Effect of polymer stabilizers' viscosity on red sand structure strength and dust pollution resistance

This paper numerically calculates the pressure distributions of a rudder of a ship for structure strength design. The sections profile of the rudder is NACA0020 airfoil. The viscous flow is simulated by FLUENT commercial software, while the model and mesh is generated by GAMBIT software. A 2D viscous flow around a NACA0020 airfoil is calculated firstly. Some notices are given here about the magnitude of computing domain, the density distribution and the numbers of grid nodes on the airfoil surface in order to gain better results. Then, based on these experiences, the viscous flow around a 3D rudder is simulated. The calculated pressure coefficients on the rudder’s section are compared with the experiment results and BEM results of the potential theory. At the attack angles and , the three results agree well with each other. However, when the attack angle is , the viscous results from FLUENT give better agreement with the experiment results than the BEM results. This conclusion confirms that the viscosity effect is great in the case of large attack angles.

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Failure Analysis on a Counterweight Assembly of an Aeroengine

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.339.342 ◽

2011 ◽

Vol 339 ◽

pp. 342-348

Author(s):

Hai Jun Tang ◽

Hong Yu Yao

Keyword(s):

Heat Treatment ◽

Stress Concentration ◽

Failure Analysis ◽

Failure Mechanism ◽

Treatment Process ◽

Hardness Test ◽

Heat Treatment Process ◽

Material Loss ◽

Structure Strength ◽

Crucial Part

The paper presents a failure analysis on a counterweight assembly installed on crank shaft which resulted in an in-flight shutdown of a piston aeroengine. The counterweight assembly failure includes counterweight block material loss and fractured washer which is the most crucial part for in-flight shutdown in this type of aeroengine. Macro observation, fractography analysis, metallography analysis and hardness test were conducted on the failed counterweight assembly. The result shows that failure mechanism of counterweight block and washer is fatigue. The washer failure is likely due to inappropriate heat treatment process and continuous impact in flight by slightly tilted roller. Counterweight material loss is attributed to stress concentration, low structure strength and impact came from the tilted roller. Finally some safety suggestion on design and maintenance is given.

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Optimization Design of Pressure Shell in Underwater Vehicle Based on Response Surface Model

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.419-420.89 ◽

2009 ◽

Vol 419-420 ◽

pp. 89-92

Author(s):

Zhuo Yi Yang ◽

Yong Jie Pang ◽

Zai Bai Qin

Keyword(s):

Finite Element ◽

Response Surface ◽

Optimization Design ◽

Engineering Application ◽

Element Model ◽

Response Surface Model ◽

Design Stage ◽

Surface Model ◽

Design Variables ◽

Structure Strength

Cylinder shell stiffened by rings is used commonly in submersibles, and structure strength should be verified in the initial design stage considering the thickness of the shell, the number of rings, the shape of ring section and so on. Based on the statistical techniques, a strategy for optimization design of pressure hull is proposed in this paper. Its central idea is that: firstly the design variables are chosen by referring criterion for structure strength, then the samples for analysis are created in the design space; secondly finite element models corresponding to the samples are built and analyzed; thirdly the approximations of these analysis are constructed using these samples and responses obtained by finite element model; finally optimization design result is obtained using response surface model. The result shows that this method that can improve the efficiency and achieve optimal intention has valuable reference information for engineering application.

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