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numerical simulation on compressive buckling behavior of thin steel skins in unilateral contact with rigidconstraints

Nicholas KEAGE, Christopher MAIOLO, Rebecca PIEROTTI, Xing MA

《结构与土木工程前沿（英文）》 2011年 第5卷 第3期   页码 335-343 doi: 10.1007/s11709-011-0121-y

摘要： In this paper, a practical test and finite element analysis has been undertaken to further investigate the effects of contact buckling. A test rig was designed and constructed to record vertical and transverse deflections of compressively loaded steel skin plates. The boundary conditions were modeled as fully fixed. A finite element analysis was also undertaken using the software package Strand7. Results from both analyses have been examined and compared to data established from previous studies on contact buckling. Both the finite element analysis and practical results correlate well with this data. The result of the investigation has confirmed contact buckling theories and has foreshadowed the onset of the newly observed phenomenon of secondary contact buckling.

关键词： compressive     buckling     thin steel skins     unilateral contact     rigid constraints    

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Fundamental buckling of circular plates with elastically restrained edges and resting on concentric rigid

Lokavarapu Bhaskara Rao, Chellapilla Kameswara Rao

《机械工程前沿（英文）》 2013年 第8卷 第3期   页码 291-297 doi: 10.1007/s11465-013-0255-9

摘要：

This work presents the existence of buckling mode switching with respect to the radius of concentric rigid ring support. The buckling mode may not be axisymmetric as previously assumed. In general, the plate may buckle in an axisymmetric mode but when the radius of the ring support becomes small, the plate may buckle in an asymmetric mode. The optimum radius of the concentric rigid ring support for maximum buckling load is also determined. Introducing internal rigid ring support, when placed at an optimal position increases the elastic buckling load capacity by 149.39 percent. The numerical results obtained are in good agreement with the previously published data.

关键词： buckling     circular plate     elastically restrained edge     rigid ring support     mode switching    

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Finite element modeling of environmental effects on rigid pavement deformation

Sunghwan KIM,Halil CEYLAN,Kasthurirangan GOPALAKRISHNAN

《结构与土木工程前沿（英文）》 2014年 第8卷 第2期   页码 101-114 doi: 10.1007/s11709-014-0254-x

摘要： In this study, finite element (FE)-based primary pavement response models are employed for investigating the early-age deformation characteristics of jointed plain concrete pavements (JPCP) under environmental effects. The FE-based ISLAB (two-and-one-half-dimensional) and EverFE (three-dimensional) software were used to conduct the response analysis. Sensitivity analyses of input parameters used in ISLAB and EverFE were conducted based on field and laboratory test data collected from instrumented pavements on highway US-34 near Burlington, Iowa. Based on the combination of input parameters and equivalent temperatures established from preliminary studies, FE analyses were performed and compared with the field measurements. Comparisons between field measured and computed deformations showed that both FE programs could produce reasonably accurate estimates of actual slab deformations due to environmental effects using the equivalent temperature difference concept.

关键词： jointed plain concrete pavements (JPCP)     curling and warping     sensitivity analyses     rigid pavement analysis and design     finite element analysis (FEA)    

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Modeling of semi-rigid beam-to-column steel joints under extreme loading

C FANG, B A IZZUDDIN, A Y ELGHAZOULI, D A NETHERCOT

《结构与土木工程前沿（英文）》 2013年 第7卷 第3期   页码 245-263 doi: 10.1007/s11709-013-0215-9

摘要： Joints play an important role in providing ductility for steel-composite structures subject to extreme loading conditions, such as blast, fire and impact. Due to sound energy dissipation capability and fabrication efficiency, semi-rigid joints have increasingly received attention during the last decade. This paper presents a component approach for modeling semi-rigid beam-to-column joints based on Eurocode3, where the post-elastic response, including component strain hardening and ultimate rotational capacity, is also considered. Failure criteria are defined based on the ultimate deformation capacity of components and bolt-rows. The model enables a direct integration of joint response into global frame models with the consideration of axial deformability, such that the interaction between bending moment and axial force within the joints can be realistically captured. In addition, elevated temperature can be considered in the joint model via the degradation of the component response. Through comparisons with available test data, the joint model is shown to have good accuracy, and the failure criteria are found to be reliable yet conservative. The strain hardening response of components is shown to have significant influence on the ultimate bending capacity of the joints, while neglecting it usually leads to a conservative prediction.

关键词： semi-rigid joint     component method     ductility     elevated temperature    

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Phenolic rigid organic filler/isotactic polypropylene composites. III. Impact resistance property

Heming LIN, Dongming QI, Jian HAN, Zhiqi CAI, Minghua WU

《化学科学与工程前沿（英文）》 2009年 第3卷 第2期   页码 176-181 doi: 10.1007/s11705-009-0203-8

摘要： A novel phenolic rigid organic filler (KT) was used to modify isotactic polypropylene (iPP). The influence of KT particles on the impact resistance property of PP/KT specimens (with similar interparticles distance, 1.8 μm) was studied by notched izod impact tests. It was found that the brittle-ductile transition (BDT) of the PP/KT microcomposites took place at the filler content of about 4%, and the impact strength attains the maximum at 5% (with filler particles size of 1.5 μm), which is about 2.5 times that of unfilled iPP specimens. The impact fracture morphology was investigated by scanning electron microscopy (SEM). For the PP/KT specimens and the high-density polyethylene/KT (HDPE/KT) specimens in ductile fracture mode, many microfibers could be found on the whole impact fracture surface. It was the filler particles that induced the plastic deformation of interparticles ligament and hence improved the capability of iPP matrix on absorbing impact energy dramatically. The determinants on the BDT were further discussed on the basis of stress concentration and debonding resistance. It can be concluded that aside from the interparticle distance, the filler particles size also plays an important role in semicrystalline polymer toughening.

关键词： rigid organic filler     polypropylene     impact resistance    

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Analysis of inventory level under procurement constraints in supply chain

CHANG Guangshu

《机械工程前沿（英文）》 2007年 第2卷 第3期   页码 361-363 doi: 10.1007/s11465-007-0063-1

摘要： Because the inventory is one of the major factors that affect the performance of the supply chain system, efficient reduction of an inventory can effectively reduce the cost level of the total supply chain. Therefore, inventory management is an important means to optimize the operation of a supply chain and enhance the competitive advantage. Considering the (, ) policy in an inventory management, this paper establishes a model of the inventory level. Then, the change of the inventory level with and without the procurement constraints is analyzed, and their expectation and variance calculated. Consequently, the order point can be determined accurately to reduce the inventory level and the operation risk.

关键词： supply     efficient reduction     system     expectation     procurement    

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Structural optimization of typical rigid links in a parallel kinematic machine

Xinjun LIU, Zhidong LI, Xiang CHEN

《机械工程前沿（英文）》 2011年 第6卷 第3期   页码 344-353 doi: 10.1007/s11465-011-0227-x

摘要：

The motion dynamics and accuracy of parallel kinematic machines largely depend on the weights and rigidity of typical rigid links. Therefore, these parts should be designed in such a way that they are light but rigid. This work employs the techniques of topology and size optimization to design two typical rigid links of a parallel kinematic machine (PKM) and subsequently obtains applicable structures for them. The calculation models are established, and a new algorithm called the Guide-Weight method is introduced to solve topology optimization problems. The commercial software Ansys is used to perform size optimization.

关键词： topology optimization     size optimization     parallel kinematic machine (PKM)    

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Dispersion of a novel phenolic rigid organic filler in isotactic polypropylene matrix by solution-mixing

Dongming QI, Xiaoli ZHAO, Zhijie CHEN, Peng HUANG, Jun CAO

《化学科学与工程前沿（英文）》 2012年 第6卷 第4期   页码 395-402 doi: 10.1007/s11705-012-1269-2

摘要： A novel phenolic rigid organic filler (named KD) with a high melting point was dispersed in an isotactic polypropylene (iPP) matrix by solution-mixing and/or melt-mixing. A series of KD/iPP blends was prepared with or without addition of maleic anhydride-grafted polypropylene (MAPP) as a compatibilizer. Influences of MAPP and mixing methods on the filler dispersion were studied using polaried optical microscope (POM), scanning electron microscope (SEM) and tensile test. The filler particles are always inclined to form large irregular aggregates in the iPP matrix due to their significant differences in polarity and solubility in solvent. However, an iPP/MAPP/KD (PMK) blend containing filler particles with a quasi-spherical shape (~97.8 nm in diameter) and narrow particle size distribution (polydispersity index= 1.076) was successfully prepared by incorporating MAPP to reduce the interfacial tension and surface free energy between the dispersion phase and the continuous phase, and adopting a spray-drying method after solution-mixing to suppress the increase of the size of the dispersed phase during the removal of solvent.

关键词： dispersion     rigid organic filler     isotactic polypropylene     mixing    

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models to explore the solution space of large nonlinear systems underlying flowsheet simulations with constraints

《化学科学与工程前沿（英文）》 2022年 第16卷 第2期   页码 183-197 doi: 10.1007/s11705-021-2073-7

摘要： Flowsheet simulations of chemical processes on an industrial scale require the solution of large systems of nonlinear equations, so that solvability becomes a practical issue. Additional constraints from technical, economic, environmental, and safety considerations may further limit the feasible solution space beyond the convergence requirement. A priori, the design variable domains for which a simulation converges and fulfills the imposed constraints are usually unknown and it can become very time-consuming to distinguish feasible from infeasible design variable choices by simply running the simulation for each choice. To support the exploration of the design variable space for such scenarios, an adaptive sampling technique based on machine learning models has recently been proposed. However, that approach only considers the exploration of the convergent domain and ignores additional constraints. In this paper, we present an improvement which particularly takes the fulfillment of constraints into account. We successfully apply the proposed algorithm to a toy example in up to 20 dimensions and to an industrially relevant flowsheet simulation.

关键词： machine learning     flowsheet simulations     constraints     exploration    

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Resilience strategies for sustainable supply chains under budget constraints in the post COVID-19 era

《工程管理前沿（英文）》   页码 143-157 doi: 10.1007/s42524-022-0236-y

摘要： The COVID-19 outbreak has caused uncertainty risk surges, increased sustainable supply chain vulnerabilities, and challenges to sustainable supply chain resilience (SSCR) management. Therefore, improving SSCR is necessary to alleviate vulnerabilities, and SSCR management must generate large capital investments. However, the economic downturn brought about by the COVID-19 epidemic has made some companies have limited budgets that can be used to improve SSCR. Therefore, the design of resilience solutions needs to fully consider the constraints of budgetary costs. Most of the existing related literature only discusses optimal resilience solutions under certain cost constraints, so such resilience solutions cannot be applied to most enterprises. In this study, we set the cost constraint as a variable quantity, using resilience efficiency and customer satisfaction as indicators, to determine the changing laws of optimal resilience strategies when cost constraints change. These rules can be applied to enterprises with different budgeted costs. Our findings suggest that companies should prioritize sacrificing resilience measures (RMs) related to adaptive capacity when budget costs gradually decline, and RMs related to absorptive capacity are indispensable at all budget levels. Furthermore, the pursuit of environmental and social sustainability cannot be abandoned, no matter how limited the flexible budget may be.

关键词： sustainable supply chain     customer requirement     resilience efficiency     customer satisfaction     budget constraint    

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Study on rigid-flexible coupling dynamics of hub-plate system

ZHAO Feiyun, XIE Yongcheng, ZHANG Ming, HE Yinbiao

《能源前沿（英文）》 2007年 第1卷 第2期   页码 181-188 doi: 10.1007/s11708-007-0023-9

摘要： Dynamic modeling of a rotating flexible hub-plate system is investigated by using Jourdain s variation principle in which the finite element method (FEM) is used as discretization method for a flexible plate. Different from the previous modeling of a plate with a prescribed large overall motion, the coupling between large overall motion of the system and elastic deformation of the flexible plate is taken into account in the proposed coupling model. The quadratic terms are included in the strain-displacement expression, such that the dynamic stiffening terms are included. Simulation of a rotating hub-plate system indicates that the linear model based on linear strain-displacement assumption may lead to erroneous results in the case of high rotation speed. Conservation of energy verifies the validity of the proposed model. Furthermore, frequency analysis of a hub-plate system shows the difference between the frequencies of the system with free and prescribed large overall motion, and parameter analysis of the system reveals the coupling characteristics of the rotational motion and the deformation.

关键词： discretization     erroneous     Furthermore     Different     Conservation    

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Performance study on T-stub connected semi-rigid joint between rectangular tubular columns and H-shaped

Guochang LI, Hongping YU, Chen FANG

《结构与土木工程前沿（英文）》 2013年 第7卷 第3期   页码 296-303 doi: 10.1007/s11709-013-0217-7

摘要： This paper investigates the performance of T-stub connected semi-rigid joint of rectangular tubular columns and H-shaped steel beams. The finite element analysis software ABAQUS is used to analyze the nonlinear performance of the joint under monotonic loading. Meanwhile, the dimensions of T-stub, column and beam are considered as analytic parameters to discuss the performance of the joint. The analysis shows that the thickness and the length of T-stub webs, the height of beam section, bolt diameter, shear connector and the preloaded force affect the performance of the joint largely, and the thickness of the steel tube, the thickness and length of T-stub flange, bolt spacing have relatively little influences on the performance of the joint. The research results indicate that this joint is semi-rigid joint.

关键词： rectangular tubular columns     T-stub     semi-rigid     nonlinear finite element analysis     moment-rotation curves    

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emission reduction targets with minimum abatement costs: An enterprise-level allocation method with constraints

《环境科学与工程前沿（英文）》 2022年 第16卷 第2期 doi: 10.1007/s11783-021-1459-6

摘要：

• Quantification of efficiency and fairness of abatement allocation are optimized.

关键词： Pollutant emission reduction allocation     Emission reduction measures     Total abatement cost     Economic efficiency     Abatement space    

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Phenolic rigid organic filler/isotactic polypropylene composites. II. Tensile properties

QI Dongming, SHAO Jianzhong, WU Minghua, NITTA Kohhei

《化学科学与工程前沿（英文）》 2008年 第2卷 第4期   页码 396-401 doi: 10.1007/s11705-008-0077-1

摘要： A novel phenolic rigid organic filler (KT) was used to modify isotactic polypropylene (iPP). The influence of KT particles on the tensile properties of PP/KT microcomposites was studied by uniaxial tensile test and the morphological structures of the stretched specimens were observed by scanning electron microscopy (SEM) and polarized optical microscopy (POM). We found that the Young’s modulus of PP/KT specimens increased with filler content, while the yield and break of the specimens are related to the filler particles size. The yield stress, the breaking stress and the ultimate elongation of PP/KT specimens were close to those of unfilled iPP specimens when the maximal filler particles size is less than a critical value, which is 7 ?m at a crosshead speed of 10 mm/min and 3 ?m at 200 mm/min, close to that of glass bead but far more than those of other rigid inorganic filler particles. The interfacial interaction was further estimated from yield stress, indicating that KT particles have a moderate interfacial interaction with iPP matrix. Thus, the incorporation of small KT particles can reinforce iPP matrix and simultaneously cause few detrimental effects on the other excellent tensile properties of iPP matrix, due to their organic nature, higher specific area, solid true-spherical shape and the homogenous dispersion of the ROF particles in microcomposites.

关键词： maximal     uniaxial tensile     unfilled     excellent tensile     influence    

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Application and development of modern long-span space structures in China

Shilin DONG, Yang ZHAO, Dong XING

《结构与土木工程前沿（英文）》 2012年 第6卷 第3期   页码 224-239 doi: 10.1007/s11709-012-0166-6

摘要： Modern long-span space structures, developed during the 1970s and 1980s, are light and effective structures based on new technologies and light-weight high-strength materials, such as membranes and steel cables. These structures include air-supported membrane structures, cable-membrane structures, cable truss structures, beam string structures, suspen-domes, cable domes, composite structures of cable dome and single-layer lattice shell, Tensairity structures and so forth. For the premodern space structures widely used since the mid-twentieth century (such as thin shells, space trusses, lattice shells and ordinary cable structures), new space structures have been developed by the combination of different structural forms and materials. The application of prestressing technology and the innovation of structural concepts and configurations are also associated with modern space structures, including composite space trusses, open-web grid structures, polyhedron space frame structures, partial double-layer lattice shells, cable-stayed grid structures, tree-type structures, prestressed segmental steel structures and so forth. This paper provides a review of the structural characteristics and practical applications in China of modern rigid space structures, modern flexible space structures and modern rigid-flexible combined space structures.

关键词： modern long-span space structures     rigid space structures     flexible space structures     rigid-flexible combined space structures     application and development    

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标题 作者 时间 类型 操作

numerical simulation on compressive buckling behavior of thin steel skins in unilateral contact with rigidconstraints

Nicholas KEAGE, Christopher MAIOLO, Rebecca PIEROTTI, Xing MA

期刊论文

Fundamental buckling of circular plates with elastically restrained edges and resting on concentric rigid

Lokavarapu Bhaskara Rao, Chellapilla Kameswara Rao

期刊论文

Finite element modeling of environmental effects on rigid pavement deformation

Sunghwan KIM,Halil CEYLAN,Kasthurirangan GOPALAKRISHNAN

期刊论文

Modeling of semi-rigid beam-to-column steel joints under extreme loading

C FANG, B A IZZUDDIN, A Y ELGHAZOULI, D A NETHERCOT

期刊论文

Phenolic rigid organic filler/isotactic polypropylene composites. III. Impact resistance property

Heming LIN, Dongming QI, Jian HAN, Zhiqi CAI, Minghua WU

期刊论文

Analysis of inventory level under procurement constraints in supply chain

CHANG Guangshu

期刊论文

Structural optimization of typical rigid links in a parallel kinematic machine

Xinjun LIU, Zhidong LI, Xiang CHEN

期刊论文

Dispersion of a novel phenolic rigid organic filler in isotactic polypropylene matrix by solution-mixing

Dongming QI, Xiaoli ZHAO, Zhijie CHEN, Peng HUANG, Jun CAO

期刊论文

models to explore the solution space of large nonlinear systems underlying flowsheet simulations with constraints

期刊论文

Resilience strategies for sustainable supply chains under budget constraints in the post COVID-19 era

期刊论文

Study on rigid-flexible coupling dynamics of hub-plate system

ZHAO Feiyun, XIE Yongcheng, ZHANG Ming, HE Yinbiao

期刊论文

Performance study on T-stub connected semi-rigid joint between rectangular tubular columns and H-shaped

Guochang LI, Hongping YU, Chen FANG

期刊论文

emission reduction targets with minimum abatement costs: An enterprise-level allocation method with constraints

期刊论文

Phenolic rigid organic filler/isotactic polypropylene composites. II. Tensile properties

QI Dongming, SHAO Jianzhong, WU Minghua, NITTA Kohhei

期刊论文

Application and development of modern long-span space structures in China

Shilin DONG, Yang ZHAO, Dong XING

期刊论文