Search results

This paper aims to develop a three dimensional(3D) finite element model for a section of pipeline under axial membrane stresses, which contains two high-aspect-ratio semi-elliptical internal surface cracks, and further uses it to investigate the effect of the separation distance of these two cracks on their fracture mechanics properties( e.g. the stress intensity factor and the -stress ).
Formulation of stress intensity factors and -stress The stress intensity factor and the -stress over the fronts of the relevant surface cracks are two key fracture mechanics parameters used in this paper.
In linear elastic fracture mechanics, the stress intensity factor is often assumed to be a unique parameter that controls the fracture process.
From these figures, of the point , rather than the other points and , is more affected over the separation distance of the two cracks which is almost one time of the half-crack length of the cracks, while -stresses of all the three points are only sensitive within the separation distance of one quarter of the crack length.
American Petroleum Institute, The American Society of Mechanical Engineers.

The parameters tested by single-factor tests are: liquor, explosion pressure, heat preservation time, and the charge of sodium hydrate and sodium silicate.
If you take close look at paper and paper products, you notice that even simple papers and boards do not only consist solely of cellulose fibers，but also contain many additives that guarantee the particular use properties of the papers[1].
Treatment of raw material was carried out by steam explosion using single-factor tests.
Fig.3 shows that the explosion press affects macrostickies content.
The optimal press was the highest press, but at this press some boards produced internal bubbles, which negatively affected their mechanical properties.

This is because moisture significantly impacts the physical and mechanical properties of wood [2].
Its physical and mechanical properties.
It has moderate physical-mechanical properties (bulk mass 630-790 kg/m3).
Its mechanical properties are lower than Pine.
Yamaguchi, Prediction of mechanical properties by means of semi-destructive methods: A review.

Effects of cement properties on stress distributions at the dentin-cement-post interfaces have been studied using 3D explicit finite element simulations.
The types of cement do not affect the failure initiation location on the cement.
The post related factors (modulus of elasticity, diameter and length) influence the stress fields occurred within the post [1] but the maximum stress values in the restored tooth system are rather insensitive to post materials [2].
The detailed description of the finite element modeling, selected material properties, loading description and dimension of the tooth are given in [7].
This relatively low stress is due to the lower stiffness property of the orthotropic post (modulus in fiber direction = 44 GPa).

System nonlinearities, uncertainties, structure flexibility and other factors can’t be ignored in controller design.
It can not only solve the freedom problem, but also avoid affecting the calculation of the interaction force.
The material properties of inverted arm were defined in ANSYS, the 8 nodes solid element Solid45 was selected using intelligent grid division.
All these factors have had serious impact on system stability and dynamic characteristics, especially the control precision is difficult to predict by influence of load characteristics[4]。
The strategy effectively overcomes the effect of nonlinearity, parameter uncertainty, un-modeled dynamics and other factors.

Hygrothermal conditions are well known to affect both the microstructure and mechanical properties of composite materials.
Epoxy specimens experienced a general decrease in mechanical properties.
It was also evidenced that seawater immersion decreased the interfacial properties of the composites more significantly that dematerialized water immersion [7].Ultimate tensile strength, which is a fiber-dominated property, was also found to degrade after exposure to hydrothermal conditions [8].
The diffusion characteristics of moisture in PMCs are susceptible to the influence of such factors as hydrothermal conditions, constituents of materials, etc.
Standard Testing Method for Moisture Absorption Properties and Equilibrium Conditioning of Polymer Matrix Composite Materials (2010) ASTM International.

Material Properties Both of the sheet materials used in the study possess a thickness of 1.37mm and a nominal yielding strength of 350MPa.
The tested material properties are summarized in Table 1.
Table 1 Quasi-static mechanical properties of HSLA340 and DP590 Material Direction y[MPa] u [MPa] n r HSLA340 0° 354.90 442.17 0.129 0.93 45° 355.08 437.84 0.129 1.12 90° 364.54 441.76 0.130 1.04 DP590 0° 45° 90° 364.48 357.36 358.03 660.45 661.10 651.82 0.158 0.158 0.154 1.07 1.16 0.85 *Where y, u and n are yield strength, tensile strength and strain-hardening exponent, respectively.
It seems that the non-uniform distribution of thickness and material property induced by stamping process have little influence on the collapse initiation of HSLA340 LBHF stamped component, however it does affect the subsequent deformation mode being a perturbation.
It is found that residual forming data are significant factors affecting structure crash performance which can result in different crash behaviors for different forming conditions.

And the surface property of extruded thread is similar to rolled thread.
But the research material in this paper was the high strength steel, and which had high strength, well transverse plastic property and fracture toughness property.
In cold extrusion technology of internal thread of high strength steel there are many important factors affecting the quality of extruded section such as technological design of cold extrusion and design of technological parameters for the extrusion tap.
This paper choused the length of press section L1, the length of correcting section on the petrous pyramid L2 and cone angle α for the design variables from the many factors affecting extrusion quality of internal thread as showed in Fig.1.
Zhang: Chinese Journal of Mechanical Engineering, 2002, 8(38):45-49

When the rocket is launched, the impact of the mechanical properties and elastic deformation of the composite material directional tube on the rocket movement cannot be ignored.
Considering the flexible deformation of the FRP directional tube, the finite element method is used to perform an explicit dynamic analysis of the rocket launch process, to simulate the interaction between the rocket and the directional tube, and to understand the dynamic mechanical properties of the FRP directional tube.
Composite materials have anisotropic elastic properties, and the difference between anisotropic elasticity and isotropic elasticity is only in the stress-strain relationship.If it is a cylindrical orthotropic body and one of the symmetry axes of the material is parallel to the longitudinal axis of the tube, the strain-stress relationship of the composite material is: In addition to the aforementioned flexibility coefficients that represent the elastic properties of materials, engineering elastic constants are often used to represent the elastic properties of materials in engineering.
The initial disturbance is an important factor affecting the dispersion of rockets.
Conclusion Through simulation modeling and numerical calculation, the law of motion of the rocket launched in the directional tube and the dynamic mechanical properties of the FRP directional tube are mastered, and the following conclusions are drawn: a.

The main process parameters affecting injection molding of microcellular foamed plastics The major factors affecting the quality and production of microcellular foamed plastics are three aspects of raw materials, molding process and molding equipment.
After the raw material and forming equipment are determined, the deciding factor is the molding process parameters.
At the same time, it directly affects the amount of gas dissolved in the melts.
And the structure of the nozzle, runner and cavity and geometric parameters are all the important factors influencing the flow resistance.
The main characteristics of microcellular foam injection molding products can reduce weight on the basis of keeping the original mechanical properties of products.