dipl.ing. hans j. kolitzus · artificial athlete berlin hans j. kolitzus, ist. institut fÜr...

INSTITUT FÜR SPORTBODENTECHNIK

Dipl.Ing. Hans J. Kolitzus

Artificial Athlete Berlin

Hans J. Kolitzus, IST

INSTITUT FÜR SPORTBODENTECHNIKIST Consulting GmbHDipl.Ing. Hans J. Kolitzus

OriginalArtificial AthleteBerlin 1968


Artificial Athlete Berlin„1968“ Version

This 1st Artificial Athlete was designed by the Federal Institute of TestingMaterials in Berlin (BAM) in the early 60ies. It worked with very low

viscous oil which was pressed through wholes in the shaft when the dropweight plunged into the oil pot. The drop weight carried an

accelerometer. The peak deceleration was a parameter to describe theshock absorbing behaviour of the surface. It was designed for area-elastic sports hall surfaces. Since it was unpractical for use on site

(spilling out of oil) and not suitable on point-elastic surfaces the(Modified) Artificial Athlete Berlin was developed (1975).


Artificial Athlete Berlin„1995“ Version

The (Modified) Artificial Athlete wasdeveloped with a steel spring as ashock absorbing unit. Since about1990 the spring is precisely milledwith 3 wires to an accurate springnumber of 2000 N/mm. The wingson top of the test foot are neededwhen the mechanical system of theAA Berlin is used to act as an AAStuttgart.


Artificial AthleteBerlin „1995“

Test foot, load celland spring in detail;problem here is thespecification of thespring number andits tolerances. Noneof the standardsaddresses this (theforce-deformationcharacteristic is notcompletely linear).


Artificial AthleteBerlin „1995“

Testfoot + Springassembled


DIN Reference Norm

The Reference Norm wasinitially developed by SKZfor DIN 18032-2 in 1996 asa calibration tool. It is set tohave 53% FR by definition.Unfortunately, according tothe internationally acknow-ledged test procedure ithas only 50% FR. Thereference norm is used asa replacement of a sportssurface with known FR.


ISSS Reference Norms

The ISSS has improvedthe design of theReference Norms andmanufactured them withdifferent FR levels (35 - 45- 55). The reference normswere „calibrated“ by theaverage of the results of 10test labs (see referenceddocuments)


Artificial AthleteBerlin „1995“Studded Testfoot

This is a UEFA specifctest foot. It is unclearwhat exactly is to bedetermined incomparison to the flattest foot: stability?


DIN 18032-2DIN 18035-7

FIHEN 14808 IAAF FIFA UEFA

Spring recommendedto be milled

recommendedto be milled




Spring Number 2000 ± 60N/mm

2000 ± 60N/mm

2000 ± 60N/mm

2000 ± 60N/mm

2000 ± 60N/mm

Load Cell 10 kN Class 0.1 10 kN Class 0.2 10 kN Class 0.2 10 kN Class 0.2 10 kN Class 0.2

Mass ofTest Foot 3.0 ± 0.3 kg 3.0 ± 0.3 kg 3.0 ± 0.3 kg 3.0 ± 0.3 kg 3.0 ± 0.3 kg

Test Foot Radius 500 mm Radius 500 mm Radius 500 mm Radius 500 mm Radius 500 mm

Test foot Variant --- --- --- --- studded

Design of Device


Test Realization

DIN 18032-2DIN 18035-7


Number ofImpacts

min. 3until ∆FR <2 3 3 3 3

Waiting Period 1 min 60 s 60 +/ 10 s 1 min +/- 10 s 60 +/- 10 s

RelevantImpacts last 2 2 + 3 2 + 3 2 + 3 1 = listed

2 + 3


Recording

DIN 18032-2DIN 18035-7


MeasuringChannel Class

linear 1-1000 Hz(-1 dB)

ISO 6467>= 1 kHz

ISO 6467>= 1 kHz

ISO 6467>= 1 kHz

ISO 6467>= 1 kHz

Analog Filter not specified(500 Hz) not specified 500 Hz

Butterw 2 pole120 Hz (-3 dB)

or500 Hz

Digital Filter Butterw 2 pole120 Hz (-3 dB)





Range ofMeasuringSystem

not specified <= 4 times oftest reading

<= 4 times oftest reading



Sampling Rate not specified >= 2 kHz >= 2 kHz >= 2 kHz >= 2 kHz


Calibration

DIN 18032-2DIN 18035-7


ReferenceSurface

SteelDisk (10mm)glued on top of

200mm Concrete6.60 ±0.25 kN 6.60 ±0.25 kN 6.60 ±0.25 kN 6.60 ±0.25 kN

Number ofDrops 5 11 not specified 11 not specified


Evaluation

DIN 18032-2DIN 18035-7


Name of DeviceKünstlicher

Sportler BerlinAA Berlin

Procedure 1 Artificial AthleteBAA Test Method 1

ShockAbsorbtion

Artificial Athlete

Name ofParameter

KraftAbbau(Force

Reduction)

ShockAbsorption Force Reduction Force Reduction Force Reduction

CorrectionMethod

Reference Normset 53 % = RN

∆FR =53 - FR(RN) %

--- --- --- ---

Correction FRres =FR - ∆FR --- --- --- ---


Discrepancy

DIN ./. World

∆FR = 2.5 - 3.0 %

the „DIN Bonus“This means that Force Reduction determined in Germany isalways 3% (absolute) higher than anywhere else in the world. DINwas notified of this but did not react.


Effect of Digital Filter: 2-pole


Effect of Digital Filter : 9-pole


Effect of Digital Filter

On soft sports surfaces such as synthetic turf, the force response(black) shows an overlaid vibration. This is caused by a resonanceeffect within the AA and is not a characteristic of the surface. It can beseen from the two graphs that it is necessary to use a 9-pole filter toeliminate the vibration and receive a smooth resulting trace (red). Thisis important to determine a reliable peak force for evaluation. Althoughthis effect occurs also on FMPA test devices the effect is denied. The9-pole filter is agreed among all ISSS labs (except FMPA Stuttgart). Itshould be considered to use an 120Hz FFT filter (green) because it isavailable on all computerized recording systems and provides bestadjustment to the original trace.


OriginalAA Stuttgart1968

The drop weightwas then 50kg.Here the deviceis shown whenmeasuring thehorizontaldeformation.


OriginalAA Stuttgart1968

Determinationof DeformationTrough.


Artificial Athlete Stuttgart„1995“ Version(DIN 18032-2:1996)

Drop weight is reduced to 20 kg. In orderto achieve the same impactcharacteristic the drop height and thespring number were adjusted. Thus thesame mechanical device can be used forAA Berlin and Stuttgart. The deformationpick-ups in this picture are withdrawnfrom the AA (actually need to sit on thewings of the test foot). Is it necessarythat the spring carries a cap ? No !


Artificial Athlete Stuttgart„1995“ Version(DIN 18032-2:1996)

Problem: how to specify the zero-line?

IAAF: release drop weight (20kg)„statically“ on spring, set deformationpick-ups to zero; lift the drop weight andrun the test.

Synthetic turf: pre-load 0.01 N/mm2

which means 3.5 kg caused by test foot.

dipl.ing. hans j. kolitzus · artificial athlete berlin hans j. kolitzus, ist. institut fÜr...

Documents