Experiment of torsional response induced by the Q –delta resonance

2020 ◽  
Author(s):  
Fumiya Mizutori ◽  
Masayuki Kohiyama
Keyword(s):  
Delta Resonance ◽  
Torsional Response

Influence of Prestressing on Torsional Response of Concrete Beams

PCI Journal ◽  
1978 ◽  
Vol 23 (3) ◽  
pp. 54-73 ◽  
Author(s):  
Denis Mitchell ◽  
Michael P. Collins
Keyword(s):  
Concrete Beams ◽  
Torsional Response

The effect of element strength assignment on the torsional response of stiffness-eccentric systems

2013 ◽  
Vol 40 (7) ◽  
pp. 655-662
Author(s):  
George K. Georgoussis
Keyword(s):  
Structural Design ◽  
Shear Force ◽  
Ground Motions ◽  
Building Structures ◽  
Centre Of Mass ◽  
Base Shear ◽  
Structural Behaviour ◽  
Torsional Response ◽  
Building Models ◽  
Storey Building

Building structures of low or medium height are usually designed with a pseudostatic approach using a base shear much lower than that predicted from an elastic spectrum. Given this shear force, the objective of this paper is to evaluate the effect of the element strength assignment (as determined by several building codes) on the torsional response of inelastic single-storey eccentric structures and to provide guidelines for minimizing this structural behaviour. It is demonstrated that the expected torque about the centre of mass (CM) may be, with equal probability, positive (counterclockwise) or negative (clockwise). This result means that the torsional strength should also be provided in equal terms in both rotational directions, and therefore the base shear and torque (BST) surface of a given system must be symmetrical (or approximately symmetrical). In stiffness-eccentric systems, appropriate BST surfaces may be obtained when a structural design is based on a pair of design eccentricities in a symmetrical order about CM, and this is shown in representative single-storey building models under characteristic ground motions.

Experimental Study on the Continuous Type Three-Dimensional Control of the Cable-Stayed Bridge

2011 ◽  
Vol 71-78 ◽  
pp. 1933-1937
Author(s):  
Jia Yun Xu ◽  
Ji Chen ◽  
Xian Wei Qu ◽  
Wen Kai Gong
Keyword(s):  
Angular Displacement ◽  
Three Dimensional ◽  
Wind Tunnel Test ◽  
Highway Bridge ◽  
Changjiang River ◽  
Continuous Type ◽  
Torsional Response ◽  
Cable Stayed Bridge ◽  
Bridge Model ◽  
Wind Induced Vibration

This paper takes a Chinese Changjiang River highway bridge as engineering background, and a kind of continuous three-dimensional (vertical, lateral and torsion)controllers which can apply in the large span cable-stayed bridge is presented. The controllers can control vertical, lateral and torsional response of bridge wind-induced vibration at the same time. Through comparative wind tunnel test of the bridge model with and without controllers, some important conclusions are made as follows: when the continuous three-dimensional controllers are installed on the bridge model, its flutter critical wind speed increases significantly (mostly increases 33.36%); Meanwhile, there is a certain degree of reduction in its RMS values of vertical, lateral and torsional angular displacement response.

scholarly journals Experimental Study of the Shaft Penetration Factor on the Torsional Dynamic Response of a Drive Train

Machines ◽  
2018 ◽  
Vol 6 (3) ◽  
pp. 31 ◽  
Author(s):  
Hans Meeus ◽  
Björn Verrelst ◽  
David Moens ◽  
Patrick Guillaume ◽  
Dirk Lefeber
Keyword(s):  
Experimental Study ◽  
Torsional Vibration ◽  
Torsional Stiffness ◽  
Vibration Measurement ◽  
Dynamic Amplification Factor ◽  
Torsional Mode ◽  
Penetration Factor ◽  
Torsional Response ◽  
Major Interest ◽  
Drive Trains

Typical rotating machinery drive trains are prone to torsional vibrations. Especially those drive trains that comprise one or more couplings which connect the multiple shafts. Since these vibrations rarely produce noise or vibration of the stationary frame, their presence is hardly noticeable. Moreover, unless an expensive torsional-related problem has become obvious, such drive trains are not instrumented with torsional vibration measurement equipment. Excessive levels can easily cause damage or even complete failure of the machine. So, when designing or retrofitting a machine, a comprehensive and detailed numerical torsional vibration analysis is crucial to avoid such problems. However, to accurately calculate the torsional modes, one has to account for the penetration effect of the shaft in the coupling hub, indicated by the shaft penetration factor, on the torsional stiffness calculation. Many guidelines and assumptions have been published for the stiffness calculation, however, its effect on the damping and the dynamic amplification factor are less known. In this paper, the effect of the shaft penetration factor, and hence coupling hub-to-shaft connection, on the dynamic torsional response of the system is determined by an experimental study. More specifically, the damping is of major interest. Accordingly, a novel academic test setup is developed in which several configurations, with each a different shaft penetration factor, are considered. Besides, different amplitude levels, along with both a sweep up and down excitation, are used to identify their effect on the torsional response. The measurement results show a significant influence of the shaft penetration factor on the system’s first torsional mode. By increasing the shaft penetration factor, and thus decreasing the hub-to-shaft interference, a clear eigenfrequency drop along with an equally noticeable damping increase, is witnessed. On the contrary, the influence of the sweep up versus down excitation is less pronounced.

Torsional characterization of ropes used offshore

2008 ◽  
Vol 43 (2) ◽  
pp. 121-139 ◽  
Author(s):  
I M L Ridge
Keyword(s):  
Experimental Data ◽  
Torsional Response ◽  
In Series ◽  
Different Levels

The first part of this paper presents a general discussion of the various problems which must be addressed when combining different ropes in series or, in some cases, in using a rope in conditions where it is rotationally unrestrained. The paper will pay particular attention to the various classes of rope used in the offshore environment and their main torsional characteristics. In the second part, equipment is shown which is suitable for the measurement of the torsional response of various rope constructions at different levels of twist. Experimental data are presented for a variety of rope constructions at sizes comparable with those used in offshore applications. Comparison is made with data obtained in similar previous studies but with smaller‐diameter ropes.

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