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Dynamic modeling and coupling characteristics of rotating inclined beams with twisted-shape sections

Jin ZENG, Chenguang ZHAO, Hui MA, Bangchun WEN

《机械工程前沿（英文）》 2020年 第15卷 第3期   页码 374-389 doi: 10.1007/s11465-019-0580-8

摘要： In the existing literature, most studies investigated the free vibrations of a rotating pre-twisted cantilever beam; however, few considered the effect of the elastic-support boundary and the quantification of modal coupling degree among different vibration directions. In addition, Coriolis, spin softening, and centrifugal stiffening effects are not fully included in the derived equations of motion of a rotating beam in most literature, especially the centrifugal stiffening effect in torsional direction. Considering these deficiencies, this study established a coupled flapwise–chordwise–axial–torsional dynamic model of a rotating double-tapered, pre-twisted, and inclined Timoshenko beam with elastic supports based on the semi-analytic method. Then, the proposed model was verified with experiments and ANSYS models using Beam188 and Shell181 elements. Finally, the effects of setting and pre-twisted angles on the degree of coupling among flapwise, chordwise, and torsional directions were quantified via modal strain energy ratios. Results showed that 1) the appearance of torsional vibration originates from the combined effect of flapwise–torsional and chordwise–torsional couplings dependent on the Coriolis effect, and that 2) the flapwise–chordwise coupling caused by the pure pre-twisted angle is stronger than that caused by the pure setting angle.

关键词： elastic-support boundary     pre-twisted beam     semi-analytic method     modal strain energy ratio     torsional vibration    

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叶轮机械弯扭叶片的研究现状及发展趋势

王仲奇,郑严

《中国工程科学》 2000年 第2卷 第6期   页码 40-48

摘要：

弯扭叶片在20世纪90年代已在英、美等发达国家较普遍地得到应用，在我国也成功地应用于蒸汽轮机，在航空发动机涡轮中的应用也有了良好的开端。文章就叶片弯曲降低能量损失的机理以及静态和动态实验对采用弯曲叶片的效果做了综合评述，对压气机采用弯曲叶片的科研进展，以及遇到的难点也作了概要的介绍。根据我们的设计经验，在文章的最后总结了弯曲叶片级设计时应遵循的几条原则。

关键词： 弯扭叶片     二次流     叶栅气动力学    

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Scaling up of cluster beam deposition technology for catalysis application

《化学科学与工程前沿（英文）》 2021年 第15卷 第6期   页码 1360-1379 doi: 10.1007/s11705-021-2101-7

摘要： Many research works have demonstrated that the combination of atomically precise cluster deposition and theoretical calculations is able to address fundamental aspects of size-effects, cluster-support interactions, and reaction mechanisms of cluster materials. Although the wet chemistry method has been widely used to synthesize nanoparticles, the gas-phase synthesis and size-selected strategy was the only method to prepare supported metal clusters with precise numbers of atoms for a long time. However, the low throughput of the physical synthesis method has severely constrained its wider adoption for catalysis applications. In this review, we introduce the latest progress on three types of cluster source which have the most promising potential for scale-up, including sputtering gas aggregation source, pulsed microplasma cluster source, and matrix assembly cluster source. While the sputtering gas aggregation source is leading ahead with a production rate of ~20 mg·h–1, the pulsed microplasma source has the smallest physical dimensions which makes it possible to compact multiple such devices into a small volume for multiplied production rate. The matrix assembly source has the shortest development history, but already show an impressive deposition rate of ~10 mg·h–1. At the end of the review, the possible routes for further throughput scale-up are envisaged.

关键词： nanoparticle     cluster     cluster beam deposition     magnetron sputtering     heterogeneous catalysis    

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“叶轮机械弯扭叶片的研究现状及发展趋势”简评

陈矛章

《中国工程科学》 2000年 第2卷 第6期   页码 94-94

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Nonlinear analysis of pre-tensioned glass wall facade by stability function with initial imperfection

Siu-Lai CHAN, Yaopeng LIU, Andy LEE,

《结构与土木工程前沿（英文）》 2010年 第4卷 第3期   页码 376-382 doi: 10.1007/s11709-010-0086-2

摘要： Pre-tensioned high strength trusses using alloy steel bar are widely used as glass wall supporting systems because of the high degree of transparency. The breakage of glass panes in this type of system occurs occasionally, likely to be due to error in design and analysis in addition to other factors like glass impurity and stress concentration around opening in a spider system. Most design does not consider the flexibility of supports from finite stiffness of supporting steel or reinforced concrete beams. The resistance of lateral wind pressure of the system makes use of high tension force coupled with the large deflection effect, both of which are affected by many parameters not generally considered in conventional structures. In the design, one must therefore give a careful consideration on various effects, such as support settlement due to live loads and material creep, temperature change, pre-tension force, and wind pressure. It is not uncommon to see many similar glass wall systems fail in the wind load test chambers under a design wind speed. This paper presents a rigorous analysis and design of this type of structural systems used in a project in Hong Kong, China. The stability function with initial curvature is used in place of the cubic function, which is only accurate for linear analysis. The considerations and analysis techniques are believed to be of value to engineers involved in the design of the structural systems behaving nonlinearly.

关键词： tension system     glass wall     nonlinear analysis     pre-tensioning     second-order analysis    

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A pre-compensation method of the systematic contouring error for repetitive command paths

D. L. ZHANG,Y. H. CHEN,Y. P. CHEN

《机械工程前沿（英文）》 2015年 第10卷 第4期   页码 367-372 doi: 10.1007/s11465-015-0367-5

摘要：

For a repetitive command path, pre-compensating the contouring error by modifying the command path is practical. To obtain the pre-compensation value with better accuracy, this paper proposes the use of a back propagation neural network to extract the function of systematic contouring errors. Furthermore, by using the extracted function, the contouring error can be easily pre-compensated. The experiment results verify that the proposed compensation method can effectively reduce contouring errors.

关键词： contouring error     pre-compensation     motion control system     back propagation (BP) neural network    

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Experimental and parametrical investigation of pre-stressed ultrahigh-performance fiber-reinforced concrete

《结构与土木工程前沿（英文）》 2023年 第17卷 第3期   页码 411-428 doi: 10.1007/s11709-023-0928-3

摘要： In this study, ultrahigh-performance fiber-reinforced concrete (UHPFRC) used in a type B70 concrete sleeper is investigated experimentally and parametrically. The main parameters investigated are the steel fiber volume fractions (0%, 0.5%, 1%, and 1.5%). Under European standards, 35 UHPFRC sleepers are subjected to static bending tests at the center and rail seat sections, and the screw on the fastening system is pulled out. The first cracking load, failure load, failure mode, crack propagation, load–deflection curve, load–crack width, and failure load from these tests are measured and compared with those of a control sleeper manufactured using normal concrete C50. The accuracy of the parametric study is verified experimentally. Subsequently, the results of the study are applied to UHPFRC sleepers with different concrete volumes to investigate the effects of the properties of UHPFRC on their performance. Experimental and parametric study results show that the behavior of UHPFRC sleepers improves significantly when the amount of steel fiber in the mix is increased. Sleepers manufactured using UHPFRC with a steel fiber volume fraction of 1% and a concrete volume less than 25% that of standard sleeper B70 can be used under the same loads and requirements, which contributes positively to the cost and surrounding environment.

关键词： pre-stressed concrete sleeper     ultrahigh performance fiber-reinforced concrete     pull-out test     static bending test     steel fiber     aspect ratio     volume fraction    

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Investigation into viability of using two-stage (pre-placed aggregate) concrete in Irish setting

John O’MALLEY, Hakim S. ABDELGADER,

《结构与土木工程前沿（英文）》 2010年 第4卷 第1期   页码 127-132 doi: 10.1007/s11709-010-0007-4

摘要： Two-stage (pre-placed aggregate) concrete (TSC) consists of coarse aggregate, which is first deposited into the formwork, and grout, which is later pumped into the formwork from the bottom up to bind the stone together into a monolith. During the course of this study the formation of grout for two stage concrete was investigated using readily available 5 mm sand mixed in a slow speed paddle mixer.  Silica fume and a superplasticizer were used in the mix to see if the necessary stability and fluidity could be achieved without the use of a specialized plant, essentially to see if TSC could be produced on a small scale using native Irish aggregates. A much higher degree of sedimentation was recorded during testing than was expected. As a result, the use of 5 mm sand and a slow speed mixer in combination were found to be not conducive to the successful production of TSC grout, without further research and testing.

关键词： grout     pre-placed     concrete     two-stage concrete (TSC)    

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Optimization of denitrifying phosphorus removal in a pre-denitrification anaerobic/anoxic/post-aeration+ nitrification sequence batch reactor (pre-A

Weihua Zhao, Meixiang Wang, Jianwei Li, Yu Huang, Baikun Li, Cong Pan, Xiyao Li, Yongzhen Peng

《环境科学与工程前沿（英文）》 2018年 第12卷 第5期 doi: 10.1007/s11783-018-1084-1

摘要：

A novel two sludge pre-A2NSBR system was developed.

Advanced N and P removal was optimized to treat real domestic wastewater.

Nitrifiers and PAOs were enriched with 19.41% and 26.48%, respectively.

Acetate was demonstrated as the high-quality carbon source type.

关键词： Denitrifying phosphorus removal     C/N ratio     Nitrate recycling     Carbon source type     Biological nutrient removal     Pre-A2NSBR system    

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Evaluation of the static and dynamic structural performance of segmental pre-stressed concrete box girder

Ali Fadhil NASER, Zonglin WANG

《结构与土木工程前沿（英文）》 2013年 第7卷 第2期   页码 164-177 doi: 10.1007/s11709-013-0196-8

摘要： The objectives of this study are to explain the repairing and strengthening methods which are used to improve the structural performance of the bridge structure, to analyze the static and dynamic responses after strengthening, and to evaluate the performance of the bridge structure after repairing and strengthening. The methods of repairing and strengthening include reconstruction the deck of the bridge by casting 10 cm layer of concrete, strengthening the web and bottom floor of box girders of middle spans and side spans by sticking the steel plates, strengthening the whole bridge structure by using external pre-stressing tendons, and treatment the cracks. The results of theoretical analysis show that the values of tensile stress and vertical deflection are decreased and the compressive stress is increased after strengthening. There are not tensile stresses are appeared in the sections of the bridge structure. The modal analysis results show that the value of natural frequency is equal to 2.09 Hz which is more than the values before strengthening which is equal to 1.64 Hz, indicating that the stiffness of the bridge structure is improved and the strengthening process is effective to improve the cracks resistance and bearing capacity of the bridge structure.

关键词： structural performance     steel plates     external pre-stressing     cracks     grouting method     static    

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Techno-economic comparison of three technologies for pre-combustion CO

Simon Roussanaly, Monika Vitvarova, Rahul Anantharaman, David Berstad, Brede Hagen, Jana Jakobsen, Vaclav Novotny, Geir Skaugen

《化学科学与工程前沿（英文）》 2020年 第14卷 第3期   页码 436-452 doi: 10.1007/s11705-019-1870-8

摘要： This paper compares the techno-economic performances of three technologies for CO capture from a lignite-based IGCC power plant located in the Czech Republic: (1) Physical absorption with a Rectisol-based process; (2) Polymeric CO -selective membrane-based capture; (3) Low-temperature capture. The evaluations show that the IGCC plant with CO capture leads to costs of electricity between 91 and 120 €·MWh , depending on the capture technology employed, compared to 65 €·MWh for the power plant without capture. This results in CO avoidance costs ranging from 42 to 84 €· , mainly linked to the losses in net power output. From both energy and cost points of view, the low-temperature and Rectisol based CO capture processes are the most efficient capture technologies. Furthermore, partial CO capture appears as a good mean to ensure early implementation due to the limited increase in CO avoidance cost when considering partial capture. To go beyond the two specific CO -selective membranes considered, a cost/membrane property map for CO -selective membranes was developed. This map emphasise the need to develop high performance membrane to compete with solvent technology. Finally, the cost of the whole CCS chain was estimated at 54 €· once pipeline transport and storage are taken into consideration.

关键词： carbon capture and storage (CCS)     techno-economic comparison     pre-combustion capture     physical solvent     low-temperature capture    

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Hybrid flexural components: Testing pre-stressed steel and GFRP bars together as reinforcement for flexural

Mohammed FARUQI, Oved I. MATA, Francisco AGUINIGA

《结构与土木工程前沿（英文）》 2018年 第12卷 第3期   页码 352-360 doi: 10.1007/s11709-017-0453-3

摘要：

Concrete members historically have used either pre-stressed steel or steel bars. In recent years there has been an increased interest in the use of fiber reinforced polymer (FRP) materials. However, the flexure behavior of a hybrid system reinforced by the combination of pre-stressed steel and glass fiber reinforced (GFRP) is still relatively unknown. The purpose of this work is to study this. Two slabs of 100 and 150-millimeter thickness, with a span of 2.1 m reinforced with both pre-stressing steel and GFRP were constructed and tested to failure using ACI 318-11 and ACI 440.1R-15. The concrete had strength of 31 MPa and the slabs were respectively reinforced with 5#4 bars and 3#5 bars. Each slab had 37.41 mm2 prestressing wire with a failure stress of 1722.5 MPa. The experimental flexural strength and deflection of slabs were compared with their respective sizes theoretical slabs. The theoretical slabs were either reinforced with pre-stressed steel or GFRP rebars, or a hybrid system. It was found that the hybrid system produces better results.

关键词： Partial pre-stressing     composite structures     GFRP bars    

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China’s pre-2020 CO

Hailin WANG

《能源前沿（英文）》 2019年 第13卷 第3期   页码 571-578 doi: 10.1007/s11708-019-0640-0

摘要： China achieved the reduction of CO intensity of GDP by 45% compared with 2005 at the end of 2017, realizing the commitment at 2009 Copenhagen Conference on emissions reduction 3 years ahead of time. In future implementation of the “13th Five-Year Plan (FYP),” with the decline of economic growth rate, decrease of energy consumption elasticity and optimization of energy structure, the CO intensity of GDP will still have the potential for decreasing before 2020. By applying KAYA Formula decomposition, this paper makes the historical statistics of the GDP energy intensity decrease and CO intensity of energy consumption since 2005, and simulates the decrease of CO intensity of GDP in 2020 and its influences on achieving National Determined Contribution (NDC) target in 2030 with scenario analysis. The results show that China’s CO intensity of GDP in 2020 is expected to fall by 52.9%–54.4% than the 2005 level, and will be 22.9%–25.4% lower than 2015. Therefore, it is likely to overfulfill the decrease of CO intensity of GDP by 18% proposed in the 13th FYP period. Furthermore, the emission reduction potentiality before 2020 will be conducive to the earlier realization of NDC objectives in 2030. China’s CO intensity of GDP in 2030 will fall by over 70% than that in 2005, and CO emissions peak will appear before 2030 as early as possible. To accelerate the transition to a low-carbon economy, China needs to make better use of the carbon market, and guide the whole society with carbon price to reduce emissions effectively. At the same time, China should also study the synergy of policy package so as to achieve the target of emission reduction.

关键词： China’s National Determined Contribution     emission reduction potential     scenario analysis     CO2 emissions peak    

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Virtual pre-assembly for large steel structures based on BIM, PLP algorithm, and 3D measurement

Ying ZHOU, Wan WANG, Hanbin LUO, Yan ZHANG

《工程管理前沿（英文）》 2019年 第6卷 第2期   页码 207-220 doi: 10.1007/s42524-019-0016-5

摘要： The current physical pre-assembly method of large steel structures is time consuming and costly and requires large sites. Thus, the pre-assembly of large steel structures in a virtual way, starting from building information modeling (BIM), is an interesting alternative to the physical one. In this study, an innovative method for virtual pre-assembly is proposed on the basis of BIM, plane-line-point algorithm, and 3D measurement. This method determines the optimal analytical least squares of the various built components. The technique verifies the feasibility of the steel structure assembly and the fulfillment of the design geometries, starting from the real data obtained by an accurate metric survey of the fabricated steel elements. The method is applied to a real case, and obtained results largely satisfy the prefixed research objectives. Suggestions to improve the proposed method are also discussed.

关键词： steel structure     pre-assembly     BIM     plane-line-point     3D measurement    

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Processing parameter optimization of fiber laser beam welding using an ensemble of metamodels and MOABC

《机械工程前沿（英文）》 2022年 第17卷 第4期 doi: 10.1007/s11465-022-0703-5

摘要： In fiber laser beam welding (LBW), the selection of optimal processing parameters is challenging and plays a key role in improving the bead geometry and welding quality. This study proposes a multi-objective optimization framework by combining an ensemble of metamodels (EMs) with the multi-objective artificial bee colony algorithm (MOABC) to identify the optimal welding parameters. An inverse proportional weighting method that considers the leave-one-out prediction error is presented to construct EM, which incorporates the competitive strengths of three metamodels. EM constructs the correlation between processing parameters (laser power, welding speed, and distance defocus) and bead geometries (bead width, depth of penetration, neck width, and neck depth) with average errors of 10.95%, 7.04%, 7.63%, and 8.62%, respectively. On the basis of EM, MOABC is employed to approximate the Pareto front, and verification experiments show that the relative errors are less than 14.67%. Furthermore, the main effect and the interaction effect of processing parameters on bead geometries are studied. Results demonstrate that the proposed EM-MOABC is effective in guiding actual fiber LBW applications.

关键词： laser beam welding     parameter optimization     metamodel     multi-objective    

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标题 作者 时间 类型 操作

Dynamic modeling and coupling characteristics of rotating inclined beams with twisted-shape sections

Jin ZENG, Chenguang ZHAO, Hui MA, Bangchun WEN

期刊论文

叶轮机械弯扭叶片的研究现状及发展趋势

王仲奇,郑严

期刊论文

Scaling up of cluster beam deposition technology for catalysis application

期刊论文

“叶轮机械弯扭叶片的研究现状及发展趋势”简评

陈矛章

期刊论文

Nonlinear analysis of pre-tensioned glass wall facade by stability function with initial imperfection

Siu-Lai CHAN, Yaopeng LIU, Andy LEE,

期刊论文

A pre-compensation method of the systematic contouring error for repetitive command paths

D. L. ZHANG,Y. H. CHEN,Y. P. CHEN

期刊论文

Experimental and parametrical investigation of pre-stressed ultrahigh-performance fiber-reinforced concrete

期刊论文

Investigation into viability of using two-stage (pre-placed aggregate) concrete in Irish setting

John O’MALLEY, Hakim S. ABDELGADER,

期刊论文

Optimization of denitrifying phosphorus removal in a pre-denitrification anaerobic/anoxic/post-aeration+ nitrification sequence batch reactor (pre-A

Weihua Zhao, Meixiang Wang, Jianwei Li, Yu Huang, Baikun Li, Cong Pan, Xiyao Li, Yongzhen Peng

期刊论文

Evaluation of the static and dynamic structural performance of segmental pre-stressed concrete box girder

Ali Fadhil NASER, Zonglin WANG

期刊论文

Techno-economic comparison of three technologies for pre-combustion CO

Simon Roussanaly, Monika Vitvarova, Rahul Anantharaman, David Berstad, Brede Hagen, Jana Jakobsen, Vaclav Novotny, Geir Skaugen

期刊论文

Hybrid flexural components: Testing pre-stressed steel and GFRP bars together as reinforcement for flexural

Mohammed FARUQI, Oved I. MATA, Francisco AGUINIGA

期刊论文

China’s pre-2020 CO

Hailin WANG

期刊论文

Virtual pre-assembly for large steel structures based on BIM, PLP algorithm, and 3D measurement

Ying ZHOU, Wan WANG, Hanbin LUO, Yan ZHANG

期刊论文

Processing parameter optimization of fiber laser beam welding using an ensemble of metamodels and MOABC

期刊论文