Casting defects and microstructure distribution characteristics of aluminum alloy cylinder head with complex structure

A356-T6 cast aluminum alloy is a light weight structural material, but fatigue crack initiates and propagates from a casting defect leading to final fracture. Thus it is important to eliminate casting defects. In this study, friction stir processing (FSP) was applied to A356-T6, in which rotating tool with probe and shoulder was plunged into the material and travels along the longitudinal direction to induce severe plastic deformation, resulting in the modification of microstructure. Two different processing conditions with low and high tool rotational speeds were tried and subsequently fully reversed fatigue tests were performed to investigate the effect of processing conditions on the crack initiation and propagation behavior. The fatigue strengths were successfully improved by both conditions due to the elimination of casting defects. But the lower tool rotational speed could further improve fatigue strength than the higher speed. EBSD analyses revealed that the higher tool rotational speed resulted in the severer texture having detrimental effects on fatigue crack initiation and propagation resistances.

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Research on the Parameter Optimization of Certain Complex Structure

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.268-270.200 ◽

2011 ◽

Vol 268-270 ◽

pp. 200-204

Author(s):

Bao Cheng Zhang ◽

Peng Fei Zhao ◽

Peng Li

Keyword(s):

Structural Design ◽

Cylinder Head ◽

Maximum Stress ◽

Combustion Engine ◽

Mechanical Load ◽

Structural Parameters ◽

Complex Structure ◽

Parameter Study ◽

Side Plate ◽

Von Mises

Using the method of the parameter study, some important dimensions of the cylinder head of an internal-combustion engine are analyzed. Under the mechanical load, the variational rules of the Von Mises maximum stress on cylinder head are obtained, which are influenced by the thickness of the floor plate, head plate, jobbing sheet, standing partition board, and side plate of inlet port and exhaust port. A hypothesis is verified that there is an ideal matching point among those above-mentioned main parameters. The quantificational proportion relations, between these key structural parameters and Von-Mises maximum stress of cylinder head, can provide a good help for the cylinder head’s structural design.

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Numerical Simulation of Mold Filling and Solidification Process of a Disc Aluminum Alloy in Pressure Die Casting

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.121-126.254 ◽

2011 ◽

Vol 121-126 ◽

pp. 254-258

Author(s):

Bai Yang Lou ◽

Fang Li Liu ◽

Kang Chun Luo

Keyword(s):

Numerical Simulation ◽

Mathematical Model ◽

Aluminum Alloy ◽

Die Casting ◽

Solidification Process ◽

Mold Filling ◽

Casting Defects ◽

Casting Simulation ◽

Pressure Die Casting ◽

Filling And Solidification

The numerical simulations of mold filling and solidification process for the A380 aluminum alloy were done by the supposed mathematical model. The casting defects in the process of mold filling and solidification were predicted by the result of the casting simulation. The casting defects of simulation are well compared with the practice. Some measures presented were improved for the existing technological process.

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Research the Utilization Rate of Aluminum Alloy Material

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.595.79 ◽

2014 ◽

Vol 595 ◽

pp. 79-82

Author(s):

De Ying Sun

Keyword(s):

Aluminum Alloy ◽

Complex Structure ◽

Unit Cost ◽

High Strength ◽

Alloy Sheet ◽

Machining Process ◽

Utilization Rate ◽

Material Consumption ◽

The Individual ◽

The Cost

There are many parts in aerospace fixing device, the 7075 - t351 brand aluminum alloy is a commonly used material of these parts [2].The material has high strength, good toughness, wear resistance and resistance to spalling corrosion resistance and other characteristics; After the machining deformation, comprehensive mechanical processing performance is good [1]. As a result, the materials are widely used in aerospace equipment. Smaller wall thickness, complex structure, multiple azimuth need processing, is the characteristics of these parts, make the individual parts machining material consumption is larger, increase the cost of the material consumption. In this paper, through the analysis of part structure and machining process, adopt to layout method, in order to improve the utilization rate of aluminum alloy sheet metal, reduce the unit cost.

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Local Triads of Sensors to Mine Collocated Acceleration for Structural Health Monitoring of an Aluminum Beam With Bolted Joints

Volume 1: Development and Characterization of Multifunctional Materials; Modeling, Simulation and Control of Adaptive Systems; Structural Health Monitoring; Keynote Presentation ◽

10.1115/smasis2014-7597 ◽

2014 ◽

Author(s):

Ioannis T. Georgiou

Keyword(s):

Aluminum Alloy ◽

Research Effort ◽

Complex Structure ◽

Three Dimensional ◽

Local Area ◽

Bolted Joints ◽

Critical Area ◽

Local Areas ◽

Vibration Wave ◽

Aluminum Beam

Several aerospace, space, and naval platforms process a core structural system assembled wholly or partially by aluminum alloy elementary structures, such as beams, plates, and cylinders, among others. Aluminum alloys are preferred due to light weight and corrosion resistance. The formed complex aluminum alloy structure is characterized by a number of joints where different structural elements are joined together. Areas with joints are prone to damage. Some joints are made by bolts for assembly and reassembly purposes. A loose bolt can be considered as a man-induced damage in the whole complex structure. This damage can result in a catastrophic failure. The vibration and elastic wave propagation-based monitoring of a critical area bearing bolt joints can offer a reliable monitoring. In this work, we present a basic experimental research effort. We consider an aluminum alloy beam composed of two sunbeams joined by means of two bolts. The bolts are healthy in the sense that they are tight to the level of design recommended force. We use three mono-axial sensors in three dimensional arrangement and mine vibration-wave data in the form of collocated signals. These signals are analyzed by means of the proper orthogonal decomposition transform. The local tri-axial arrangement of mono-axial sensors is used to collect collocated acceleration signals in two local areas. One of the local areas contains the bolted joints. The other local area contains the free end of the structure. This is not considered as a critical area but a boundary accessible area. The POD modal structures of collocated vibration signals are quite different. The behavior is compared to that of structure without bolted joints.

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Numerical Simulation Analysis of Aluminium Alloy Wheels Casting Defects and Casting Process Optimization

Materials Science Forum ◽

10.4028/www.scientific.net/msf.749.125 ◽

2013 ◽

Vol 749 ◽

pp. 125-132 ◽

Cited By ~ 1

Author(s):

Lv Ming Yang ◽

Li Li Zhao ◽

Qing Qing Zhang ◽

Tie Tao Zhou

Keyword(s):

Mechanical Properties ◽

Numerical Simulation ◽

Aluminum Alloy ◽

Casting Process ◽

Shrinkage Cavity ◽

Uniaxial Tensile ◽

Uniaxial Tensile Test ◽

Casting Defects ◽

Pressure Casting ◽

Aluminum Alloy Casting

In the low pressure casting process of A356 aluminum alloy wheel hub, casting defects including shrinkage cavity, shrinkage porosity, impurity and pore usually occur inside the casting. These defects affect the mechanical properties of the casting. To solve this problem, we conducted a study based on a cooperation project with a well-known domestic automobile wheel manufacturer. In the present study, uniaxial tensile test of aluminum alloy casting containing defects was simulated and analysed, and the effect of types and number of defects on mechanical properties was studied by finite element analysis software. Statistical analysis of the data was provided by the manufacturer. It has been found that the degassing technology is effective by the quantitative analysis method. Based on the analyses of experimental data and the numerical simulation it is deduced that the tensile strength of casting increases with the increase of the defects due to the presence of impurity. This was confirmed in this research project, it has been observed that the defect rate of the casting sample is reduced from 5%-6% to less than 1%.

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