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Out-of-plane elastic buckling load and strength design of space truss arch with a rectangular section

Senping WANG; Xiaolong LIU; Bo YUAN; Minjie SHI; Yanhui WEI

《结构与土木工程前沿（英文）》 2022年 第16卷 第9期   页码 1141-1152 doi: 10.1007/s11709-022-0866-5

摘要： The out-of-plane stability of the two-hinged space truss circular arch with a rectangular section is theoretically and numerically investigated in this paper. Firstly, the flexural stiffness and torsional stiffness of space truss arches are deduced. The calculation formula of out-of-plane elastic buckling loads of the space truss arch is derived based on the classical solution of out-of-plane flexural-torsional buckling loads of the solid web arch. However, since the classical solution cannot be used for the calculation of the arch with a small rise-span ratio, the formula for out-of-plane elastic buckling loads of space truss arches subjected to end bending moments is modified. Numerical research of the out-of-plane stability of space truss arches under different load cases shows that the theoretical formula proposed in this paper has good accuracy. Secondly, the design formulas to predict the out-of-plane elastoplastic stability strength of space truss arches subjected to the end bending moment and radial uniform load are presented through introducing a normalized slenderness ratio. By assuming that all components of space truss circular arches bear only axial force, the design formulas to prevent the local buckling of chord and transverse tubes are deduced. Finally, the bearing capacity design equations of space truss arches are proposed under vertical uniform load.

关键词： torsional stiffness     strength design     elastic buckling     space truss arches     out-of-plane    

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Seismic response of precast reinforced concrete wall subjected to cyclic in-plane and constant out-of-plane

《结构与土木工程前沿（英文）》 2021年 第15卷 第5期   页码 1128-1143 doi: 10.1007/s11709-021-0753-5

摘要： This paper provides insight into the seismic behavior of a full-scale precast reinforced concrete wall under in-plane cyclic loading combined with out-of-plane loading replicated by sand backfill to simulate the actual condition of basement walls. The tested wall exhibited flexural cracks, owing to the high aspect ratio and considerable out-of-plane movement due to lateral pressure from the backfill. The wall performed satisfactorily by exhibiting competent seismic parameters and deformation characteristics governed by its ductile response in the nonlinear phase during the test with smaller residual drift. Numerical analysis was conducted to validate experimental findings, which complied with each other. The numerical model was used to conduct parametric studies to study the effect of backfill density and aspect ratio on seismic response of the proposed precast wall system. The in-plane capacity of walls reduced, while deformation characteristics were unaffected by the increase in backfill density. An increase in aspect ratio leads to a reduction in in-plane capacity and an increase in drift. Curves between the ratio of in-plane yield capacity and design shear load of walls are proposed for the backfill density, which may be adopted to determine the in-plane yield capacity of the basement walls based on their design shear.

关键词： precast wall     basement wall     out-of-plane response     quasi-static test     sand backfill     seismic parameters    

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Design and stability analysis of continuous skew tied-arch bridge over Bin Jiang River

YU Jiancheng, TONG Hao, HUANG Wei

《结构与土木工程前沿（英文）》 2008年 第2卷 第1期   页码 37-42 doi: 10.1007/s11709-008-0004-z

摘要： A tied arch bridge without wind bracing was built over the Bin Jiang River, with oblique angle of 20°. Its main design details are described and mechanical performances are analyzed. The stability analytical types are also introduced and the first elastic stability theory is used. A space finite element model has been built to analyze the stability performances in both construction and operation stages for single span or continuous, orthogonal or oblique bridge. The influence of stiffness of the end crossbeam is also analyzed. The result shows that out-plane buckling occur for a rigid tie and similar no matter whether it is single span or continuous and orthogonal or oblique. When there are more and stronger inner crossbeams, the influence of the end crossbeams on arch stability becomes unremarkable.

关键词： out-plane buckling     unremarkable     crossbeam     stability analytical     orthogonal    

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Mechatronic design of a novel linear compliant positioning stage with large travel range and high out-of-plane

Hua LIU, Xin XIE, Ruoyu TAN, Lianchao ZHANG, Dapeng FAN

《机械工程前沿（英文）》 2017年 第12卷 第2期   页码 265-278 doi: 10.1007/s11465-017-0453-y

摘要：

Most of the XY positioning stages proposed in previous studies are mainly designed by considering only a single performance indicator of the stage. As a result, the other performance indicators are relatively weak. In this study, a 2-degree-of-freedom linear compliant positioning stage (LCPS) is developed by mechatronic design to balance the interacting performance indicators and realize the desired positioning stage. The key parameters and the coupling of the structure and actuators are completely considered in the design. The LCPS consists of four voice coil motors (VCMs), which are conformally designed for compactness, and six spatial leaf spring parallelograms. These parallelograms are serially connected for a large travel range and a high out-of-plane payload capacity. The mechatronic model is established by matrix structural analysis for structural modeling and by Kirchhoff’s law for the VCMs. The sensitivities of the key parameters are analyzed, and the design parameters are subsequently determined. The analytical model of the stage is confirmed by experiments. The stage has a travel range of 4.4 mm× 7.0 mm and a 0.16% area ratio of workspace to the outer dimension of the stage. The values of these performance indicators are greater than those of any existing stage reported in the literature. The closed-loop bandwidth is 9.5 Hz in both working directions. The stage can track a circular trajectory with a radius of 1.5 mm, with 40 mm error and a resolution of lower than 3 mm. The results of payload tests indicate that the stage has at least 20 kg out-of-plane payload capacity.

关键词： mechatronic design     linear compliant positioning stage     large travel range     high out-of-plane payload capacity     spatial parallelogram     voice coil motor     sensitivity analysis    

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Seismic safety evaluation methodology for masonry building and retrofitting using splint and bandage technique with wire mesh

Pravin Kumar Venkat Rao PADALU; Yogendra SINGH

《结构与土木工程前沿（英文）》 2022年 第16卷 第4期   页码 478-505 doi: 10.1007/s11709-022-0817-1

摘要： The paper presents a seismic safety assessment of unreinforced masonry (URM) building using two approaches. The first approach uses the ‘Pier Analysis’ method, based on the concept of equivalent lateral stiffness, where in-plane and out-of-plane actions are considered independently. The second approach is developed with the program SAP2000, where the linear response is evaluated using continuum ‘finite element modelling’ (FEM). Both methods are compared to evaluate the safety of wall piers and the differences in the outcomes under combined gravitational and lateral seismic forces. The analysis results showed that few wall elements are unsafe in in-plane and out-of-plane tension. It is also observed that the pier analysis method is conservative compared to FEM, but can be used as a simplified and quick tool in design offices for safety assessment, with reasonable accuracy. To safeguard the URM wall piers under lateral loads, a retrofitting technique is adopted by providing vertical and horizontal belts called splints and bandages, respectively, using welded wire mesh (WWM) reinforcement. The study using the ‘Pier Analysis’ shows that the lateral load capacity of unsafe URM piers can be enhanced up to 3.67 times and made safe using the applied retrofitting technique. Further, the retrofitting design methodology and recommendations for application procedures to on-site URM buildings are discussed in detail.

关键词： unreinforced masonry     seismic in-plane and out-of-plane forces     pier analysis     finite element modelling     splint and bandage technique with wire mesh    

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Structural performance of a façade precast concrete sandwich panel enabled by a bar-type basalt fiber-reinforced polymer connector

《结构与土木工程前沿（英文）》 2023年 第17卷 第1期   页码 122-137 doi: 10.1007/s11709-022-0894-1

摘要： In this study, a novel diagonally inserted bar-type basalt fiber reinforced polymer (BFRP) connector was proposed, aiming to achieve both construction convenience and partially composite behavior in precast concrete sandwich panels (PCSPs). First, pull-out tests were conducted to evaluate the anchoring performance of the connector in concrete after exposure to different temperatures. Thereafter, direct shear tests were conducted to investigate the shear performance of the connector. After the test on the individual performance of the connector, five façade PCSP specimens with the bar-type BFRP connector were fabricated, and the out-of-plane flexural performance was tested under a uniformly distributed load. The investigating parameters included the panel length, opening condition, and boundary condition. The results obtained in this study primarily indicated that 1) the bar-type BFRP connector can achieve a reliable anchorage system in concrete; 2) the bar-type BFRP connector can offer sufficient stiffness and capacity to achieve a partially composite PCSP; 3) the boundary condition of the panel considerably influenced the out-of-plane flexural performance and composite action of the investigated façade PCSP.

关键词： precast concrete sandwich panel     basalt fiber reinforced polymer     pull-out performance     shear performance     out-of-plane flexural performance    

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Thermal buckling behavior of laminated composite plates: a finite-element study

Houdayfa OUNIS,Abdelouahab TATI,Adel BENCHABANE

《机械工程前沿（英文）》 2014年 第9卷 第1期   页码 41-49 doi: 10.1007/s11465-014-0284-z

摘要：

In this paper, the thermal buckling behavior of composite laminated plates under a uniform temperature distribution is studied. A finite element of four nodes and 32 degrees of freedom (DOF), previously developed for the bending and mechanical buckling of laminated composite plates, is extended to investigate the thermal buckling behavior of laminated composite plates. Based upon the classical plate theory, the present finite element is a combination of a linear isoparametric membrane element and a high precision rectangular Hermitian element. The numerical implementation of the present finite element allowed the comparison of the numerical obtained results with results obtained from the literature: 1) with element of the same order, 2) the first order shear deformation theory, 3) the high order shear deformation theory and 4) the three-dimensional solution. It was found that the obtained results were very close to the reference results and the proposed element offers a good convergence speed. Furthermore, a parametrical study was also conducted to investigate the effect of the anisotropy of composite materials on the critical buckling temperature of laminated plates. The study showed that: 1) the critical buckling temperature generally decreases with the increasing of the modulus ratio EL/ET and thermal expansion ratio αT/αL, and 2) the boundary conditions and the orientation angles significantly affect the critical buckling temperature of laminated plates.

关键词： thermal buckling     laminated composite plates     anisotropy     critical buckling temperature     finite-element method     high precision rectangular Hermitian element    

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A review of salting-out effect and sugaring-out effect: driving forces for novel liquid-liquid extraction

Chuhan Fu, Zhuoxi Li, Zengran Sun, Shaoqu Xie

《化学科学与工程前沿（英文）》 2021年 第15卷 第4期   页码 854-871 doi: 10.1007/s11705-020-1980-3

摘要： Biofuels and bio-based chemicals are getting more and more attention because of their sustainable and renewable properties and wide industrial applications. However, the low concentrations of the targeted products in their fermentation broths, the complicated components of the broths and the high energy-intensive separation and purification process hinder the competitiveness of biofuels and biochemicals with the petro-based ones. Hence, the production and the separation of biofuels and bio-based chemicals in energy-saving, low-cost and greenness ways become hot topics nowadays. This review introduces the separation technologies (salting-out extraction, salting-out, sugaring-out extraction, and sugaring-out) that extract biobutanol, 1,3-propanediol, 2,3-butanediol, acetoin, organic acids and other bio-based chemicals from fermentation broths/aqueous solutions. Salting-out/sugaring-out extraction and salting-out/sugaring-out technologies display the high separating efficiency and the high targeted product yields. In addition, they are easy to operate and require low cost for separating products. Hence, they are the effective and potential technologies for separating targeted products in the wide industrial applications. The successful research into the salting-out/sugaring-out and salting-out/sugaring-out extraction not only affords biofuels and biochemical but also opens a door for the development of novel separation methods.

关键词： salting-out     sugaring-out     extraction     biofuels     biochemicals     application    

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Experimental study and numerical simulation on compressive buckling behavior of thin steel skins in unilateral

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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Finite element analysis of creep for plane steel frames in fire

Hui ZHU, Yuching WU

《结构与土木工程前沿（英文）》 2012年 第6卷 第3期   页码 297-307 doi: 10.1007/s11709-012-0162-x

摘要： Steel is widely used for the construction of bridges, buildings, towers, and other structures because of its great strength, light weight, ductility, and ease of fabrication, but the cost of fireproofing is a major disadvantage. Therefore, the resistance of a steel structure to fire is a significant subject for modern society. In the past, for simplification, creep behavior was not taken into account in research on the resistance of a steel structure to fire. However, it was demonstrated that the effect of creep is considerable at temperatures that commonly reach 600°C and should not be neglected in this context. In this paper, a co-rotational total Lagrangian finite element formulation is derived, and the corresponding numerical model is developed to study the creep behavior of plane steel frames in fire conditions. The geometric nonlinearity, material nonlinearity, high temperature creep, and temperature rate of change are taken into account. To verify the accuracy and efficiency of the numerical model, four prototypical numerical examples are analyzed using this model, and the results show very good agreement with the solutions in the literature. Next, the numerical model is used to analyze the creep behavior of the plane steel frames under decreasing temperatures. The results indicate that the effect of creep is negligible at temperatures lower than 500°C and is considerable at temperatures higher than 500°C. In addition, the heating rate is a critical factor in the failure point of the steel frames. Furthermore, it is demonstrated that the deflection at the midpoint of the steel beam, considering creep behavior, is approximately 13% larger than for the situation in which creep is ignored. At temperatures higher than 500°C, the deformed steel member may recover approximately 20% of the total deflection. The application of the numerical model proposed in this paper is greatly beneficial to the steel industry for creep analysis, and the numerical results make a significant contribution to the understanding of resistance and protection for steel structures against disastrous fires.

关键词： creep     plane steel frame     fire     finite element method     geometric nonlinearity    

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Finding buckling points for nonlinear structures by dynamic relaxation scheme

Mohammad REZAIEE-PAJAND, Hossein ESTIRI

《结构与土木工程前沿（英文）》 2020年 第14卷 第1期   页码 23-61 doi: 10.1007/s11709-019-0549-z

摘要： Dynamic Relaxation Method (DRM) is an explicit approach for solving the simultaneous systems of equations. In this tactic, the fictitious mass and damping are added to the static governing equations, and an artificial dynamic system is constructed. By using DRM for nonlinear analysis, the structural static equilibrium path is obtained. This outcome is extremely valuable, since it leads to the behavior of structures. Among the finding related to the structural static path are the critical and buckling points for nonlinear structures. In this paper, a new way for calculating the load factor is proposed by setting the external work zero. Mixing the dynamic relaxation scheme with external work technique has not been formulated so far. In all incremental-iterative methods, the load factor increment sign should be determinated by extra calculations. This sign leads to increase or decrease of the load increment. It is worth emphasizing that sign of the load factor increment changes at the load limit points. Therefore, the sign determinations are required in the common work control methods. These disadvantages are eliminated in the proposed algorithm. In fact, the suggested load factor depends only on the Dynamic Relaxation (DR) fictitious parameters. Besides, all DR calculations are performed via vector operation. Moreover, the load factor is calculated only by one formula, and it has the same relation in the all solution processes. In contrast to the arc length techniques, which requires the sign determined, the proposed scheme does not need any sign finding. It is shown that author’s technique is quicker than the other dynamic relaxation strategies. To prove the capability and efficiency of the presented scheme, several numerical tests are performed. The results indicate that the suggested approach can trace the complex structural static paths, even in the snap-back and snap-through parts.

关键词： load factor     external work     dynamic relaxation     static equilibrium path     large displacement    

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Zooming in and out of ferroptosis in human disease

《医学前沿（英文）》 2023年 第17卷 第2期   页码 173-206 doi: 10.1007/s11684-023-0992-z

摘要： Ferroptosis is defined as an iron-dependent regulated form of cell death driven by lipid peroxidation. In the past decade, it has been implicated in the pathogenesis of various diseases that together involve almost every organ of the body, including various cancers, neurodegenerative diseases, cardiovascular diseases, lung diseases, liver diseases, kidney diseases, endocrine metabolic diseases, iron-overload-related diseases, orthopedic diseases and autoimmune diseases. Understanding the underlying molecular mechanisms of ferroptosis and its regulatory pathways could provide additional strategies for the management of these disease conditions. Indeed, there are an expanding number of studies suggesting that ferroptosis serves as a bona-fide target for the prevention and treatment of these diseases in relevant pre-clinical models. In this review, we summarize the progress in the research into ferroptosis and its regulatory mechanisms in human disease, while providing evidence in support of ferroptosis as a target for the treatment of these diseases. We also discuss our perspectives on the future directions in the targeting of ferroptosis in human disease.

关键词： ferroptosis     human disease     iron metabolism     lipid peroxidation     antioxidation    

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Flexural-torsional buckling behavior of aluminum alloy beams

Xiaonong GUO,Zhe XIONG,Zuyan SHEN

《结构与土木工程前沿（英文）》 2015年 第9卷 第2期   页码 163-175 doi: 10.1007/s11709-014-0272-8

摘要： This paper presents an investigation on the flexural-torsional buckling behavior of aluminum alloy beams (AAB). First, based on the tests of 14 aluminum alloy beams under concentrated loads, the failure pattern, load-deformation curves, bearing capacity and flexural-torsional buckling factor are studied. It is found that all the beam specimens collapsed in the flexural-torsional buckling with excessive deformation pattern. Moreover, the span, loading location and slenderness ratio influence the flexural-torsional buckling capacity of beams significantly. Secondly, besides the experiments, a finite element method (FEM) analysis on the flexural-torsional buckling behavior of AAB is also conducted. The main parameters in the FEM analysis are initial imperfection, material property, cross-section and loading scheme. According to the analytical results, it is indicated that the FEM is reasonable to capture mechanical behavior of AAB. Finally, on the basis of the experimental and analytical results, theoretical formulae to estimate the flexural-torsional buckling capacity of AAB are proposed, which could improve the application of present codes for AAB.

关键词： flexural-torsional buckling     aluminum alloy beams (AAB)     finite element method (FEM)     theoretical formula    

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Probabilistic stability of uncertain composite plates and stochastic irregularity in their buckling mode

《结构与土木工程前沿（英文）》   页码 179-190 doi: 10.1007/s11709-022-0888-z

摘要： In this study, the mechanical properties of the composite plate were considered Gaussian random fields and their effects on the buckling load and corresponding mode shapes were studied by developing a semi-analytical non-intrusive approach. The random fields were decomposed by the Karhunen−Loève method. The strains were defined based on the assumptions of the first-order and higher-order shear-deformation theories. Stochastic equations of motion were extracted using Euler–Lagrange equations. The probabilistic response space was obtained by employing the non-intrusive polynomial chaos method. Finally, the effect of spatially varying stochastic properties on the critical load of the plate and the irregularity of buckling mode shapes and their sequences were studied for the first time. Our findings showed that different shear deformation plate theories could significantly influence the reliability of thicker plates under compressive loading. It is suggested that a linear relationship exists between the mechanical properties’ variation coefficient and critical loads’ variation coefficient. Also, in modeling the plate properties as random fields, a significant stochastic irregularity is obtained in buckling mode shapes, which is crucial in practical applications.

关键词： uncertain composite plate     stochastic assume mode method     Karhunen−Loève theorem     polynomial chaos approach     plate buckling     irregularity in buckling mode shapes    

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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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标题 作者 时间 类型 操作

Out-of-plane elastic buckling load and strength design of space truss arch with a rectangular section

Senping WANG; Xiaolong LIU; Bo YUAN; Minjie SHI; Yanhui WEI

期刊论文

Seismic response of precast reinforced concrete wall subjected to cyclic in-plane and constant out-of-plane

期刊论文

Design and stability analysis of continuous skew tied-arch bridge over Bin Jiang River

YU Jiancheng, TONG Hao, HUANG Wei

期刊论文

Mechatronic design of a novel linear compliant positioning stage with large travel range and high out-of-plane

Hua LIU, Xin XIE, Ruoyu TAN, Lianchao ZHANG, Dapeng FAN

期刊论文

Seismic safety evaluation methodology for masonry building and retrofitting using splint and bandage technique with wire mesh

Pravin Kumar Venkat Rao PADALU; Yogendra SINGH

期刊论文

Structural performance of a façade precast concrete sandwich panel enabled by a bar-type basalt fiber-reinforced polymer connector

期刊论文

Thermal buckling behavior of laminated composite plates: a finite-element study

Houdayfa OUNIS,Abdelouahab TATI,Adel BENCHABANE

期刊论文

A review of salting-out effect and sugaring-out effect: driving forces for novel liquid-liquid extraction

Chuhan Fu, Zhuoxi Li, Zengran Sun, Shaoqu Xie

期刊论文

Experimental study and numerical simulation on compressive buckling behavior of thin steel skins in unilateral

Nicholas KEAGE, Christopher MAIOLO, Rebecca PIEROTTI, Xing MA

期刊论文

Finite element analysis of creep for plane steel frames in fire

Hui ZHU, Yuching WU

期刊论文

Finding buckling points for nonlinear structures by dynamic relaxation scheme

Mohammad REZAIEE-PAJAND, Hossein ESTIRI

期刊论文

Zooming in and out of ferroptosis in human disease

期刊论文

Flexural-torsional buckling behavior of aluminum alloy beams

Xiaonong GUO,Zhe XIONG,Zuyan SHEN

期刊论文

Probabilistic stability of uncertain composite plates and stochastic irregularity in their buckling mode

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