External maintenance auxiliary damping device for track system

Abstract

The utility model discloses an external maintenance auxiliary damping device for a track system, which is mounted on the inner side of a trapezoidal sleeper of an existing track or above the middle of a track plate and comprises a mass tuning plate filled with damping particles. Vibration energy is consumed through collision and friction between the damping particles and the wall face and mutual collision and friction between the damping particles, so that the vibration reduction effect is achieved, especially vertical vibration is eliminated, and a track is prevented from being damaged; meanwhile, as a whole, the mass tuning plate is in direct contact with the track, the natural vibration frequency of the whole mass tuning plate is close to the natural vibration frequency of the track plate, and therefore the effects of mass tuning, negative-phase movement relative to vibration of the track plate and vibration reduction are achieved, and the vibration reduction device has the double vibration reduction effects.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the field of vibration and noise control of rail transit, concretely is a kind of external maintenance auxiliary damping device for track system. BACKGROUND

[0002] Rail transit refers to a kind of traffic tool or transport system, which needs to run on a specific track, including subway, light rail, railway system and the like.But in the actual vehicle operation process, vibration and noise of different degrees are generated, and the vertical vibration is the most damaging and threatening to the railway system.For the control problem of rail transit vibration and noise, the existing track damping and noise reduction measures mainly reduce (lose) the stiffness of track structure, and this kind of engineering measure is most widely used and has remarkable effect.However, this method will increase the track structure vibration displacement, induce rail corrugation, cause vehicle running irregularity, reduce comfort, increase vehicle internal noise, and also cause fastener spring bar fracture, track slab cracking and other diseases.

[0003] Therefore, it is necessary and urgent to explore technical means such as increasing structural member damping and keeping track structure stiffness unchanged to ensure the smoothness and comfort of vehicle operation and reduce related diseases.

[0004] Especially for the track line in operation, how to give a good vibration reduction modification scheme with low investment under the condition of finding that the vibration is large has great practical value.

[0005] Due to the above reasons, the utility model is based on the above engineering problems, based on theoretical research and a large number of investigations, a kind of external maintenance auxiliary damping device for track system is designed, which can assist the vibration reduction of existing line or newly built track slab and sleeper, and does not need to replace the track slab or sleeper of existing track, without affecting the main line operation. INVENTION CONTENTS

[0006] In order to overcome the above problems, the utility model person has made arduous research, and designed an external maintenance auxiliary damping device for track system, which is installed in the inside of ladder sleeper of existing track or above the middle part of track slab.The damping device includes mass tuning plate, and the inside of the mass tuning plate is filled with damping particles, which consume vibration energy through collision and friction with wall surface and mutual collision and friction between damping particles, so as to realize damping effect, especially eliminate vertical vibration and avoid damaging track;At the same time, as a whole, the mass tuning plate directly contacts with track, and the self-vibration frequency of mass tuning plate as a whole is close to the self-vibration frequency of track slab, so as to realize mass tuning, and the vibration of mass tuning plate relative to track slab is "negative phase" motion, which plays a damping role, so the damping device has double damping effect, thereby completing the utility model.

[0007] Specifically, the utility model aims at providing a kind of external maintenance auxiliary damping device for track system, which is installed in the inside of ladder-shaped sleeper of existing track or installed on the top of middle part of track slab of existing track to maintain the existing track;

[0008] The existing track is a track in operation, which supports steel rail through ladder-shaped sleeper or track slab;

[0009] The damping device includes a mass-tuned plate 1, which is filled with damping particles inside, and the damping particles are selected from one or more of iron sand, lead particles, steel balls and sand;

[0010] The vibration energy is consumed by the collision and friction between damping particles and the wall of mass-tuned plate 1 and the collision and friction between damping particles.

[0011] The cavity 2 containing the damping particles is formed in the inside of the mass-tuned plate 1, and the damping particles 3 are filled in the cavity 2.

[0012] The volume ratio of the damping particles in the cavity 2 of the mass-tuned plate 1 is 80-90%.

[0013] When the damping device is installed in the inside of ladder-shaped sleeper,

[0014] The opening end of the cavity 2 is located at the top surface of the mass-tuned plate 1, and a cover plate 4 is arranged at the top of the cavity 2 to block the opening end.

[0015] Grooves 11 are formed at both sides of the bottom of the mass-tuned plate 1, and the mass-tuned plate 1 is clamped on the ladder-shaped sleeper through the grooves 11.

[0016] A strip-shaped damping pad 51 is arranged in the groove 11, the top of the strip-shaped damping pad 51 supports the mass-tuned plate 1, and the bottom of the strip-shaped damping pad 51 abuts against the ladder-shaped sleeper.

[0017] The size of the mass-tuned plate 1 is 1174mm in length, 1015mm in width and 97mm in thickness.

[0018] The effective volume in the cavity 2, i.e. the space volume that can be used to contain damping particles, is 928mm×715mm×45mm=0.0298584m 3 .

[0019] When the damping device is installed on the top of middle part of track slab 9,

[0020] The opening end of the cavity 2 is located at the side of the mass tuning plate 1, and a side plate 6 is arranged at the side of the cavity 2 to block the opening end.

[0021] A full-paved damping pad 52 is arranged at the bottom of the mass tuning plate 1,

[0022] A fixing device is arranged at the outer side of the mass tuning plate 1, the fixing device comprises a fastening rod 71 surrounding the outer side of the mass tuning plate 1, and a pad 72 is arranged at both ends of the fastening rod 71, the fixing device is fixed on the track plate through the pad 72, and the mass tuning plate 1 and the full-paved damping pad 52 are fixed on the track plate 9 through the fixing device.

[0023] The mass tuning plate 1 has a size of 2000mm in length, 800mm in width and 75mm in height;

[0024] The effective volume in the cavity 2, that is, the space volume capable of being used to contain the damping particles is 1980mm*780mm*55mm=0.084942m 3 .

[0025] The beneficial effects of the utility model include:

[0026] (1) The external maintenance auxiliary damping device for the track system is installed above the middle part of the track plate of the existing track or the inner side of the two existing trapezoidal track sleepers, and the device has a great effect on assisting in improving the damping effect of the track structure of the existing line;

[0027] (2) The external maintenance auxiliary damping device for the track system is particularly suitable for the case that the damping measure of the track structure of the existing line is damaged, fails, has reduced function and cannot be replaced, and the device can increase and improve the damping effect of the track structure of the existing line without affecting the operation of the existing line;

[0028] (3) The external maintenance auxiliary damping device for the track system has the double effects of mass tuning damping and damping particle damping, and the damping effect is much higher than that of the damping measure of using one of them alone;

[0029] (4) The external maintenance auxiliary damping device for the track system is internally provided with damping particles, and compared with the vibration system of "mass + spring", the damping particles are collided between each other and between the particles and the container wall to consume energy, so that the vibration of the track structure is rapidly attenuated, and the damping and noise reduction effects are better;

[0030] (5) The external maintenance auxiliary damping device for the track system has damping particles arranged in the inside, the frequency covers low frequency to high frequency, has broad spectrum, has damping effect on vibration of all frequency bands, and the frequency of the common track plate and the sleeper is mostly concentrated in 20-80Hz, and the damping effect on the low frequency band is poor. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 Fig. 4 shows the overall schematic view of the external maintenance auxiliary damping device for the track system provided by the utility model installed in the inside of the ladder sleeper of the existing track;

[0032] Figure 2 Fig. 5 shows the sectional view of the external maintenance auxiliary damping device for the track system provided by the utility model installed in the inside of the ladder sleeper of the existing track;

[0033] Figure 3 Fig. 6 shows the perspective view of the external maintenance auxiliary damping device for the track system provided by the utility model installed in the inside of the ladder sleeper of the existing track;

[0034] Figure 4 Fig. 7 shows the damping pad structure schematic view of the external maintenance auxiliary damping device for the track system provided by the utility model installed in the inside of the ladder sleeper of the existing track;

[0035] Figure 5 Fig. 8 shows the cover plate structure schematic view of the external maintenance auxiliary damping device for the track system provided by the utility model installed in the inside of the ladder sleeper of the existing track;

[0036] Figure 6 Fig. 9 shows the overall schematic view of the external maintenance auxiliary damping device for the track system provided by the utility model installed above the middle part of the track plate of the existing track;

[0037] Figure 7 Fig. 10 shows the structure schematic view of the mass tuning plate of the external maintenance auxiliary damping device for the track system provided by the utility model installed above the middle part of the track plate of the existing track;

[0038] Figure 8 Fig. 11 shows the structure schematic view of the fixing device of the external maintenance auxiliary damping device for the track system provided by the utility model installed above the middle part of the track plate of the existing track.

[0039] REFERENCE NUMERALS

[0040] 1-mass tuning plate

[0041] 11-slot

[0042] 2-cavity

[0043] 3-damping particles

[0044] 4-cover plate

[0045] 51-strip damping pad

[0046] 52-full damping pad

[0047] 6-side plate

[0048] 71-fastening rod

[0049] 72-pad block

[0050] 8-ladder sleeper

[0051] 9-track plate DETAILED DESCRIPTION

[0052] The utility model will be further explained in detail below by the drawings and examples. Through these explanations, the features and advantages of the utility model will become more clear and explicit.

[0053] The special word "exemplary" here means "as an example, embodiment or illustration". Any embodiment explained as "exemplary" here does not necessarily mean that it is superior or better than other embodiments. Although various aspects of the embodiments are shown in the drawings, the drawings are not necessarily drawn to scale unless specifically indicated.

[0054] The utility model provides a kind of external maintenance auxiliary damping device for track system, as shown in Figure 1 And Figure 6 The damping device is placed in the inside of ladder sleeper of existing track or installed on the upper middle part of track plate of existing track to maintain the existing track;The existing track is track in operation, and the ladder sleeper or track plate is used to support steel rail;

[0055] In the present application, the damping device is mainly used for the maintenance of existing track, and the maintenance is carried out without affecting the normal operation of existing track, i.e. the damping device is placed in the predetermined position of existing track to realize the maintenance of existing track, and the damping effect of existing track is improved.

[0056] In the present application, the ladder sleeper and track plate respectively refer to two common track laying schemes in track system;

[0057] The ladder-shaped sleeper in the present application comprises two longitudinal beams extending along the length direction of the steel rail, the steel rail is fixed by being mounted on the rail bearing platform, a plurality of transverse connecting mechanisms are arranged between the two longitudinal beams, there is a free space between the two longitudinal beams, so that the damping device in the present application can be clamped into the free space; in actual engineering, the frame-type track slab also has a similar free space as the ladder-shaped sleeper, and the damping device in the present application can also be clamped into the free space, so the ladder-shaped sleeper in the present application includes the traditional ladder-shaped sleeper, and also includes other similar sleeper structures such as the frame-type track slab, that is, the sleeper structure allowing the damping device in the present application to be clamped between the two longitudinal beams can be classified as the ladder-shaped sleeper in the present application.

[0058] The track slab in the present application includes a whole and complete continuous track slab, which can simultaneously bear two steel rails, and such a track slab does not have longitudinal beams, that is, there is no free space allowing the damping device in the present application to be clamped, so for the track slab of such a structure, the damping device in the present application is directly laid and installed on the track slab and located between the two steel rails.

[0059] The damping device comprises a mass tuning plate 1, and the mass tuning plate 1 is filled with damping particles selected from one or more of iron sand, lead particles, steel balls and sand; the present inventor finds that the preferred order of the damping particle materials is lead, steel, iron and sand, and the appropriate damping particles can be selected according to the damping performance requirements and economy.

[0060] Preferably, the damping particles in the present application are approximately spherical in shape, which can make the mutual collision and vibration more irregular, and the overall damping effect is best, more preferably, the particle size of the damping particles is 0.1-1 mm, preferably 0.2-0.6 mm; a plurality of damping particles filled in a cavity can have particle sizes that are not completely consistent with each other, as long as they are within the limited range, the present inventor finds that when the particle size is controlled in the above-mentioned 0.2-0.4 mm, the overall damping effect is best.

[0061] The vibration energy is consumed through the collision and friction of the damping particles with the wall surface of the mass tuning plate 1 and the mutual collision and friction between the damping particles.

[0062] A cavity 2 accommodating the damping particles is formed in the interior of the mass tuning plate 1; the damping particles 3 are filled in the cavity 2. The cavity 2 is a closed cavity, which can prevent liquid from entering the cavity, ensure that the cavity maintains a dry state, and avoid affecting the damping effect.

[0063] In a preferred embodiment, the volume ratio of the damping particles in the cavity 3 of the mass tuning plate 1 is 80-90%, preferably about 85%. The applicant has found that, in view of the vibration characteristics of the railway system, the damping performance is best when the volume ratio is about 85%, which can maximize the damping effect.

[0064] In a preferred embodiment, as shown in Figure 1 、 Figure 2 、 Figure 3 、 Figure 4 and Figure 5 , when the damping device is installed inside the ladder-shaped sleeper 8, the sleeper in the present application is a ladder-shaped sleeper with a sleeper length of 6 meters.

[0065] The open end of the cavity 2 is located at the top surface of the mass tuning plate 1, and a cover plate 4 is arranged at the top of the cavity 2 to block the open end.

[0066] Grooves 11 are formed at the bottom of the mass tuning plate 1 on both sides, and the mass tuning plate 1 is clamped on the ladder-shaped sleeper through the grooves 11. That is, the top of the mass tuning plate 1 is located above the ladder-shaped sleeper, and the bottom of the mass tuning plate 1 is located between two ladder-shaped sleepers, so that the mass tuning plate 1 can be fixed and limited by the ladder-shaped sleepers.

[0067] A strip-shaped damping pad 51 is arranged in the groove 11, the top of the strip-shaped damping pad 51 supports the mass tuning plate 1, and the bottom of the strip-shaped damping pad 51 abuts against the ladder-shaped sleeper.

[0068] When the damping device is installed inside the ladder-shaped sleeper, the size of the mass tuning plate 1 is 1174mm in length, 1015mm in width, and 97mm in thickness;

[0069] The effective volume in the cavity 2, i.e., the space volume that can be used to contain damping particles, is 928mm×715mm×45mm=0.0298584m 3 .

[0070] In a preferred embodiment, as shown in Figure 6 、 Figure 7 and Figure 8 , when the damping device is installed above the middle part of the track slab,

[0071] The open end of the cavity 2 is located at the side surface of the mass tuning plate 1, and a side plate 6 is arranged at the side of the cavity 2 to block the open end.

[0072] Preferably, a full-paved damping pad 52 is arranged at the bottom of the mass tuning plate 1; a fixing device is arranged at the outer side of the mass tuning plate 1, which includes a fastening rod 71 surrounding the outer side of the mass tuning plate 1, and a pad 72 is arranged at both ends of the fastening rod 71, and the fixing device is fixed to the track plate through the pad 72.

[0073] The full-paved damping pad at the bottom of the mass tuning plate 1, similar to the strip-shaped damping pad between the sleeper and the mass tuning plate, can both play a role of “spring”, amplifying the “movement” stroke, acceleration, etc. of the damping particle container, thereby playing a role of increasing the damping effect of the damping particles. In addition, the damping pad can absorb part of the vibration energy of the track plate (sleeper), and by selecting damping pads with different sizes and static moduli, the vibration frequency of the track plate (sleeper) can be tuned, and the damping effect can be improved.

[0074] Preferably, when the damping device is installed above the middle part of the track plate, the size of the mass tuning plate 1 is 2000mm in length, 800mm in width, and 75mm in height.

[0075] The effective volume in the cavity 2, i.e. the space volume that can be used to contain damping particles, is 1980mm x 780mm x 55mm = 0.084942m 3 .

[0076] Embodiment

[0077] A 1000-meter-long experimental track is selected, and the experimental track is arranged with trapezoidal sleepers. In order to simulate the part of the damaged railway to be repaired, old trapezoidal sleepers and related fasteners and rails are selected to build the experimental track, and the construction quality of each part of the experimental track is ensured to be consistent as much as possible.

[0078] A 6-car B-type vehicle with an axle load of 14 tons is used, and the vehicle distance and wheelbase are 12.6m and 2.25m respectively. The vehicle passes through the experimental track at a speed of 69km / h, and the vertical vibration level at the measurement point of the track is measured to be 82.3dB.

[0079] Then, an external maintenance auxiliary damping device for the track system is laid on the trapezoidal sleeper, and the damping device is installed on the inner side of the trapezoidal sleeper. As shown in Figure 1 The damping device includes a mass tuning plate, and a cavity for containing iron sand particles is formed in the mass tuning plate; the volume ratio of the iron sand particles in the cavity is 85%;

[0080] Grooves are formed at both sides of the bottom of the mass tuning plate, and the mass tuning plate is lapped on the trapezoidal sleeper through the grooves;

[0081] A strip-shaped damping pad is arranged in the groove, the top of the strip-shaped damping pad supports the mass-tuned plate, and the bottom of the strip-shaped damping pad abuts against the trapezoidal sleeper.

[0082] One mass-tuned plate is installed on each group of trapezoidal sleepers in a lap joint manner; the mass-tuned plate has a size of 1174 mm in length, 1015 mm in width and 97 mm in thickness.

[0083] The effective volume of the cavity in the mass-tuned plate, i.e. the space volume capable of supporting damping particles, is 928 mm x 715 mm x 45 mm = 0.0298584 m 3

[0084] After the external maintenance auxiliary damping device for the rail system is installed, the 6-car B-type vehicle of the subway train passes through the experimental track at a speed of 69 km / h, and the vibration level of the vertical vibration of the track at the same measurement point is measured to be 77.4 dB.

[0085] Comparative Example 1

[0086] On the track of the embodiment, a damping device is installed inside the trapezoidal sleeper, as shown in Figure 1 The damping device includes a mass-tuned plate, and a cavity for accommodating iron sand particles is formed in the mass-tuned plate; in the cavity, the volume ratio of the iron sand particles is 60%;

[0087] Grooves are formed on both sides of the bottom of the mass-tuned plate, and the mass-tuned plate is lap-jointed on the trapezoidal sleeper through the grooves;

[0088] A strip-shaped damping pad is arranged in the groove, the top of the strip-shaped damping pad supports the mass-tuned plate, and the bottom of the strip-shaped damping pad abuts against the trapezoidal sleeper.

[0089] One mass-tuned plate is installed on each group of trapezoidal sleepers in a lap joint manner; the mass-tuned plate has a size of 1174 mm in length, 1015 mm in width and 97 mm in thickness.

[0090] The effective volume of the cavity in the mass-tuned plate, i.e. the space volume capable of supporting damping particles, is 928 mm x 715 mm x 45 mm = 0.0298584 m 3

[0091] After the damping device is installed, the 6-car B-type vehicle of the subway train passes through the experimental track at a speed of 69 km / h, and the vibration level of the vertical vibration of the track at the same measurement point is measured to be 79.2 dB.

[0092] Comparative Example 2

[0093] On the track of the embodiment, a damping device is laid, which is installed inside the trapezoidal sleeper, as shown in Figure 1 The damping device comprises a mass-tuned plate, a cavity for containing iron sand particles is formed inside the mass-tuned plate; in the cavity, the volume ratio of the iron sand particles is 85%;

[0094] Grooves are formed on both sides of the bottom of the mass-tuned plate, and the mass-tuned plate is overlapped on the trapezoidal sleeper through the grooves;

[0095] A strip-shaped damping pad is arranged in the groove, the top of the strip-shaped damping pad supports the mass-tuned plate, and the bottom of the strip-shaped damping pad abuts against the trapezoidal sleeper.

[0096] One mass-tuned plate is overlapped and installed on each group of trapezoidal sleepers; the size of the mass-tuned plate is 1174 mm in length, 825 mm in width, and 97 mm in thickness;

[0097] The effective volume of the cavity in the mass-tuned plate, i.e. the space volume that can be used to contain damping particles, is 928 mm x 515 mm x 45 mm = 0.0215064 m 3

[0098] After laying and installing the damping device, the subway train 6-vehicle B-type vehicle passes through the experimental track at a speed of 69 km / h, and the vertical vibration level of the track at the same measurement point is measured to be 78.8 dB.

[0099] Comparative Example 3

[0100] On the track of the embodiment, a damping device is laid, which is installed inside the trapezoidal sleeper, as shown in Figure 1 The damping device comprises a mass-tuned plate, a cavity for containing iron sand particles is formed inside the mass-tuned plate; in the cavity, the volume ratio of the iron sand particles is 85%;

[0101] Grooves are formed on both sides of the bottom of the mass-tuned plate, and the mass-tuned plate is overlapped on the trapezoidal sleeper through the grooves;

[0102] A strip-shaped damping pad is arranged in the groove, the top of the strip-shaped damping pad supports the mass-tuned plate, and the bottom of the strip-shaped damping pad abuts against the trapezoidal sleeper.

[0103] One mass-tuned plate is overlapped and installed on each group of trapezoidal sleepers; the size of the mass-tuned plate is 1174 mm in length, 825 mm in width, and 97 mm in thickness;

[0104] The effective volume of the cavity in the mass-tuned plate, i.e. the space volume that can be used to contain damping particles, is 928 mm x 515 mm x 45 mm = 0.0215064 m3

[0105] After laying and installing the damping device, the subway train 6 carriages B type car passes through the experimental track at a speed of 69 km / h, and the vertical vibration level of the track at the same measurement point is 78.9 dB.

[0106] From the above examples and comparative examples, it can be seen that the external maintenance auxiliary damping device for the track system can obviously reduce the vibration generated when the train passes.

[0107] The utility model is described above in combination with preferred embodiments, but these embodiments are only exemplary and serve only to illustrate. On this basis, various substitutions and improvements can be made to the utility model, and these all fall within the scope of protection of the utility model.

Claims

1. An external maintenance aid damping device for a rail system, characterized in that The damping device is installed in the inner side of the ladder-shaped sleeper of the existing track or above the middle part of the track plate of the existing track to maintain the existing track; The existing track is a track in operation, and the ladder-shaped sleeper or the track plate supports the steel rail; The damping device comprises a mass tuning plate (1) filled with damping particles inside; The vibration energy is consumed through the collision and friction between the damping particles and the wall of the mass tuning plate (1) and the collision and friction between the damping particles.

2. The external maintenance auxiliary damping device for the track system according to claim 1, wherein, a cavity (2) for accommodating the damping particles is formed in the mass tuning plate (1); and the damping particles (3) are filled in the cavity (2).

3. The external maintenance auxiliary damping device for the track system according to claim 2, wherein, the volume proportion of the damping particles in the cavity (2) of the mass tuning plate (1) is 80-90%.

4. The external maintenance auxiliary damping device for the track system according to claim 2, wherein, when the damping device is installed in the inner side of the ladder-shaped sleeper, the opening end of the cavity (2) is located on the top surface of the mass tuning plate (1), and a cover plate (4) is arranged on the top of the cavity (2) to block the opening end.

5. The external maintenance auxiliary damping device for the track system according to claim 4, wherein, a slot (11) is formed on the bottom of the mass tuning plate (1) on both sides, and the mass tuning plate (1) is clamped on the ladder-shaped sleeper through the slot (11).

6. The external maintenance auxiliary damping device for the track system according to claim 5, wherein, a strip-shaped damping pad (51) is arranged in the slot (11), the top of the strip-shaped damping pad (51) supports the mass tuning plate (1), and the bottom of the strip-shaped damping pad (51) abuts against the ladder-shaped sleeper.

7. The external maintenance auxiliary damping device for the track system according to claim 4, wherein, the size of the mass tuning plate (1) is 1174 mm in length, 1015 mm in width, and 97 mm in thickness. The effective volume in the cavity (2), i.e. the volume of space available for holding the damping particles, is 928 mm x 715 mm x 45 mm = 0.0298584 m 3 .

8. The external maintenance auxiliary damping device for the track system according to claim 2, wherein, when the damping device is installed above the middle part of the track plate (9), the opening end of the cavity (2) is located on the side surface of the mass tuning plate (1), and a side plate (6) is arranged on the side of the cavity (2) to block the opening end.

9. The external maintenance auxiliary damping device for the track system according to claim 8, wherein, a full-paved damping pad (52) is arranged on the bottom of the mass tuning plate (1), A fixing device is arranged on the outer side of the mass tuning plate (1), the fixing device comprises a fastening rod (71) arranged around the outer side of the mass tuning plate (1), and a pad (72) is arranged at both ends of the fastening rod (71), the fixing device is fixed on the track plate through the pad (72), and the mass tuning plate (1) and the full-paving damping pad (52) are fixed on the track plate (9) through the fixing device.

10. The external maintenance auxiliary damping device for a rail system according to claim 8, characterized in that, The mass tuning plate (1) has a size of 2000 mm in length, 800 mm in width and 75 mm in height. The effective volume in the cavity (2), i.e. the volume of space available for holding the damping particles, is 1980 mm x 780 mm x 55 mm = 0.084942 m3 3 .

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