In order to eject water column with regular shape for hydraulic impact tests, inertia projecting devices are developed. In these devices, a projecting cylinder filled with water is accelerated under huge push of gas gun. When arriving to set speed, the cylinder would impact buffer and suddenlly halt. Then water column in the cylinder will eject under inertial function. In the device for ejecting smaller water column, as impact force is small, projecting cylinder is made of high strength steel material, and can be used again after impacting buffer made of rubber material. In the device for ejecting larger water column, as impact force is huge, projecting cylinder is made of low strength steel material, and will damage after impacting buffer made of high strength material. Using these devices, tests are respectively conducted to eject water column with masses of 30kg and 800kg, and speed and shape of water column all satisfyed requirement of .hydraulic impact tests.
There are many advantages of semi-solid processing technology such as energy saving, high efficiency and net-shaped processing. So it is a promising manufacturing technology in 21 century .It is the premise of getting the non-dendrite semisolid slurry to realize the semisolid processing.This paper reviewed the development of the technique of preparation for semi-solid state slurry and introduced some new researchment about the technique of preparation slurry for semi-solid processing. It researched a new technique of preparation for semi-solid state slurry—cooling by the sine function to produced the semi-solid state slurry. The result showed that the aluminum alloy melt was cooled and controlled nucleation and limited growth in the sine wave The fundamental principles through which sound semi-solid slurry can be effectively obtained were summarized.On the basis of the experiment and simulation,it analysised the temperature field and the flow field of the semisolid 2A12 slurry flow through sine passage. The result showed that there is the cooling and the self-stirring when the semisolid 2A12 slurry flow through sine passage. The fundamental principles through which sound semi-solid slurry can be effectively obtained were summarized. Finally, we presented a patent this simple process .
The multi-axial constitutive behavior of poled and unpoled ferroelectric ceramic PZT53
is measured under different proportional tension-torsion loading and compression-torsion loading
until destroy. Deformation is measured using strain gauges. These results are used to map out
“Switching” and “destroy” surfaces. The two surfaces are found to be a function of the polarization.
Switching surface is similar to Mises and Tresca yield surface. Destroy behavior corresponds to
maximal principal normal stress rule. For poled PZT53, the effect of bias electric field on its
multiaxial behavior has also been exploited.The results indicated that the “Switching” surface
disappear with the increased bias electric. The ultimate goal is to develop an experimentally
validated micromechanics based phenomenological constitutive model for ferroelectric materials.
Cylindrical shell is a kind of common used structure in engineering. Interest in the
response of cylindrical shells to local impact loading has increased over the last few years. A
structure always endures working load more or less. For a cylindrical shell, the working load
commonly is internally pressure. In this paper, a numeral simulation of wedge block impact
internally Pressured cylindrical shell was carried out. The dynamic failure process of the structure
was obtained. The consistency between experimental observation and numerical simulation is
satisfactory.
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