scholarly journals Coupling Effect of Eccentricity and Slenderness Ratios on RCFST Column Instability Modes

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Chao Guo ◽  
Zhengran Lu
Keyword(s):  
Theoretical Analysis ◽  
Analytical Procedure ◽  
Coupling Effect ◽  
Slenderness Ratio ◽  
Steel Tube ◽  
Eccentricity Ratio ◽  
Stability Behavior ◽  
Instability Modes ◽  
The Stability ◽  
Parametric Analyses

The instability damage modes of rectangle concrete-filled steel tube (RCFST) columns that are subjected to eccentric compression can be divided into two types based on the modified Jezek analytical procedure, namely, the eccentricity ratio (γ) and the slenderness ratio (λ) coupling effect. The RCFST columns have unilateral compression yield failure mode when γ is small. However, it has compressive and tensile mode on both sides when the value of γ is large. In this work, parametric analyses were performed to test 32 RCFST long columns by varying γ with different λ combinations. From the analysis, it was found that the results of the theoretical analysis of the load-tension strain (P-ε) responses and the instability modes of the RCFST long columns are similar to the experimental results. Further, the proposed analytical method aids in better understanding the effects of γ and λ coupling on the stability behavior of the RCFST columns.

scholarly journals The Influence of Torsional-Lateral Coupling on the Stability Behavior of Geared Rotor Systems

1988 ◽  
Vol 110 (4) ◽  
pp. 563-571 ◽  
Author(s):  
P. Schwibinger ◽  
R. Nordmann
Keyword(s):  
High Performance ◽  
Coupling Effect ◽  
Practical Importance ◽  
Coupled System ◽  
Oil Film ◽  
Stability Behavior ◽  
Rotor Systems ◽  
Lateral Vibrations ◽  
Lateral Coupling ◽  
The Stability

In high-performance turbomachinery trouble often arises due to unstable asynchronous lateral vibrations. The instabilities are mostly caused by oil film bearings, clearance excitation, internal damping, annular pressure seals in pumps, or labyrinth seals in turbocompressors. In recent times as an additional influence the coupling between torsional and lateral vibrations is considered, which is of practical importance in geared rotor systems. In the literature [1, 2], some field problems are described, where in geared drive trains unstable lateral vibrations occurred together with torsional oscillations. This presentation studies the influence of torsional-lateral coupling on the stability behavior of a simple geared system supported by oil film bearings. The coupling effect is investigated by parameter studies and a sensitivity analysis for the uncoupled and the coupled system.

The Research on the Stability of the Steel Tube Filled with Steel-Reinforce Concrete Subjected to Axial Compression after High Temperature

2014 ◽  
Vol 578-579 ◽  
pp. 1601-1604
Author(s):  
Bai Dong Zhao ◽  
Xiao Yu ◽  
Pei Chao Chen
Keyword(s):  
Reinforced Concrete ◽  
High Temperature ◽  
Axial Compression ◽  
Slenderness Ratio ◽  
Reinforce Concrete ◽  
Steel Tube ◽  
Composite Column ◽  
Steel Reinforced Concrete ◽  
The Stability

In this paper, we do the research on the steel tube filled with steel-reinforced concrete subjected to axial compression after high temperature by changing the temperature and the slenderness ratio.The influence of the temperature and slenderness ratio on the composite column and its stability formula of the composite column after high temperature was gotten by the research.

scholarly journals Bearing Capacity Studies on Square Steel Tube Confined Steel Reinforced Concrete Column under Eccentric Load

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Tongfeng Zhao
Keyword(s):  
Reinforced Concrete ◽  
Bearing Capacity ◽  
Slenderness Ratio ◽  
Steel Tube ◽  
Concrete Column ◽  
Eccentricity Ratio ◽  
Reinforced Concrete Column ◽  
Eccentric Load ◽  
Steel Reinforced Concrete ◽  
Square Steel Tube

In the present study, an experimental research was conducted on square steel tube confined steel reinforced concrete column under eccentric load. The major parameters of the specimens included slenderness ratio, eccentricity ratio, and structural steel reinforced ratio. According to the tested results, the eccentricity ratio, from 0 to 0.55, significantly affects the structural bearing capacity. The slenderness ratio, from 3 to 8, and steel reinforced ratio, from 0.3 to 0.41, slightly affect the capacity. Furthermore, a numerical analysis program was developed, and the calculated results are well consistent with the experimental results. Also, the theoretical formula for eccentrically loaded columns was proposed based on numerical results.

Nonlinear Analysis on Square Steel Tube Filled with Steel Reinforced High Strength Concrete Subjected to Bi-Compression Bending Load

2012 ◽  
Vol 166-169 ◽  
pp. 908-913
Author(s):  
Wei Ouyang
Keyword(s):  
Nonlinear Analysis ◽  
Slenderness Ratio ◽  
High Strength ◽  
Steel Tube ◽  
Analysis Procedure ◽  
Eccentricity Ratio ◽  
Initial Stiffness ◽  
Steel Reinforced Concrete ◽  
Bending Load ◽  
Square Steel Tube

This paper presents a nonlinear analysis of square steel tube columns filled with steel reinforced concrete subjected to bi-compression bending load. Calculated results agree well with the tested results. Further, Different parameters of members were analyzed using nonlinear analysis procedure. Results showed that Slenderness ratio, stirrup ratio and eccentricity ratio have tremendous influence on capacity and initial stiffness. Steel reinforced ratio and eccentricity angle have secondary influence on capacity and initial stiffness.

An hourglass-type electromagnetic isolator with negative resistance electromagnetic shunt circuit

2020 ◽  
Vol 64 (1-4) ◽  
pp. 549-556
Author(s):  
Yajun Luo ◽  
Linwei Ji ◽  
Yahong Zhang ◽  
Minglong Xu ◽  
Xinong Zhang
Keyword(s):  
Vibration Isolation ◽  
Electromechanical Coupling ◽  
Coupling Effect ◽  
Negative Resistance ◽  
Isolation System ◽  
Amplitude Vibration ◽  
Vibration Responses ◽  
The Stability ◽  
Isolation Performance ◽  
Shunt Circuit

The present work proposed an hourglass-type electromagnetic isolator with negative resistance (NR) shunt circuit to achieve the effective suppression of the micro-amplitude vibration response in various advanced instruments and equipment. By innovatively design of combining the displacement amplifier and the NR electromagnetic shunt circuit, the current new type of vibration isolator not only can effectively solve the problem of micro-amplitude vibration control, but also has significant electromechanical coupling effect, to obtain excellent vibration isolation performance. The design of the isolator and motion relationship is presented firstly. The electromechanical coupling dynamic model of the isolator is also given. Moreover, the optimal design of the NR electromagnetic shunt circuit and the stability analysis of the vibration isolation system are carried out. Finally, the simulation results about the transfer function and vibration responses demonstrated that the isolator has a significant isolation performance.

scholarly journals An assessment of methanolysis and other factors used in the analysis of carbohydrate-containing materials

1971 ◽  
Vol 125 (4) ◽  
pp. 1009-1018 ◽  
Author(s):  
R. E. Chambers ◽  
J. R. Clamp
Keyword(s):  
Hydrochloric Acid ◽  
Analytical Procedure ◽  
Internal Standard ◽  
Inorganic Contaminants ◽  
Rotary Evaporation ◽  
Silver Salts ◽  
Methanolic Hydrochloric Acid ◽  
Different Temperatures ◽  
The Stability ◽  
Analytical System

The stability of monosaccharides in methanolic hydrochloric acid of different strengths and at different temperatures was determined. They are generally stable for 24h in methanolic 1m- and 2m-hydrochloric acid at both 85°C and 100°C, but undergo considerable destruction in methanolic 4m- and 6m-hydrochloric acid at 100°C. Analysis of glycopeptides and oligosaccharides of known composition showed that release of carbohydrate was complete within 3h in methanolic 1m-hydrochloric acid at 85°C. Removal of methanolic hydrochloric acid by rotary evaporation resulted in considerable losses of monosaccharides, which could be prevented by prior neutralization. Methanolysis caused extensive de-N-acetylation of acetamidohexoses, so that a re-N-acetylation step is necessary in the analytical procedure. The addition of acetic anhydride for this purpose also prevented loss of internal standard by adsorption on the insoluble silver salts used in neutralization. Several trimethylsilylating agents were studied and suitable conditions are recommended. The effects on the analytical system of water and some common organic and inorganic contaminants are assessed.

The Effects of Geometric Irregularities of Journals on the Performance of Porous Bearings

1994 ◽  
Vol 208 (2) ◽  
pp. 141-145 ◽  
Author(s):  
T S Chennabasavan ◽  
R Raman
Keyword(s):  
Theoretical Analysis ◽  
Carrying Capacity ◽  
Load Carrying Capacity ◽  
Eccentricity Ratio ◽  
Attitude Angle ◽  
Load Carrying ◽  
Permeability Variation ◽  
Very High

In the theoretical analysis of porous bearings the journal has so far been assumed to be ideal, that is perfectly cylindrical. In the present analysis the geometric irregularities of the journal, such as circumferential undulations and barrel/bellmouth shapes, are taken into account. The permeability variation along the length of the bearing as found in commercial bearings has also been taken into account. The present analysis reveals that, at the critical Sommerfeld number, the friction is very low compared to the very high value for an ideal journal. The present analysis also reveals that the friction and the attitude angle are lower for any Sommerfeld number and that the load-carrying capacity is lower for any eccentricity ratio than that for an ideal journal.

Mathematical Model Establishment and Analysis on the Pipe Deformation under External Pressure with the Ovality

2013 ◽  
Vol 760-762 ◽  
pp. 2263-2266
Author(s):  
Kang Yong ◽  
Wei Chen
Keyword(s):  
Mathematical Model ◽  
Theoretical Analysis ◽  
Yield Strength ◽  
Residual Stresses ◽  
Numerical Simulations ◽  
Significant Influence ◽  
External Pressure ◽  
Pipe Diameter ◽  
Axial Loads ◽  
The Stability

Beside the residual stresses and axial loads, other factors of pipe like ovality, moment could also bring a significant influence on pipe deformation under external pressure. The Standard of API-5C3 has discussed the influences of deformation caused by yield strength of pipe, pipe diameter and pipe thickness, but the factor of ovality degree is not included. Experiments and numerical simulations show that with the increasing of pipe ovality degree, the anti-deformation capability under external pressure will become lower, and ovality affecting the stability of pipe shape under external pressure is significant. So it could be a path to find out the mechanics relationship between ovality and pipe deformation under external pressure by the methods of numerical simulations and theoretical analysis.

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