TEST REQUIREMENTS AND IT EXECUTION FOR THE VELOCITY

DEPENDENT ENERGY DISSIPATION DEVICES

Deh-Shiu Hsu, Yung-Feng Lee, Chien-Yuan Hou and Juan-The Lee

Department of Civil Engineering, National Cheng Kung University, Tainan, Taiwan, R.O.C.

dsusu@mail.ncku.edu.tw

Both of displacement dependent and velocity dependent energy dissipation devices need to be passed by performance test before it is used in the real world.

Experiment is extremely important for the process of engineering applications. Most of the experiments are failure test. In case of experiments to the energy dissipation devices, the experiments are non-failure test.

Sampling test — for the items of failure test.The quality is not hundred percent assured for the element installed in the engineering projects.

Experiment for energy dissipation devices is non-failure test.Test can be done to every single devices.The devices can be used no matter before or after the test.

Static testDynamic testproperties of the energy dissipation devices.Unless we know the properties of the devices, it can not be designed and installed in the structures.

to obtain the

For fluid damper :

Resisting force = f ( orifice ratio, orifice shape, density of fluid, property of fluid, …)

The properties of the damper devices can be investigated not only by sampling test, but also by testing performed to each of the individual dampers. F = CVn

C : damping factorDamping factor is highly sensitive to the primary factors related.

“All devices should be tested to confirm acceptable behavior

under large earthquake loading”

— SEAOC Blue Book recommended

The analysis, design, and construction issues associated with the use of energy dissipation devices, specially for fluid viscous velocity dependent devices, are not well understood by most of design professionals and building officials. With the installation of such devices, panel review for the design and the tests to the devices will be much more important.

Full scale cyclic test be certainly considered as a very qualified test method to detect the properties of the devices.

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Displacement (mm)

Res

istin

g Fo

rce

(kN

)

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Velocity (mm/sec)

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)

• Time consumed• Limitation of the capacity of test facilities It is allowed to use impact tests of full

size units, combined with both cyclic test and impact test of reduced scale units to detect the properties of the full size devices, in particular for the velocity dependent devices such as fluid viscous dampers.(FEMA,1997)

Cyclic testDrop

hammer test

Full size devices

Properties?

Reduced small size devices

Hammer Test :

It is recognized that hammer test did not afford the response functions with respect to the excitations such as subjected by real earthquakes. However, some of the factors, such as damping factor of the damper, can be obtained by the hammer test.

Hammer test is introduced instead of preparing and maintaining such facilities to meet the required test capacities.

Test Example :A locally produced fluid damper is tested both for cyclic test and hammer impact test.

Orifice ratio : 1.607% Silicone glue : Si100

Orifice rate

%

A2

1002

1 A

A

A1

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Displacement (mm)

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Velocity (mm/sec)

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istin

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(kN

)Testing result for the case of frequency 2.5Hz and amplitude 10mm.

Testing result for the case of frequency 3.0Hz and amplitude 10mm.

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Testing result for the case of frequency 3.5Hz and amplitude 10mm.

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Cyclic Test : F = 0.19V

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V elo c ity (m m /sec )

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Res

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F ittin g c u rv e , F = 0 .1 9 V 0 .1 H z , 1 0 m m 0 .2 H z , 1 0 m m 0 .5 H z , 1 0 m m 1 .0 H z , 1 0 m m 1 .5 H z , 1 0 m m 2 .0 H z , 1 0 m m 2 .5 H z , 1 0 m m 3 .0 H z , 1 0 m m

Drop Hammer TestExample : single caseData taken : 200 HzMass : 750 kgdrop height : 120 mm

0 0 .1 0 .2 0 .3 0 .4 0 .5 0 .6

T im e (sec )

0

1 0

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3 0

4 0

Dis

plac

emen

t (m

m)

0 0 .1 0 .2 0 .3 0 .4 0 .5 0 .6

T im e (sec )

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Res

istin

g Fo

rce

(kN

)

0 0 .1 0 .2 0 .3 0 .4 0 .5 0 .6

T im e (sec )

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Vel

ocity

(m

m)

Group of data for a certain damper

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V e lo c ity (m m /se c )

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Res

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orce

(kN

)

F ittin g c u rv e , F = 0 .1 9 V d ro p h am m e r te s t

F=0.19V

1. Drop hammer test is one of the available method, probably is a necessary tool, for the practical development and application for the use of the velocity dependent energy dissipation devices to the aseismatic engineering.

2. The damper under tested introduced herein happen to get the linear relation between resisting force and velocity, i.e., F = CV. In fact, the function of the resisting force with respect to velocity could be nonlinear, i.e. F = CVn, n≠1. However, cyclic test, as well as drop hammer test, can be used to detect the damping factor C, and the value of n.

Conclusion and suggestion

3.Due to the highly sensitivity of the damper property with slightly difference of the possible related variables, in order to assure the quality of the dampers installed in structures for the purpose of aseismatic engineering, performance test executed to each one of the devices could be necessary. In other words, can not be ignored by the excuse of lacking of testing facilities.