Experimental studies on shear failure of freeze-bonds in saline ice: Part I. Set-up, failure mode and freeze-bond strength

Abstract Bond strength is one of the most important parameters and can affect the macroscopic mechanical properties and the damage state of the rock to some degree. The coarse-grained sandstone with strength of less than 40 MPa was studied by the controlled variable method. The influence of parallel bond strength on the peak strength and failure mode of coarse-grained sandstone was simulated, the evolution law of peak strength and failure mode of bond strength were comprehensively analyzed. The results show that the peak strength of rock was positively correlated with the bond strength, the difference value between tensile and shear crack was negatively correlated with tensile bond strength and positively correlated with shear bond strength. Tensile-shear bond strength ratio less than 0.5, the peak strength of the rock was usually stable at the certain extreme value under a constant tensile bond strength. Tensile crack was negatively correlated with the tensile-shear bond strength ratio, shear crack was positively correlated with the tensile-shear bond strength ratio. The failure mode of coarse-grained sandstone is shear failure. The research results can be used to guide the ground control of other mine stopes or roadways with weak cementation lithology.

Download Full-text

Bond Properties of Ceramic Concrete Reinforced by Bamboo Bar

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.477-478.920 ◽

2013 ◽

Vol 477-478 ◽

pp. 920-925 ◽

Cited By ~ 1

Author(s):

Jian Zhou ◽

Hai Ning Liu ◽

Su Ma ◽

Jing Jing Li ◽

He Tao Hou

Keyword(s):

Bond Strength ◽

Failure Mode ◽

Shear Failure ◽

Constitutive Relationship ◽

Bond Properties ◽

Concrete Material ◽

Pull Out ◽

Laminated Bamboo ◽

Relationship Of ◽

Type Bond

Bond properties of ceramic concrete reinforced by bamboo bar were investigated based on pull-out tests. The influences of strength grade of ceramic concrete, material type, bond length, side length and notch spacing of bamboo bar on the bond strength between the bamboo bars and ceramic concrete were studied. The results show that the bond failure mode of ceramic concrete reinforced by bamboo bar without notch is majorly pulling-out failure, however, ceramic concrete reinforced by restructured bamboo (RB) bar with notch appears shear failure mode. The ultimate bond strength of ceramic concrete reinforced by RB bars is higher than that of ceramic concrete reinforced by laminated bamboo (LB) bar, which is close to that of ceramic concrete reinforced by plastic bars,but lower than that of ceramic concrete reinforced by steel bars under the same condition. When the notch spacing is 15 mm, the bond strength of ceramic concrete reinforced by RB bars is the highest. The conclusions can be usable for the the constitutive relationship of ceramic bamboo-reinforced concrete.

Download Full-text

Crack Coalescence and Failure Patterns in Brittle Rock-Like Specimens with Pre-Existing Fissures under Uniaxial Loading: Experimental Studies

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.665.117 ◽

2015 ◽

Vol 665 ◽

pp. 117-120

Author(s):

Ri Hong Cao ◽

Ping Cao ◽

Hang Lin

Keyword(s):

Failure Mode ◽

Shear Failure ◽

Failure Process ◽

Experimental Studies ◽

Crack Coalescence ◽

Careful Examination ◽

Failure Patterns ◽

The Difference ◽

Three Fissures ◽

Coalescence Pattern

In practical engineering, the joints or fissures with similar characteristics are commonly found in natural rocks, they decrease the mechanics properties of the rock mass and also can be seen as a source of initiation of new discontinuities. The previous studies (experimental or numerical) has promoted the understanding of coalescence patterns or failure process obtained from brittle specimens which contain single, two or three fissures. However, the failure characteristics of multi-fissure specimens has not been studied comprehensively. In this paper, the crack coalescence pattern and failure mode of the rock-like materials with multi-fissures have been explored. Based on the experiment results, under unaxial compression, we found that the coalescence modes between fissures can be generally classified into three categories: T/S/M pattern. Moreover, due to the difference of inclination angle and fissure numbers, the specimens present different failure mode. Careful examination all of specimens, the failure mode can be classified into 4 categories: Mix failure model(shear+splitting), Shear failure, Stepped path, Intact failure.

Download Full-text

Study on the Effect of Bond Strength on the Failure Mode of Coarse-Grained Sandstone in Weakly Cemented Stratum

Minerals ◽

10.3390/min12010055 ◽

2021 ◽

Vol 12 (1) ◽

pp. 55

Author(s):

Xianda Yang ◽

Lihui Sun ◽

Jiale Song ◽

Bensheng Yang ◽

Chengren Lan ◽

...

Keyword(s):

Bond Strength ◽

Failure Mode ◽

Shear Bond Strength ◽

Shear Failure ◽

Peak Strength ◽

Tensile Bond Strength ◽

Coarse Grained ◽

Strength Ratio ◽

Shear Cracks ◽

Tensile Shear

Bond strength is one of the most important parameters and can affect the macroscopic mechanical properties and the damage state of rock to some degree. Coarse-grained sandstone was studied using the controlled variable method. The influence of parallel bond strength on the peak strength and failure mode of coarse-grained sandstone was simulated, and the evolution law of peak strength and the failure mode of bond strength were comprehensively analyzed. The results show that the peak strength of the rock was positively correlated with the bond strength; the difference in quantity between the tensile and shear cracks was negatively correlated with tensile bond strength and positively correlated with shear bond strength. With a tensile-shear bond strength ratio of less than 0.5, the peak strength of the rock was usually stable at the certain extreme value under a constant tensile bond strength. The tensile cracks were negatively correlated with the tensile-shear bond strength ratio, and the shear cracks were positively correlated with the tensile-shear bond strength ratio. The main failure mode of the coarse-grained sandstone in the weakly cemented stratum of the Hongqinghe coal mine is shear failure. The research results can be used to guide the ground control of other mine stopes or roadways with weak cementation lithology.

Download Full-text

Application of intelligent orienteering based on Internet of things

EURASIP Journal on Wireless Communications and Networking ◽

10.1186/s13638-020-01814-1 ◽

2020 ◽

Vol 2020 (1) ◽

Author(s):

Donghui Zhang ◽

Ruijie Liu

Keyword(s):

Internet Of Things ◽

Network Architecture ◽

Emergency Services ◽

Simulation Experiment ◽

Experimental Studies ◽

Signal Stability ◽

Anchor Nodes ◽

Set Up ◽

The Relationship ◽

The Internet Of Things

Abstract Orienteering has gradually changed from a professional sport to a civilian sport. Especially in recent years, orienteering has been widely popularized. Many colleges and universities in China have also set up this course. With the improvement of people’s living conditions, orienteering has really become a leisure sport in modern people’s life. The reduced difficulty of sports enables more people to participate, but it also exposes a series of problems. As the existing positioning technology is relatively backward, the progress in personnel tracking, emergency services, and other aspects is slow. To solve these problems, a new intelligent orienteering application system is developed based on the Internet of things. ZigBee network architecture is adopted in the system. ZigBee is the mainstream scheme in the current wireless sensor network technology, which has many advantages such as convenient carrying, low power consumption, and signal stability. Due to the complex communication environment in mobile signal, the collected information is processed by signal amplification and signal anti-interference technology. By adding anti-interference devices, video isolators and other devices, the signal is guaranteed to the maximum extent. In order to verify the actual effect of this system, through a number of experimental studies including the relationship between error and traffic radius and the relationship between coverage and the number of anchor nodes, the data shows that the scheme studied in this paper has a greater improvement in comprehensive performance than the traditional scheme, significantly improving the accuracy and coverage. Especially the coverage is close to 100% in the simulation experiment. This research has achieved good results and can be widely used in orienteering training and competition.

Download Full-text

Monosaccharide Biosynthesis Pathways Database

Glycobiology ◽

10.1093/glycob/cwab030 ◽

2021 ◽

Author(s):

Jaya Srivastava ◽

P Sunthar ◽

Petety V Balaji

Keyword(s):

Expression Profiling ◽

Experimental Studies ◽

Structural Complexity ◽

Evolutionary Relationships ◽

Enzyme Assays ◽

Biosynthesis Pathway ◽

Knock Out ◽

Set Up ◽

Function Relationship ◽

Natural Glycans

Abstract A distinctive feature of glycans vis-à-vis proteins and nucleic acids is its structural complexity which arises from the huge repertoire of monosaccharides, isomeric linkages and branching. A very large number of monosaccharides have so far been discovered in natural glycans. Experimentally, pathways for the biosynthesis have been characterized completely for 55 monosaccharides and partially for a few more. However, there is no single platform which provides information about monosaccharide biosynthesis pathways and associated enzymes We have gathered 572 experimentally characterized enzymes of 66 biosynthesis pathways from literature and set up a first of its kind database called the Monosaccharide Biosynthesis Pathways Database http://www.bio.iitb.ac.in/mbpd/). Annotations such as the reaction catalysed, substrate specificity, biosynthesis pathway and PubMed IDs are provided for all the enzymes in the database. Sequence homologs of the experimentally characterized enzymes found in nearly 13,000 completely sequenced genomes from Bacteria and Archaea have also been included in the database. This platform will help in the deduction of evolutionary relationships among enzymes such as aminotransferases, nucleotidyltransferases, acetyltransferases and SDR family enzymes. It can also facilitate experimental studies such as direct enzyme assays to validate putative annotations, establish structure–function relationship, expression profiling to determine the function, determine the phenotypic consequences of gene knock-out/knock-in and complementation studies.

Download Full-text

Intelligent diagnosis and analysis of brain lymphoma based on imaging features

Journal of Intelligent & Fuzzy Systems ◽

10.3233/jifs-189808 ◽

2021 ◽

pp. 1-11

Author(s):

Yipu Mao ◽

Muliang Jiang ◽

Fanyu Zhao ◽

Liling Long

Keyword(s):

Imaging Techniques ◽

Experimental Studies ◽

Diagnostic Value ◽

Imaging Features ◽

Flow Properties ◽

Brain Lymphoma ◽

Diagnosis And Prognosis ◽

Primary Brain Lymphoma ◽

Set Up ◽

Prognosis Evaluation

Currently, DSC has been extensively studied in the diagnosis, differential diagnosis and prognosis evaluation of brain lymphoma, but it has not obtained a uniform standard. By combining DSC imaging features, this study investigated the imaging features and diagnostic value of several types of tumors such as primary brain lymphoma. At the same time, this study obtained data from brain lymphoma patients by data collection and set up different groups to conduct experimental studies to explore the correlation between IVIM-MRI perfusion parameters and DSC perfusion parameters in brain lymphoma. Through experimental research, it can be seen that the combination of two perfusion imaging techniques can more fully reflect the blood flow properties of the lesion, which is beneficial to determine the nature of the lesion.

Download Full-text

Machine learning-based failure mode identification of RCSPSW

IABSE Congress, Christchurch 2021: Resilient technologies for sustainable infrastructure ◽

10.2749/christchurch.2021.1150 ◽

2021 ◽

Author(s):

Dongqi Jiang ◽

Shanquan Liu ◽

Tao Chen ◽

Gang Bi

Keyword(s):

Machine Learning ◽

Failure Mode ◽

Failure Modes ◽

Shear Failure ◽

Tall Buildings ◽

Shear Walls ◽

Superior Performance ◽

Ann Model ◽

Mode Recognition ◽

Wide Range

<p>Reinforced concrete – steel plate composite shear walls (RCSPSW) have attracted great interests in the construction of tall buildings. From the perspective of life-cycle maintenance, the failure mode recognition is critical in determining the post-earthquake recovery strategies. This paper presents a comprehensive study on a wide range of existing experimental tests and develops a unique library of 17 parameters that affects RCSPSW’s failure modes. A total of 127 specimens are compiled and three types of failure modes are considered: flexure, shear and flexure-shear failure modes. Various machine learning (ML) techniques such as decision trees, random forests (RF), <i>K</i>-nearest neighbours and artificial neural network (ANN) are adopted to identify the failure mode of RCSPSW. RF and ANN algorithm show superior performance as compared to other ML approaches. In Particular, ANN model with one hidden layer and 10 neurons is sufficient for failure mode recognition of RCSPSW.</p>

Download Full-text

Studies of the Flame Spraying of Polymers

Thermal Spray 1996: Proceedings from the National Thermal Spray Conference ◽

10.31399/asm.cp.itsc1996p0251 ◽

1996 ◽

Author(s):

D.J. Varacalle ◽

K.W. Couch ◽

V.S. Budinger

Keyword(s):

Bond Strength ◽

Combustion Process ◽

Experimental Studies ◽

Polymer Coatings ◽

Flame Spraying ◽

Knoop Microhardness ◽

Resultant Coating ◽

Strength Characterization ◽

Thermally Sprayed

Abstract Experimental studies of the subsonic combustion process have been conducted in order to determine the quality and economics of polyester, epoxy, urethane, and hybrid polyester-epoxy coatings. Thermally sprayed polymer coatings are of interest to several industries for anti-corrosion applications, including the infrastructural, chemical, automotive, and aircraft industries. Classical experiments were conducted, from which a substantial range of thermal processing conditions and their effect on the resultant coating were obtained. The coatings were characterized and evaluated by a number of techniques, including Knoop microhardness tests, optical metallography, image analysis, and bond strength. Characterization of the coatings yielded thickness, bond strength, hardness, and porosity.

Download Full-text

Robust H∞ Control of STMDs Used in Structural Systems by Hardware in the Loop Simulation Method

Actuators ◽

10.3390/act9030055 ◽

2020 ◽

Vol 9 (3) ◽

pp. 55

Author(s):

Huseyin Aggumus ◽

Rahmi Guclu

Keyword(s):

Natural Frequencies ◽

Experimental Studies ◽

Mr Damper ◽

Simulation Method ◽

Control Element ◽

Structural Systems ◽

Hardware In The Loop ◽

Building Model ◽

Mass Damper ◽

Set Up

This paper investigated the performance of a semi-active tuned mass damper (STMD) on a multi-degree of freedom (MDOF) building model. A magnetorheological (MR) damper was used as a control element that provided semi-activity in the STMD. The Hardware in the Loop Simulation (HILS) method was applied to mitigate the difficulty and expense of experimental studies, as well as to obtain more realistic results from numerical simulations. In the implementation of this method for the STMD, the MR damper was set up experimentally, other parts of the system were modeled as computer simulations, and studies were carried out by operating these two parts simultaneously. System performance was investigated by excitation with two different acceleration inputs produced from the natural frequencies of the MDOF building. Additionally, a robust H ∞ controller was designed to determine the voltage transmitted to the MR damper. The results showed that the HILS method could be applied successfully to STMDs used in structural systems, and robust H ∞ controls improve system responses with semi-active control applications. Moreover, the control performance of the MR damper develops with an increase in the mass of the STMD.

Download Full-text