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Mechanical Model and Analysis on Movement of Rock Strata between Coal Seams in Pillar Upward Mining of Left-Over Coal GuoRui Feng a, Jing Zheng *,b , YaFeng Ren c, CongMing Zhong d and LiXun Kang e 1College of Mining Engineering, Taiyuan University of Technology, Taiyuan 030024, China azjgenq@yahoo.cn, bfguorui@163.com, crenyafeng0322@163.com, ddahuamm2002@yahoo.com.cn, ekanglixun@sohu.com *Corresponding author Key words: pillar, upward mining of left-over coal, rock strata between coal seams, movement Abstract Work out control measures for pillar upward mining of left-over coal, in view of coal floor movement, this paper analyzes theoretical foundation and mechanical properties of mechanical model on coal floor movement of rock strata between coal seams in pillar upward mining of left-over coal and presents a simplified corresponding mechanical condition.
Taking into the relation between layer movement and time consideration, the PTh model is used to show its rheological properties.
It shows that overlying rock movement above the goaf is a temporal and spatial process, which has the obvious rheological properties and the rock movement is relevant with time factors significantly.
If time properties are not considered, according to the basic hypothesis of elastic-plastic mechanics, the rheology instantaneously finished, thus many instantaneous deformations can't be explained.
The PTh model is used to show rheological properties about coal floor movement, by using a two-dimension model, mechanical model of coal floor movement is set up and both ends of cantilever beam are fixed.

Mechanical Properties of Filler Metal in Si3N4/Austenitic Stainless Steel/Si3N4 Joints as Measured by Nanoindentation and Its Relationship to the Interfacial Strength Daniel Cáceres1, Raquel Polanco2, Pilar Miranzo2 and María Isabel Osendi2 1 Dpto.
Recently, some efforts have been devoted to relate nanoindentation derived properties -elastic modulus and hardness- to other mechanical properties of metals such as tensile strength or to the same properties measured by bulk methods [1-2].
Furthermore, due to the tip size and positioning capability, the nanoindentation technique allows evaluating elastic properties as a function of the distance to the bonding interface, which at times can be of interest [3].
The increase in E and H could be attributed to two factors, such as the nucleation of nitride species (CrxNy) within the interlayer after bonding [7] or even to the joining process itself as the foil is subjected to temperature and pressure affecting dislocations.
Summary The shear strength of Si3N4 joined using different ss foils was dependent on the composition of minor elements and was directly related to the elastic properties of the foils after bonding.

Three main factors are cracking, wrinkling and springback during the process of the sheet metal stamping forming.
Experimental Study There are many factors of the affecting springback, such as material properties, thickness of sheet metal, the condition of friction, the geometric parameter of mold and the parameters of technology during the processing, they have different degrees effects on springback.
Material Properties.
Table 3 Material properties Material Poisson ratio Elasticity modulus(MPa) Yield strength(MPa) Hardelling index Density(ton/mm 3) 6111 0.33 2.07×105 183 0.265 7.85×10-9 The Model of FEM.
Before applying the load, the parameters in table 3 are added to the table of material properties.

The materials used in producing bipolar plate are greatly affecting its final properties.
Through this study, the properties of bipolar plate composite will be observed.
One of the key factors limiting fuel cell commercialization is the development of bipolar plates, which are one of PEMFC’s main components.
The addition of CB not only improves the electrical conductivity but also improves the mechanical properties.
Muchtar, The Effects of Thickness Reduction and Particle Sizes on The Properties Graphite – Polypropylene Composite, International Journal of Mechanical and Materials Engineering (IJMME), Vol.6 (2011), No.2, 194-200

Based on compression tests of closed-cell Al alloy foam measured, mchanical properties and energy absorption capability had been investigated.
Properties of uniaxial compression, energy absorption capability and energy absorption efficiency have been studied.
Properties of energy absorption Properties of energy absorption are characterized by energy absorption capacity W [2]
It has good compressive properties because of the feature of its structure.
The densification starting point and fracture morphology are important factor to affect energy absorption.

High-speed high-precision CNC processing technology plays a very important position in the CNC machining industry,machine disturbance,however,an important factor affecting the machining accuracy,the ball screw feed drive as an important part of the machine directly affects the operating characteristics of the machine.Ball screw drive system,Solidworks,Ansys,Adams the establishment of machine tool,rigid-flexible couping the multibody dynamics model,the dynamic characteristic curve of the machine.Compared with the rigid body model simulation results verify the feasibility of rigid-flexible coupling modeling method,optimized to provide the basis of the structural design of the machine components.
In fact, due to their material properties, as well as the influence of the coupling mode, mechanism often have a certain flexibility which will affect the dynamic characteristics of the element, to produce the noise and vibration.
(2)Define the entity model unit type, material properties, real constants meshing, and the establishment of a flexible body and rigid body coupling at the interface nodes point.
Figure 8 , transmission speed of workbench is uniform in the process of movement, but the drive components due to deformation appear go fast or go slow and jump movement .Thereby affecting the smooth machine tools processing and machining accuracy.
Mechanical Engineering and Automation, Vol.3 (2009),p.37-39,(In Chinese)

It was found that additional contact areas due to pile-ups have a significant effect on determination of mechanical properties by the nanoindenter.
Introduction Nanoindentation tests are commonly used for studying the mechanical properties of materials at a very small scale.
It was shown that the Oliver-Pharr approach for determining mechanical properties leads to either an overestimation or underestimation of the calculated values for elastic modulus and hardness [[] A.
Furthermore, it has been pointed out that the pile-up and the sink-in behavior are dependent on other mechanical properties of the material as well as its processing history [[] Y.
The major factors affecting the pile-up and/or sink-in are the work hardening rate, the ratio of the elastic modulus to yield strength (E/σy), and the ratio of contact depth to the maximum depth of indentation (hc/hmax).

The dynamic mechanical response and the fracture toughness of the aluminum alloy were measured by SHPB with different wedge shapes, and the influences of wedge shape on determination of dynamic fracture toughness was analyzed in this study.
The mechanical properties of this material are listed in Table 1.
Table 1 The common mechanical properties of 7075-T6 aluminum alloy Young’s module Poisson ratio Yield strength Tensile strength Elongation Area reduction Fracture toughness 72GPa 0.33 559MPa 607MPa 9.7% 20.4% Experiment Setup.
Fig.4 The load history obtained from the SHPB loading three-point bending specimen test Fig.5 The dynamic stress intensity for the specimen calculated by the load data However, there were many other factors influencing the calculating results, such as the contact state between the incident bar and specimen, or the specimen’s dimension.
In order to eliminate those affecting factors mentioned above, the experiments were conducted repeatedly without specimen.

In recent years, with the development of rock engineering, a large number of rock physical and mechanical tests have been carried out which show that the laboratory test results are seriously affected by two main factors.
The factors above make the laboratory test data discrete, the coefficient of variation can generally reach 15% to 30% [4].
Physical and mechanical properties of rock materials.
Horsrud, Estimating mechanical properties of shale from empirical correlations, J.
Li, Experimental study on rock physical and mechanical properties in Danjiangkou reservoir area, J.

The process of fatigue crack growth is generally random nature, due to many sources of variability, such as external loading, material properties and geometry conditions.
In this investigation, the fatigue crack growth tests were conducted for five compact tension (CT) specimens of the FSWed 7075-T651 aluminum alloys, base metal (BM), heat affected zones (HAZ) and weld metal (WM), especially three different constant stress intensity factor range (SIFR) controls.
FSW is concerned as one of the most important welding developments in over two decades, because of the advantages which avoids some of the defects seen in conventional fusion welds, and better mechanical properties including low residual stresses.
Regardless of how carefully they are generated, show significant scatter which depends on uncontrolled factors.
As is seen in the Figures, there is not negligible influence of material property, BM, WM and HAZ.