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Strain Energy Decomposition Influence in the Phase-Field Crack Modelling at the Microstructural Level of Heterogeneous Materials Karlo Seleš1,a, Zdenko Tonković1,b, Ante Jurčević1,c, Jurica Sorić1,d 1University of Zagreb, Faculty of Mechanical Engineering and Naval Architecture, I.
The microstructural geometries of the nodular cast iron obtained with the metallographic examination and the material properties of an academic brittle material have been used in numerical simulations where the graphite nodules have been considered as porosities.
For the brittle material behaviour assumption, the phase-field approach is mostly based on the Griffith's linear elastic fracture mechanics theory, where the crack evolution depends on the material properties, in particular the fracture stress/strain and the fracture toughness, and external factors, such as mechanical loads [2,3].
Since at this moment, the here presented phase-field model predicts brittle fracture initiation and propagation, the nodular cast iron ductile material properties have been replaced with the academic brittle material characteristics in this work.
However, it is also evident that different decomposition models can affect the crack branching and propagation prediction.

They have great mechanical resistance and they can be improved constantly by changing the components to achieve the targeted properties.[1] Most prosthetic works are made of metal-ceramics or metal-acrylate.
The microscopic image shows that the metallic structure is not affected by corrosive agents and did not break under the mechanical strain.
Usually the materials qualities concerning mechanical properties, chemical resistance to aggressive substances, wear resistance are reflected in the high costs of the prosthetic works which become unaffordable to certain categories of people.
Among the studied structures we found that the chrome structure is one of the best affordable, the allergic reactions are scarce and the mechanical and chemical properties very good.
The gaudent structure which used to be often encountered in the past might be cheaper but its properties are much lower.

Introduction With the continuous development of the human economy, the growing demand for energy, resources, mining depth and intensity is increasing, the impact of deep coal occurrence frequency and intensity has also increased, coal and rock from the impact of disasters is often associated with coal seam - the destruction of the roof system, so you can consider using combination of coal and rock mechanical properties of compressive failure tests to explore coal-the top issue of system instability[1-3].
Accuracy of the specimen's Republic of China Ministry of Coal Industry Ministry to meet the standard "physical and mechanical properties of coal and rock determination" requirement.
Image color enhancement designed to improve visual resolution, and color categories that affect the visual resolution and contrast the two main factors.
Mechanical system will have a pressure bump instability.
CT Identification of Rock Danage Properties[J].

CFRP composites differ from metals in many ways because composite has two phases of materials with drastically distinguished mechanical and thermal properties.
The machining, especially, significantly affects these materials, thus leading to various modes of damages including fiber breakage, matric cracking and fiber pullout [2].
The layered structure of carbon fiber also affected the generation of cutting damages.
In addition, the moving direction of cutting edges is also becoming a key-factor to reduce the generation of cutting damages.
References [1] X.Huang, Fabrication and properties of carbon fibers, Materials, 2(2009)2369-2403

Control and Mechanism Analysis of Serrated Chip Formation in High Speed Machining of Aluminum Alloy 7050-T7451 Qihang Shi1,a, Zongcheng Hao1,b, Shuai Wang1,c, Xiuli Fu1,d* and Hui Wang1,e 1Department of Mechanical Engineering, University of Jinan, Jinan, 250022, China aqh_shi1@163.com, bzc_hao22@163.com, c1256382660@qq.com, d*me_fuxl@ujn.edu.cn, ew_hui21@163.com Keywords: Aluminum alloy 7050-T7451; High speed cutting; Chip formation; Plastic-brittle conversion Abstract.
Under the condition of high speed cutting, the high speed impact of the cutter on the workpiece and the shear behavior lead to the high strain rate of the material in the deformation zone, which makes the dynamic mechanical properties of the workpiece change dramatically, and then directly affects the chip formation mechanism [4,5] and chip shape evolution [6,7].
Since the thermal softening effect occupies the main deformation influencing factors, the material softens, and the serration section is easier due to the pressing action.
The serration frequency is the determining factor for the chip serration unit.
Figure 4 Morphological evolution of aluminum alloy 7050-T7451 high speed cutting chip (a. v = 314 m/min; b. v = 943 m/min; c. v = 1257 m/min; d. v = 1571 m/min; e. v = 2513 m/min; f. v = 3738 m/min) The dynamic mechanical properties of materials are changed by high strain rate in high speed cutting.

The vibration would not only bring forth the tower's extra-stress which will affect the structural strength, but also affected the distortion and vibration of the wind wheel.Meanwhile, it's possible that the tower would resonate with revolving wind wheel and thus affected the performance of wind units[1].
Over the past decade, as it has features such as it won't affect the normal use ,it only need to determine the dynamic response of structure and it need not expencive excitation set,the research of Modal Analysis of vibration caused by Ambient Excitation has been a popular subject in recognition system of civil engineering[2].
Vibration Test Testing Principle It's difficult to adopt controllable factitious exciter such as sine wave and impulse to test the vibration of the tower of wind driven generator, and the test will be affected by force magnitude, the weight and hardness of hammer, the position of percussion point.
Acknowledgements 2009MS0718 The Nature Science Foundation Projects of Inner Mongolia, Research On Mechanical Properties And Dynamic Response of Large Wind Tower; 51068021 The National Natural Science Foundation, Research on Performance Analysis and Design Method of Lattice Concrete Filled Steel Tube Wind Tower.
Vol. 42 (2009), p. 31 In Chinese [4] Chong REN, Wei ZHANG and Fuquan ZHANG: Mechanical & Electrical Engineering Technology.

If the outburst happens, the results of it will affect the normal mining process, destroy the equipment, threaten the worker’s life, etc..
In the paper, we think that the study on the physical and mechanical properties of coal and rock with and without gas is the primary task to resolve the outburst problem in the mine.
In order to study the creep properties of rock-liked materials, laboratory experiments are the main methods to investigate time-dependent mechanical properties of rocks through long-term testing and observations, strict control of the testing conditions and elimination of the effects of secondary factors in time-dependency [5-8].
Analyzing the previous experimental results of coal creep properties and considering the shortcoming of General Kelvin model, one nonlinear damage creep model of coal is founded based on the general Kelvin model.
As the general Kelvin model can describe the elastic and viscous deformation perfectly, so in the following, we choose the Kelvin model as the basic model to describe the creep properties of coal.

Introduction A201aluminum alloy has the highest mechanical properties among all the cast aluminum alloys, and which is also an important structural material used in aerospace industry and military area.
Chang, “The Study of Castability And Mechanical Properties of High Strength A201 Aluminum Alloy,” CSIST Report (1989) [2] Y.S.
Kuo, “The Influence of Cooling Rate on the Mechanical Properties and Porosity Content of High Strength Aluminum Alloy Castings ”, Foundry Technology (Zhuzao Jishu) , Vol.29, No.11, (Nov. 2008) 1513-1517
Hatch, “Aluminum Properties and Physical Metallurgy” ch.6, ASM (1984) [6] ASM Metals Handbook “Castings” Vol.15 9th.
Panchanathen, “Section Feeding Efficiency Factor － A New Parameter for Soundness Evaluation,” AFS Transactions Vol.82, (1974), 165-168

Research the Excavation Angle Affect on Seismic Dynamic Response of Slope A Fa-you1，a , KONG Ji-ming2,b, NI Zhen-qiang2,c 1 Faculty of Land Resource Engineering, Kunming University of Science and Technology, Kunming Yunnan 650093, China 2Institute of mountain Hazards and Environment，Chinese Academy of Sciences, Chengdu Sichuan 610041, China aafayou@163.com Keywords: seismic dynamic response, excavation angle, slope Abstract.
Slope excavation is one of the main factors to mutation and the seismic dynamic response to earthquake mountain disasters will be different caused by different excavation angle.
Seismic activity frequent in our country western and the mountainous widespread distribution, and excavation damage slope wide distribution and quantity, a large number of casualties and property losses to the country and people caused by seismic mountain disaster of excavation damage slope.
Physical and mechanical parameters of the slope are shown in Table 1.
Table 1 Physical and mechanical parameters of the slope rock Density(kg.m-3) Elastic modulus (Gpa) Poisson's ratio granite 2,800 45 0.1 The transient dynamic analysis technology was adopted for dynamic analysis of structure.

The roll speed is most important factor in the roll cater.
The mechanical property of the strip with smooth scribed surface became better.
Mechanical property of the strip cast using the single roll caster equipped with the scraper was almost as same as that of strip cast by D.C. casting.
Summary Properties of a single roll caster equipped with a scraper were shown in this paper.
Properties of the AA5182 strip by a single roll caster equipped with a scraper were almost as same as these of the strip made by D,C. casting.