Advanced Materials Research Vols. 712-715

Abstract: Aimed at deflection fracturing by oriented perforation, a two-dimensional, non-steady and two-phase Finite Element Method (FEM) is established. Taking a battery of wells in the inverted nine-spot rhombus pattern as object of study, it is reported that law of different crack initiation angle (CIA) affecting deflection fracturing. In the respect of daily oil production and cumulative oil production, the dual fracture with different CIA is more than straight fracture. So it is feasible to use deflection fracturing of oriented perforation to increase the production of the special low permeability oilfield. In contrast to dual fractures with different fracturing initiation angles, we can see that the wider CIA, the higher cumulative oil production. So we can draw such a conclusion that when deflection fracturing is implemented, angle should be increased if the working condition is permitted so as to increase the production of oil well.

Abstract: In order to meet the requirement of small deformation of "T"-shaped bed with three-point support, based on the idea of meta-structure, making use of bionics, a new unit structures - hollow hexagonal prism is put forward. Through the analysis of the static characteristic of the different unit structures, it is shown that hollow hexagonal prism has strong advantages as unit structures. Thereafter, using hollow hexagonal prism of different cross-section circumcircle diameter and wall thickness as unit structures of "T" shaped bed, through the bed static characteristics analysis, the design principles of bed designed by the use of hollow hexagonal prism is summarized.

Abstract: The numerical analysis model about pile-raft foundation was bulited by using finite element analysis software.The raft settlement, pile-top counterforce and soil counter force were analyzed by changing the thickness of raft .The thickness were 0.15m,0.20m,0.25m and 0.30m. It was said that it could effectively reduce the raft uneven settlement and realize the redistribution of the pile and soil counterforce by increasing raft thickness.After changing the pile length and the raft thickness The rule of raft settlement were analyzed. After the pile length and thickness of optimization,it was good to control settlement of the pile raft foundation.

Abstract: In this paper,the calculation methods of the horizontal stiffness of the Boiler horizontal support are given to calculate the boiler level support rigidity simple and accurate, and can be applied in boiler design.,and the conditions of horizontal stiffness of the Boiler horizontal support are given to ensure the stability of the intermediate columns in the boiler frame.

Abstract: The composite material has been widely used in aircraft structures. But this kind of material has some shortage such as poor impact resistance, low residual compressive strength, which have a negative influence on the performance of aircraft structures. In this paper, simulations of low-velocity impact and compression process of composite laminates with AL ply and different core material has been done. The simulation results show that softer core materials and AL ply with certain thickness can improve the residual compressive strength

Abstract: The research is to solve nonlinear constrained optimization problems by the method of sequence quadratic programming (SQP) in MATLAB optimization toolbox and mathematical programming theory. This paper taking the high strength of WN gears drive as design target and the WN gears drive optimization design model of actual project is put forward by the concrete examples which are widely used in modern machine of the high speed and heavy load WN gears drive. Using the optimization design model to analyze the relationship about gear drive parameters on contact and bending fatigue strength. This research adopts the formula fitting design method not only improved design efficiency but also provided application foundation for CAD design of WN gears driving.

Abstract: Self-drilling screws are the primary means of fastening for cold-formed steel members in cold-formed thin-gauge steel residential construction because it can drill their own holes and form their own threads. The fabrication of connections is the most labour intensive aspect of the cold-formed thin-gauge steel construction process, thus a better understanding of the behaviour of screw connections could lead to optimum connection design and reducing the cost of the fabrication. The study carried out to investigate the behaviour of single-shear connections using self-drilling screws in the cold-formed steel construction. The focus of this study is on the influence of the number of screws and screw spacing on the strength of self-drilling screw connection. These parameters are varied to determine their influences on the connection strength. The failure load and failure modes were obtained and observed from the tests carried out in the laboratory. Bearing and tilting failures occurred during the testing of these specimens. The predicted connection strengths were calculated using American Iron and Steel Institute (AISI) design equations. A total of 24 specimens of single shear test showed that connection strength is linearly proportional to the number of screw in the connection. Results of the specimen with spacing more than 3d show better correlation with the calculated results as compared to specimens with screw spacing less than 3d.

Abstract: t is required to use specialized large-scale pressure cooker to process and cook rice in high altitude. The design of large-scale pressure cooker with composite bottom is a very complicated process, involving in nominal operating pressure, safe pressure and breakdown pressure, etc., especially the advantage of composite-bottom pressure cooker possesses, which are fast heat conduction, high efficiency and energy conservation, but it is very easy to ignore thermo-mechanical coupling effect which the compound aluminum steel of pressure cooker with composite bottom exerted in the hot operation working condition in the process of designing pressure cooker, once the bottom is dropped due to the condition of high temperature, the whole feeding equipment will not work properly. Analysis software ANSYS is applied to make simulating calculation for thermo-mechanical coupling of super-huge type pressure cooker with composite bottom, verifying if it can operate properly in the field condition of long time and high temperature.

Abstract: Determination of double-K fracture parameter using both analytical and weight function method is carried out in present research. In calculating the cohesive fracture toughness, two situations are divided at critical load. Wedge-splitting tests with ten temperatures varying from 20oC to 600oC are implemented. The complete load-crack opening displacement curves are obtained from which the initial and critical fracture toughness could be calculated experimentally. The validation of double-K fracture model to the post-fire concrete specimens is proved. Meanwhile the weight function method agrees well with the analytical method.

Abstract: Sizing of material flaw is addressed in the multipath scene, and a method is developed to detect an isolated sized flaw and estimate its height based on imaging theory of different path profiles. A signal model based on the multipath higher order reflections of the flaw is built to detect the sized flaw. Multipaths are predicted and identified on the basis of the direct reflection path, which is relatively easy to be identified using the conventional flaw detection techniques. Direct reflection path and combined path are applied to detect the flaw from the top, and multipath w is to detect its bottom of the flaw. Ultrasonic imaging is formed and synthesized by all the identified multipaths, which shows the size of the material flaw. Simulations and experimentations demonstrate that the flaw sizing can be calculated utilizing the time-of-arrivals of the multipath signals.