0. Summary and Survey. This paper is concerned with obtaining strict upper and lower bounds on the eigenvalues of a particular nontrivial convex membrane, the half-L, which is fixed or free at the boundary. The upper bound is obtained from a matrix eigenvalue calculation; the matrix problem may be regarded as a difference scheme although it is derived using piecewise linear functions in a Rayle...

In the recently introduced Variable-Shape heaving wave energy converters, buoy changes its shape actively in response to changing incident waves. this study, a Lagrangian approach for dynamic modeling of spherical Wave Energy Converter is described. The classical bending theory used write stress–strain equations flexible body using Love’s approximation. elastic shell assumed have an axisymmetri...

Many inequality relations between real vector quantities can be succinctly expressed as “weak (sub)majorization” relations using the symbol ≺w. We explain these ideas and apply them in several areas, angles between subspaces, Ritz values, and graph Laplacian spectra, which we show are all surprisingly related. Let Θ(X ,Y) be the vector of principal angles in nondecreasing order between subspace...

This paper is concerned with solving large-scale eigenvalue problems by algebraic sub-structuring and contour integral. We combine Algebraic Sub-structuring (AS) method and the Contour Integral Rayleigh-Ritz (CIRR) method. The AS method calculates approximate eigenpairs fast and has been shown to be efficient for vibration and acoustic analysis. However, the application areas of this method hav...

The IDR method of Sonneveld and van Gijzen [SIAM J. Sci. Comput., 31:1035–1062, 2008] is shown to be a Petrov-Galerkin (projection) method with a particular choice of left Krylov subspaces; these left subspaces are rational Krylov spaces. Consequently, other methods, such as BiCGStab and ML(s)BiCGStab, which are mathematically equivalent to some versions of IDR, can also be interpreted as Petro...

The radiation impedance is an essential parameter in analyzing the vibroacoustic response of planar source. In order to calculate acoustic rectangular plate with arbitrary boundary conditions, a unified approximate approach proposed this study. displacement function expressed form supplemented two-dimensional Fourier cosine series, which can be solved by Rayleigh–Ritz method. radiated field fro...

The harmonic block Arnoldi method can be used to find interior eigenpairs of large matrices. Given a target point or shift to which the needed interior eigenvalues are close, the desired interior eigenpairs are the eigenvalues nearest and the associated eigenvectors. However, it has been shown that the harmonic Ritz vectors may converge erratically and even may fail to do so. To do a better job...