Slowly rotating relativistic stars. IIIA - The static stability criterion recovered

1975 ◽  
Vol 195 ◽  
pp. 203 ◽  
Author(s):  
J. B. Hartle
Keyword(s):  
Stability Criterion ◽  
Static Stability ◽  
Relativistic Stars

Walking Stability Analysis of Multi-Legged Crablike Robot over Slope

2013 ◽  
Vol 572 ◽  
pp. 636-639
Author(s):  
Xi Chen ◽  
Gang Wang
Keyword(s):  
Mathematical Model ◽  
Stability Analysis ◽  
Stability Criterion ◽  
Stability Margin ◽  
Static Stability ◽  
Matlab Simulation ◽  
And Performance ◽  
The Stability ◽  
The Mathematical Model ◽  
The Relationship

This paper deals with the walking stability analysis of a multi-legged crablike robot over slope using normalized energy stability margin (NESM) method in order to develop a common stabilization description method and achieve robust locomotion for the robot over rough terrains. The robot is simplified with its static stability being described by NESM. The mathematical model of static stability margin is built so as to carry out the simulation of walking stability over slope for the crablike robot that walks in double tetrapod gait. As a consequence, the relationship between stability margin and the height of the robots centroid, as well as its inclination relative to the ground is calculated by the stability criterion. The success and performance of the stability criterion proposed is verified through MATLAB simulation and real-world experiments using multi-legged crablike robot.

Stability of a strut with one end fixed and the other pinned only at the first bifurcation point

2017 ◽  
Vol 23 (11) ◽  
pp. 1433-1443 ◽  
Author(s):  
M Jin
Keyword(s):  
Potential Energy ◽  
Bifurcation Point ◽  
Stability Criterion ◽  
Minimum Energy ◽  
Static Stability ◽  
The Other ◽  
Buckling Mode ◽  
Small Deflection ◽  
Deflection Theory ◽  
The Second Variation

In the sense of the Lagrange–Dirichlet minimum energy stability criterion, the static stability of a strut with one end fixed and the other pinned only at the first bifurcation point is investigated analytically. The second variation of potential energy expressed by the deflection is semi-positive-definite only at the first bifurcation point and vanishes only in the ‘buckling mode’ in small deflection theory. The fourth variation of potential energy is positive in the ‘buckling mode’. The potential energy of the strut at the first bifurcation point is proved to hold a minimum. Based on the Lagrange–Dirichlet stability criterion, the strut at the first bifurcation point is stable.

scholarly journals A quasi-radial stability criterion for rotating relativistic stars

2011 ◽  
Vol 416 (1) ◽  
pp. L1-L5 ◽  
Author(s):  
Kentaro Takami ◽  
Luciano Rezzolla ◽  
Shin’ichirou Yoshida
Keyword(s):  
Stability Criterion ◽  
Relativistic Stars

scholarly journals Static Stability Criterion for Walking Robots on Irregular Terrains.

1998 ◽  
Vol 16 (8) ◽  
pp. 1076-1082 ◽  
Author(s):  
Shigeo Hirose ◽  
Hideyuki Tsukagoshi ◽  
Kan Yoneda
Keyword(s):  
Stability Criterion ◽  
Static Stability ◽  
Walking Robots

Stability Limits of Reversible-Pump Turbines in Turbine Mode of Operation and Measurements of Unstable Characteristics

2012 ◽  
Vol 134 (11) ◽  
Author(s):  
Grunde Olimstad ◽  
Torbjørn Nielsen ◽  
Bjarne Børresen
Keyword(s):  
Stability Criterion ◽  
Input Parameter ◽  
Static Stability ◽  
Pump Turbine ◽  
Water Column Stability ◽  
Pressure Dependency ◽  
Previous State ◽  
Input Variables ◽  
Unstable Part ◽  
Turbine Mode

Measurements have been performed on a reversible-pump turbine model installed in a closed loop conduit system. The characteristics of the unstable pump turbine in turbine mode show a hysteresis pattern. Hence the output of the system is dependent on the previous state of the flow and not only the input variables. The hysteresis pattern is a characteristic of the whole system, but is caused by the unstable pump turbine. The unstable part of the characteristics was measured by three different methods: 1) by transient sampling of data during the transition between operation modes, 2) by throttling valves that steepens the friction-loss curve, and 3) by switching the causality in the system such that the torque becomes an input parameter and the speed of rotation becomes an output parameter. In the valve throttling measurements a pressure dependency was seen for the characteristics at high nondimensional speeds. This was further investigated by additional measurements of the characteristics at three different pressure levels. A rigid-water-column stability analysis has been conducted. The classic H-Q criterion describes static stability for a pump turbine with constant speed of rotation. With the speed of rotation as a variable, there is a new static stability criterion in addition to the dynamic stability criterion.

Wachstum und Wertleistung der Douglasie in Abhängigkeit von der Standraumgestaltung

2012 ◽  
Vol 163 (3) ◽  
pp. 96-104 ◽  
Author(s):  
Joachim Klädtke ◽  
Ulrich Kohnle ◽  
Edgar Kublin ◽  
Andreas Ehring ◽  
Hans Pretzsch ◽  
...  
Keyword(s):  
Wood Quality ◽  
Volume Growth ◽  
Static Stability ◽  
Douglas Fir ◽  
Breast Height ◽  
Monetary Analysis ◽  
Starting Conditions ◽  
Tree Number ◽  
Clear Differentiation ◽  
Further Development

Growth and value production of Douglas-fir under varying stand densities The investigation is focused on the effects of initial tree number and thinning on growth and value performance of Douglas-fir stands. Data base is a coordinated Douglas-fir spacing experiment in South Germany, started 40 years ago and comprising variants of tree numbers with 500, 1,000, 2,000 and 4,000 Douglas-firs per hectare. The treatment was performed according to a standardized experiment program. The results show that at low initial tree numbers, the diameter on breast height (DBH) of (pre)dominant trees at the beginning of the observations (with 12 m top height) is bigger than at higher initial plant numbers. Accordingly, the quotient of height (H) to DBH (as an indicator for tree's static stability) is lower. The further development of DBH and H/DBH quotient is decisively determined by stand treatment, which superimposes the effect of the initial tree number. The total volume growth shows a clear differentiation, too, the variants with initially high tree numbers appearing on top. In the monetary analysis, this ranking is reversed: despite a supposed inferior wood quality, the variants with lower initial tree numbers clearly outperform the ones with higher numbers in terms of value. From these results, the following silvicultural recommendations for Douglas-fir can be derived: the initial tree numbers should be in the range from 1,000 to 2,000 plants per hectare. On technically not accessible sites, even lower tree numbers may come into question. The strong influence of stand treatment on DBH and H/DBH development highlights the problem of postponed thinnings, for this causes growth and stability losses even under favorable starting conditions in terms of competition.

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