Advanced Materials Research Vols. 314-316

Abstract: ZG30Cr06A as a newly developed material is made into needling of mining machinery’s hydraulic support. Its tensile strength is up to 800MPa. In the paper, the weldability of ZG30Cr06A was thoroughly studied. The sensitivity to cold crack of ZG30Cr06A was tested by means of maximum hardness of HAZ and Y-slit type cracking test. And the variation of microstructure and properties of weld joints under different welding energy conditions was studied. The results show that ZG30Cr06A steel has a certain cold crack and hot crack tendency and a little reheat crack sensitivity in welding. Embrittlement and softening often appear in the HAZ. When the workspaces of 30mm were welded at room temperature, the maximum hardness of HAZ was up to 389HV. And the joints have a tendency to quenched hardening and bigger sensitive to cold crack. The welded joints would not produce cold crack when the preheat temperature is up to 120°C in welding. Because there is more influence of welding energy input on the microstructure and properties of joint, so in order to avoid the appearance of embrittlement and softening in HAZ and ensure weld quality, the welding energy input of ZG30Cr06A steel whose thickness is 30mm should be controlled less than 40 kJ/cm during the welding.

Abstract: This paper analyses seepage model of rubber-plastic porous tube by the Darcy law based on its material characteristics. Integrating seepage examinations the seepage law of porous tube was found ,providing theoretical basis for actual application of rubber-plastic porous tube in drip irrigation、aeration and so on .

Abstract: A 2D and 3D thermo-elastic-plastic (TEP) FE Analysis has been developed to simulate the angular distortion induced by Gas Metal Arc Welding (GMAW) process on combination of butt and T-joint with thickness of 9 mm. The material used in this study was low alloy Manganese Carbon steel S355J2G3. In this research, SYSWELD 2010 with its computation management tool known as Multipassed Welding Advisor (MPA) was used to analyze the distortion behaviour of combined joint types. To model the heat source of GMAW, Goldak’s double ellipsoid representation which is available within this FEA code was selected. The final objective of this research is hence aimed to be base line study to provide preliminary information in preparing the tools or equipments for experimental investigation.

Abstract: Pre-tensioning forces are, in essence, the application of selective clamping forces on components prior to machining to create a “stress field” envelope that aids the processes of components. Utilisation of pretension forces prior to process offers advantages of increasing component rigidity, thus reducing the deflection from process, and holding the components in a way to counteract the machining forces etc. However, the scientific research of pre-tensioning forces has not been extensively or comprehensively investigated. The aim of this paper is to investigate the impact of applying pre-tensioning forces on thin walled components, and more specifically, focuses on the development of appropriate fixtures to achieve optimal performance from pre-tensioning. Finite Element Analyses (FEA) were used intensively to analyse the impact of pre-tensioning forces on components during machining process considering machining deflections. After the FE models were validated from experiments, stiffness of components under the action of pre-tensioning forces can be predicted for the development of future fixture design

Abstract: In this paper, the capability of linear thermo-elastic numerical analysis method to estimate the welding deformations was investigated. The weld induced deformation is considered as the major stumbling block that can affect the dimensional accuracy. Based on this fact, welding distortion is necessarily to be predicted, if experimental investigation becomes expensive, to minimize the negative effects, improve the quality of welded parts and finally to reduce production cost. In this study, the welding distortions on butt and T-joints with thicknesses of 4 mm and 6 mm were simulated using relatively new FEM software WELD PLANNER developed by ESI Group. The material used for the simulation was low Carbon steel. By comparing the results between simulation and experiment, it was found out that this software provided immediate solution for computational analysis time and was capable to predict the distortion within acceptable accuracy.

Abstract: In this study, tensional mechanical properties of sheet metal with heating-lines after laser scanning are investigated based on the thermal-microstructure-mechanical model. The phase transformations, during laser scanning of sheet metal, are calculated by coupling the thermal history from finite element analysis with a phase transformation kinetic model. The flow stresses of material are obtained from the constitutive relationship of the phases based on the mixture strain hardening laws. The results show that the influence of the heating-lines number on tensional mechanical properties of material is obvious. The mechanical properties are related to the distribution of microstructure in heat affected zone after laser scanning.

Abstract: On many occasions, the wired communications technologies can not meet the actual needs, such as in the operating in the wild or harsh environment. If using communication module built by radio frequency communication chip to achieve the data transmission of two regions of space, take MCU as a control component to achieve the freely data communication docking. This will be a good way to solve the wireless communications problems.

Abstract: Accurate predictive modelling is an essential prerequisite for optimization and control of production in modern manufacturing environments. In this paper, an adaptive neuro-fuzzy inference system (ANFIS) model was developed to predict the surface roughness in high speed turning of AISI P 20 tool steel. Experiments were designed and performed to collect the training and testing data for the proposed model based on orthogonal array. For decreasing the complexity of the ANFIS structure, principal component analysis (PCA) was used to deal with the experimental data. The comparison between predictions and experimental data showed that the proposed method was both effective and efficient for modelling surface roughness.

Abstract: Friction stir welding(FSW), a new solid-state joining process, is wildly used in the fields of aviation, aerospace and other high technology industries for many advantages over traditional fusion welding. Computer modeling is an important tool for the prediction and optimization of the FSW process. According to the characteristics of FSW of 7075 aluminum alloy plate, a 3D coupled thermo-mechanical FE model of this process was built under the ABAQUS/explicit environment based on the solution of several key techniques, such as heat boundary condition treating, material properties definition, ALE adaptive meshing technology, etc., and validated experimentally. Then, simulation and analysis of the complex plastic deformation behavior of the process were carried out. The results show that in the stable stage of the welding, the zone of equivalent plastic deformation decreases from the top surface of weld to the bottom surface; the plastic deformation of metal ahead of the welding tool is larger than that behind the welding tool; moreover the zone of equivalent plastic deformation is concentrated behind the tool.

Abstract: In this paper, with the ANSYS, stress distribution and safety factor of marine diesel engine connecting rod were analyzed by using 3D finite element method. The results show that the position of maximum principal stress is transition location of small end and connecting rod shank at maximum stretch condition. The value of stress is 24.69 MPa in dangerous position. The position of maximum principal stress is transition location of small end and connecting rod shank at maximum stretch condition. The value of stress is 198.65 MPa in dangerous position. Safety factor is 2.51.