scholarly journals Numerical Analysis for the Progressive Failure of Binary-Medium Interface under Shearing

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Rihong Cao ◽  
Wenyu Tang ◽  
Hang Lin ◽  
Xiang Fan
Keyword(s):  
Shear Strength ◽  
Bond Strength ◽  
Normal Stress ◽  
Strength Ratio ◽  
Normal Stresses ◽  
Stress Increase ◽  
Tensile Cracks ◽  
Medium Interface ◽  
High Bond ◽  
High Bond Strength

Binary-medium specimens were fabricated using the particle flow code, and the shear strength, dilatancy, and failure behavior of the binary-medium specimens with different bond strength ratios (0.25, 0.5, 0.75, and 1.0) under different normal stresses were studied. Numerical results show that the bond strength ratio and normal stresses considerably influence the shear strengths of binary-medium interface. Shear strength increases as the bond strength ratio and normal stress increase. The dilation of interfaces with high bond strength ratios is more evident than those of interfaces with lower bond strength ratios, and the curves for the high bond strength ratio exhibit remarkable fluctuations during the residual stage. At increased normal stress and bond strength ratio, the peak dilation angle shows decreasing and increasing trends successively. In this study, the specimens exhibited three kinds of failure modes. In mode II, the sawtooth experienced shear failure, but some tensile cracks appeared on the interface of the binary-medium. In mode III, no sawtooth was cut off, indicating tensile failure on the interface. At a low bond strength ratio, damage or failure is mostly concentrated in the upper part of the model. Failure parts gradually transfer to the lower part of the model when the bond strength ratio and normal stress increase. Furthermore, evident tensile cracks occur on the interface. When the bond strength ratio reaches 1.0, the failure mode of the specimen gradually transforms from sheared-off failure to chip-off failure. The number of microcracks in the specimens indicates that the lower the bond strength ratio, the more severe the damage on the specimens.

Shear strength and dilative characteristics of an unsaturated compacted completely decomposed granite soil

2010 ◽  
Vol 47 (10) ◽  
pp. 1112-1126 ◽  
Author(s):  
Md. Akhtar Hossain ◽  
Jian-Hua Yin
Keyword(s):  
Shear Strength ◽  
Normal Stress ◽  
Matric Suction ◽  
Water Retention Curve ◽  
Direct Shear ◽  
Normal Stresses ◽  
Soil Water Retention Curve ◽  
Strength Data ◽  
Decomposed Granite ◽  
Completely Decomposed Granite

Shear strength and dilative characteristics of a re-compacted completely decomposed granite (CDG) soil are studied by performing a series of single-stage consolidated drained direct shear tests under different matric suctions and net normal stresses. The axis-translation technique is applied to control the pore-water and pore-air pressures. A soil-water retention curve (SWRC) is obtained for the CDG soil from the equilibrium water content corresponding to each applied matric suction value for zero net normal stress using a modified direct shear apparatus. Shear strength increases with matric suction and net normal stress, and the failure envelope is observed to be linear. The apparent angle of internal friction and cohesion intercept increase with matric suction. A greater dilation angle is found at higher suctions with lower net normal stresses, while lower or zero dilation angles are observed under higher net normal stresses with lower suctions, also at a saturated condition. Experimental shear strength data are compared with the analytical shear strength results obtained from a previously modified model considering the SWRC, effective shear strength parameters, and analytical dilation angles. The experimental shear strength data are slightly higher than the analytical results under higher net normal stresses in a higher suction range.

Sol-Gel Coating Facilitating Si-to-Si Wafer Bonding at Low Temperature

2005 ◽  
Author(s):  
J. Wei ◽  
S. S. Deng ◽  
C. M. Tan
Keyword(s):  
Low Temperature ◽  
Bond Strength ◽  
Wafer Bonding ◽  
Intermediate Layer ◽  
Bonding Temperature ◽  
Sol Gel ◽  
Bond Quality ◽  
Bubble Generation ◽  
High Bond ◽  
High Bond Strength

Silicon-to-silicon wafer bonding by sol-gel intermediate layer has been performed using acid-catalyzed tetraethylthosilicate-ethanol-water sol solution. High bond strength near to the fracture strength of bulk silicon is obtained at low temperature, for example 100°C. However, The bond efficiency and bond strength of this intermediate layer bonding sharply decrease when the bonding temperature increases to elevated temperature, such as 300 °C. The degradation of bond quality is found to be related to the decomposition of residual organic species at elevated bonding temperature. The bubble generation and the mechanism of the high bond strength at low temperature are exploited.

Bonding of Polyethylene to Metals and Rubber with Hydrogenated Polybutadiene

1962 ◽  
Vol 35 (4) ◽  
pp. 1060-1062
Author(s):  
A. I. Yakubchik ◽  
S. Ya Grilikhes ◽  
B. I. Tikhomirov ◽  
V. S. Purlova
Keyword(s):  
Bond Strength ◽  
Adhesive Composition ◽  
High Bond ◽  
High Bond Strength ◽  
Hydrogenated Polybutadiene

Abstract The adhesive composition based on hydrogenated unbranched 1,4-polybutadiene gives a high bond strength between polyethylene and brass, and brass-plated metal, and rubber.

scholarly journals Research on the Properties of High-strength Gypsum Based Tile Adhesive in Interior Decoration

2020 ◽  
Vol 165 ◽  
pp. 05015
Author(s):  
Ji Xiu Zhang ◽  
Ye Zhang ◽  
Ji Kang Liu ◽  
Yuan Chao Miao ◽  
Sai Hong Duan
Keyword(s):  
Bond Strength ◽  
Dimensional Stability ◽  
High Strength ◽  
High Dimensional ◽  
Strength Development ◽  
Interior Decoration ◽  
High Bond ◽  
High Bond Strength ◽  
Early Strength ◽  
Interface Treatment

In this paper, a new early strength tile adhesive is prepared by using α- high strength gypsum and its properties are discussed. The research methods refer to relevant Chinese standards. The results show that the tensile bond strength of the adhesive can reach 0.6 MPa in one day and 1.5 MPa in 7 days, which is close to 80% of 28-day strength. It is indicating that the adhesive has high bond strength, rapid strength development, and high dimensional stability. It effectively solves the problems that the traditional cement-based tile adhesive is prone to hollowing, falling off, and cracking. Additionally, no interface treatment is required during the using process of this gypsum-based adhesive.

Mechanical Strength and Resistance to Ultraviolet Radiation of Repairing Mortars Based on Epoxy Resin

2011 ◽  
Vol 391-392 ◽  
pp. 807-811
Author(s):  
Fang Liu ◽  
Zhi Bin Zhang ◽  
Ling Ling Xu ◽  
Ming Shu Tang
Keyword(s):  
Compressive Strength ◽  
Bond Strength ◽  
Epoxy Resin ◽  
Cement Mortar ◽  
Light Radiation ◽  
Mortar Specimen ◽  
High Durability ◽  
High Bond ◽  
High Bond Strength ◽  
Peak Value

The epoxy resin based repairing material(REM) is suitable for repairing cracks and holes in concrete or broken concrete due to its high bond strength and high durability. The compressive strength and flexile strength are 76.4MPa and ＞12.5MPa at 28d, and the retest strength still remain 73.4MPa and ＞12.5MPa respectively. The fracture location of cement mortar specimen bonded by RME is at cement mortar, that is, the bond strength between REM and cement mortar is more than mortar itself. The compressive strength of RME keeps 93.3% under ultraviolet light radiation (Peak Value 308nm, 49.5 W/m2) for 1700h.

scholarly journals A Tough, Water-Resistant, High Bond Strength Adhesive Derived from Soybean Meal and Flexible Hyper-Branched Aminated Starch

Polymers ◽  
2019 ◽  
Vol 11 (8) ◽  
pp. 1352 ◽  
Author(s):  
Yi Zhang ◽  
Jieyu Zhang ◽  
Mingsong Chen ◽  
Jing Luo ◽  
Sheldon Q. Shi ◽  
...  
Keyword(s):  
Bond Strength ◽  
Soybean Meal ◽  
Water Resistance ◽  
Crosslinking Agent ◽  
Crosslinking Density ◽  
Chain Structure ◽  
High Bond ◽  
High Bond Strength ◽  
Branched Structure ◽  
Long Chain

Soybean meal (SM)-based adhesive exhibited a great potential to replace petroleum-derived ones to alleviate the energy crisis and eliminate carcinogenic formaldehyde. However, the bad water resistance (caused by low crosslinking density) and inherent brittleness of SM adhesive severely hindered its application. However, improving crosslinking density is generally accompanied by a toughness reduction of the adhesive. Herein, we developed a flexible long-chain starch with a hyper-branched structure (HD), and incorporated it with SM and a crosslinking agent to prepare a novel SM adhesive. Results showed that this adhesive exhibited both excellent water resistance and enhanced toughness. The wet bond strength of plywood fabricated using this adhesive was 354.5% higher than that of SM adhesive. These achievements are because introducing HD with hyper-branched groups enhanced crosslinking density, while HD’s flexible long-chain structure improved toughness of the adhesive. This HD can promote the development of tough and hydrophobic bio-based composites.

scholarly journals Adhesive bonding of resin cements to cast titanium with adhesive primers

2012 ◽  
Vol 23 (3) ◽  
pp. 218-222 ◽  
Author(s):  
Marina Di Francescantonio ◽  
Marcelo Tavares de Oliveira ◽  
Luiz Gustavo Dias Daroz ◽  
Guilherme Elias Pessanha Henriques ◽  
Marcelo Giannini
Keyword(s):  
Bond Strength ◽  
Titanium Surface ◽  
Adhesive Bonding ◽  
Resin Cement ◽  
Resin Cements ◽  
Relyx Unicem ◽  
Testing Data ◽  
High Bond ◽  
High Bond Strength ◽  
Post Hoc

The purpose of this study was to evaluate the effects of adhesive primer applications on the bond strength of resin cements to cast titanium. Four adhesive primers - Metaltite, Metal Primer II, Alloy Primer and Ceramic Primer - and their respective resin cements - Bistite II DC, Link Max, Panavia F 2.0, RelyX Unicem and RelyX ARC - were tested. Cast plates were prepared from titanium ingots (n=6 specimens/cement) and had their surfaces airborne-particle abraded with Al2O3 (50 μ m). Three resin cement cylinders were built on each bonded titanium surface, using a cylindrical translucent tubing mold and were subjected to micro-shear testing. Data were analyzed statistically by two-way ANOVA and Tukey's post-hoc test (α=0.05). The application of Metal Primer II and Ceramic Primer resulted in significant higher bond strength for Link Max and RelyX Unicem resin cements, respectively, than nonuse of adhesive primers. Panavia F 2.0 and RelyX ARC yielded high bond strength means with or without adhesive primers. The use of adhesive primers might increase the bond strength to cast titanium depending on the resin cement used.

scholarly journals Numerical Shear Tests on the Scale Effect of Rock Joints under CNL and CND Conditions

2020 ◽  
Vol 2020 ◽  
pp. 1-15 ◽  
Author(s):  
Xige Liu ◽  
Wancheng Zhu ◽  
Lankun Li
Keyword(s):  
Shear Strength ◽  
Normal Stress ◽  
Scale Effect ◽  
Shear Behavior ◽  
Shear Displacement ◽  
Rock Joints ◽  
Peak Shear Strength ◽  
Normal Stresses ◽  
Shear Tests ◽  
Joint Length

The scale effect of rock joint shear behavior is an important subject in the field of rock mechanics. There is yet a lack of consensus regarding whether the shear strength of rock joints increases, decreases, or remains unchanged as the joint size increases. To explore this issue, a series of repeated and enlarged numerical joint models were established in this study using the particle flow code (PFC2D). The microparameters were calibrated by uniaxial compression tests and shear tests on the concrete material under the constant normal loading (CNL) condition. Three different normal stresses were adopted in numerical shear tests with joint specimen lengths ranging from 100 mm to 800 mm. In addition to the commonly used CNL, the constant normal displacement (CND) condition was established for the purposes of this study; the CND can be considered an extreme case of the constant normal stiffness (CNS) condition. The shear stress-shear displacement curves changed from brittle failure to ductile failure alongside a gradual decrease in peak shear strength as joint length increased. That is, an overall negative scale effect was observed. Positive scale effect or no scale effect is also possible within a limited joint length range. A positive correlation was also observed between the peak shear displacement and joint length, and a negative correlation between shear stiffness and joint length. These above statements are applicable to both repeated and enlarged joints under either CNL or CND conditions. When the normal stress is sufficiently high and shear dilatancy displacement is very small, the shear behavior of rock joints under CNL and CND conditions seems to be consistent. However, for shear tests under low initial normal stress, the peak shear strength achieved under the CND condition is much higher than that under the CNL condition, as the normal stresses of enlarged joints increase to greater extent than the repeated ones during shearing.

Effect of Chlorhexidine Application Methods on Microtensile Bond Strength to Dentin in Class I Cavities

2010 ◽  
Vol 35 (6) ◽  
pp. 618-623 ◽  
Author(s):  
Y-E. Chang ◽  
D-H. Shin
Keyword(s):  
Clinical Practice ◽  
Phosphoric Acid ◽  
Bond Strength ◽  
Clinical Relevance ◽  
Class I ◽  
Microtensile Bond Strength ◽  
High Bond ◽  
High Bond Strength ◽  
Application Methods

Clinical Relevance In order to secure high bond strength in clinical practice, 2% chlorhexidine application after etching with 37% phosphoric acid is the recommended procedure.

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