wuhan Institute of TechnologyWuhan430073China School of Civil Engineering Wuhan UniversityWuhan430072China State Key Laboratory of Intelligent Construction and Healthy Operation and Maintenance of Deep Underground Engineering China University of Mining and TechnologyXuzhou221116China

In the context of repositories for nuclear waste,understanding the behavior of gas migration through clayey rocks with inherent anisotropy is crucial for assessing the safety of geological disposal *** primary mechanism for gas breakthrough is the opening of micro-fractures due to high gas *** occurs at gas pressures lower than the combined strength of the rock and its minimum principal stress under external loading *** investigate the mechanism of microscale mode-I ruptures,it is essential to incorporate a multiscale approach that includes subcritical microcracks in the modeling *** this contribution,we derive the model from microstructures that contain periodically distributed microcracks within a porous *** damage evolution law is coupled with the macroscopic poroelastic system by employing the asymptotic homogenization method and considering the inherent hydro-mechanical(HM)anisotropy at the *** resulting permeability change induced by fracture opening is implicitly integrated into the gas flow *** examples are presented to validate the developed model step by *** analysis of local macroscopic response is undertaken to underscore the influence of factors such as strain rate,initial damage,and applied stress,on the gas migration *** examples of direct tension tests are used to demonstrate the model’s efficacy in describing localized failure ***,the simulation results for preferential gas flow reveal the robustness of the two-scale model in explicitly depicting gas-induced fracturing in anisotropic clayey *** model successfully captures the common behaviors observed in laboratory experiments,such as a sudden drop in gas injection pressure,rapid build-up of downstream gas pressure,and steady-state gas flow following gas breakthrough.

关键词： Deep geological repositories Mode-I microcracks Time-dependent damage Fracturing process Anisotropic rock

Generation and characterization of nanobodies targeting GPCR

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Biophysics Reports 2024年第1期10卷 22-30页

作者： Shenglan Zhang Zhiran Fan jianfeng liu Bioland Laboratory (Guangzhou Regenerative Medicine and Health Guangdong Laboratory) Cellular Signaling laboratory International Research Center for Sensory Biology and Technology of MOST Key Laboratory of Molecular Biophysics of MOE College of Life Science and Technology Huazhong University of Science and Technology

G protein-coupled receptors(GPCRs) are a large family of cell membrane proteins that are important targets for drug discovery. Nanobodies, also known as VHH(variable domains of heavy chain-only antibodies, HcAbs) antibodies, are small antibody fragments derived from camelids that have gained significant attention as potential therapeutics for targeting GPCRs due to their advantages over conventional antibodies. However, there are challenges in developing nanobodies targeting GPCRs, among which epitope accessibility is the most significant because the cell membrane partially shields the GPCR surface. We developed a universal protocol for making nanobodies targeting GPCRs using the cell membrane extract of GPCR-overexpressing HEK293 cells as the llama/alpaca immunization antigen. We constructed an immune VHH library and identified nanobodies by phage display bio-panning. The monoclonal nanobodies were recombinantly expressed in Escherichia coli(E. coli) and purified to characterize their binding potency.

关键词： Nanobody Single domain antibody Heavy chain-only antibody GPCR G protein-coupled receptor

A flexible multiscale algorithm based on an improved smoothed particle hydrodynamics method for complex viscoelastic flows

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Applied Mathematics and Mechanics(English Edition) 2024年第8期45卷 1387-1402页

作者： Jinlian REN Peirong LU Tao JIANG jianfeng liu Weigang LU College of Mathematical Science Yangzhou University College of Hydraulic Science and Engineering Yangzhou University

Viscoelastic flows play an important role in numerous engineering fields,and the multiscale algorithms for simulating viscoelastic flows have received significant attention in order to deepen our understanding of the nonlinear dynamic behaviors of viscoelastic fluids. However, traditional grid-based multiscale methods are confined to simple viscoelastic flows with short relaxation time, and there is a lack of uniform multiscale scheme available for coupling different solvers in the simulations of viscoelastic fluids. In this paper, a universal multiscale method coupling an improved smoothed particle hydrodynamics(SPH) and multiscale universal interface(MUI) library is presented for viscoelastic flows. The proposed multiscale method builds on an improved SPH method and leverages the MUI library to facilitate the exchange of information among different solvers in the overlapping domain. We test the capability and flexibility of the presented multiscale method to deal with complex viscoelastic flows by solving different multiscale problems of viscoelastic flows. In the first example, the simulation of a viscoelastic Poiseuille flow is carried out by two coupled improved SPH methods with different spatial resolutions. The effects of exchanging different physical quantities on the numerical results in both the upper and lower domains are also investigated as well as the absolute errors in the overlapping domain. In the second example, the complex Wannier flow with different Weissenberg numbers is further simulated by two improved SPH methods and coupling the improved SPH method and the dissipative particle dynamics(DPD) method. The numerical results show that the physical quantities for viscoelastic flows obtained by the presented multiscale method are in consistence with those obtained by a single solver in the overlapping domain. Moreover, transferring different physical quantities has an important effect on the numerical results.

关键词： 35Q30 76A10 76M28 complex viscoelastic flow dissipative particle dynamics (DPD) improved smoothed particle hydrodynamics (SPH) multiscale method multiscale universal interface (MUI) O373

A mite parasitoid,Pyemotes zhonghuajia,negatively impacts the fitness traits and immune response of the fall armyworm,Spodoptera frugiperda

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Journal of Integrative Agriculture 2024年第1期23卷 205-216页

作者： Yanfei Song Tai’an Tian Yichai Chen Keshi Zhang Maofa Yang jianfeng liu Institute of Entomology Guizhou Provincial Key Laboratory for Agricultural Pest Management of the Mountainous RegionGuizhou University/Scientific Observing and Experiment Station of Crop Pests in GuiyangMinistry of Agriculture and Rural AffairsGuiyang 550025China Administration of Guizhou Fanjingshan National Nature Reserve Jiangkou 554400China Centre for Biodiversity and Biosecurity School of Biological SciencesThe University of AucklandAuckland 1072New Zealand College of Tobacco Science Guizhou UniversityGuiyang 550025China

Parasitoids are key regulators in ecological communities and widely used as agents in biocontrol *** fall armyworm,Spodoptera frugiperda,recently invaded multiple continents and caused substantial economic losses in *** zhonghuajia,a newly identified mite parasitoid,has shown potential for controlling various agricultural insect ***,this study tested the performance of *** in parasitising *** also investigated the sublethal effects of parasitism by *** on host fitness traits,transgenerational impacts,and cellular and humoral *** result showed that the fifth-instar larvae of *** parasitised by 40 *** were all dead(i.e.,a lethal effect),while parasitism by 5 or 10 *** was considered sublethal since many *** survived to adulthood and produced offspring after *** sublethal influences from parasitism by *** resulted in reduced pupal weight,adult emergence rate and fecundity,but increased developmental time and *** at both lethal(40 mites)and sublethal(10 mites)levels impaired the cellular and humoral immunity of *** study presents the first empirical evidence that mite parasitoids can negatively influence host ***,it provides insights into the biocontrol potential of mite parasitoids and their interactions with hosts.

关键词： Pyemotes zhonghuajia Spodoptera frugiperda immunity parasitically-induced influence biocontrol parasitoid

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Failure transition of shear-to-dilation band of rock salt under triaxial stresses

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第1期16卷 56-64页

作者： jianfeng liu Xiaosong Qiu Jianxiong Yang Chao Liang Jingjing Dai Yu Bian State Key Laboratory of Hydraulics and Mountain River Engineering Sichuan UniversityChengdu610065China CNPC Key Laboratory of Oil and Gas Underground Storage Engineering Langfang065007China College of Water Resource and Hydropower Sichuan UniversityChengdu610065China

Great potential of underground gas/energy storage in salt caverns seems to be a promising solution to support renewable *** the underground storage method,the operating cycle unfortunately may reach up to daily or even hourly,which generates complicated pressures on the salt ***,the mechanical behavior of rock salt may change and present distinct failure characteristics under different stress states,which affects the performance of salt cavern during the time period of full *** reproduce a similar loading condition on the cavern surrounding rock mass,the cyclic triaxial loading/unloading tests are performed on the rock salt to explore the mechanical transition behavior and failure characteristics under different *** results show that the rock salt samples pre-sent a diffused shear failure band with significant bulges at certain locations in low confining pressure conditions(e.g.5 MPa,10 MPa and 15 MPa),which is closely related to crystal misorientation and grain boundary *** the elevated confinement(e.g.20 MPa,30 MPa and 40 MPa),the dilation band dominates the failure mechanism,where the large-size halite crystals are crushed to be smaller size and new pores are *** failure transition mechanism revealed in the paper provides additional insight into the mechanical performance of salt caverns influenced by complicated stress states.

关键词： Rock salt Cyclic mechanical loading Shear band Dilation band Underground gas storage(UGS)

Investigation of the block toppling evolution of a layered model slope by centrifuge test and discrete element modeling

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第1期16卷 112-122页

作者： Leilei Jin Hongkai Dong Fei Ye Yufeng Wei jianfeng liu Changkui Wang State Key Laboratory of Hydraulic and Mountain River Engineering College of Water Resource and HydropowerSichuan UniversityChengdu610065China State Key Laboratory of Geohazard Prevention and Geoenvironment Protection Chengdu University of TechnologyChengdu610059China

Primary toppling usually occurs in layered rock slopes with large anti-dip *** this paper,the block toppling evolution was explored using a large-scale centrifuge *** block column in the layered model slope was made of cement *** artificial cracks perpendicular to the block column were *** gages,displacement gages,and high-speed camera measurements were employed to monitor the deformation and failure processes of the model *** centrifuge test results show that the block toppling evolution can be divided into seven stages,*** compression,formation of major tensile crack,reverse bending of the block column,closure of major tensile crack,strong bending of the block column,formation of failure zone,and complete *** toppling is characterized by sudden large deformation and occurs in *** wedge-shaped cracks in the model incline towards the *** observations show that block toppling is mainly caused by bending failure rather than by shear *** tensile strength also plays a key factor in the evolution of block *** simulation results from discrete element method(DEM)is in line with the testing *** stress exists at the backside of rock column during toppling *** concentration results in the fragmented rock column and its degree is the most significant at the slope toe.

关键词： Block toppling Centrifuge Anti-dip slope Failure mechanism Discrete element method