Advanced Materials Research Vols. 479-481

Abstract: A numerical study of the effect of Bubble Layer on Propulsion performance is carried out by using the Air-Liquid Mixture Model. The effect of factors, such as air flow rate, air injected positions on propulsion performance are investigated. The following findings are obtained: (1) In the open water conditions, the air injected inlet is farther away from the propeller center, the little more effect on the propulsion performance; Along with the increase of air flow, the effect of bubbly layer on the propulsion performance increases slightly. (2)Because of the hull form and the clearance between the bottom and the blades tip, bubble layer has small effect on propulsion performance of deep-vee hull form ship propelled by propeller.

Abstract: To study the dynamic mechanical changes in litchi pitting process and improve the accuracy of litchi pitting, this paper established a 3-D solid assembly model of litchi, fixture and tool and conducted the finite element discrete of the model by using ANSYS / LS-DYNA software. In addition, the deformations and stress states of litchi’s multi-layer structure under the effects of tool and fixture were simulated and calculated by the LS-DYNA971 solver. The results showed that the deformations and stresses of litchi’s multi-layer structure changed with the increase of cutting depth, and appeared the maximum amplitude out of sync. When the litchi was gonna cut through, the stress amplitude of fruit pulp was the maximum among litchi’s multi-layer structure and the stress amplitude of fruit pulp was the minimum. Pulp would reach its maximum stress when cutting through the litchi, and because of its low strength, the breakage was prone to occur. The stress of fruit stone was large in the initial stage, and big fruit stone was easily led to the breakage for its overlarge stress. In pitting process, the deformation and slippage of litchi would take place with fixture clamping and tool pitting, so this is a complex dynamic deformation process. This study is urgent to make more comprehensive and systematic researches.

Abstract: Finite element method is carried out to calculate the fracture mechanics parameter of interfacial cracking of TSOP (Thin Small Outline Package). Fracture mechanics approach together with finite element results are used to study the impacts of material properties and thickness of die attach on the energy release rate at crack tip of interfacial delamination between die pad and die attach. The results show that larger Young’s modulus, smaller CTE as well thinner thickness of die attach can reduce ERR at crack tip during reflow.

Abstract: The non-uniform equivalent beam design method for non-uniform beam of mechanical structure was proposed. Its equivalent mechanical models of tension or compression and bending was established. Moreover, the erro between the result of FEM and the result of non-uniform equivalent beam design method is less than 5% so as to verify the accuracy of non-uniform equivalent beam design method for typical parameter bending cantilever beam and the tension link. The study in the paper provides a new method and basis for design and calculation of similar mechanical structures.

Abstract: Stop Clock Design-for-Testability (DFT) and Scan Dump DFT are integrated and implemented to trap the digital logic inside combinational and sequential logics for fault isolation (FI) purpose. Both DFTs enable functional test result to be dumped out structurally during functional test at manufacturing. Validation is performed on RTL simulation using test pattern and it is shown that the real silicon data matched the simulation results. Hence a new FI method has been established on the fly, capable in manufacturing.

Abstract: In order to get the optimistic structure property and design parameters of a car body, the system of vehicle body concept design (VCD-ICAE) was developed by us to make the body design in the conceptual phase in the paper. It can build parametric geometry modeling and FEM model of body-in-white (BIW) automatically, and the structural stiffness was calculated. Based on the former model, a multi-objective optimization of the total body was designed to afford the reasonable parameters for detailed model of BIW, which realized lightweight of the whole body and high stiffness. In the paper, the total theory and flowchart of vehicle body concept design were afforded. An example with real body’s data was shown to prove the validity of the multi-objective optimization module in VCD-ICAE system. Finally, the optimal design scheme of the body was provided.

Abstract: The finite element model of a folded parachute is established in this paper. The dynamic change of structure and flow field during the parachute inflation process is obtained based on Arbitrary Lagrangian-Eulerian (ALE) coupling calculation. The accuracy of results is verified by wind tunnel tests. The present work is significant for improving parachute performance analysis, and also can be referenced by other fabrics analysis.

Abstract: Virtual surface measurement is necessary to assist the actual measurement of large deployable space antenna structure. To realize a virtual surface measurement on this kind of structures, we take several steps to get the virtual measurement images. A virtual 3D model of the antenna structure and virtual hung system are constructed; virtual measure rules, coded marks and uncoded marks are also built up. The pinhole camera model is used to simulate the actual photogrammetric measurement tools. Through examples with OpenCV tools, the virtual measurement method is verified to be reasonable. Then different resolution images of perspective projections of the virtual measurement in virtual camera positions and orientations are obtained. Proper selections of the camera resolution and proper positions and orientations of the camera are found through virtual measurement experiments. Such results can be used in an actual photogrammetric measurement. The virtual measurement method can be used to reduce the attempt times and to assist the actual measurement with available photogrammetric measurement tools.

Abstract: Automatic multi-function flat frying machine set crank up the tea, science articles, squash, Hui dry in a multi-functional machine structure, staffing fried tea mimic the mechanism of continuous complete Na, friction, pressure, shaking, turning, etc. frying action, the use of computer systems in the process of tea frying temperature, pressure, dry speed process monitoring; through the frying process performance parameters of the test analysis showed that: the automatic multi-function flat frying machine frying tea tea quality of tea samples close to hand-frying, frying by the expert assessment of mechanical parameters were better than some of the tea hand-frying, with the promotional value.

Abstract: Hydraulic fracture, as a stimulation treatment, has been widely used in process of oil exploring in oil well. But in tight sandstone reservoir, it still exist many problem due to compactness, low-permeability, hardness and brittleness characters of the sandstone. To resolve the problem above-mentioned,this text considering the low natural productivity status of tight sandstone reservoir in Yanji Basin, to analyze the reservoir characters of tight sandstone reservoir base on density testing and mechanic parameters testing of the stone. The results shown that the special reservoir characters of tight sandstone sand lead to high fracture pressure of formation, poor connectivity of fracture, filtration and backflow problems of fracturing fluid. So we put forward reasonable recommendations for fracturing to resolve the problem above-mentioned. Through the application of oriented perforating technology, improvement of fracture fluid system and fracturing technology, provide a new effective technological measure for fracturing in tight sandstone, and promoting the development of fracturing technology in tight sandstone reservoir.