scholarly journals Experimental Dynamic Behavior of Free-Standing Multi-Block Structures Under Seismic Loadings

2008 ◽  
Vol 12 (6) ◽  
pp. 953-979 ◽  
Author(s):  
Fernando Peña ◽  
Paulo B. Lourenço ◽  
Alfredo Campos-Costa
Keyword(s):  
Dynamic Behavior ◽  
Free Standing ◽  
Seismic Loadings ◽  
Block Structures

Dynamic Behavior and Design of Offshore Caissons

1978 ◽  
Vol 18 (05) ◽  
pp. 291-299
Author(s):  
S.T. Hong ◽  
J.C. Brooks
Keyword(s):  
Dynamic Behavior ◽  
Experimental Studies ◽  
Design Procedure ◽  
Operational Experience ◽  
Dynamic Effects ◽  
Free Standing ◽  
Well Production ◽  
Single Well ◽  
Time Required ◽  
Short Time

Abstract Free-standing caissons are used for supporting flare pipes and single-well production platforms. However, caissons tend to be flexible and dynamically sensitive, and the static design practice may not be adequate for this type of practice may not be adequate for this type of structure. To assess motion effect on the integrity of the structural system and to quantify the allowable motion for safe operation on board a caisson platform, analytical and experimental studies of platform, analytical and experimental studies of the dynamic behavior of a caisson structure were conducted and are described here. The analytical simulations agree well statistically with The motion measurements. A caisson design procedure considering dynamic effects was developed Design considerations include ultimate strength failure, fatigue failure, excessive motion, and possible damage during installation. A key feature in an effective caisson design is that the upper part of the caisson should be made as small as possible so that wave loading and the caisson period can be minimized The fatigue design procedure was verified with past caisson operational experience. To illustrate past caisson operational experience. To illustrate the procedure, a flare-pipe support caisson in 185 ft of water was designed and analyzed. Introduction Free-standing caissons are used for supporting flare pipes or single-well production platforms. The attractiveness of a caisson structure lies in the potential economy and the short time required for potential economy and the short time required for fabrication and installation. However, a caisson tends to be flexible, and dynamic effects may increase the design requirements from both strength and functional standpoints. To assess the motion effect on the integrity of the structural system and to quantify the allowable motion level for effective operation on board a caisson platform, analytical and experimental studies of the dynamic behavior of a caisson structure were conducted, and a procedure was formulated for designing a caisson considering dynamic effects. Observations from the experimental data and computer simulations of the caisson behavior are described. Verification of the computer simulation and some useful information for developing and using such simulations as well as practical interpretation of the analytical results practical interpretation of the analytical results also are given. Differences between a static design and a dynamic design are illustrated in an example design of a flare-support caisson in 185 ft water. MOTION MEASUREMENT Motion data were taken from a caisson platform offshore Louisiana. General dimensions of the caisson are shown in Fig. 1. SPEJ P. 291

scholarly journals Multidrum Stone Columns at the Pompeii Archaeological Site: Analysis of Geometrical Properties and State of Preservation

Heritage ◽  
2020 ◽  
Vol 3 (4) ◽  
pp. 1069-1082
Author(s):  
Francesca Autiero ◽  
Giuseppina De Martino ◽  
Marco Di Ludovico ◽  
Annamaria Mauro ◽  
Andrea Prota
Keyword(s):  
Dynamic Behavior ◽  
Seismic Vulnerability ◽  
Archaeological Site ◽  
Research Area ◽  
Stone Columns ◽  
Geometrical Parameters ◽  
Seismic Action ◽  
Free Standing ◽  
Geometrical Properties ◽  
Wide Range

The seismic vulnerability of ancient free-standing multidrum stone columns is an important issue for the preservation of Greek and Roman archaeological sites. Such elements show a complex and highly non-linear dynamic behavior, requiring specific and sophisticated structural analysis. Different numerical studies on the dynamic behavior of ancient multidrum stone columns found that their seismic response is sensitive to their geometrical parameters, as well as to the material elastic properties, the kinetic coefficient of friction and the amplitude and frequency of the seismic action. Therefore, in the present research, a detailed survey of free-standing multidrum stone columns representative of a wide range of elements at the Pompeii Archaeological site was developed to provide a primary evaluation of the seismic vulnerability of such elements based on their geometrical properties. The study focuses on 103 multidrum grey-tuff columns, from four areas at the site: tetrastyle atrium of Casa del Fauno at Regio VI and Quadriportico dei Teatri, Foro Triangolare and Palestra Sannitica at Regio VIII. Grey tuff was a typically locally sourced natural stone, used as a building material in ancient Pompeii. The research areas included both private (Casa del Fauno) and public buildings (Quadriportico dei Teatri, Foro Triangolare and Palestra Sannitica). The mean overall geometrical properties affecting the seismic behavior of the columns in each research area and the discussion of the collected results are herein presented.

Stress-Driven Dynamic Behavior of Free-Standing Bent-Core Liquid Crystal Filaments

2014 ◽  
Vol 468 (1) ◽  
pp. 101-113 ◽  
Author(s):  
T. Ostapenko ◽  
S. M. Salili ◽  
A. Eremin ◽  
A. Jákli ◽  
R. Stannarius
Keyword(s):  
Liquid Crystal ◽  
Dynamic Behavior ◽  
Free Standing

An In-Situ Tem Study of the Dynamic Behavior of Domain Walls in a Free-Standing Lead Titanate Thin Film Under External Stress

1995 ◽  
Vol 404 ◽  
Author(s):  
S. B. Ren ◽  
C. J. Lu ◽  
H. M. Shen ◽  
Y. N. Wang
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Dynamic Behavior ◽  
Domain Walls ◽  
High Stress ◽  
Ferroelectric Thin Film ◽  
External Stress ◽  
In Situ Tem ◽  
Free Standing

AbstractThe evolution of domain structure with external stress in a free-standing PbTiO3 ferroelectric thin film of ˜100nm in thickness is observed by in-situ TEM technique. The thin film is composed of granular grains of ˜100nm in diameter, most of them appear to be single-domained whereas others are multi-domained showing domains of different sizes(5˜20nm). For some single-domained grains new domains appear during tension. For multi-domained grains, rearrangement of domain walls and coarsening of domains have been observed during tension. In many cases the domain walls disappear under high stress, i.e., a multi-domained grain changes into a single-domained grain. However, it is also observed that a large portion of single-domained grains appear not to respond to external stress. The dynamic behavior of domain walls in very thin ferroelectric thin films may help to understand the switching of these very thin films.

Ball bearing turbocharger vibration management: application on high speed balancer

2020 ◽  
Vol 21 (6) ◽  
pp. 619
Author(s):  
Kostandin Gjika ◽  
Antoine Costeux ◽  
Gerry LaRue ◽  
John Wilson
Keyword(s):  
Dynamic Behavior ◽  
High Speed ◽  
Internal Combustion Engines ◽  
Ball Bearing ◽  
Squeeze Film ◽  
Design And Technology ◽  
Squeeze Film Damper ◽  
Damping Coefficients ◽  
Bearing Loads ◽  
Stiffness And Damping

Today's modern internal combustion engines are increasingly focused on downsizing, high fuel efficiency and low emissions, which requires appropriate design and technology of turbocharger bearing systems. Automotive turbochargers operate faster and with strong engine excitation; vibration management is becoming a challenge and manufacturers are increasingly focusing on the design of low vibration and high-performance balancing technology. This paper discusses the synchronous vibration management of the ball bearing cartridge turbocharger on high-speed balancer and it is a continuation of papers [1–3]. In a first step, the synchronous rotordynamics behavior is identified. A prediction code is developed to calculate the static and dynamic performance of “ball bearing cartridge-squeeze film damper”. The dynamic behavior of balls is modeled by a spring with stiffness calculated from Tedric Harris formulas and the damping is considered null. The squeeze film damper model is derived from the Osborne Reynolds equation for incompressible and synchronous fluid loading; the stiffness and damping coefficients are calculated assuming that the bearing is infinitely short, and the oil film pressure is modeled as a cavitated π film model. The stiffness and damping coefficients are integrated on a rotordynamics code and the bearing loads are calculated by converging with the bearing eccentricity ratio. In a second step, a finite element structural dynamics model is built for the system “turbocharger housing-high speed balancer fixture” and validated by experimental frequency response functions. In the last step, the rotating dynamic bearing loads on the squeeze film damper are coupled with transfer functions and the vibration on the housings is predicted. The vibration response under single and multi-plane unbalances correlates very well with test data from turbocharger unbalance masters. The prediction model allows a thorough understanding of ball bearing turbocharger vibration on a high speed balancer, thus optimizing the dynamic behavior of the “turbocharger-high speed balancer” structural system for better rotordynamics performance identification and selection of the appropriate balancing process at the development stage of the turbocharger.

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