Nonlinear Dynamic Behavior of Fixed Jacket-Type Offshore Platforms Subjected to Simultaneously Acting Wave and Earthquake Loads

2004 ◽  
Author(s):  
A. K. Etemad ◽  
A. R. M. Gharabaghi ◽  
M. R. Chenaghlou
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Dynamic Response ◽  
Dynamic Behavior ◽  
Persian Gulf ◽  
Nonlinear Dynamic ◽  
Longitudinal Component ◽  
Offshore Platforms ◽  
Nonlinear Dynamic Response ◽  
Earthquake Loads

The nonlinear dynamic response of jacket-type offshore platform (which has been installed in Persian Gulf) under simultaneously wave and earthquake loads is conducted. The interaction between soil and piles is modeled by Konagai-Nogami model. The structure is modeled by finite element method. The analyses include models with the longitudinal component of earthquake and wave in the same direction and in different directions. The results indicate that when the longitudinal component of earthquake and wave are in the same direction, wave may reduce the response of studied platform and when they are in different directions, in some cases there is an increase in the response of platform.

Study of Nonlinear Dynamic Behavior of a Typical Jacket Type Platform Under Environmental Loading (Wave and Current) and Blast Overpressure

2004 ◽  
Author(s):  
M. Dousti ◽  
A. R. M. Gharabaghi ◽  
M. R. Chenaghlou
Keyword(s):  
Finite Element ◽  
Dynamic Behavior ◽  
Persian Gulf ◽  
Nonlinear Dynamic ◽  
The Other ◽  
Plastic Strains ◽  
Environmental Loading ◽  
Finite Element Software ◽  
Blast Overpressure ◽  
The One

In this paper the behavior of a jacket platform, which is installed in Persian Gulf under blast overpressure, is evaluated and interaction between blast and operating environmental wave and current loads is studied. Using finite element software the whole parts of platform, which include topside and jacket sections are modeled. The real pressure of blast load is applied for conducting the analyses. The study involves elastic and elasto-plastic analyses, which in the last one (elasto-plastic) the geometry and material nonlinearity have been considered. In the studied platform the results show that the interaction between blast and operating environmental wave and current loads is negligible but the comparison between two models, the one in which the whole parts of platform are modeled and the other one which only topside is modeled indicates that there are appreciable differences between the axial plastic strains.

scholarly journals Dynamic Analysis of Bolted Cantilever Beam with Finite Element Method Considering Thread Relation

2020 ◽  
Vol 10 (20) ◽  
pp. 7036
Author(s):  
Chao Cao ◽  
Xueyan Zhao ◽  
Zhenghe Song
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Dynamic Response ◽  
Dynamic Analysis ◽  
Cantilever Beam ◽  
Nonlinear Dynamic ◽  
Beam Model ◽  
Nonlinear Phenomenon ◽  
Bolted Joint ◽  
Element Method

There are complex nonlinear behaviors and mechanisms in the bolted joint interface. Thus, the bolted joint is crucial to the complex nonlinear dynamic response of the structure. However, in the traditional structural dynamic analysis, the screw connection is usually neglected, which makes it challenging to analyze and study the nonlinear dynamic behavior of bolted structures. Hence, based on the Timoshenko beam theory and finite element method, this paper introduces a model considering thread connection to analyze the dynamic response under different excitation. Eventually, the results indicate that owing to the local nonlinearity of bolts, the whole bolted cantilever beam shows hardening-type characteristics. In addition, the frequency response curve also depicts the typical nonlinear phenomenon of instability and uncertainty, namely bifurcation, which preliminarily verifies the correctness and accuracy of the bolted cantilever beam model.

Influence of Lubricant Traction Coefficient on Cage's Nonlinear Dynamic Behavior in High-Speed Cylindrical Roller Bearing

2017 ◽  
Vol 139 (6) ◽  
Author(s):  
Wenhu Zhang ◽  
Sier Deng ◽  
Guoding Chen ◽  
Yongcun Cui
Keyword(s):  
Dynamic Response ◽  
Dynamic Behavior ◽  
Nonlinear Dynamic ◽  
High Speed ◽  
Roller Bearing ◽  
Mass Center ◽  
Nonlinear Dynamic Response ◽  
Traction Coefficient ◽  
Cylindrical Roller Bearing ◽  
Cylindrical Roller

In this paper, the formulas of elastohydrodynamic traction coefficients of four Chinese aviation lubricating oils, namely, 4109, 4106, 4050, and 4010, were obtained by a great number of elastohydrodynamic traction tests. The nonlinear dynamics differential equations of high-speed cylindrical roller bearing were built on the basis of dynamic theory of rolling bearings and solved by Hilber–Hughes–Taylor (HHT) integer algorithm with variable step. The influence of lubricant traction coefficient on cage's nonlinear dynamic behavior was investigated, and Poincaré map was used to analyze the influence of four types of aviation lubricating oils on the nonlinear dynamic response of cage's mass center. The period of nonlinear dynamic response of cage's mass center was used to assess cage's stability. The results of this paper provide the theoretical basis for selection of aviation lubricating oil.

Nonlinear Dynamic Behavior of a Motorcycle’s Forecarriage During Braking

2006 ◽  
Vol 129 (6) ◽  
pp. 837-844
Author(s):  
F. Braghin ◽  
M. Brembilla ◽  
G. Brambilla ◽  
M. Pezzola
Keyword(s):  
Numerical Model ◽  
Dynamic Response ◽  
Dynamic Behavior ◽  
Nonlinear Dynamic ◽  
Experimental Tests ◽  
Design Parameters ◽  
Numerical Experience ◽  
Flexural Mode ◽  
Nonlinear Dynamic Response ◽  
Braking System

An experimental and numerical experience was carried out to investigate the nonlinear dynamic response of the forecarriage of a motorcycle, paying attention to a particular type of vibration that occurs during the braking. In fact, it was found that, in particular conditions of load on the handlebar, braking pressure, speed and temperature, the first flexural mode of the front fork is strongly excited. Thanks to the numerical model, solutions to these undesired vibrations were identified. Experimental tests were carried out modifying the design parameters of the motorcycles and of the braking system as suggested by the numerical model thus verifying that the purposed solutions were effective.

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