We study the preconditioning of the stiffness matrix which arises from the discretization of the Poisson equation using IsoGeometric Method (IGM). A study of condition number of stiffness matrices, resulting from NURBS based IGM, suggests that novel preconditioning techniques are needed for fast and efficient iterative solvers for the resulting linear system. As a first step towards preconditio...

A = aerodynamic stiffness matrix C = speed of sound E = complex Fourier matrix f , F = physical and modal forces h = height of stream tube j = imaginary unit K, M = stiffness and mass matrices NB = number of blades P, Q = modal transformation matrices p = flow pressure Q = flow mass flux at the boundary q = generalized (modal) coordinate s = distance along the boundary T = period of flow unstea...

This paper focuses on the performance evaluation of the parallel manipulators for milling of composite materials. For this application the most significant performance measurements, which denote the ability of the manipulator for the machining are defined. In this case, optimal synthesis task is solved as a multicriterion optimization problem with respect to the geometric, kinematic, kinetostat...

We study connections between vibrational spectra and average nearest neighbor number in disordered clusters of colloidal particles with attractive interactions. Measurements of displacement covariances between particles in each cluster permit calculation of the stiffness matrix, which contains effective spring constants linking pairs of particles. From the cluster stiffness matrix, we derive vi...

The stiffness of a parallel manipulator is not only concerned with its detailed structure but also affected by the allocation scheme of actuators. Even though the precise values of stiffness cannot be derived since the link structure is not definitive at the stage of mechanism design, the effect of the allocation of actuators on the mechanism stiffness can be qualitatively evaluated in order to...

a parametrik investigation was conducted to study the non-linear behavior of precast and cast-in-place reinforced concrete beam-column connections subjected to tabas seismic forces (1979). the behavior of these types of connections in a four stories structure with respect to strength, ductility , stiffness, and bond deterioration at the joint core are presented and discussed. calculation result...

How organ-shaping mechanical imbalances are generated is a central question of morphogenesis, with existing paradigms focusing on asymmetric force generation within cells. We show here that organs can be sculpted instead by patterning anisotropic resistance within their extracellular matrix (ECM). Using direct biophysical measurements of elongating Drosophila egg chambers, we document robust me...

The research presented in this thesis addresses the problem of updating an analytical model using a parametric Reference Basis approach. In this method, some parameters are assumed to be accurate (e.g. natural frequencies, mode shapes and mass matrix), while others are adjusted so that the eigenvalue equation is satisfied. Updating is done with the use of principal submatrices, and the method s...

Many studies simulates the machining process by using a single degree of freedom springmass sytem to model the tool stiffness, or the workpiece stiffness, or the unit toolworkpiece stiffness in modelings 2D. Others impose the tool action, or use more or less complex modelings of the efforts applied by the tool taking account the tool geometry. Thus, all these models remain two-dimensional or so...

J.H. van Dieën Spinal segments with altered stiffness causing spinal deformations and low-back pain might be identifiable by comparing stiffness values between adjacent levels, since positive or negative outliers might indicate a clinically relevant condition. The stiffness matrix of a structure can be obtained by parameter estimation techniques such as model updating, which requires the constr...