To study the fire protection effect of the nanocoating on the liquefied petroleum gas (LPG) tank under fire, the waveletfiniteelementmethod is applied in analyzing the thermal stress, temperature, and pressures dist...
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To study the fire protection effect of the nanocoating on the liquefied petroleum gas (LPG) tank under fire, the waveletfiniteelementmethod is applied in analyzing the thermal stress, temperature, and pressures distribution laws of uncoated, coated, and nanocoated LPG tanks. First, the relating research on nanocoating and the wavelet finite-element method is studied, respectively, and the feasibility of this research is analyzed. Second, the theoretical model of fire protection analysis of nanocoating is established, and the property of wavelet analysis, temperature field model, and turbulent flow model are constructed, respectively. Finally, the simulation is carried out, and the distribution laws of thermal stress, temperature, and pressure are obtained. Simulation results show that the nanocoated LPG has better heat insulation character, and it can be used as a passive fireproof system that can cooperate with rain fire extinguishing systems to reduce the explosion hazard of a LPG tank under fire. The wavelet finite-element method has higher calculating efficiency and precision.
We present a wavelet finite-element method (WFEM) based on B-spline wavelets on the interval (BSWI) for three-dimensional (3D) frequency-domain airborne EM modeling using a secondary coupled-potential formulation. The...
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We present a wavelet finite-element method (WFEM) based on B-spline wavelets on the interval (BSWI) for three-dimensional (3D) frequency-domain airborne EM modeling using a secondary coupled-potential formulation. The BSWI, which is constructed on the interval (0, 1) by joining piecewise B-spline polynomials between nodes together, has proved to have excellent numerical properties of multiresolution and sparsity and thus is utilized as the basis function in our WFEM. Compared to conventional basis functions, the BSWI is able to provide higher interpolating accuracy and boundary stability. Furthermore, due to the sparsity of the wavelet, the coefficient matrix obtained by BSWI-based WFEM is sparser than that formed by general FEM, which can lead to shorter solution time for the linear equations system. To verify the accuracy and efficiency of our proposed method, we ran numerical experiments on a half-space model and a layered model and compared the results with one-dimensional (1D) semi-analytic solutions and those obtained from conventional FEM. We then studied a synthetic 3D model using different meshes and BSWI basis at different scales. The results show that our method depends less on the mesh, and the accuracy can be improved by both mesh refinement and scale enhancement.
fTo analyze the thermal stress distribution of ceramic-coated pistons, the waveletfinite-element was constructed by using the Daubechies wavelet scale function as the interpolating function. The thermal stress distri...
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fTo analyze the thermal stress distribution of ceramic-coated pistons, the waveletfinite-element was constructed by using the Daubechies wavelet scale function as the interpolating function. The thermal stress distributions of the conventional and ceramic-coated diesel engine pistons were obtained, respectively. The calculated results obtained by wavelet finite-element method were compared with test results and the simulation results gained by ANSYS software. Through analyzing the calculation results, the wavelet finite-element method was convergent and had higher analysis precision than the traditional finite-elementmethod. The wavelet finite-element method avoids the numerical oscillation during analysis of the transient-state thermal stress fields of the piston. The wavelet finite-element method showed advantages for analyzing the high gradient problems. The wavelet finite-element method provides a preferable theoretical basis for optimizing the design of the ceramic-coated diesel piston. DOI: 10.1061/(ASCE)EM.1943-7889.0000302. (C) 2012 American Society of Civil Engineers.
The wavelet-based methods are powerful to analyse the field problems with changes in gradients and singularities due to the excellent multi-resolution properties of wavelet functions. wavelet-based finiteelements are...
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The wavelet-based methods are powerful to analyse the field problems with changes in gradients and singularities due to the excellent multi-resolution properties of wavelet functions. wavelet-based finiteelements are often constructed in the wavelet space where field displacements are expressed as a product of wavelet functions and wavelet coefficients. When a complex structural problem is analysed, the interface between different elements and boundary conditions cannot be easily treated as in the case of conventional finite-elementmethods (FEMs). A new wavelet-based FEM in structural mechanics is proposed in the paper by using the spline wavelets, in which the formulation is developed in a similar way of conventional displacement-based FEM. The spline wavelet functions are used as the element displacement interpolation functions and the shape functions are expressed by wavelets. The detailed formulations of typical spline waveletelements such as plane beam element, in-plane triangular element, in-plane rectangular element, tetrahedral solid element, and hexahedral solid element are derived. The numerical examples have illustrated that the proposed spline waveletfinite-element formulation achieves a high numerical accuracy and fast convergence rate. Copyright (c) 2005 John Wiley & Sons, Ltd.
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