Search results

Introduction The spindle is the main mechanical component in grinder.
The static and dynamic stiffness of the spindle directly affect the grinding productivity and quality [1].
The structural properties of the grinding spindle depend on spindle shaft, bearings, stator, rotor, grinding wheel and the spindle assembly.
Angular contact ball bearings are most commonly used in high-speed spindles due to their low-friction properties and ability to withstand external loads in both axial and radial directions.
The stiffness and damping of bearings is related with the structure, lubrication, load, vibration and other factors of bearings.

The degradation of material properties caused by the synergetic effect of cyclic stress and corrosion pits severely affects the integrity and safety of aircraft structures [4].
A large number of studies have shown that utilizing the network to predict the fatigue behavior affected by complex factors is feasible, efficient and reliable [7, 8].
Its chemical composition and mechanical properties are shown in Tables 1 and 2 respectively.
Table 1 Chemical composition of the material Composition Al Mg Mn Fe Cr Zr Cu Zn Content (wt %) 87.1~91.25 1.8~2.8 0.2~0.6 0.15 0.1~0.25 0.1 1.4~2.0 5.0~7.0 Table 2 Mechanical properties of the material Yield strength[MPa] Tensile strength[MPa] Elastic modulus[GPa] 469 557 71.9 Fig.1 Shape and dimensions of the specimen (thickness=3mm).
The neural network method can better demonstrate its superiority especially for the complex process affected by the interacting of multifarious factors involved in actual environment.

Researches mainly focus on the processing properties, mechanical properties and creep properties [1].
The chemical compositions and mechanical properties at room temperature of the experimental P92 steels in this study are shown in Table 1 and Table 2, respectively.
The Steady creep rate represents the creep properties of the materials.
Creep fracture time reflects the material’s fracture properties.
So its effect on the mechanical properties is very small.

Studies on effect of T6I4 and T6I6 type treatments on the mechanical properties of 354 are not available in published literature.
The effect of carrying out artificial aging at two different temperatures (in two steps) on the mechanical properties obtained has not been studied on 354 alloy.
The specified mechanical properties for the T61 condition are shown in Table 2.
Mechanical properties obtained after the two step artificial aging – 100 °C and 170 °C – are shown in Table 5.
It is considered that reinforcement between the two steps of aging is necessary to achieve an improved combination of mechanical properties.

A reduction in the tensile properties and fatigue life of aluminium alloy castings has been observed on account of material porosity[3, 4].Casting defects lead to not only reduced values of mechanical properties but also high scatter of these properties [2].
Aging temperature has been found to be an important parameter with respect to the mechanical properties obtained after heat treatment.
Table 1: Mechanical properties for two-step aged Hipped and non-Hipped samples of 354 S.No.
Table 2: Mechanical properties for modified aging treatment of Hipped and non-Hipped samples of 354 S.No.
It appears that in this case the scatter has also been influenced by other factors.

A Research on the Principle of Thermo- Stress Sizing and its Application for Titanium Alloy Sheet Minghe Chen1, a, Lansheng Xie1,b , Lei Liu2,c 1 College of Mechanical and Mechanical Electrical Engineering, University of Aeronautics & Astronautics, Nanjing, China 210016 2Shanghai Aircraft Manufacturing CO.
The results show quantitatively effects of main factors, such as material property, part geometry, temperature and time for the rule of hot sizing.
They may be used to estimate technological parameters of thermal stress sizing.In addition thermo-mechanical characteristics under standard temperatures of forming or sizing and the experimental curves of thermo-stress sizing for Ti-6Al-4V .
Fig.1 High temperature softening and stress relaxation principle diagram Stress Relaxation Experiments of TC4 Titanium Alloy Sheet To build theory support for making full use of the affects of creep and stress relaxation in designing the continuous casting process, we simulated the conditions of the temperature, strain rate and stress during continuous straightening and did experiments of elevated temperature creep, stress relaxation and elevated tension on Gleeble 3500 thermal-force simulation machine after cleaning the surface of the samples.

Comprehensively considering the lateral force, axial force, bending moment and other factors of the spring section, .
Then define the spring material according to the physical and chemical properties of the given 17/7PH steels under the status of ASTM A313-631 CH-900, and load it in the finite element model.
According to the characteristics of the spring and its shear stress, the regression model consisted of the third-order polynomial expression should be able to reflect the regression properties of the maximum shear stress.
Figure 3 The predictive error interval when the confidence is 99% (the model with the maximum shear stress) It has been observed from this model that the most active factor affecting the inner stress of the spring is the spring wire diameter, while the pitch plays only a small role in the shear stress of the spring.
Wahl, “Mechanical Springs 2nd Edition”.

The SLM final parts are characterized by high mechanical properties and satisfactory physicochemical properties.
However, master the SLM process, correct optimization and thus account for the appearance of the defects is essential to know all factors, which have been an influence on the final properties of the manufactured details.
The one of the most important factors are process parameters (there are over 40 different SLM/SLS process parameters), which can be classified into six categories (Table 1): material and initial powder properties (1), powder bed properties (2), laser parameters (3), scan strategy (4), build environmental (5), sintered layer properties (6), out of which it is possible to defined as controlled parameters (parameters, which can be easily modifiable during process) can be distinguished [21-26].
Four groups of post-process defect can be distinguished: anisotropy and porosity (1), hot cracking defects affecting geometric deformations and dimensional inaccuracy, surface quality (3) and insufficient mechanical properties (4): Figure 2.
However, other important factors such as absorption, heat transfer or solid/liquid interface have a significant effect on the physical behavior of properties of laser beam-powder material system and leading to the non-linear response of all system.

The elastic property of the film is one of the key factors influencing performance of the coating.
With the change of the static force and the specimen elasticity, contact stiffness will change, and the results show that the atomic force acoustic microscopy techniques can effectively measure the elastic properties of the sample.
Nix Mechanical Properties of Thin Films.
Mapping Mechanical Properties on the Nanoscale Using Atomic-Force Acoustic Microscopy.
Zhao., Quantitative measurement of nanomechanical properties in composite materials (M), Stony Brook University, 2010.5 [8] H.J.

The studies are focused on the fatigue properties in an ultra-low cycle fatigue regime where the fracture occurs approximately within 100 cycles [5].
Rotation frequency is specified as 8 r/min to reduce the affecting strain rate, t denotes the notch depth, f denotes the deflection, Kt denotes the stress concentration factor.
Fig. 1 The strain-life curve for different stress concentration factors at t=1.3(a); t=2(b).
The results suggest that the strain values are the key factors affecting fracture and stress concentration factor is a secondary factor.
Fig. 3 The damage-life curve for different stress concentration factors at t=1.3(a); t=2.0(b).