Analysis of the Crack Fracture Morphology of the Asphalt Mixture under Tensile Stress Effects

2011 ◽  
Vol 250-253 ◽  
pp. 3533-3537 ◽  
Author(s):  
Li Hua Zhao ◽  
Jing Yun Chen ◽  
Sheng Wu Wang
Keyword(s):  
Brittle Fracture ◽  
Fracture Surface ◽  
Tensile Stress ◽  
Mechanical Characteristics ◽  
Asphalt Mixture ◽  
Fracture Morphology ◽  
Microscopic Mechanism ◽  
Interface Zone ◽  
Stress Effects ◽  
Bending Fracture

Through studying the bending fracture and cleavage fracture of the asphalt mixture within the different temperature condition, confirming that the temperature influences the microscopic mechanism of mixture cracking: the fracture is relatively flat with low temperture, the destruction of the asphalt mixture is also mainly result of the brittle fracture; As the temperature rise, fracture surface becomes coarse, some part show large plastic elapse deformation. Adding fiber can reduce thickness of the asphalt membrane, improve the bonding strength of asphalt mastic, and greatly increase the ratio of the aggregate fracture and interface zone fracture, so as to enhance the asphalt mixture crack-resistance. The fracture morphology of asphalt mixture has a better reflection for its mechanical characteristics.

Fracture Morphology and Residual Stresses of TiAl-Based Alloys Sheet Fabricated by EB-PVD

2006 ◽  
Vol 324-325 ◽  
pp. 307-310
Author(s):  
De Ming Zhang ◽  
Gui Qing Chen ◽  
Chun Mei Zhang ◽  
Jie Cai Han
Keyword(s):  
Free Surface ◽  
Numerical Calculation ◽  
Tensile Stress ◽  
Residual Stresses ◽  
Intergranular Fracture ◽  
Cleavage Fracture ◽  
Vacuum Annealing ◽  
Fracture Morphology ◽  
Columnar Crystal ◽  
X Ray

The TiAl-based alloys sheet with 150 mm × 100 mm × 0.4 mm was fabricated successfully by using EB-PVD method. The fracture morphology and residual stresses of the sheet were analyzed by SEM, numerical calculation and X-ray stress analyzer. The results indicate that before stripping, the depositional layers have a higher compressive stress, and the substrate has a very lower tensile stress. For the isolated TiAl-based alloys sheet, the microstructure of as-deposited sheet is columnar crystal, and the residual stresses distribution on the free surface has a trend that its magnitude decreased gradually from center to edges. After vacuum annealing at 1273 K for 16 h, the columnar crystal transforms into the equiaxed, the residual stresses on the free surface are eliminated ultimately, and the fracture of the material is diverted from the manner of intergranular fracture to the mixed manner of intergranular fracture with cleavage fracture.

scholarly journals Investigation of Effective Mechanical Characteristics of Nanomodified Carbon-Epoxide Composite by Numerical and Analytical Methods

2021 ◽  
Vol 12 (5) ◽  
pp. 535-541
Author(s):  
M.O. Kaptakov
Keyword(s):  
Mechanical Properties ◽  
Numerical Modeling ◽  
Fracture Surface ◽  
Mechanical Characteristics ◽  
Modeling Methods ◽  
Fullerene Soot ◽  
The Matrix ◽  
Numerical And Analytical Methods ◽  
Composite Samples

In this work, the mechanical properties of composite samples prepared using a conventional and nanomodified matrix were studied. The thickness of the monolayers in the samples was 0,2 μm. It was found in experiments, that the addition of fullerene soot as a nanomodifierled to an increase in the mechanical properties of the samples along the direction of reinforcement. At the same time, an improvement in the quality of the contact of the matrix with the fibers in the samples with the nanomodifier was observed: on the fracture surface, the nanomodified matrix envelops the fibers, while the usual matrix completely exfoliates. The obtained effects of changing the strength of composites can be associated, among other things, with a change in the level of residual stresses arising in composites during nanomodification. Analytical and numerical modeling methods are used to explain these effects.

Anisotropic Mechanical Properties of Rapid Prototyping Parts Fabricated by Stereolithography

2021 ◽  
Vol 13 (9) ◽  
pp. 1812-1819
Author(s):  
Na-Na Yang ◽  
Hao-Rui Liu ◽  
Ning Mi ◽  
Qi Zhou ◽  
Li-Qun He ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Elastic Modulus ◽  
Brittle Fracture ◽  
Fracture Surface ◽  
Elongation At Break ◽  
Build Orientation ◽  
Range Distribution ◽  
Anisotropic Mechanical Properties ◽  
Orientation Experiment

Stereolithography (SLA)-manufactured parts behave with anisotropic properties due to the varying interface orientations generated by the layer-based manufacturing process. Part build orientation is a very important factor of anisotropic mechanical properties. In this paper, the build orientation experiment was designed to study the anisotropic behaviour of the mechanical properties of the SLA parts based on the orientation relationship between the force and the layer. The results show that there are obvious brittle characteristics on the fracture surface of the specimens and microcracks perpendicular to the direction of the layer distributed on the side of the fracture. The mechanical properties under brittle fracture have different degrees of sensitivity to the build orientation. Among all the build orientations, whether a specimen is built flat or on an edge shows obvious difference in tensile strength, and the relative range distribution reaches 35%. The changes in elastic modulus and the elongation at break are the most obvious in different angles relative to the XY plane, and the relative range distribution reaches 62% and 56% respectively. In all the build orientations designed, the tensile strength is the largest when it is placed on the edge at 0° with Y-axis in the XY plane, the elastic modulus is the largest when it was placed vertically, and the elongation at break is the largest when it is placed flat at 45° with Y-axis in the XY plane.

Fracture Behavior of an AlMgMnSc Alloy at Different Temperatures

2021 ◽  
Vol 1016 ◽  
pp. 292-296
Author(s):  
Yuliya Igorevna Borisova ◽  
Diana Yuzbekova ◽  
Anna Mogucheva
Keyword(s):  
Tensile Strength ◽  
Ultimate Tensile Strength ◽  
Brittle Fracture ◽  
Fracture Surface ◽  
Strain Rate ◽  
Fracture Behavior ◽  
Fine Grained ◽  
Angular Pressing ◽  
Different Temperatures ◽  
Elongation To Failure

An Al-4.57Mg-0.35Mn-0.2Sc-0.09Zr (wt. %) alloy was studied in the fine-grained state obtaining after equal channel angular pressing. The mechanical behavior of alloy at the temperatures 173 K, 298 K and 348 K and at strain rate 1×10–3 s–1 is studied. Increase of the temperature testing from 173 K to 348 K decreases the yield stress by 80 MPa, the ultimate tensile strength by 60 MPa while elongation-to failure increases by a factor of 1.4. It was found that at temperatures of 298 and 173 K, the studied alloy mainly demonstrates the mode of ductile fracture, and at a temperature of 348 K the mechanism can be described as mixed ductile-brittle fracture. It was also established that of the studied alloy is the temperature dependence of the size of the dimples on the fracture surface. The formation of smaller dimples in the samples deformed at 298 K was observed.

The Microscopic Analysis on the Crankshaft Fracture Surface of the Compressor

2014 ◽  
Vol 912-914 ◽  
pp. 837-840
Author(s):  
Wei Dong Chen
Keyword(s):  
Heat Treatment ◽  
Brittle Fracture ◽  
Fracture Surface ◽  
Grain Refinement ◽  
Stress Fracture ◽  
Failure Modes ◽  
Microscopic Analysis ◽  
Dendritic Segregation ◽  
Micro Analysis

Fracture is the most common failure modes of the crankshaft, under normal circumstances often result in serious consequences. So study the reasons for the crankshaft fracture, thus achieving the purpose of controlling and reducing accidents, is very realistic. In this paper, for example, a factory break 4M16 compressor crankshaft. Through micro-analysis of the crankshaft fracture, the 4M16 compressor crankshaft is a low stress fracture of brittle fracture .The fracture is mainly due to dendritic segregation cause tissue caused by uneven. Solution to the problem is to increase the ratio of forging the forging, heat treatment when the grain refinement.

scholarly journals Study on the Creep Behavior of a Ni3Al-Based Single Crystal Alloy at 850°C/450 MPa

2020 ◽  
Vol 2020 ◽  
pp. 1-7
Author(s):  
Liwu Jiang ◽  
Yu Yang ◽  
Meiling Wu ◽  
Min Cai
Keyword(s):  
Fracture Surface ◽  
Single Crystal ◽  
Creep Behavior ◽  
Creep Deformation ◽  
Fracture Mechanism ◽  
Crystal Orientation ◽  
Fracture Morphology ◽  
Cutting Mechanism ◽  
Single Crystal Alloy ◽  
Fracture Morphologies

The creep behaviors of Ni3Al-based single crystal alloy IC6SX with [001] and [111] orientations under the condition of 850°C/450 MPa were investigated. The effect of crystal orientation on the creep lives, fracture morphology, fracture mechanism, and dislocation evolution of the alloys with different orientations was analyzed systematically. The results showed that the creep lives of the alloy were closely related to the crystal orientation under the condition of 850°C/450 MPa. The creep lives of the single crystal alloys with [001] and [111] orientations were 56.3 h and 126.9 h, respectively. Moreover, the fracture morphologies of the two alloys with [001] and [111] orientations were different. The results showed that some holes formed at the fracture surface of the alloy with [111] rather than [001] orientation. Furthermore, the surface near the fracture of the two alloys with [001] and [111] orientations was serrated. Therefore, the fracture mechanism of the single crystal alloys with [001] and [111] orientations was ductile fracture. In addition, a large number of dislocations cut into the γ ′ phase. Therefore, the cutting mechanism of dislocations in the alloys with [001] and [111] orientations was the creep deformation mechanism.

scholarly journals Research on Rock Fracture Surface Morphology Characterization under Brazilian Test

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Zhigang Feng ◽  
Xuezai Pan ◽  
Guoxing Dai ◽  
Hongguang Liu
Keyword(s):  
Fracture Surface ◽  
Rock Fracture ◽  
Fracture Morphology ◽  
Brazilian Test ◽  
Variation Method ◽  
Fracture Surfaces ◽  
Modulus Maximum ◽  
Loading Modes ◽  
Morphology Characterization ◽  
Maximum Method

In order to test the differences in the morphology characterization of rock fracture surfaces under different loading directions and rates, the following three steps are operated. Firstly, using Brazilian test, the Brazilian discs are loaded to fracture under different loading modes. Secondly, each rock fracture surface is scanned with a highly accurate laser profilometer and accordingly the coordinates of three lines on every rock fracture surface and three sections of every line are selected to analyze their fracture morphology characterization. Finally, modulus maximum method of wavelet transform, including a new defined power algorithm and signal to noise ratio, and fractal variation method are used to determine the differences in rock fracture surfaces’ morphology characterization under different loading directions and rates. The result illustrates that both modulus maximum and fractal variation method can detect anisotropy of rock fracture failure. Compared to modulus maximum method, fractal variation method shows stronger sensitivity to the change of loading rates, which is more suitable to differentiate the rock fracture surface’s morphology characterization under different loading modes.

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