345 Fast Finite Element Analysis of responses for an elastic frame connected by nonlinear springs having elastic principal axes in arbitrary directions

2009 ◽  
Vol 2009 (0) ◽  
pp. _345-1_-_345-6_
Author(s):  
Takao YAMAGUCHI ◽  
Miyoshi WATANABE ◽  
Ken-ichi NAGAI ◽  
Shinichi MARUYAMA
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Element Analysis ◽  
Nonlinear Springs ◽  
Principal Axes

An Improved Method for Designing Flexure-Based Nonlinear Springs

2012 ◽  
Author(s):  
Qiaoling Meng ◽  
Giovanni Berselli ◽  
Rocco Vertechy ◽  
Vincenzo Parenti Castelli
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Compliant Mechanisms ◽  
Empirical Equations ◽  
Element Analysis ◽  
Closed Form Solutions ◽  
Nonlinear Springs ◽  
Aspect Ratios ◽  
Analytical Relations ◽  
Flexural Hinges

Monolithic Flexure-based Compliant Mechanisms (MFCM) can functionally act as nonlinear springs by providing a desired load-displacement profile at one point on their structure. Once the MFCM topology is chosen, these particular springs can be conveniently synthesized by resorting to the well-known Pseudo-Rigid-Body approximation, whose accuracy strongly depends on the modeling precision of the flexures’ principal compliance. For various types of flexures, closed-form solutions have been proposed which express the compliance factors as functions of the flexure dimensions. Nonetheless, the reliability of these analytical relations is limited to slender, beam-like, hinges undergoing small deflections. In order to overcome such limitations, this paper provides empirical equations, derived from finite element analysis, that can be used for the optimal design of circular, elliptical, and corner-filleted flexural hinges with general aspect ratios on the basis of both principal compliance and maximum bearable stress. As a case study, a nonlinear spring conceived as a four-bar linkage MFCM is synthesized and simulated by means of finite element analysis. Numerical results confirm that the aforementioned empirical equations outperform their analytical counterparts when modeling thick cross-section hinges undergoing large deflections.

226 Fast Finite Element Analysis for Elastic Block supported by Plural Nonlinear Springs

2005 ◽  
Vol 2005 (0) ◽  
pp. _226-1_-_226-6_
Author(s):  
Takao YAMAGUCHI ◽  
Atsushi IZAWA ◽  
Ken-ichi NAGAI ◽  
Shinichi MARUYAMA
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Element Analysis ◽  
Nonlinear Springs

scholarly journals Vertical Stiffness Functions of Rigid Skirted Caissons Supporting Offshore Wind Turbines

2021 ◽  
Vol 9 (6) ◽  
pp. 573
Author(s):  
AbdelRahman Salem ◽  
Saleh Jalbi ◽  
Subhamoy Bhattacharya
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Offshore Wind ◽  
Element Analysis ◽  
Vertical Stiffness ◽  
Closed Form Solutions ◽  
Principal Axes ◽  
Modes Of Vibration ◽  
Bending Modes ◽  
Tower Vibration

Suction Bucket Jackets (SBJs) need to be fundamentally designed to avoid rocking modes of vibration about the principal axes of the set of foundations and engineered towards sway-bending modes of tower vibration. Whether or not such type of jackets exhibit rocking modes depends on the vertical stiffness of the caissons supporting them. This paper therefore derives closed form solutions for vertical stiffness in three types of ground profiles: linear, homogenous, and parabolic. The expressions are applicable to suction caissons having an aspect ratio (depth: diameter) between 0.2 and 2 (i.e., 0.2 < L/D < 2). The work is based on finite element analysis followed by non-linear regression. The derived expressions are then validated and verified using studies available in literature. Finally, an example problem is taken to demonstrate the application of the methodology whereby fundamental natural frequency of SBJ can be obtained. These formulae can be used for preliminary design and can also be used to verify rigorous finite element analysis during detailed design.

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