Search results

Introduction NBR has good oil resistance, water resistance, air tightness and heat resistance properties, mainly used for the production of oil washers, gaskets, oil seal materials，which have been widely used in the aerospace field.
Owing to the influence exerted by the mechanical stress, heat and oxygen in the air, environmental media and other factors, the NBR’s compression rate decreases relatively, Such as materials gradually sclerosis and crack, the variation of physical and chemical properties, mechanical properties, electrical properties change and so on, which leading to the production of all kinds of security hidden danger even accidents.
So the rubber material aging behavior in-depth study of the various countries' cause extensive attention of researchers.which resulting to the loss of NBR’s excellent mechanical and sealing properties.
Owing to the natural aging test’s long period, and NBR’s effect factors can't be researched separatly, a perfect experimental result are not able to get in a short time.
Mechanical rejuvenation in polymer glasses：fact of fallacy[J].

The influence of this dynamic precipitation on creep properties is discussed.
Introduction Poor creep property at high temperatures is one of the factors to limit the extensive applications for magnesium alloys.
Other factors such as the segregation of primary alloying elements also affects the creep properties of magnesium alloys.
The annealing treatments like T4 treatment can effectively increase the creep properties.
This volume change seems to accelerate the growing of voids and is detrimental to the creep properties.

As a conclusion, palm olein has better performance properties in terms of friction reduction (coefficient of friction) and wear resistance (anti-wear properties) at low and high speed.
Vegetable oils are on one of the alternatives with properties comparable to mineral oils as base oil for lubricants.
Fig 2: Wear rate (load= 10N and 50N, sliding speed=1, 2, 3, 4 and 5 m/s) Wear rate depends on the mechanical properties of the material, ductility and the toughness of the material.
The application of resistant force to the pin as it touched the disk was one factor causing wear.
,oleated:Tribological,oxidation and low temperature properties,” Bio resources Technology, 99:7333-7340.

The plasma nitriding process is one of the basic chemical-heat treatment processes used to improve the mechanical properties of structural steels.
However, there is rarely a direct relationship between salt spray resistance and corrosion resistance in other environments, because individual factors affecting corrosion, e.g. the formation of protective layers vary considerably in specific conditions.
Evaluating and judging the appearance of samples depends on subjective factors.
Plasma nitrided structural materials of higher classes show better anti-corrosion properties compared to lower classes of steels such as material 11 373.
[8] Dong-Cherng Wen, Plasma nitriding of plastic mold steel to increase wear and corrosion properties.

Introduction So far, for the subject of mechanical property of the concrete structure and formwork support system during the construction period, there have been some experimental research and discussion, which has obtained certain research experience and results, at home and abroad.
The U.S. has obtained the relation between carrying capacity and various load types through numerical analysis and considers that the internal brace force and the bending of floor are greatly affected by construction load types[3].
Fang Dongping et al.[4] studied the factors which affect the safety of formwork support system, mainly including construction period, construction live load and layers of formwork support.
Conclusion (1) Regarding that, in the formwork support system which is concurrent with the structure, the removing of bottom formwork and development of concrete age will affect the mechanical performance of the formwork support system.
(2) The construction period has a relatively large influence, which is larger when the age is earlier, on the mechanical performance of the formwork support.

The thermal and mechanical properties of the test material are summarized in Table 2.
Identification of process parameters In general, factors affecting quality objectives in turning are feed-rate, spindle speed, cutting speed, depth of cut, geometrical and mechanical properties of the material, configurations of the machine tool and cutting tool, cutting fluid, rigidity and machine tool stability, etc.
Main effects plots represent the state of influence of the factors on the responses.
In contrast, in several cases the lines show a strong tendency to interbreed while being extended, confirming the existence of significant interactions among the factors affecting cutting forces; therefore these interactions should be taken into account when formulating the corresponding response models.
Fig. 11: Influence of factors of stochastic models on the responses of cutting force component 5.2.

Hot forging die is provided in the service process is affected by the complicated and severe, its life is generally low, which directly affect the forging cost and quality and economic benefit of production units.
In hot die forging process and forging die mainly bear the mechanical load and thermal load of high intensity, the combination of the two, the die to produce all kinds of damage, the damage form seriously affect the work of forging die, even failure.
So, thermal load and mechanical load can be regarded as affecting the service life of hot forging die with the two most fundamental factors, under the condition of the mechanical load stability, thermal stress is the most fundamental reason of hot forging die failure.
The environment temperature is 300, Air convection coefficient 25.9611.Due to the heat pipe cooled hot forging die structure with temperature change range is larger, so in the process of calculation, it needs to consider the change of the temperature dependent material properties, boundary temperature and radiation boundary conditions and structure, so this is a typical nonlinear thermal analysis of the problems, this paper USES the finite element method for iteration solving structural model.
But to be sure, in the lower die of opening will weaken its strength and other mechanical properties, in under the lower die or mold base of open pore structure design, adopt tight circular honeycomb structure design can better reduce due to the impact of opening to the mold intensity[7].

The optimal value of tensile strength was obtained by using the Large-the-Best characteristic of the Taguchi Method to obtain the important control factors of this experiment; a validation experiment was carried out by using the adjusted factors. 1.
A tensile testing machine was used for welded test pieces to test the mechanical properties of interfused heterogeneous plastic materials after ultrasonic was applied.
Method, which suggests to regard about a half of control factors as important factors, and the rest of half as unimportant factors.
According to this table, the S/N ratio of the optimal design has a small error of accuracy. 4.4 Analysis of variance The main purpose is to evaluate the experiment error amount, and judge whether the experimental factors are important factors and the relative contribution of the factors by using statistical verification method.
The four key factors are hardening time, welding time, welding pressure and motor speed.

The research on the corrosion and its effect on the mechanical properties of rebar are increasing [8-12].
These will affect the mechanical properties of rebar.
Li, Effect of corrosion on mechanical properties of reinforcing bar HPB235, Advanced Materials Research, 450-451 (2012) 201-204
Wang, Mechanical properties of rebar HRB400 after corrosion, Advanced Materials Research, 753-755 (2013) 516-519
Li, Effect of corrosion on mechanical properties of rebar HRB335, Advanced Materials Research, 753-755 (2013) 539-542.

Fig. 1 General geometry of a typical parabolic spring Literature review Fatigue life prediction is based on knowledge of both the number of cycles the part will experience at any given stress level during that life cycle and another influential environmental and use factors.
In order to make a correlation between phase and mechanical properties, the sample hardness values were also measured for comparison purpose of both near fracture and non-fracture area.
One of the factor that contribute to this is both simulation and analysis used the same geometry and other input like the boundary condition, meshing size and material properties.
The fatigue limits of the same kind of steels can be affected by such microstructural parameters as size and shape of prior austenite grains, martensite, and precipitates and by mechanical properties such as tensile properties [11].
Dieter, in: Mechanical Metallurgy. 3rd ed.