Search results

Introduction Many engineering structures are subjected to random loading in service and the fatigue life affected by load sequence.
Load case (2) Load case (1) Load case (4) Load case (3) Fig. 1 Display of load histories cases with different sequences (From high to low and low to high load ratio) SPECIMEN GEOMETRY MATERIAL PROPERTIES LOADINGS FATIGUE CRACK GROWTH MODELS Austen Model M.
Forman Model NASGRO Model Results (Fatigue Crack Growth, Number of Cycles, Stress Intensity factor) FATIGUE CRACK GROWTH AND LIFE PREDICTION Is the predicted life accepted?
Using VAL in practice, the fatigue life is often affected by load or cycle sequences.
The number of blocks has also affected the results, which is three for the first set and four for the second set of block loading.

All these factors lead to greater loading on track bed, which changes its shape under increasing load and thereby affects the track geometry parameters.
The kernel function then explicitly determines the properties of the transformation.
Mechanical shock was excited with a special hammer from Brüel&Kjaer, which had force sensor, in a radial direction on the rail head.
The acceleration values are therefore considerably lower than in the sensor located at the foot of the rail (Fig. 2), which was located closer to the source of mechanical impulse.
Conclusion Analysis of signals obtained during the measurement and analysis of responses to mechanical shock provide a new detailed view of the transition and transient characteristics of railway constructions.

Qian a College of Mechanical and Electrical Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, P.
Introduction Diamond is full of excellent performance in the physical and chemical properties, such as high hardness and thermal conductivity, low friction coefficient and thermal expansion.
However, in practice, the quite identical results have been acquired in the present series of experiments, which are mainly affected by: (i) The residual stresses will arouse the degradation of the mechanical performance of the brazed diamond.
In contrast, the grains of the electroplated and sintered abrasive tools are always enwrapped in the connecting layer through the mechanical and physical incrustation forces, which also determines the weak joining effects to the grains; (ii) Depending on the newly-formed compounds, the wetting behavior between the diamond grains and the filler material could be promoted and thus the contacting region of them could be distinctly increased, hence the joining strength is improved effectively; (iii) The residual compressive stress in the brazed diamond grains has the remarkable influences on enhancing the strength of the grains.
As a result of the comprehensive influences of the three factors mentioned above, the grains and the filler layer of brazed diamond tools are capable of achieving the joining so strong and perfect that those of the electroplated and sintered tool could never come true.

The input transient and material properties by NRC/EPRI PTS benchmark study [50] were used in the analysis.
(1) Influence of semi-elliptical crack extension method (2) Material properties (Cu and Ni contents, and initial RTNDT) In these analyses, the input condition in Table 3 was used except for material properties.
The material properties for the analysis (1) and (2) are shown in Table 4
(2) Result on material properties (Cu and Ni contents and initial RTNDT) The influence of material properties was investigated.
The properties of Material 1 and Material 2 used in the analysis are compared in Table 4.

It has been well recognized that the physical and mechanical properties are strongly affected by atomic defects such as vacancies and antisite atoms.
Major topics on the mechanical properties of B2 FeAl alloys are a drastic change in microhardness with the vacancy concentration [1] and an anomalous increase in yield stress with rising temperature [2].
Internal friction technique is one of the best ways to reveal the defect properties.
In addition to the temperature dependence of internal friction, the study of the amplitude-dependent internal friction is the most promising way to investigate the mechanical properties in the microplastic range [11].
George, Thermal vacancies and high-temperature mechanical properties of FeAl, Phys.

Since the characteristics of molecular motion differ above and below the glass transition temperature Tg, the mechanical properties differ markedly above and below Tg.
The main factors in the strain-holding conditions to affect these characteristics are temperature, time and strain during strain-holding.
(1) Dynamic mechanical properties The relationships between storage elastic modulus E' and loss tangent tan δ versus temperature T of the film obtained by a dynamic mechanical test are shown in Fig. 2.
(2) Tensile deformation properties The relationships between stress and strain at Tg and Tg±20K obtained by the tension test under strain rate of 50%/min are shown in Fig 3.
References [1] Hayashi, S., 1993, Properties and Applications of Polyurethane Series Shape Memory Polymer, Inter.

Measurement of the Internal Relative Humidity Distribution in Concrete Jikai Zhoua, Xudong Chenb, Jian Zhangc and Xiaowei Kand College of Civil and Transportation Engineering, Hohai University, Nanjing, Jiangsu, 210098, China azhoujikai@163.com, bchenxudong.1212@163.com, czuzu1104@qq.com, dkan1986@163.com Keywords: Concrete; Internal Relative Humidity; New Measurement System Abstract: The internal relative humidity (RH) and humidity gradients in concrete at early ages have a significant influence upon the properties of concrete, where exists a great discrepancy among the test results under different methods.
It has great significance for researching shrinkage characteristic of concrete at early ages and the free water effect on the dynamic mechanical properties of concrete.
Considering the above factors, the humidity sensors used in the new measure system are a capacitive type of humidity sensors made in Switzerland (SHT7X, 6mm×20mm).
The property of the new measurement system was analyzed, and the changing laws of the internal RH in concrete are studied in this part.
That is, the moisture distribution in concrete was affected by self-desiccation as well as moisture diffusion of concrete.

A mechanical action is applied to cause the media to rub against the component surfaces.
They are typically used to characterize the bearing properties of a surface to study the different profiles fabricated in different conditions.
Both the motion types and part trajectory within the charge depend upon several factors [11]: shape and material of media and of parts, filling percentage of barrel, dry or wet operation, rotational speed.
In the case of SF the action modifies the morphology of the peak: an evident cutting mechanism flattens the peak, but also the sides are affected.
[3] ISO 13565/3Geometrical product specifications (GPS) – Surface texture: Profile method; Surfaces having stratified functional properties - Part 3: Height characterization using the material probability curve, (1998), Technical report

There are two methods to resolve the problem: one is improving the properties of wheels steel and the other is optimizing the design of wheels.
The security and life span of a wheel is not only determined by the dynamic load, but also affected by the distribution of residual stress at a great extent.
Excellent residual stress distribution has become one factor of estimating the design of wheels.
The mechanical properties and chemical composition of wheel steel are showed in Table 1 and Table 2.
Influence of surface treatment on hardness and residual stress well as contract fatigue properties of 40 Cr steel.

The present work was aimed to investigate the HAP feedstock flow properties via rheological analysis using 100 % of PS binder.
The result indicated that mixing temperature was the main factor and can give high influence to the feedstock homogeneity and affect the properties to the next process.
Regarding to its properties it can be injection molded at lower operating temperature and obtain lower viscosity feedstock.
The higher temperature will contribute to less viscous and high flowability properties.
Norhamidi, Powder Injection Molding of SS316L/HA Composite: Rheological Properties and Mechanical Properties of the Green Part Journal of Applied Sciences Research, (2012) Vol 8(11), p. 5317-5321