2225 Effects of impact velocity and slenderness ratio on dynamic buckling loads for long columns

2007 ◽  
Vol 2007.1 (0) ◽  
pp. 279-280
Author(s):  
Koji MIMURA ◽  
Tsutomu UMEDA ◽  
Hiroyuki YAKA
Keyword(s):  
Impact Velocity ◽  
Slenderness Ratio ◽  
Dynamic Buckling ◽  
Buckling Loads

EFFECTS OF IMPACT VELOCITY AND SLENDERNESS RATIO ON DYNAMIC BUCKLING LOAD FOR LONG COLUMNS

2008 ◽  
Vol 22 (31n32) ◽  
pp. 5596-5602 ◽  
Author(s):  
K. MIMURA ◽  
T. UMEDA ◽  
M. YU ◽  
Y. UCHIDA ◽  
H. YAKA
Keyword(s):  
Impact Velocity ◽  
Dynamic Load ◽  
Slenderness Ratio ◽  
Testing Machine ◽  
Dynamic Buckling ◽  
Impact Testing ◽  
Buckling Load ◽  
Square Function ◽  
Buckling Loads ◽  
The Impact

In this research, the buckling behavior of long columns under dynamic load was investigated both experimentally and numerically, and an effective buckling criterion for dynamic load was derived from the results in terms of the impact velocity and the slenderness ratio. In the experiments, a free fall drop-weight type impact testing machine was employed. The dynamic buckling loads were measured by the load sensing block, and the displacements were measured by a high speed magnetic-resistance device. In the numerical analyses, dynamic FEM code 'MSC-Dytran' was used to simulate the typical experimental results, and the validity and the accuracy of the simulations were checked. The dynamic buckling loads at various impact velocities were then systematically investigated. From both experimental and simulated results, it was found that the dynamic to static buckling load ratios can be successfully described as a square function of the slenderness ratio of the columns, while they can be also described by a power law of the applied impact velocity.

Experimental Evaluation of Dynamic Buckling Load of GFRP Rod for Gas Circuit Breaker

2014 ◽  
Vol 566 ◽  
pp. 593-598 ◽  
Author(s):  
H. Hashimoto ◽  
H. Yaka ◽  
I Riku ◽  
T. Umeda ◽  
K. Mimura
Keyword(s):  
Slenderness Ratio ◽  
Circuit Breaker ◽  
Dynamic Buckling ◽  
Buckling Load ◽  
Elastic Buckling ◽  
Time Duration ◽  
Buckling Loads ◽  
Compression Load ◽  
Power Substation ◽  
The Impact

Dynamic elastic buckling behaviors of GFRP and Aluminum rods were experimentally investigated. In a gas circuit breaker of an electric power substation, an operating rod consisting of insulating materials is connected to an interrupter. The rod securely insulate between the interrupter and an operating mechanism. The rod is configured with a slender rod made of Glass Fiber Reinforced Plastics (GFRP). When the gas circuit breaker ends the opening operation, impulsive compression load acts on the GFRP rod. To develop a smaller and lighter GFRP rod, dynamic buckling loads of the rod must be studied. In this study, dynamic elastic buckling loads for slender GFRP and aluminum rods were investigated by an experimental method. The drop weight impact tests of the GFRP rods and aluminum rods were employed. In the testing device, a special load cell called the “Load Sensing Block” was used to measure the dynamic load of long time duration. Slender GFRP rods with various lengths were axially loaded at the impact velocities ranging from 0.75m/s to 4.5m/s. From the experimental results, an empirical criterion for the dynamic buckling load of the GFRP rod was proposed in terms of the impact velocity and the slenderness ratio. Furthermore, results showed the proposed criterion could successfully describe the buckling behavior of not only the GFRP rod but also the aluminum rod.

Effects of Solid Viscosities, Loading Velocities and Initial Deflections to Dynamic Buckling Loads of a Column

1969 ◽  
Vol 73 (706) ◽  
pp. 890-894
Author(s):  
Shin-Ichi Suzuki
Keyword(s):  
Dynamic Load ◽  
Analytical Methods ◽  
Dynamic Buckling ◽  
Static Loads ◽  
Buckling Loads ◽  
Load Factors

It is a well-known fact that buckling values for columns under dynamical loads are different from those under static loads. Meier, Gerard and Davidson have already investigated the dynamics of the buckling of elastic columns theoretically and experimentally, and Hoff discussed analytical methods in detail. However, solid viscosities are neglected in all these researches. Previously, the author obtained the relationships between dynamic load factors and solid viscosities, and it was found that their effects on dynamic load factors cannot be neglected. It will be interesting to investigate the relationships between solid viscosities and dynamic buckling values.

DYNAMIC BUCKLING AND POSTBUCKLING OF A COMPOSITE SHELL

2010 ◽  
Vol 10 (04) ◽  
pp. 791-805 ◽  
Author(s):  
CHRISTOS C. CHAMIS
Keyword(s):  
Solution Method ◽  
Composite Shell ◽  
Dynamic Buckling ◽  
Dynamic Loads ◽  
Composite Cylindrical Shell ◽  
Buckling Loads ◽  
Loading Rates ◽  
Computer Codes ◽  
Updated Lagrangian ◽  
Composite Mechanics

A computationally effective method for evaluating the dynamic buckling and postbuckling of thin composite shells is described. It is a judicious combination of available computer codes for finite element, composite mechanics and incremental structural analysis. The solution method is an incrementally updated Lagrangian. It is illustrated by applying it to a thin composite cylindrical shell subjected to dynamic loads. Buckling loads are evaluated to demonstrate the effectiveness of the method. A universal plot is obtained for the specific shell that can be used to approximate buckling loads for different dynamic loading rates. Results from this plot show that the faster the rate, the higher the buckling load and the shorter the time. They also show that the updated solution can be carried out in the postbuckling regime until the shell collapses completely. Comparisons with published literature indicate reasonable agreement.

Dynamic Buckling of a Damped Externally Pressurized Imperfect Cylindrical Shell

1979 ◽  
Vol 46 (2) ◽  
pp. 372-376 ◽  
Author(s):  
D. F. Lockhart
Keyword(s):  
Cylindrical Shell ◽  
Circular Cylindrical Shell ◽  
Asymptotic Expression ◽  
Simple Relation ◽  
Dynamic Buckling ◽  
Fourier Component ◽  
Buckling Mode ◽  
Buckling Loads ◽  
Imperfect Cylindrical Shell ◽  
Step Loading

The dynamic buckling of a finite damped imperfect circular cylindrical shell which is subjected to step-loading in the form of lateral or hydrostatic pressure is examined by means of a perturbation method. The imperfection is assumed to be small. An asymptotic expression for the dynamic buckling load is obtained in terms of the damping coefficient and the Fourier component of the imperfection in the shape of the classical buckling mode. A simple relation which is independent of the imperfection is then obtained between the static and dynamic buckling loads.

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