Effect of induction post-heating temperature on the morphology, microstructure and mechanical performance of the heat affected zone in laser-induction hybrid cladding of full-scale rail

Compared with scaled-model testing, full-scale destructive testing is more reliable since the test has no size effect and can truly record the mechanical performance of the structure. However, due to the high cost, only very few full-scale destructive tests have been conducted on the flexural behavior of prestressed concrete (PC) box girders with girders removed from decommissioned bridges. Moreover, related destructive testing on the flexural behavior of a new precast box girder has been rarely reported. To investigate the flexural behavior and optimize the design, destructive testing of a 30-meter full-scale simply supported prestressed box girder was conducted at the construction site. It is illustrated that the failure mode of the tested girder was fracture of the prestressing tendon, and the corresponding maximum compressive strain in the top flange was only 1456 μ ε , which is far less than the ultimate compressive strain (3300 μ ε ). Therefore, the concrete in the top flange was not fully utilized. A nonlinear analysis procedure was performed using the finite strip method (FSM). The validity of the analysis was demonstrated by comparing the analytical results with those of the full-scale test in the field and a scaled model test in a laboratory. Using the developed numerical method, parametric analyses of the ratio of reinforcement were carried out. The prestressing tendon of the tested girder was increased from four strands to six strands in each duct. After the optimization of the prestressed reinforcement, the girder was ductile and the bearing capacity could be increased by 44.3%.

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Additive Manufacturing of High-Entropy Alloys: A Review

Entropy ◽

10.3390/e20120937 ◽

2018 ◽

Vol 20 (12) ◽

pp. 937 ◽

Cited By ~ 28

Author(s):

Shuying Chen ◽

Yang Tong ◽

Peter Liaw

Keyword(s):

Mechanical Properties ◽

Additive Manufacturing ◽

High Efficiency ◽

Mechanical Performance ◽

Heating Temperature ◽

Intermetallic Phase ◽

Solid Solution Phase ◽

High Entropy Alloys ◽

Scanning Method ◽

High Entropy

Owing to the reduced defects, low cost, and high efficiency, the additive manufacturing (AM) technique has attracted increasingly attention and has been applied in high-entropy alloys (HEAs) in recent years. It was found that AM-processed HEAs possess an optimized microstructure and improved mechanical properties. However, no report has been proposed to review the application of the AM method in preparing bulk HEAs. Hence, it is necessary to introduce AM-processed HEAs in terms of applications, microstructures, mechanical properties, and challenges to provide readers with fundamental understanding. Specifically, we reviewed (1) the application of AM methods in the fabrication of HEAs and (2) the post-heat treatment effect on the microstructural evolution and mechanical properties. Compared with the casting counterparts, AM-HEAs were found to have a superior yield strength and ductility as a consequence of the fine microstructure formed during the rapid solidification in the fabrication process. The post-treatment, such as high isostatic pressing (HIP), can further enhance their properties by removing the existing fabrication defects and residual stress in the AM-HEAs. Furthermore, the mechanical properties can be tuned by either reducing the pre-heating temperature to hinder the phase partitioning or modifying the composition of the HEA to stabilize the solid-solution phase or ductile intermetallic phase in AM materials. Moreover, the processing parameters, fabrication orientation, and scanning method can be optimized to further improve the mechanical performance of the as-built-HEAs.

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Full-scale multi-functional test platform for investigating mechanical performance of track–subgrade systems of high-speed railways

Railway Engineering Science ◽

10.1007/s40534-020-00221-y ◽

2020 ◽

Vol 28 (3) ◽

pp. 213-231

Author(s):

Wanming Zhai ◽

Kaiyun Wang ◽

Zhaowei Chen ◽

Shengyang Zhu ◽

Chengbiao Cai ◽

...

Keyword(s):

High Speed ◽

Mechanical Performance ◽

Full Scale ◽

Functional Test ◽

Railway Track ◽

High Speed Railway ◽

Ballastless Track ◽

Railway Infrastructure ◽

Test Platform

Abstract Motivated by the huge practical engineering demand for the fundamental understanding of mechanical characteristics of high-speed railway infrastructure, a full-scale multi-functional test platform for high-speed railway track–subgrade system is developed in this paper, and its main functions for investigating the mechanical performance of track–subgrade systems are elaborated with three typical experimental examples. Comprising the full-scale subgrade structure and all the five types of track structures adopted in Chinese high-speed railways, namely the CRTS I, the CRTS II and the CRTS III ballastless tracks, the double-block ballastless track and the ballasted track, the test platform is established strictly according to the construction standard of Chinese high-speed railways. Three kinds of effective loading methods are employed, including the real bogie loading, multi-point loading and the impact loading. Various types of sensors are adopted in different components of the five types of track–subgrade systems to measure the displacement, acceleration, pressure, structural strain and deformation, etc. Utilizing this test platform, both dynamic characteristics and long-term performance evolution of high-speed railway track–subgrade systems can be investigated, being able to satisfy the actual demand for large-scale operation of Chinese high-speed railways. As examples, three typical experimental studies are presented to elucidate the comprehensive functionalities of the full-scale multi-functional test platform for exploring the dynamic performance and its long-term evolution of ballastless track systems and for studying the long-term accumulative settlement of the ballasted track–subgrade system in high-speed railways. Some interesting phenomena and meaningful results are captured by the developed test platform, which provide a useful guidance for the scientific operation and maintenance of high-speed railway infrastructure.

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Поверхностная закалка колесной стали высокоэнтальпийной плазменной струей// Journal of Technical and Natural Sciences 1(10), 2019/ OEAPS Inc.(Open European Academy of Public Sciences); Chief Editor Vitaly Yakovlev- Berlin, Germany. 26.01.2019: OEAPS Inc., 2019. - pp. 8-26.

10.31219/osf.io/ka68p ◽

2019 ◽

Author(s):

Серик Кажимович Бийжанов ◽

Амангельды Токешович Канаев

Keyword(s):

Plasma Treatment ◽

Heat Affected Zone ◽

Heating Temperature ◽

Chief Editor ◽

Natural Sciences ◽

Austenite Decomposition ◽

Surface Plasma ◽

European Academy ◽

Maximum Heating Temperature ◽

Maximum Heating

В статье дается подробное описание процесса поверхностной плазменной обработки тяжело нагруженных стальных деталей. Для решения вопроса о типе структур, возникающих в зоне термического влияния и, следовательно, об их свойствах, определяются скорости охлаждения в каждом микрообъеме, с последующим сопоставлением с термокинетическими кривыми распада аустенита при определенной концентрации аустенита и максимальной температуре нагрева.The article provides a detailed description of the process of surface plasma treatment of heavily loaded steel parts. To solve the problem of the type of structures arising in the heat-affected zone and, therefore, their properties, the cooling rates in each microvolume are determined, followed by comparison with the thermokinetic austenite decomposition curves at a certain austenite concentration and maximum heating temperature.

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Paper 22: Development of Vibration Monitoring Techniques to Aid in Evaluating the Mechanical Performance of Rotating Machinery

Proceedings of the Institution of Mechanical Engineers Conference Proceedings ◽

10.1243/pime_conf_1969_184_534_02 ◽

1969 ◽

Vol 184 (18) ◽

pp. 209-217

Author(s):

A. H. R. Streatfield

Keyword(s):

Full Advantage ◽

Mechanical Performance ◽

Rotating Machinery ◽

Full Scale ◽

Vibration Monitoring ◽

Mechanical Reliability ◽

Considerable Effort ◽

Monitoring Equipment ◽

Thermodynamic Performance ◽

Air Compressors

Considerable effort has been expended towards improving the thermodynamic performance of rotary air compressors and full advantage has been taken of these advances by modifying the design, installation, or application of the machines in full-scale plant. In large industrial units the economics of operation are demonstrated by the availability of the plant, i.e. time available for production. This reflects directly on the mechanical reliability and, in particular, the means for monitoring the mechanical performance in order to give forward warning of maintenance or adjustment requirements. For this purpose various techniques are in the course of development and this paper deals with the amplification of vibration monitoring equipment of the accelerometer and proximity probe types.

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Mechanical performance of full-scale precast steel fibre-reinforced concrete pipes

Engineering Structures ◽

10.1016/j.engstruct.2014.11.033 ◽

2015 ◽

Vol 84 ◽

pp. 287-299 ◽

Cited By ~ 12

Author(s):

Nedal Mohamed ◽

Ahmed M. Soliman ◽

Moncef L. Nehdi

Keyword(s):

Reinforced Concrete ◽

Steel Fibre ◽

Mechanical Performance ◽

Full Scale ◽

Fibre Reinforced Concrete ◽

Steel Fibre Reinforced Concrete ◽

Concrete Pipes

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Mechanical performance of full-scale Pompeii-like masonry panels

Construction and Building Materials ◽

10.1016/j.conbuildmat.2020.118964 ◽

2020 ◽

Vol 251 ◽

pp. 118964

Author(s):

Francesca Autiero ◽

Giuseppina De Martino ◽

Marco Di Ludovico ◽

Andrea Prota

Keyword(s):

Mechanical Performance ◽

Full Scale

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Mechanical performance of pavement structures with paving slabs – Part II: Numerical simulation tool validated by means of full-scale accelerated tests

Engineering Structures ◽

10.1016/j.engstruct.2014.10.055 ◽

2015 ◽

Vol 98 ◽

pp. 221-229 ◽

Cited By ~ 6

Author(s):

J. Füssl ◽

W. Kluger-Eigl ◽

L. Eberhardsteiner ◽

R. Blab

Keyword(s):

Numerical Simulation ◽

Mechanical Performance ◽

Full Scale ◽

Simulation Tool ◽

Accelerated Tests ◽

Pavement Structures

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Application of Support Vector Machine to Predicting Mechanical Properties of TC4

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.189-193.1854 ◽

2011 ◽

Vol 189-193 ◽

pp. 1854-1857 ◽

Cited By ~ 1

Author(s):

Zhe Zhe Hou ◽

Yan Liang Du ◽

Wei Gang Zhao ◽

Meng Zhao ◽

Shuang Chao Peng

Keyword(s):

Mechanical Properties ◽

Heat Treatment ◽

Support Vector Machine ◽

Mechanical Performance ◽

Heating Temperature ◽

Heating Time ◽

Experimental Results ◽

Support Vector ◽

Machine Method ◽

Tc4 Alloy

On the basis of numerous experimental results the effect of heat treatment on mechanical properties of TC4 alloy is studied. A computer model expressing the relationships between heat treatment and mechanical properties has been established with supported vector machine method. The input parameters were determined by the heating temperature and heating time which are important factors of the mechanical performance, and the output parameters are tensile and yield strength and elongation. The model is established by libsvm with RBF kernel function, e-SVR and proper parameters. Experimental results show that prediction accuracy made by using support vector machine reached over 95%, and the model has good learning precision and generalization and it can be used for predicting the mechanical properties of TC4 alloy.

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