Rev 1.1

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AN-VI: A NEW VIBRATION ABSORBER ELASTOMETER

1 VIBRATION AND THEIR EFFECTS .................................................................................................... 2

2 WHAT IS AN-VI? .................................................................................................................................... 2

3 SHOCKS AND IMPACT VIBRATIONS ............................................................................................... 2

4 SHOCK ABSORPTION .......................................................................................................................... 2

5 CONTINUOUS VIBRATIONS ............................................................................................................... 2

6 AN-VI AND THE ABSORPTION OF SHOCK ENERGY ................................................................... 3

7 REBOUND ELASTICITY OF ELASTOMERS AS A FUNCTION OF TEMPERATURE .............. 4

8 AN-VI DAMPING PROPERTIES .......................................................................................................... 5

9 AN-VI AND TRANSITORY PHENOMENA ......................................................................................... 6

10 MECHANICAL FEATURES OF AN-VI ................................................................................................ 8

11 Examples of AN-VI compounds ............................................................................................................ 9

12 AN-VI AND CHEMICAL AGENTS ...................................................................................................... 11

13 ELECTRICAL FEATURES OF AN-VI ................................................................................................ 12

14 WHERE AN-VI CAN BE USED .......................................................................................................... 12

15 THOSE WHO HAVE TRIED AN-VI SAY… ....................................................................................... 13

16 AVAILABLE SHAPES .......................................................................................................................... 13

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1 VIBRATION AND THEIR EFFECTS

When machines are functioning , they vibrate, causing wear to their parts and to their supporting structures reducing the production quality. The vibrations, transferred to structures, are also harmful to people working nearby. The vibrating structures create noise which in turn becomes a source of disturbance.

2 WHAT IS AN-VI?

AN-VI is a new member of the rubber family, with substantially different characteristics to those of traditional elastomers. It has the elasticity of a good rubber but it also has unusual damping capacities: by deformation it absorbs energy from an elastic material and as a damper it dissipates the energy absorbed. One part of the energy is converted into heat while the other part is returned so slowly as to have practically no dynamic effects. In solid form AN-VI can be used to reduce shock and impact stress effects as a vibration damper. Foamed it finds use with specific not too heavy loads.

3 SHOCKS AND IMPACT VIBRATIONS

If we compare what happens when a small metal ball is dropped on a slab of AN-VI and on a slab of some other elastic material, we will see: The elastic material is compressed and “energized”. This given energy is then returned to the ball which bounces. Instead AN-VI is slow in neutralizing the impact-inducted deformation and returns to its original shape with no bounce action, the impact energy is “disapated” inside AN-VI. The absorbed energy is not given back to the ball and is also filtered out from affecting the underlying surface. This proves AN-VI’s claims to reduce shock effects and to attenuate impact vibrations generated by repeated blows of metal on metal.

4 SHOCK ABSORPTION

Another feature of AN-VI is its shock-absorbing capacity. AN-VI is excellent for use where shock vibration is added to constant vibrations.

5 CONTINUOUS VIBRATIONS

As a rule, machines are insulated from their base plates by vibration-damping supports. The machine-plus-support system has a natural frequency of oscillation determined by the mass of the machine and the elasticity of the supports. In operation, the machine vibrates at a frequency depending on the speed of rotation . If the vibration frequency is higher than the natural frequency, AN-VI absorbs the energy and decidedly cuts down the transmission of vibration to base-plate. When the vibration frequency is near the natural frequency, as it is, for example, in the start-up and stopping stages of the machine, AN-VI acts as a shock absorber, limiting machine oscillation. Machine-made vibrations are transmitted to the metal covering panels. This then act as a sounding board. Noise can be reduced by damping the vibrations with suitable material on panels, in such a way that the mechanical energy associated with the vibrations is then converted into head and dissipated. A sheet of foamed AN-VI on the metal is the answer. A metal-panel sandwich with AN-VI filling is an excellent noise-deadening arrangement.

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6 AN-VI AND THE ABSORPTION OF SHOCK ENERGY

Several tests have shown that AN-VI reduces the effects of shock and cuts the vibrations generated by the impact of repeated blows of metal on metal. The graphs illustrate the force transmitted by a free-falling steel ball on a load cell Between the ball and the instrument there are 3 test pieces consisting alternatively of natural rubber, ethyl-vinylacetate (E.V.A.) and AN-VI. The test was performed under equal conditions (highness of the fall and size of the pieces): AN-VI absorbs the shock energy completely (there is no second or rebound shock) and this reduces the transmitted force.

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The value found were: RUBBER 144 E.V.A. 120 AN-VI 100

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7 REBOUND ELASTICITY OF ELASTOMERS AS A FUNCTION OF TEMPERATURE

One of the major characteristics which sets AN-VI apart from other good quality elastomers is its rebound elasticity. This quantity is a parameter expressing the capacity of the material to dissipate mechanical energy. It is measured by means of an instrument called the Rebound Pendulum Which measures how much mechanical energy is put back into a steel ball falling from a specific height on to a test piece of the material under examination. With AN-VI, for temperature between 0° and 30°, less than 5% of the ball’s prefall potential energy is put back into the ball. The remaining 95% is dissipated by the AN-VI. On the picture AN-VI’s rebound elasticity is illustrated in comparison with that of other common elastomers, as a function of temperature. In a range of temperature from -20° to +60°C, which includes most normal applications, the rebound elasticity of An-VI is decidedly lower than that of all other elastomers.

The picture shows the behavior of AN-VI according to the frequency of vibration, compared with other different elastomers. The chart was defined from the Politecnico di Torino - Interdisciplinary Mechatronics Laboratory during an experiment carried out using AN-VI to stabilize electrodynamics rotor-bearings. The study demonstrated that the use of AN-VI is the solution also where other elastomers highlight various kinds of limits.

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8 AN-VI DAMPING PROPERTIES

AN-VI’s capacity in extensively damping both impulse and transitory vibrations as well as stationary and pseudostationary dynamic actions is apparent in its hysteresis behaviour.

GIVEN AN OSCILLATOR:

SYMBOL TABLE

time frequency pulsation displacement speed acceleration force mass elastic stiffness viscous damping hysteresis stiffness imaginary unit viscous damping factor hysteresis damping factor natural pulsation natural frequency natural period natural damping factor

t f

w = 6,28 f s(t)

v(t) = ds(t) / dt a(t) = dv (t) / dt

F (t) M K B C i

nv = B / (2 Sqr (K/M))

ni= C/2K wo= Sqr (K/M)

fo= (1/6,28) Sqr (K/M)

To= 1/fo no=nv + ni

S Hz

rad/s m

m/s (m/s)/s

N Kg

N/m N /(m/s)

N/m

ad ad

rad/s Hz s

ad

F (t) = Ma(t) + Bv(t) + (K + iC) s (t)

Take test pieces of various materials and subject them to a squash s (t) of unit amplitude ( 1 cm ),changing according to harmonic law ( with pulsation w ). Then:

s(t) = (1 cm) sin (wt)

Graph the relationship between the squash (s) and the force (F) required to produce the desired displacement The behaviour shown in the first figure on next page refers to a perfectly elastic material, such as steel. The relation between ( s ) and ( F ) is a straight line whose slope (K) represents the elastic stiffness of the sample.

F(t) = K s(t) = K ((1 cm) sin (w t))

The elastic energy ( Ee ) required to cover the load-phase (half circle)

Ee = ½ K (2 cm)2

Is given back in total in the upload phase. The behaviour of the elastomers, shown in the other figures on next page, diverges from that of the steel in that the straight lines of steel becomes an s/F closed curve and represents the hysteresis circle of the material. The area enclosed by the curve is a measure of the hysteresis Energy (E) expended in one circle of the system. The ratio (Ri) between hysteresis energy (Ei) and the energy associated with the elastic half-cycle (Ee) is an index of the material’s hysteretic dissipative capacities:

Ri = Ei / Ee

The hysteresis properties of materials are espressed in terms of hysteretic stiffness (C), orhysteretic damping coefficient, wich has the same dimensions as elastic stiffness (K), and therefore the total force (F) to be applied to the sample to produce the cycle is given by:

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F(t) = (K + iC) x (t) = K (1 cm) sin (wt) + C (1 cm) cos(wt)

The ratio ( 2 nl ) between the two stiffnesses represents the loss factor or hysteresis damping factor or hysteresis damping factor. The parameter:

nl = C / (2K)

is connected to the Energy ratio ( Rl ) by the formula:

Rl = (3,14) nl The greater the hysteresis capacity for dissipating mechanical Energy, the fatter is the cycle shape. With the test, the difference between the behaviours of AN-VI and other elastomers can be quantified. Given that all good quality rubbers have respectable hysteresis damping factor (ni), AN-VI’s particularly high. THE HYSTERESIS OF STEEL, RUBBER AND AN-VI

STEEL RUBBER AN-VI Force (N)

Displacement (cm)

Force (N)

Displacement (cm)

Force (N)

Displacement (cm)

PARAMETERS RUBBER AN-VI

Rebound elasticity at 20°C

Loss factor: 2ni = C / K

Hysteresis factor: ni = C / (2K)

Energy ratio: Ri = Ei / Ee

From 20% to 40%

From 10% to 30%

From 5% to 15%

From 16% to 47%

From 2% to 5%

From 120% to’ 80%

From 60% to 90%

From 188% to 283%

9 AN-VI AND TRANSITORY PHENOMENA

Transitory phenomena have their origin in events which last only for a very short time. A theoretical example, schematically very simple, is the rectangular impulse illustrated below in the figure, resulting from the application of a load ( F ), which remains constant for a period of time ( T ). In actual fact the response of the mechanical system is usually characterized by complex oscillatory phenomena during the loading phase, in passing from ( 0 ) to ( F ). Higher is the natural damping factor ( no ) of the system quicker is the phenomena disappearing. The diagrams on pages 10 and 11 give evidence of the differences in behaviour between an ordinary rubber ( no = 30% ) and AN-VI ( no = 60% ). The extent of displacement depends upon the stiffness ( K ) of the system. Response oscillation amplitude a ( t ) is inversely proportional to the mass ( M ). The diagrams confirm that significant effects are obtained through the use of AN-VI insofar as the transitory phenomena caused by the system’s free oscillations are concerned, both in the loading phase and in the unloading phase. The shorter oscillation damping time also reduces the risk of dangerous synchronizations due to the superimposing of return waves on the outgoing waves.

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The pictures show the transitory for the different materials.

Force (N)

Time (s)

RUBBER AN-VI

Displacement (cm)

Time (s)

Displacement (cm)

Time (s)

Accelerations (cm/s

2)

Time (s)

Accelerations (cm/s2)

Time (s)

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10 MECHANICAL FEATURES OF AN-VI

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11 Examples of AN-VI compounds

Mixtures with different percentages of AN-VI can be made to obtain different material properties according to different usages, (e.g.: different specific gravity and hardness or elasticity). You can find below as example the mechanical properties of 4 different compounds and the frequency response of the M4 at temperatures of -20 ° C +20 ° C and +80 ° C.

PRODUCT: M1 M2 M3 M4

Density 1,02 1,07 1,14 1,19

kg/dm³

Hardness (DIN 53505) 36 41 51 58

Shore A

100% Young's Modulus (DIN53504) 0,73 1,06 1,85 2,79

MPa

300% Young's Modulus (DIN53504) 1,93 4,5 6,67 10,66

MPa

Tensile Strength (DIN53504) 12,43 13,76 13,79 12,73

MPa

Abrasion Resistance (DIN 53516) - 231 149 84

mm³

Elongation at Break (DIN 53504) 5 0,5 6 1

%

Elongation at Break (DIN 53504) 681 470 444 320

%

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12 AN-VI AND CHEMICAL AGENTS

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13 ELECTRICAL FEATURES OF AN-VI

AN-VI is classified, from an electrical point of view as an insulating material. Anyway, even if it cannot be classified as material with ESD protection, the quantity of the charge generated by triboelectric effect is limited: undergoing to a rubbing process, AN-VI features an accumulation inferior to 500V, while normal insulating plastics gets tens of thousands Volt. According to the above features, the material results to be particularly suitable to be used in electrical and electronics field in direct contact with circuitry without any particular risk of conduction or electrostatic discharges.

14 WHERE AN-VI CAN BE USED

AN-VI is a positive solution in conquering vibration problem in a large number of machines. A major application sector are those of machines with metal hammering on metal, with reciprocating parts, and precision machines where protection mast be provided against vibrations coming from neighbouring mechanism. APPLICATIONS FOR AN-VI Industrial sector Vibration deadening in rotatory and reciprocating machines, linings for hoppers and containers suffering shock from falling materials, vibratory separators, metal panel deadening, handgrip covers, portable machine tool uncouplers. Automotive, Rail , Aereospace, Naval e Yachts Lining and covers, rebound bumpers, racing car interiors. Railwais superstructure Rail chairs, superstructure paltform supports, signlling and shunting box connections. Building Slab supports, bearings, joints, floating floors. Electronics and precision instrumentation Coverings, equipment supports and fixings. Hi-Fi Coverings, supports and fixings for soundboxes and record-players. Hydraulics Piping anchorage, pump uncouplers, joint seals. Office machines Supports and base plates for printers and computers. Aeronautics Helicopter landing platforms.

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15 THOSE WHO HAVE TRIED AN-VI SAY…

Research - Politecnico di Torino – Laboratorio di Meccatronica

"The tests performed with different masses allowed to vary the natural frequency of the system making it clear that in the frequency range analyzed the behavior of the material remains unchanged”

"The tests carried out under different operating conditions show that the behavior of the material, in terms of loss factor and elastic modulus remains unchanged working with traction, compression and shear"

"Working with damping materials, the damping factor may be overly influenced by the temperature and frequency, the tensile strength may be inadequate, the available formats can be too thin. Not being afflicted with these problems AN-VI is the solution”

Industry – Azimut Yachts – Avigliana (TO)

"The reduction of vibratory phenomenon with rubber AN-VI improved by 12.6% (reduction of 21.9) compared to the value reached by the NBR (9.3%), despite the thickness of 3 mm for AN-VI and 10mm for the NBR "

"The vibration values measured show more than one characteristic frequency, but with extremely low levels. Too low to make any consideration "

"The rubber AN-VI showed its excellent characteristics, was always superior in performance"

16 AVAILABLE SHAPES

AN-VI in foamed form (light load) is distributed in sheets of different formats and 3 thicknesses (1, 2 and 4 mm). The structure of the material is magnified in the pictures on the right.

Cubes with edge 40mm are available in solid form (heavy load), easy to work with water-jet technology to achieve the desired shape depending on the specific use

Plates of 40x40mmq size and 2,3,4 and 5 mm thickness are available in compact form, which can be used as such or die-cut to get different forms.

In solid form it can also be made basing on special design according to the customer needs, varying if necessary the compound formula to obtain the right. elastic properties. appropriate.