Substructured Dynamic Testing of Substation Disconnect Switches

2016 ◽  
Vol 32 (1) ◽  
pp. 567-589 ◽  
Author(s):  
Mohamed A. Moustafa ◽  
Khalid M. Mosalam
Keyword(s):  
Degrees Of Freedom ◽  
Dynamic Testing ◽  
Flexible Structures ◽  
Shaking Table ◽  
Support Structure ◽  
Six Degrees Of Freedom ◽  
Out Of Plane ◽  
Qualification Testing ◽  
Substation Equipment ◽  
Electrical Substation

The paper demonstrates the substructuring concept in seismic qualification testing of 550 kV electrical substation disconnect switches. In this study, the full and substructured (i.e., without support structure) switches are tested on a six degrees of freedom (DOFs) shaking table. Different combinations of translational and rotational excitations are obtained from full switch tests and used in the substructured ones. The behavior of the post insulators of the switches are compared to demonstrate validity and identify limitations of the substructuring concept applied to electrical substation equipment. From this comparison, critical DOFs for the response of post insulators in switches supported on flexible structures are identified. It is concluded that the in-plane and out-of-plane behavior of the investigated post insulators are uncoupled. The substructured tests driven by combined translational and rotational signals showed the best match with the full switch tests because the out-of-plane rotations contribute significantly to the response of the post insulators.

Out-of-Plane Solutions and Bifurcations of Submersibles in Free Positive Buoyancy Ascent

1994 ◽  
Vol 38 (04) ◽  
pp. 259-271
Author(s):  
Fotis A. Papoulias ◽  
Ibrahim Aydin
Keyword(s):  
Degrees Of Freedom ◽  
Pitchfork Bifurcation ◽  
Control Surface ◽  
Geometric Properties ◽  
Six Degrees Of Freedom ◽  
Out Of Plane ◽  
Bifurcation Solution ◽  
Extreme Sensitivity ◽  
And Control ◽  
Surface Deflections

The problem of motion stability of submersible vehicles in free positive buoyancy ascent is analyzed. Motion is allowed to occur in combined vertical and horizontal planes. Continuation and catastrophe theory techniques are employed to trace all possible steady-state solutions in six degrees of freedom, while local linearization reveals their stability properties. Vehicle geometric properties and control surface deflections are used as the primary bifurcation parameters. It is shown that multiple solutions may exist in the form of pitchfork bifurcation, solution separation, hysteresis, and teardrop branches. Regions in parameter spaces are identified where extreme sensitivity of solutions to geometric properties and hydrodynamic modeling is present.

Yield Surface of Deeply Buried Square Anchors Under Out-of-Plane Loading

2016 ◽  
Author(s):  
Tianyuan Zheng ◽  
Mark J. Cassidy ◽  
Yinghui Tian ◽  
Christophe Gaudin
Keyword(s):  
Yield Surface ◽  
Degrees Of Freedom ◽  
Research Work ◽  
Combined Loading ◽  
Mooring Line ◽  
Analytical Expression ◽  
Energy Devices ◽  
Six Degrees Of Freedom ◽  
Out Of Plane ◽  
Plate Anchor

Anchors are widely used offshore as foundation systems to moor floating platforms and renewable energy devices to provide uplift resistance in vertical or resistance in inclined direction. Most of the available research work has concentrated on in-plane loading. However, any failure of a single mooring line in a storm can cause out-of-plane loading on the remaining anchoring system. This research targets how this out-of-plane loading can affect the trajectory and ultimate holding capacity of the anchors. This paper presents results of a numerical investigation of the undrained bearing capacity of deeply buried square plate anchor in clay under six degrees-of-freedom loading. Finite element analyses are conducted to define the combined loading yield surface (or yield surface for the anchor in its current position) and an analytical expression of the yield surface is proposed and written directly in the six degrees-of-freedom loads. This analytical expression allows implementation of the yield surface in a plasticity approach, where the load-displacement relationship of the anchor can be described. The method to achieve this and also an illustration of how this framework on a simple plate anchor can be extended to predict the performance of more complex anchor geometries is described at the end of the paper in a description of future research.

A Study of an Arm Type Damper Consisting of Two Links, Two Joints and a Hinge

2002 ◽  
Author(s):  
Taichi Matsuoka ◽  
Kenichiro Omata ◽  
Yasuhisa Okano
Keyword(s):  
Degrees Of Freedom ◽  
Vibration Suppression ◽  
Experimental Results ◽  
Shaking Table ◽  
Friction Damper ◽  
Six Degrees Of Freedom ◽  
Human Arm ◽  
Three Degree Of Freedom ◽  
Ball Joints ◽  
Theoretical Results

In this paper, an arm type passive damper consisting of two links, two joints and a hinge, which is similar to a human arm, has developed. Two magnetic ball joints were used for the joints and a rotary friction damper was used for the hinge. The arm type damper has six degrees of freedom and gives damping in three translational and three rotational directions. The resisting force characteristics of the damper in three translational directions were analyzed. A trial damper was made and the load-displacement curves of the damper in three translational directions were measured. The experimental results agree with the theoretical results to some degree. Next, the damper was attached to a three-degree-of-freedom system composed of a mass, three guide rails and four coil springs, in which the mass is able to move in three translational directions along the guide rails. The seismic responses of the mass in three translational directions were measured using a two-dimensional electrohydraulic type shaking table and the experimental results were compared with the calculated results obtained by the Mathematica 3.0. The experimental results agree with the calculated results to some degree, and the effects of vibration suppression of the damper and the propriety of the calculations were substantiated.

Control of processing at multi-tool two-support setup

2020 ◽  
pp. 67-73
Author(s):  
N.D. YUsubov ◽  
G.M. Abbasova
Keyword(s):  
Degrees Of Freedom ◽  
Factor Model ◽  
Angular Displacement ◽  
Factor Models ◽  
Technological System ◽  
Displacement Control ◽  
Model Accuracy ◽  
Six Degrees Of Freedom ◽  
Angular Displacements ◽  
And Control

The accuracy of two-tool machining on automatic lathes is analyzed. Full-factor models of distortions and scattering fields of the performed dimensions, taking into account the flexibility of the technological system on six degrees of freedom, i. e. angular displacements in the technological system, were used in the research. Possibilities of design and control of two-tool adjustment are considered. Keywords turning processing, cutting mode, two-tool setup, full-factor model, accuracy, angular displacement, control, calculation [email protected]

scholarly journals Design and Calibration of a Hall Effect System for Measurement of Six-Degree-of-Freedom Motion within a Stacked Column

Sensors ◽  
2021 ◽  
Vol 21 (11) ◽  
pp. 3740
Author(s):  
Olafur Oddbjornsson ◽  
Panos Kloukinas ◽  
Tansu Gokce ◽  
Kate Bourne ◽  
Tony Horseman ◽  
...  
Keyword(s):  
Hall Effect ◽  
Degrees Of Freedom ◽  
Reactor Core ◽  
Degree Of Freedom ◽  
Life Extension ◽  
Scale Model ◽  
Design Development ◽  
Seismic Safety ◽  
Six Degrees Of Freedom ◽  
Six Degree Of Freedom

This paper presents the design, development and evaluation of a unique non-contact instrumentation system that can accurately measure the interface displacement between two rigid components in six degrees of freedom. The system was developed to allow measurement of the relative displacements between interfaces within a stacked column of brick-like components, with an accuracy of 0.05 mm and 0.1 degrees. The columns comprised up to 14 components, with each component being a scale model of a graphite brick within an Advanced Gas-cooled Reactor core. A set of 585 of these columns makes up the Multi Layer Array, which was designed to investigate the response of the reactor core to seismic inputs, with excitation levels up to 1 g from 0 to 100 Hz. The nature of the application required a compact and robust design capable of accurately recording fully coupled motion in all six degrees of freedom during dynamic testing. The novel design implemented 12 Hall effect sensors with a calibration procedure based on system identification techniques. The measurement uncertainty was ±0.050 mm for displacement and ±0.052 degrees for rotation, and the system can tolerate loss of data from two sensors with the uncertainly increasing to only 0.061 mm in translation and 0.088 degrees in rotation. The system has been deployed in a research programme that has enabled EDF to present seismic safety cases to the Office for Nuclear Regulation, resulting in life extension approvals for several reactors. The measurement system developed could be readily applied to other situations where the imposed level of stress at the interface causes negligible material strain, and accurate non-contact six-degree-of-freedom interface measurement is required.

Sign in / Sign up

Export Citation Format

Share Document