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Introduction Due to the difference of diagenesis time, rock mineral composition and the geological structure in coal measures strata, strata thickness and mechanical properties are different.
It trigger dynamic disaster of the mine, and seriously affected the safety production of the work surface and even the mining area.
Rockburst is a common dynamic phenomenon ofcoal and rock in coal mining.Because of the influence of mining method, the fault structure and other factors, coal mining generally has two sides, three sides , surrounded mined gob and various forms of isolated island working face.
Hard roof become main factor occurred rock burst in isolated working face [7-10].
Physical and mechanical parameters of coal and rock mass use geological data and the results of rock mechanics test.

The as-cast microstructures of A356 alloys contain coarse α-Al dendrites and circular eutectic silicon, which do harm to its mechanical properties.
Great affects were made to change its microstructure in order to enhance the mechanical properties [1-5].
The grain refining efficiency, grain refinement mechanisms, and the enhanced mechanical properties were investigated.
In the procedure of T6 heat treatment, quenching rate following the solution treatment is the key factor affecting the precipitation behavior [10-13].
It can be found that the size and shape factor of silicon particles were greatly improved.

Mechanical properties of heat-resistant alloys.
The properties of EP648 (SLS) after HIP and aging are given in brackets [6].
The properties of alloys obtained by modes 3 and 4 have rather high strength indices in the initial state, the conditional yield strength of the alloys is equal to or exceeds the analogous properties of the EP 648-VI cast alloy [2,3].
The mechanical properties of the alloy (σv = 1196MPa; δ-14%) obtained by the HIP+aging mode correspond to the literature data. 3.
Mazalov, Investigation of the properties of EP648 alloy obtained by the method of selective laser alloying of metal powders, Works of VIAM 2 (2015) 8-15

Two-phase Flow (Oil-Water) in Petroleum Reservoir with Irregular Geometry Including Water Injection: Effect of Porosity on the Oil Recovery Factor F.
To produce oil as efficiently as possible is important to understand the distribution of the fluid, as well as the properties of the reservoir at any time during the production process.
By comparison the cases of Table 1, one can see that by increasing porosity, the pressure difference between the producing and injection wells are affected.
Figure 5 - Oil recovery factor in the producing well 2: (a) Situation A and (b) Situation D.
Marcondes, Numerical Simulation Methods Using Adaptive-Implicit and Voronoi Meshes of Problems of Petroleum Reservoirs (PhD Thesis in Mechanical Engineering, UFSC, Santa Catarina, Brazil, 1996).

The PM processing variables are obviously important factors that affect the resultant material properties.
Keraghel et al. [5] states that increasing compaction pressure improves the resulting mechanical properties.
The porosity level effects the relevant properties such as wear resistance, thermal stability and wear rate [1-3].
Consequently, the forming variables are an important factor to understand in order to control the porosity level and the resultant properties.
Jabur, Effect of powder metallurgy conditions on the properties of porous bronze, Powder Technology, (2013) 477-483.

Austenitic stainless steel has nonmagnetic properties and is resistant to low and high temperatures.
Thus, the properties of this material are very suitable for marine construction, such as ships, buildings, and other construction.
This yield shows that pulse on time and pulse off time are the most influential factors for changes in MRR values [11].
Carbon (C) and Copper (Cu) are factors that add up in this recast layer.
In this Research, Cr23C6 can not be directly seen because of several factors, such as the most influential variables.

The same basic factors apply to both weld repair and surfacing.
Parts made of low-carbon and low-alloy steels can be repaired without adversely affecting the service life of the part.
In some cases, a discontinuity can be left in a weld without affecting the weld’s function.
Using Prony’s series method [6-7] and AutoSignal algorithm [8] the mechanical parameters of the system are determined (Table 2).
Nes, Determination of some Mechanical Properties of Welded Reinforcing Steel with Self-shielded Wires by Vibration Tests, Advanced Material Research, 1029 (2014), 206-211

However, dispersion of carbon nanotubes in polymeric matrices is a critical issue since improper nanotube dispersion can adversely affect the mechanical properties of composites.
The fractional change in resistance (∆R/ R) and average gauge factors of braided composites are provided in Table 2.
The calculated gauge factors are also indicated.
Moreover, the gauge factors are higher in case of lower concentration of chopped fibres.
Gauge factors up to 23.4 were achieved at very low level of cyclic flexural strain (0.55%).

Introduction Fatigue failures commonly take place in engineering structures and mechanical machines, and will lead to fatal accidents.
（5） The limit state function of a critical point on the structure can be expressed as , （6） where is the design life, is implicit function of random variables, such as loads, material properties and member geometry.
Table 1 defines statistical properties of the load P and fatigue factors which affect the fatigue life of the cantilever beam.
Suppose the design life of the beam is 106 cycles, the initial crack length , geometry factor .
Statistical properties of random parameters Random variable Mean Coefficient of variation Probability distribution P [N] 2×104 0.05 Normal m 0.063 0.05 Normal M 3 0.05 Normal C 1.04×10-12 0.1 Normal The optimization design on the cantilever beam can be described as follows: Step 1.

(1) Where µ is the friction factor between the copper and steel, N1 is normal contact pressure between the left wedge and the steel tube.
(5) Piston Friction Damper Testing The dynamic test analyses the mechanical properties of the above-mentioned friction damper and the factors that affect the mechanical properties by using electro-hydraulic materials testing machine.
The experimental principle is: highpressure oil is acting on the piston of moving container by the testing machine, and mechanical signal is changed into electrical signal by sensor, then compared it with the control signal and adjust the servo valve, so that the feedback signal is equal to command signals and the relative displacement of chuck of both ends and loading frequency can be controlled precisely.
The size of the frequency, amplitude and waveform character do not affect the hysteretic characteristics of the damper.