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If one considers axisymmetric forward extrusion, the main processing parameters which affect the resulting extrudate quality are; the press ratio, the die cone angle, the friction between the workpiece and the tooling, the mechanical properties of the material such as hardening and ductility characteristic, and the heating effects during forming. [1] Friction affects not only the quality of the workpiece in metal forming but also the forming force.
Friction was modeled by the Tresca model, i.e., by where m is the friction factor ().
To study how the extrusion force is affected by friction and the extrusion geometry (flat faced and conical die with 45° angle) for axisymmetric 2D extrusion, a number of simulations were run in which the friction was increased gradually from the ideal frictionless state up to a high friction state characterized by m=1.
For the case of forward extrusion considered here (extrusion ratio =25) FEA and theory predicts maximum extrusion load to be ~doubled when friction is increased from 0 up to maximum friction characterized by a friction factor equal to 1.
So in this case friction effects against the tooling seem to affect extrusion load as much as do deformation effects.

There are many factors affecting the security of fully mechanized mining face.
These factors can be divided into three major factors of man, machine, and the environment from the man - machine - environment systems engineering perspective.
After analyzing of man - machine - environment impact factors of the mechanized mining face, the comprehensive evaluation index system can be established, as shown in Fig.1.
rate reliability service life failure property temperature illumination environment humidity gas According to the equation (4) in step 2.1, we can calculate the membership degree of the evaluation factors, as shown in Table 2.
Table 2 Membership of the evaluation factors Table 3 ,and Entropy of the evaluation factors evaluation factors best good normal bad worst evaluation factors AHP method entropy method entropy weight age E1 0.8409 0.0974 0.0000 0.0000 0.0000 age E1 0.1394 0.0730 0.1004 seniority E2 0.0000 0.0008 0.9727 0.0044 0.0000 seniority E2 0.0422 0.0902 0.3780 training time E3 0.7349 0.2917 0.0005 0.0000 0.0000 training time E3 0.0767 0.0676 0.0512 good rate E4 1.0000 0.0625 0.0131 0.0005 0.0000 good rate E4 0.0283 0.0753 0.0207 repair rate E5 0.0000 0.9969 0.1550 0.0008 0.0000 repair rate E5 0.0159 0.0691 0.0108 reliability E6 0.0020 1.0000 0.1459 0.0000 0.0000 reliability E6 0.1637 0.0701 0.1132 service life E7 0.0625 1.0000 0.0625 0.0000 0.0020 service life E7 0.0511 0.0669 0.0335 comfortable E8 0.6889 0.2571 0.0003 0.0008 0.0000 comfortable E8 0.0094 0.0571 0.0049 failure E9 0.0625 1.0000 0.0625 0.0020 0.0020 failure E9 0.0924 0.0505 0.0463 property E10 0.1059 0.9727 0.0092 0.0044

The aim was to analyse how slight manufacturing variations can significantly or insignificantly affect the final wear properties.
A single sample from Group 1 was processed at 50 MPa to check whether this reduction in pressure affected the final properties.
Another factor improving the properties was the compaction pressure.
- The matrix powder affected the final properties.
Ruan, Effects of TiB2 particle size on the microstructure and mechanical properties of TiB2-based composites, Ceram.

The other is the so called thermo-mechanical coupled analysis, which means thermal and stress analysis performed consentaneously.
Table 2.Welding process specification process torch No. diameter of the weld wire [mm] weld current [A] weld voltage [V] weld angle [degree] weld velocity [m/min] Inside SAW 1 4 1200 32 -15±2 1.60 2 4 700 34 0±2 3 4 600 36 18±2 4 4 500 38 30±2 Outside SAW 1 4 1300 34 -15±2 1.70 2 4 600 36 0±2 3 4 550 38 18±2 4 4 500 40 30±2 parameters variety allowed weld current: ±18%;weld voltage: ±10%; weld velocity: ±10% Material properties.
Regarding to the material properties of the steel, MA Bo, PENG Yan, LIU Yunfei and JIA Bin [4] research on the constitutive relationship of X80 steel at temperature higher than 900℃.
Flow stress curves at temperture of 1100℃ LI Yajuan and LI Wushen[5] have researched on numerical simulation for the temperature distribution of X80 pipeline steel and given thermo-mechanical properties for X80 steel as showed in Fig. 5.
Thermo-mechanical properties of X80 steel according to LI’s research Then, in order to improve the accuracy, both of them is used in such a manner: (2) Thermal model.

Many researches on the influence of the bolt-ball joints stiffness on dynamic and static mechanical behavior of these structures are carried out by far.
The results indicate that the bending stiffness of joint and load distribution mode are the main factors impacting the stability performance of single-layer reticulated domes [8]. 4）Z.H.
The results show the bending stiffness is one of the key parameters which affects on the load-carrying capacity of such structures [10]. 6）In order to study the mechanical behavior of semi-rigid Socket joint which is widely used in spatial structures，experiments on 9 specimens were carried out．The experimental studies indicate that the Socket joint has good bending moment capacity and ductility，and it doesn’t reflect the real condition to accept it as a pinned joint [11]. 7） Buckling collapse and its analytical method of steel reticulated domes with semi-rigid ball joints are discussed.
The mechanical property of this joint model is proved to be reliable by comparing the data from experiments and finite element analysis [18,19].
Mechanical performance of single-layer reticulated domes with semi-rigid bolt-ball joints.

The modern SLM systems are intended for melting of a wide range of powder materials with different properties.
The temperature and temperature gradient determine the speed of phase transitions, chemical reactions, microstructure and properties of the material.
Under the laser processing the temperature evolution is one of the dominant factors with high temperature gradients.
The thermal properties of stainless steel INOX 304 L were as follows: a = 4,05*10-6 m2/s – thermal diffusivity, = 8,03 g/cm3 – density, c = 500 J/kg*K - heat capacity.
ISRN Mechanical Engineering 2012 (2012)

The addition of additives to the non-solvent can affect the morphology, hydrophilicity, and mechanical properties of the membrane [15].
Swelling may indicate the presence of a cavity within the polymer, potentially impacting its mechanical properties.
The smaller the cavity, the higher the mechanical properties.
Changes in the structure, porosity, and morphology of the membrane surface can be determined through several factors, namely the type of polymer, the composition and concentration of polymers, solvents, and non-solvents [25].
Zhang, “The Permeability and Mechanical Properties of Cellulose Acetate Membranes Blended with Polyethylene glycol 600 for Treatment of Municipal Sewage,” Procedia Environ.

The quality of the transmission working conditions directly is affected the overall performance of the car, therefore, crucial for transmission testing.
Mechanical properties of automotive transmission test rig, gearbox test drive efficiency and fatigue life and fatigue life of the actuator important equipment.
Therefore, the test rig is using a closed power method to measure the mechanical properties of automotive transmissions [3, 4].
Mesh of the side wall on a car Automotive transmission performance In the process of moving the car , along with changes in the road , load , speed and other factors, torque and speed gearbox also passed changes .
References [1] Automotive mechanical transmission test method for QC/T568-1999 [2] Off Venda car constructor (2nd edition) Beijing: Mechanical Industry Press, 2005 [3] Zong Gong Yang, Zhang for the public, such as: mechanical auto gearbox synchronizer test system development, Xi'an: Industrial Instrumentation & Automation, 2005 [4] Arthur Hou, etc.: Testing and sensing technology, Harbin: Harbin Institute of Technology Press, 2000.

In this work, theoretical and experimental research in areas such as evaluation mechanism, formation mechanism, influencing factors, control methods of impact line are carried out to meet the needs of the community.
The mechanical properties of the material 1 # used in this simulation are displayed in Table1.
Table 1 Mechanical properties of material 1 # code t [mm] E [MPa] σs [MPa] n r0 r45 r90 1# 0.7 2.07×105 194.2 0.231 1.744 1.917 2.401 Impact line evaluation methods.
The basic mechanical properties of the materials (1 # and 2#) in this experiment are given in Table1and Table 2.
Table 2 Mechanical properties of material 2 # code σs [Mpa] E[Mpa] σb [Mpa] δ[ %] 2# 194.2 2.07×105 315 33 Measurement of impact line.

As the cavity of secondary lining changes the stress state of structure, and increases the possibility of structural damage, the lining usually cannot continue operation, and safety and durability of tunnel lining will be affected [2, 3].
Conclusion The factors of cavity in tunnel lining consist of two aspects, which are construction technology and concrete structure.
Yu, Analysis for mechanical properties of empty holes in different positions on tunnel lining, Journal of Water Resources and Architectural Engineering, 5 (2011) 70-73
Dong, Several factors affecting the detection of voids behind tunnel support by GPR, Modern Tunneling Technology, 3 (2009) 100-104