Advanced Materials Research Vol. 787

Abstract: In this paper, I+II mixed mode fatigue crack propagation in a low alloy steel 16MnDR was experimentally investigated. Morphologies of crack growth path and fracture surface are analyzed. It is found that upon initiation from the inclined pre-crack, the newly formed crack grows in a direction to be perpendicular to the applied load, making crack mode transformation from I+II mixed mode to mode I. The crack growth is transgranular and no clear branches are presented. Striations and dimples are found on the fatigue fracture surface and the final fracture surface, respectively, showing that the material is ductile in nature.

Abstract: The shear wave velocity is an important parameter in the geo-seismic analysis. The corresponding database of shear wave velocity is founded by collecting and sorting out the data of superficial soil layers in Bohai Gulf. The scatter diagrams of soil shear wave velocity and depth are drawn using the software of ORIGIN. The exponential regression equation is selected by adopting the goodness-of-fit for evaluation index; the regression coefficients about shear wave velocity with depth of four categories of soils are fitted. The results show that there is a good relationship in the exponential form between the shear wave velocity and depth of superficial soil layers in Bohai Gulf. The obtained results can be directly provided a reference for the field without shear wave velocity.

Abstract: To simulated the magnetization change at the instant of fracture, assume that the distribution of dislocation-magnetic dipole is consistent, the models of dislocation-magnetic dipole for tensile fracture and tensile-tensile fatigue fracture are established, respectively: The distribution of magnetic dipole for tensile fracture is linear increase from distant to the fracture zone, while the distribution of magnetic dipole for tensile-tensile fatigue fracture is converging only at the fracture zone. It is found that the established model can present the change of peak-to-peak in magnetization for tensile fracture and tensile-tensile fatigue fracture.

Abstract: t is one of precondition of determining rock material dynamic parameters for one-dimension assumption of the elastic pressure bar. In order to analyze its effect by loading wave type, the dynamic stress was simulated with Ls-dynamic finite element software, when SHPB(Split Hopkinson Pressure Bar) pressure bar with diameter of 50 mm, 75 mm and 100 mm were impacted respectively by a cycle rectangular loading wave and half sine loading wave. The stress waves of cross section in different diameter pressure bar and the different distance with pressure bar end were compared and analyzed. The results indicated that the dispersion of stress waves was very serious and the matching ability of stress wave at different distances in pressure bar was poor when the rectangular wave was loaded. However, the dispersion of stress wave was not obvious with the increase of the diameter of pressure bar and the change of pressure bar when the half sine wave was loaded. The half sine loading wave which can strictly meet the one-dimension assumption is one of the ideal loading waveforms of the rocky heterogeneous materials.

Abstract: Based on the Lagranges equations, a new nonlinear dynamic gear model is established by introducing two variables of relative rotation angleand mean rotation angle. The motion equations derived with Lagranges equation exhibit nonlinear terms which are absent in the equations derived on Newtons equations. Combining with the numerical simulation, the dynamic responses in time domain and frequency domain are deduced, and it can be concluded that the responses at low speed of three different models are different. However, they are similar at the designed speed without the consideration of dissipation energy. On the contrary, the dynamic responses are similar at low speed and the simplified Newtons equation differs at the designed speed including dissipation energy.

Abstract: Reliable assessment procedures of existing RC buildings are currently available, and have been introduced in the Italian and European codes reporting new rules for seismic analysis. However, further studies are required in order to further improve such procedures and, specifically, obtain more accurate data on the behavior of beam-column joints, whose role on the global behavior of framed RC buildings can be crucial. Until now studies on this issue have been mainly devoted to joint specimens with stiff beams, however frame structures having wide (also called flexible or flat) beams are widely used in the European residential building stock. To this purpose, given the lack of knowledge, an experimental investigation on full scale beam-column joints with wide beam has been planned and is currently in progress. In the present paper the main results of three tests are reported and discussed. The role of different earthquake resistant design levels on joint performances is pointed out.

Abstract: In the working process of the loader, energy is mainly consumed in the shovelling process. It is necessary to analysis the resistance acting on the bucket. Firstly, this paper takes bucket and material systems as the research object, analyzes constitutive relation of the system and models the resistance by applying earth pressure theory. By experiments, the resistance is measured when the bucket inserts the material. Finally, the comparison of the experiments results and theoretical ones shows that the models building in the paper are reasonable.

Abstract: Non-circular gear can be seen as a variant of circular gear, whose rolling circle become non-circular rather than circular of circular gear and such kind of non-circular rolling circle is called Pitch Curve. When designing of non-circular gear, one has to decide the Pitch Curve according to given conditions before determines other parameters. Generally, there are two kinds of situations as to determine the Pitch Curve. 1).Determine the Pitch Curve according to deputy drive ratio function of non-circular gear. 2).Determine the Pitch Curve according to deputy position function. This context has been to deal with the propose of an internal-curved planet gear pump, theories of how center wheel and annular gear are designed and the design as well as the calculation of the Pitch Curve.

Abstract: In this paper the thermoelastohydrodynamic study for analysis of elliptical journal bearing (Two-lobe) operating with Newtonian lubricant has been presented. The thermo-elastic deformations of the solid parts are taken into account. To solve the Reynold's equation generalized, equation of energy and the displacement field, respectively, using two numerical techniques Computational Fluid Dynamic "CFD" and Fluid Structure Interaction "FSI". The "CFD" is used to determine the pressure, temperature and velocity fields in the lubricant film, the stress intensity and displacement field is obtained by "FSI" simulation. The influence of the operate conditions on the fields pressure, temperature displacement and stress intensity is also analysed.

Abstract: This work was designed to study the rheologicl properties of mixture of HPMC and CMC solutions because their rheologicl properties are very important in no matter food or pharmaceutical industry processing operations. Experiments were performed at different mixture ratios, shear rates and temperatures. The static and dynamic rheological properties tests were measured through the rheometer AR-550 and were investigated by using Power Law equation, Cross equation and Arrhenius equation. The results showed that the HPMC-CMC solutions behaved as typical Non-Newtonian shear-thinning fluids and had stronger non-Newtonian nature. With the concentration_(CMC) increasing, consistency coefficient K, Zero Shearing Viscosity η_0, viscous flow activation energy E, storage modulus G and loss modulus G all increased but decreased with the temperature increasing, except for Non-Newtonian index n. And viscosity was the dominant property in the mixture of HPMC-CMC solutions.