Applied Mechanics and Materials Vols. 184-185

Abstract: Dynamic filtration with rotating disks is modeled by three-dimensional graphics software and its flow field is analyzed and numerical simulated by CFD software. The mechanical stability of dynamic filtration with rotating disks in the work process is analyzed by the model of rotating flow. The results show that the farthest end of rotating disks exit the largest flow velocity. There are two circular flows, which can remove the pollutants of rotating disks. The pressure of water is gradually increased as the main flow is near cylinder of the filtration. Simulation results are consistent to the practice, which provides important theoretical basis for improving and optimization of dynamic filtration with rotating disks.

Abstract: The failure cause of one Φ127mm G105 drill pipe was investigated through mechanical properties testing, optical morphologies and fracture analysis. The results show that drill pipe’s failure reason is the "martensite" white bright layer in its out-surface caused by intense friction in drilling process. Under the effect of torque and tensile loads, lots of cracks initiated in the white bright layer and developed along the vertical. In the end, when its tensile capacity was less than the weight of drilling string, drill pipe fractured along the horizontal. In addition, H2S in the travelling environment promoted crack’s initiation and development.

Abstract: Grab bucket is one of the most important assemblies of the grab dredges whose performance largely relies upon the construction of the bucket. Dynamics is carried out stressing on the two critical points, commencing status and terminating situation, for the greatest grabbing and cutting force; and so is done on kinematics concentrating the three representative points, A, B, and C, with position, velocity, and acceleration, respectively, with which almost all of the points on the bucket may be obtained for the three kinematic parameters. Optimal desgin have been done with objective of the proper momentum and thrust force and constraint of weight, width, ratio of weight and capacity, quotiety of the rope, ascent and descent velocity of the bucket.

Abstract: How to realize signal modeling and vibration signal characteristic extraction is a very significant topic. A large amount of drilling pump vibration signals were acquired from the indoor tests. The startup signals with time consistency were segmented from these measurement signals and analyzed in detail. There are mainly such five types of vibrations in the startup signals as the pump body’s vibration, whistle, shocks in moving parts, and impacts of the value lifted off or dropped on the seat, friction or grinding between moving parts. The pump body’s vibration and whistle have good time-frequency characteristics and change very regularity, which are defined as the startup vibration in this paper. The pump body’s vibration signals are modeled by OFMM method. After to exclude the OFMM modeling signal, the remaining signal was separated into different integrated components according to their vibration sources by PFM method, a HMM whistle vibration model based on PFM parameters was achieved. Furthermore, A combination of OFMM and HMM model is used to describe the pump startup vibration. Realistic simulation on the pump’s startup vibration has been achieved. Signal simulation was also carried out by use of this combination model. This approach is expected to become a powerful tool for drilling pump’s startup vibration signal analysis and modeling.

Abstract: Studied the hygroscopic properties of winding combustible cartridge case by weighing method. Investigated residue formation of cylinder materials with different water contents by nitrogen-bomb tests. The results show that the higher the relative humidity is, the greater the equilibrium moisture content of the inside-wall material is. When the relative humidity was about 90%, its absorption rate was about 4.3%. Compared with its outside wall, the inner parts have much stronger moisture absorption properties. And the gross of combustion remains reached to the minimum when the relative humidity was about 60%.

Abstract: Ink-jet printing technology is the mainstream of digital printing, and piezoelectric ink-jet printing is the main ink-jet printing at present, besides, drop’s injection and controlling technology is the key to the development of ink-jet printing technology. The surface tension plays an important role in the drop’s generation process, it will restrict the length and the state of the drop, further influence ink-jet printing quality. Six edible ink samples with different surface tension are prepared in order to research the influence of the surface tension to the piezoelectric inkjet Printing drop state, then the drop state is observed and its speed and volume are measured through drops observatory. The result shows that the speed of drop is higher if the ink’s surface tension is lower, but the drop is easier to gather into spherical drop and it also has smaller tail length and bigger volume.

Abstract: A vertical type high speed twin roll caster can be cast an aluminum alloy strip directly from a melt at high casting speed. However defects of the cast strip occurred at faster roll speed, which includes small cracks on the cast strip and unsoundness thickness distribution. They are related to contact condition of roll surface and melt. In the present study, a grooved roll was used to eliminate the defects and adopted in terms of the cost saving. We experimented using several grooved rolls with different patterns. When the groove width was 0.45mm; depth 0.2mm; pitch 0.1mm and 1.0mm, stable casting was possible. The shape of bulge was formed on the cast strip surface by the grooved roll. As a result of color check, we found that the grooved roll eliminate the small cracks. We stopped the rotated roll during the casting to observe the contact condition between the melt and the roll, and confirmed how the bulge was formed. The as-cast strip with the bulge was able to cold rolling.

Abstract: In this paper, a parametric experiment model of V-8 diesel engine is developed. The parameters, such as the V-type angle, cylinder centre spacing, connecting rod length, flywheel width, body sinkage, cylinder head height, oil pan height and compression height are selected as research factors and their influences on the engine’s volume are studied by the orthogonal experiment. By each experiment, a new engine model is built by changing these factors’ values and the volume of the new model is calculated. Through analysis of variance, the significant relations between diesel engine volume and factors are given, which provide the criteria for the selection of the design parameters.

Abstract: This paper proposed a type of new parallel tilter with four degrees-of-freedom, whose moving platform has three rotations and one translation. The coordinate transformation is adopted to establish the position and velocity kinematics equation of the tilter. Simulation result indicated that the moving platform can move according to the set law by modifying the displacement of the piston rod in active limb.

Abstract: The engine is the most common power source in our life. For a long time, people never stopped research it. Kinematics analysis study the relationship among the position, velocity and acceleration. In recent years, with computer technology, graphics technology and automatic modeling techniques together, much kinematics analysis software came into the world, which makes the engine kinematics analysis more quickly and easily. The article base on the idea of a novel dual-rotor piston engine, describe the structure and movement principle of the driving cylinder, build the kinetic theory model of the key components, and then expand the simulation study, discuss their kinematics properties.