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Nevertheless, further growth in use will be possible with the continuous improvement of the mechanical and other exploitation properties of this material.
One of the new ways to achieve better mechanical properties of silicon nitride ceramics is the incorporation of different carbon inclusions into ceramic matrixes with the purpose to increase their fracture resistance.
Mechanical parameters of Si3N4 based ceramics.
On the other hand, the formation of CNTs agglomerations affects the value of hardness, caused by the increase of porosity: the density of composite samples is 2.681g/cm 3 against 3.125 g/cm 3 of reference ones.
Summary The controlling of the mechanical properties of Si3N4 composites is possible via the modification of their composition and processing conditions knowing how microstructure peculiarities can influence the mechanical behavior.

The mechanical properties and the chemical composition of SM430A are Extension meter 20 2 2 45 90 12 6 Strain gage Specimen Contact pad (a) (b) Fig.1.
Theoretically, the shape change caused by the plastic strain can be directly calculated by adopting the finite strain analysis, but it will take much longer computation time than that for small deformation analysis due to the geometry nonlinear properties.
Analysis model and its element division Table 1 Mechanical property of SM430A Table 2 Chemical composition of SM430A analyzed first.
After the plastic deformation is saturated, the stress distribution, which is saturated too, is the dominative factor of fretting wear.
The wear depth of specimen may affect the wear width.

Therefore, the materials used for wheels are required to have high strength, high hardness and good wear resistance, and have the combination of high toughness, good heat resistance and other properties[4].
In the actual situation, many factors can affect the wheel-rail frictional wear, so it is difficult to perform reliable quantitative calculation for the wheel-rail wear under various working conditions.
Therefore, the instantaneous flash temperature with a very high temperature would be caused and the physical and chemical properties of materials would be affected.
With the impact of various factors, the wheels produced normal load on the rail inevitably, so the bending moment had an impact on the initiation and expansion of fatigue cracks[7].
Perssonb: Investigation of factors influencing wheel–rail adhesion using a mini-traction machine.Wear.

In recent years, much effort has been spent by several research groups worldwide to provide a deeper understanding of process effects on mechanical properties, microstructure, and residual stress induced by the process [3-8].
The following step is to realize a crack propagation analysis, with the stress intensity factors (SIFs) and crack growth rates calculated by DBEM, based on the chosen crack propagation law (Eq. 2).
Nogi, Tensile properties and fracture locations of friction-stir-welded joints of 2017-T351 aluminum alloy, J.
Withers, Microstructure, mechanical properties and residual stress as a function of welding speed in aluminium AA5083 friction stir welds, Acta Mater. 51 (2003), 4791-4801
Palazzo, Influence of Process Parameters on Microstructure and Mechanical Properties in AA2024-T3 Friction Stir Welding, submitted to J.

Over-heating will lead to the malfunction of the braking system and affect the safety of vehicle.
Some of the crucial factors need to be included in the design of the brake disc such as safety, reliability, weight, durability, stability, cost and performance.
Various combinations of properties can be obtained from metal matrix composites (MMCs).
The objective is to compare their performance in terms of thermal and structural properties using FEA simulation approach.
Table 1 Materials properties of AlSiCGr hybrid MMCs and cast iron.

Introduction A lot of practice and research shows that gun muzzle disturbances is an very important factor to affect firing accuracy.Unbalanced of recoiling parts,stiffness,clearance and backlash of elevating mechanism would serious affect muzzle response,causing significant low-frequency vibration of tipping parts about trunnion,and firing accuracy of naval gun would be affected.In the literature 3,a naval gun is analyzed with nonlinear dynamics method,and the interaction between cradle arc and main gear of elevating mechanism is defined by torsion spring constraint.This approach is difficult to accurately simulate complex three dimensional contact/impact between cradle arc and main gear of elevating mechanism and it’s effect on muzzle disturbance.In the literature 4,the author considered the contact between cradle arc and main gear of elevating mechanism based on multi-body system dynamic model,but each part of gun is dealed with rigid body,especially barrel,which’s flexible has great
Engagement process of cradle arc and main gear of elevating mechanism Elevating mechanism is drived by handwheel or power,controling pitching parts movement of cannon.The structure sketch of naval gun shows in Fig.1.Strong impact between cradle arc and main gear of elevating mechanism will cause slight vibration of tipping parts about trunnion,considering factors such as transient high impact load, backlash of elevating mechanism and elastic deformation of gearing.This is a main factor caused muzzle disturbance,so the impact of cradle arc and main gear of elevating mechanism must be studied and simulated.In order to be more close to the actual, precise models of parts,mechanical model of impact and the corresponding parameters of physical properties should be considered.
Conclusions The precise 3D models of involute straight tooth gear and arc were constructed.Considering the contact between cradle arc and main gear of elevating mechanism,the dynamic simulation is carried out.The results shows that simulation results of contact model can be more fit the actual than equivalent stiffness model’s.The effect of random factors such as clearance and backlash,testing and validation related naval gun’s dynamic parameters should be further studied.

However, the CTOD transformation equation involves separating CTOD into elastic and plastic components, and employs several material factors; converting BS7448-CTOD into ASTM E1290-CTOD by the equation is not straightforward.
Table 1 shows the analytical conditions used in this calculation. σYS, + and B were set at different values for evaluating the effects of mechanical properties and specimen size on R1 and R2.
not affect both of the CTOD ratios.
Steels, mechanical properties and test conditions are listed in Table 2, where steels are based on Japanese Industrial Standards.
Table 2 Steels, mechanical properties and CTOD test conditions.

Very high cycle fatigue (VHCF) properties of welded joints under ultrasonic fatigue loading have been investigated for titanium alloy (TI-6Al-4V) and bridge steel (Q345).
In this research, the ultrasonic fatigue testing was adopted to investigate the ultra-long life fatigue properties of welded joints for bridge structure steel Q345 and titanium alloy TI-6Al-4V.
The chemical compositions in wt.% and mechanical properties of these materials used in this investigation are shown in Table 1 and Table 2.
Table 1 Chemical composition of Q345 and TI-6Al-4V Material C Si Mn S P Q345 0.15 0.38 1.36 0.00003 0.00012 Material Ti O Fe Al V TI-6Al-4V 0.91 0.002 0.004 0.055 0.035 Table 2 Mechanical properties of Q345 and TI-6AL-4V Material E /GPa /MPa UTS/MPa /g.cm-3 Q345 201 420 570 7.85 TI-6Al-4V 114 880 950 4.43 Fig.1The dimensions of specimen for Q345 and TI-6Al-4V.
Influence of Subjection to Physiological Saline Solution on Gigacycle Fatigue Properties of TI-6AL-4V.

Effect of Milling Parameters on Surface Roughness for High-speed Milling of Pre-sintering Zirconia Junwei Liu1,a, Xiaojun Yang2,b 1,2Department of Mechanical Engineering and Automation, Shenzhen Graduate School, Harbin Institute of Technology, Shenzhen 518055, China aljwxuan@gmail.com, byangxj@hitsz.edu.cn Keywords: High-speed milling, Roughness, Milling parameters, Sensitivity, Stability domain Abstract.
Zirconia has been widely concerned in dental restoration duo to its excellent properties, but its high hardness make direct milling inefficient, while pre-sintering zirconia has good machinability.
Roughness models are established on each parameter, and analysis results show the effect degree in order of spindle speed, feed engagement, cutting width, and cutting depth, spindle speed in them is a main factor.
Introduction Zirconia ceramic (ZrO2), which has been called ‘ceramic steel’, has attracted considerable interest in research of restorative dental materials for its excellent properties.
(2) As a whole, roughness curves are similar for spindle speed and feed engagement, while spindle speed change affects roughness further than feed engagement.

Finite Element Analysis To obtain the mechanical properties of Ti-0.2Pd, a tensile test was conducted and flow stress equation was induced from the mechanical properties.
The flow stress equation and main properties of Ti-0.2Pd were shown in Equation 1 and Table 1 respectively.
Fig. 4 Effect of friction factors on reduction in thickness Fig. 5 Tube diameters from simulation and experiment Table 3 shows the data of simulation result in case of friction coefficient 0.3.
It could be judged that it adversely affected the proper mechanical properties of the tube [1, 2, 4] and that the compressive stress on the internal surface was too high.
International Journal of Mechanical Sciences, 70(null), (2013), p.69–78.