JP2010091096A - Collision energy absorbing material, and collision energy absorption system using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a collision energy absorbing material capable of reducing remarkably the maximum acceleration or the maximum deceleration of an object, in collision with the object. <P>SOLUTION: This collision energy absorbing material includes skeleton structure arrayed contactingly with a plurality of cells with a closed space formed in its inside, a dilatant fluid included in at least one part out of the plurality of cells, and a mechanism formed in the skeleton structure, and for moving the dilatant fluid into the closed space in the collision. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to, for example, a collision energy absorbing material for protecting an occupant or a pedestrian that is installed in an automobile and receives an impact at the time of a collision, and a collision energy absorbing system using the same.

  2. Description of the Related Art Conventionally, there is known a device that reduces energy at the time of a secondary collision such as steering and interior materials by an inertial force applied to an occupant after an automobile collision. For example, energy absorbing materials using foamable polymer materials and collision energy absorbing materials containing particles, polymer rubber, liquids, and the like have been proposed.

In recent years, further, there has been a demand for an energy absorbing material that is compatible with protection measures for the lower limbs of a pedestrian at the time of collision with the pedestrian. For this reason, for example, in the invention related to the impact absorbing member described in Patent Document 1, a structure is proposed in which a hollow material is placed on the back of the bumper face and energy is absorbed by utilizing deformation fracture caused by the collision of the material. Has been.
JP 2004-114864 A

  However, although the technique described in Patent Document 1 can reduce the impact load at the initial stage of the collision, if the impact absorbing member is deformed to some extent thereafter, the effect of reducing the impact load is reduced, and the maximum acceleration is finally very high. There was a problem of becoming big.

  Therefore, an object of the present invention is to provide a collision energy absorbing material that can greatly reduce the acceleration in the second half of the collision and reduce the maximum acceleration or the maximum deceleration acceleration.

  In order to achieve the above object, a collision energy absorbing material according to the present invention includes a skeleton structure in which a plurality of cells each having a closed space formed therein are arranged in contact with each other, and is included in at least a part of the plurality of cells. A dilatant fluid. Furthermore, the skeleton structure has a mechanism for moving the dilatant fluid out of the closed space at the time of collision.

  According to the collision energy absorbing material of the present invention, the maximum acceleration or the maximum deceleration acceleration of the object can be reduced by generating the stress in the direction opposite to the direction in which the strain is applied in the collision with the object.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, exemplary embodiments to which the invention is applied will be described with reference to the accompanying drawings.

  The collision energy absorbing material of the present invention includes a skeleton structure in which a plurality of cells having closed spaces formed therein are arranged in contact with each other and a dilatant fluid contained in at least a part of the plurality of cells. . Furthermore, the skeleton structure has a mechanism for moving the dilatant fluid out of the closed space at the time of collision.

  FIG. 1 is a drawing schematically showing how the impact energy absorbing material of the present invention changes when it receives stress from the outside due to a collision or the like.

  As shown in FIG. 1, the collision energy absorbing material 1 of the present invention includes a dilatant fluid 3 in a skeleton structure 2 including a plurality of cells in which closed spaces are formed, and moves the dilatant fluid in the skeleton structure 2. It has mechanism 4 to do.

  For example, when an external object collides with the skeleton structure 2 of the collision energy absorbing material 1 from the direction of the thick arrow in FIG. 1, stress is applied to cause deformation. At that time, a high strain rate is applied to the dilatant fluid 3, and the dilatant fluid 3 exhibits dilatancy (strain rate curability), so that the viscosity becomes very high and stress is generated in the opposite direction to the direction in which the strain is applied. . However, if the dilatant fluid 3 cannot move, this dilatancy does not appear, so it is necessary to provide a mechanism 4 for moving the dilatant fluid out of the cell. That is, the dilatant fluid 3 can flow out from the cell to the inside or outside of the skeleton structure 2 directly or via another mechanism that moves another dilatant fluid via the mechanism 4 that moves the dilatant fluid. .

  Accordingly, when the collision energy absorbing material 1 of the present invention is used, when the object collides at a certain speed or more, the contained dilatant fluid 3 develops dilatancy, and in the opposite direction to the direction in which the strain is applied, the conventional collision is performed. Generates a greater stress than energy absorbing materials. Accordingly, the acceleration increases and the speed decreases in the initial stage of the collision. Therefore, the speed of the object is sufficiently reduced in the later stage of the collision, and the maximum deceleration acceleration can be greatly reduced without causing a large deceleration acceleration as in the case of the conventional collision energy absorbing material.

  There is preferably at least one mechanism 4 for moving the dilatant fluid for each cell in which the dilatant fluid 3 is contained. There may be a mechanism 4 for moving two or more dilatant fluids per cell in which the dilatant fluid 3 is contained. The number of mechanisms 4 that move the dilatant fluid installed in each cell in which the dilatant fluid 3 is contained may be different.

  The mechanism 4 for moving the dilatant fluid may be, for example, a communication part or a weak part. A plurality of communication parts or fragile parts may be provided, respectively, or a combination of the communication part and the fragile part may be provided. The communication part is an opening part included in a part of the skeleton structure through which the fluid can move. In the event of a collision, the dilatant fluid can move from the cell directly to the inside or outside of the skeletal structure, or through another communication part or weak part through the communication part. The fragile portion is a portion that is more easily broken by an impact than other portions. In the skeletal structure 2 containing the dilatant fluid 3 in which the stress is concentrated due to the collision, the internal pressure is increased, pressure is applied to the fragile portion, and this portion is broken and communicates. As a result, the dilatant fluid 3 can flow out directly from the cell containing it into the inside or outside of the skeletal structure 2, or through another communicating part or weak part.

  The skeleton structure 2 is not particularly limited as long as the skeleton structure 2 has a closed space in which the dilatant fluid 3 can be contained and is arranged in contact with a plurality of cells. For example, a three-dimensional lattice-like structure having hollow portions can be used. The shape and size of the cell (unit cell) are not particularly limited. Preferably, a honeycomb structure having a periodicity, a diamond-type structure, or a triangular structure as shown in FIG. 2 is used. If the structure has periodicity, a collision energy absorbing material having a uniform collision energy absorption property in a wide region can be obtained, and the skeleton structure can be easily manufactured. In addition, a honeycomb structure, a diamond structure, or a triangular structure works as an elastic body when the collision energy exceeds a certain level. Since it gradually deforms, it is suitable as a skeleton structure. Preferably, cells having these structures are stacked in 3 to 40 stages in the height direction.

  The arrangement of the mechanism for moving the dilatant fluid arranged in the skeleton structure 2 is not particularly limited, but FIG. 3 shows a preferable arrangement pattern of the communication portion 5 and the fragile portion 6 when the skeleton structure of the honeycomb structure is used. The arrangement in FIG. 3A is a pattern in which only rows communicate, the arrangement in FIG. 3B is a pattern in which only columns are communicated, and the arrangement in FIG. 3C is a pattern in which rows and columns communicate ( Hybrid). Among these patterns, the acceleration at the initial stage of the collision is large in (a), then in (c), and smallest in (b).

  The impact energy absorbing material of the present invention is deformed from the central part of the honeycomb structure at the initial stage of the impact. Therefore, in the case of (a) in which only the row communicates, since there is communication only in the skeletal structure that collapses in the initial stage of the collision, the dilatant fluid flows through this skeletal structure at the time of collision. For this reason, since a large strain rate is greatly applied to the dilatant fluid, a large viscosity increase occurs, and the acceleration at the initial stage of the collision increases. In the case of row and column communication (hybrid) in (c), since there is communication other than the skeletal structure that collapses in the initial stage of the collision, the dilatant fluid may flow through the skeletal structure that does not collapse. For this reason, in the case of FIG. 3C, the fluidity of the total dilatant fluid is deteriorated, and the strain rate is lower than in the case of FIG. In the case where only the row (b) is communicated, there is no communication between the skeletal structures that collapse in the initial stage of the collision, and all the dilatant fluid flows through the structural skeleton parts that do not collapse in the initial stage of the collision. For this reason, since the strain rate is further reduced, the increase in viscosity is reduced, and the acceleration at the initial stage of the collision is further reduced.

The material of the skeletal structure is composed of, for example, a polymer material such as resin, wood, paper, or fiber, a metal material such as aluminum, iron, copper, silver, nickel, or titanium, or an inorganic material such as ceramics, glass, or cement. ing. Moreover, the material which combined several said material may be sufficient, and composite materials, such as a fiber reinforced metal, a fiber reinforced plastic, FRP, may be sufficient. As the resin material, for example, thermoplastic resins such as polyethylene resin, polypropylene resin, polystyrene resin, acrylic resin, polyethylene terephthalate, polybutylene terephthalate, PC, ABS, PA, PPE, and copolymers thereof can be preferably used.
What is necessary is just to design suitably the size of the adjacent hollow part in this structure, thickness, intensity | strength, etc. according to the magnitude | size of the applied impact. Preferably, the size of the hollow portion is such that the maximum distance between two points in the plane is about 5 to 50 mm.

  The formation method of the skeleton structure and the mechanism for moving the dilatant fluid is not particularly limited, and a conventionally known method can be appropriately used. For example, a plurality of pipe materials can be integrally joined by welding or heat treatment. In addition to the tube material, a laminated plate material may be used. The overlapping plate material refers to a plate material obtained by superimposing a plurality of plate materials preformed by press molding or the like and integrally forming the plurality of plate materials by spot welding or the like. Alternatively, a method of pasting corrugated plate materials can be used. A means for providing a mechanism for moving the dilatant fluid in the skeleton structure is not particularly limited. For example, a thin wall portion or an opening portion may be formed in advance on a part of the side surface of the tube material or the like, or the opening portion may be formed after the skeleton structure is manufactured. When a resin is used, it may be molded into a desired shape by an injection molding method, an extrusion molding method, an injection press method, a hot press method, a blow molding method, or the like. Alternatively, an opening or a thin portion can be formed by laser heating a part of the skeleton structure.

  In the present invention, the dilatant fluid is preferably a composite material including particles and a liquid. As a result, when the strain rate at the time of collision is high, particles can be aggregated and concentrated by applying strain, and dilatancy (strain rate curability) can be expressed, absorbing the energy of the collision while decelerating the impact, Can be bottomed gently.

  Here, the shape of the particles is not particularly limited, and may be spherical or acicular, but is preferably acicular. If the particles are acicular, the surface energy is larger than that of spherical particles, and therefore aggregation occurs at a low concentration. The higher the aspect ratio of the particles, the more likely to aggregate, and the smaller the particle diameter, the more likely to aggregate. The aspect ratio of the particles is preferably 5 to 100, more preferably 20 to 100, and still more preferably 50 to 100. When the particles are spherical, the particle diameter is preferably 5 nm to 1000 nm, more preferably 5 nm to 50 nm, and even more preferably 5 nm to 20 nm. When the particles are acicular, the cross-sectional diameter is preferably 5 nm to 1000 nm, more preferably 5 nm to 20 nm, and still more preferably 5 nm to 10 nm. If the particle diameter of the spherical particles is 1000 nm or less, or the cross-sectional diameter of the acicular particles is 1000 nm or less, it is within the range of 10 to 10,000 (1 / s), which is the strain rate experienced by passengers and pedestrians in a car collision. Aggregation of particles can occur. When the particle diameter of the spherical particles is 5 nm or more, or the cross-sectional diameter of the acicular particles is 5 nm or more, the particles can be stably dispersed in the liquid without being aggregated before dispersion. Further, particles having a particle diameter of less than 5 nm are extremely difficult to produce, and are substantially difficult to produce. Here, the aspect ratio and particle diameter of the particles mean the average value of 100 particles observed with a transmission electron microscope. The cross-sectional diameter of the acicular particles means the maximum value of the major axis of the elliptical cross section. The aspect ratio is obtained as a ratio between the maximum value of the major axis and the average value of the major axis and minor axis of the cross section in the minor axis direction.

  The particle concentration depends on the particle diameter and aspect ratio, but in order for the particles to aggregate within a strain rate of 10 to 10,000 (1 / s), the particle concentration, particle diameter, and aspect ratio are generally It is preferable to satisfy the following formula. In consideration of the dispersion stability in the liquid and the degree of aggregation according to the particle concentration, the particle concentration is preferably 5 to 40 vol%, more preferably 20 with respect to the volume of the liquid and the composite material composed of the particles. ~ 40 vol%.

  The material of the particle is not particularly limited as long as it is made of a material suitable for gradually softening while reducing the collision speed by becoming hard when the strain rate at the time of collision is high. For example, particles such as alumina (boehmite (γ alumina), α alumina, etc.), silica, titania, zirconia, calcia (calcium oxide), calcium carbonate, and the like can be used. These may be used alone or in combination of two or more. Alumina particles are most suitable for obtaining needle-shaped particles having a diameter (short axis diameter) of 5 to 1000 nm and an aspect ratio of 5 or more economically advantageously.

  The method for producing the particles is not particularly limited, and a conventionally known production method can be used.

Specifically, for example, (1) the short axis length is 1 to 10 nm, the long axis length is 20 to 400 nm, and the aspect ratio is 5 to 80 as in the manufacturing method described in JP-A-2006-62905. And a method for producing alumina particles represented by the general formula Al ₂ O ₃ .nH ₂ O. This production method is suitable for producing n = 1 in the above general formula and the alumina particles are boehmite (γ alumina monohydrate). Furthermore, it is also a production method suitable for the alumina particles having a hollow portion inside. The process is as follows. First, an aqueous alkali solution is added to an aqueous aluminum metal salt solution to form an aluminum hydroxide gel-like substance in the resulting reaction mixture. Next, the reaction mixture containing the gel substance is subjected to a first heat treatment at a first temperature not lower than room temperature. After the first heat treatment, the reaction mixture containing the gel substance is subjected to a second heat treatment at a second temperature higher than the first temperature in the first heat treatment. After the second heat treatment, the reaction mixture containing the gel material is subjected to a third heat treatment at a third temperature lower than the second temperature in the second heat treatment. After the third heat treatment, the reaction mixture containing the gel substance is subjected to a fourth heat treatment at a fourth temperature not lower than room temperature.

Alternatively, (2) as in other manufacturing methods described in JP-A-2006-62905, the minor axis length is 1 to 10 nm, the major axis length is 20 to 400 nm, the aspect ratio is 5 to 80, A method for producing alumina particles represented by the formula Al ₂ O ₃ .nH ₂ O can be mentioned. This method is suitable for producing n = 0 in the general formula and the alumina particles are α-alumina. Furthermore, it is also a production method suitable for the alumina particles having a hollow portion inside. The process is as follows. First, an aqueous alkali solution is added to an aqueous aluminum metal salt solution to form an aluminum hydroxide gel-like substance in the resulting reaction mixture. Next, the reaction mixture containing the gel substance is subjected to a first heat treatment at a first temperature not lower than room temperature. After the first heat treatment, the reaction mixture containing the gel substance is subjected to a second heat treatment at a second temperature higher than the first temperature in the first heat treatment. After the second heat treatment, the reaction mixture containing the gel material is subjected to a third heat treatment at a third temperature lower than the second temperature in the second heat treatment. After the third heat treatment, the reaction mixture containing the gel substance is subjected to a fourth heat treatment at a fourth temperature not lower than room temperature. Thereafter, the boehmite particles obtained through the fourth heat treatment are fired.

  In the liquid, it is essential that the particles are stably dispersed and that the liquid itself is not altered or transformed with respect to the environmental temperature. For automotive applications, it is necessary to maintain these characteristics in the temperature range of -40 ° C to 90 ° C, although it depends on the part. From this point, water-based ones are difficult to use. Liquids such as ethanol, 2-butanone, tetrahydrofuran, cyclohexanone, and ethylene glycol can be preferably used to stably disperse particles such as alumina particles and silica particles described above, but in terms of fire and volatilization prevention, Ethylene glycol is most suitable.

  Any existing method can be used for the formulation of the particles for stabilizing the dispersion of the particles. Both the above-mentioned alumina particles and silica particles have a hydroxyl group on the particle surface, and thus tend to be difficult to disperse in liquids other than water. However, depending on organic acids such as phosphoric acid, sulfonic acid, and carboxylic acid It becomes dispersible in an organic solvent such as ethylene glycol by treatment or hydrophobic treatment with a silane coupling agent. In addition, you may add dispersing agents, such as p-toluenesulfonic acid, as needed.

  FIG. 4 is a graph showing the relationship between strain rate and viscosity of a dilatant fluid that can be used in the present invention. A dilatant fluid is prepared by mixing acicular boehmite particles (30% by volume) having a minor axis length of 0.01 μm and an aspect ratio of 10 with a liquid ethylene glycol (70% by volume). FIG. 4 shows that the viscosity increases by an order of magnitude when the strain rate increases from 1000 (1 / s) to 2000 (1 / s).

  Furthermore, the dilatant fluid of the present invention may include fibers for assisting the aggregation of particles, if necessary. The material of the fiber is not particularly limited, and for example, organic fibers such as aramid fiber, nylon (registered trademark) fiber, polyester fiber, and polyurethane fiber, inorganic fibers such as glass fiber, ceramic fiber, metal fiber, and carbon fiber are used. sell.

  Furthermore, if necessary, a dispersant (dispersion stability) such as an antioxidant, a heat stabilizer (for example, hindered phenol, hydroquinone, thioether, phosphites and substituted products thereof), other additives, and p-toluenesulfonic acid. Agent) and an additive such as water may be mixed in an appropriate amount.

  The collision energy absorbing material of the present invention may contain the dilatant fluid in the entire cells (unit cell) forming the skeleton structure, or may be contained in only some of the cells. The dilatant fluid may be arranged only in cells included in a region where stress is concentrated at the initial stage of the collision. By disposing the dilatant fluid only in the cells included in the region where stress is concentrated at the initial stage of the collision, the amount of expensive dilatant fluid used can be reduced. Even in this case, there is no significant difference in the maximum acceleration as compared with the case where the dilatant fluid is included in the entire cells forming the skeleton structure. For example, when an object collides from the side of the skeletal structure as shown in FIG. 2 (in the direction of the arrow), the portion where the stress is concentrated at the initial stage of the collision is the central portion (enclosed portion) of the skeleton structure. In this case, the mechanism for moving the dilatant fluid may be provided only on the partition wall of the cell in which the dilatant fluid is disposed.

  The method for filling the cells in the skeleton structure with the dilatant fluid is not particularly limited, and may be performed by a conventionally known method such as press-fitting or impregnation. After filling with the dilatant fluid, it can be sealed by a method such as heat fusion or adhesion.

  Next, this invention provides the collision energy absorption system which has a collision energy absorption member which enclosed the said collision energy absorption material. In particular, the collision energy absorption system of the present invention can be installed before and after an automobile.

  By disposing the collision energy absorbing member in the vicinity of the surface of the moving structure, the maximum acceleration of this object can be greatly reduced when it collides with another object. Further, even when the object collides with the structure, the maximum deceleration acceleration applied to the object can be greatly reduced.

  The collision energy absorbing member provides a collision energy absorbing system (such as a pillar in an automobile interior or a bumper in an exterior) that can reduce obstacles to passengers or pedestrians by using the collision energy absorbing member in the interior or exterior of an automobile. be able to. For example, when applied to a bumper, it is possible to protect the lower limbs of a pedestrian.

  What is necessary is just to determine suitably the material of the enclosure container used for enclosing a collision energy absorption material according to the intended purpose. For example, a resin sheet or container such as polyester or polyurethane, a metal-resin multilayer sheet (laminate sheet), or a metal container such as aluminum can be used. It is necessary to use a material that deforms quickly and easily so that the dilatant fluid of the contents can develop dilatancy (strain rate hardening) at the time of collision. Preferably, it is desirable to use a material from which shape flexibility is easily obtained, and polyester, polyurethane, and the like can be suitably used.

  The thickness of the enclosure is difficult to define uniquely because the strength and ease of deformation vary depending on the type of material used. You just have to decide. Preferably, the thickness of the enclosure is 4 to 10 mm, more preferably 4 to 8 mm, and still more preferably 4 to 6 mm. If the thickness of the sealed container is 4 mm or more, the shape retainability is excellent, and the desired dilatancy (strain rate curability) is developed without causing the container to break and the contents to leak due to the impact applied at the time of collision. It is possible to maintain an appropriate strength to the extent that it can be produced. On the other hand, if the thickness of the enclosure is 10 mm or less, preferably 8 mm or less, especially 6 mm or less, the thickness of the entire collision energy absorbing member can be reduced, and various application destinations can be selected.

  The shape of the enclosure is not particularly limited, and may be appropriately determined according to the purpose of use. A sealed container having an uneven shape or a curved shape may be used depending on the application site.

The effects of the present invention will be described using the following examples and comparative examples. However, the technical scope of the present invention is not limited to only the forms shown in the following examples.

  In the following examples and comparative examples, a 60 kg drop weight (diameter 30 cm) was dropped from a height of 6.3 m using a drop impact tester manufactured by TMC. It was made to collide with the collision energy absorption member at a speed of 11 m / s, and displacement and acceleration were measured using a sensor installed on the falling weight.

Example 1
As shown in FIG. 5 (A), a skeleton structure (total size: 10 cm × 26.0 × 10.8 cm) of a honeycomb structure composed of 5 rows and 10 columns made of polyethylene, and the communication portions 5 and only in the rows A skeletal structure 2 in which the fragile portion 6 was installed was prepared. The arrow in FIG. 5A indicates the direction in which the falling weight collides. The size of the unit cell (cell) was 15 mm on a side and 3 mm in thickness. The width of the communication part in the unit cell was 3 mm, and it was prepared by applying a laser beam and applying heat to make a hole in polyethylene. The width of the fragile portion in the unit cell was 3 mm, and the wall thickness of the fragile portion was 1.0 mm. The fragile portion was produced by a method in which the polyethylene surface was thinned by applying heat with a laser beam to melt.

  Next, 40% by volume of acicular boehmite particles having a minor axis length of 0.01 μm and a major axis length of 0.1 μm were mixed with 60% by volume of ethylene glycol to prepare a dilatant fluid. This dilatant fluid was included by injecting the entire hollow portion of the skeleton structure using a syringe, and after completion of the injection, the syringe hole was closed by thermal fusion. This was encapsulated in a bag-like polyester sheet having a thickness of 5 mm to produce an enclosure (collision energy absorbing member).

  The relationship between acceleration and displacement was determined under the measurement conditions as described above. The results are shown in FIG.

(Example 2)
The dilatant fluid was included in the unit cells in the second to fourth rows using the skeleton structure 2 having a honeycomb structure in which the connecting portions 5 and the fragile portions 6 were arranged in the arrangement shown in FIG. 5B. An enclosure was prepared in the same manner as in Example 1 except for.

  The relationship between acceleration and displacement was determined under the measurement conditions as described above. The results are shown in FIG.

(Example 3)
Inclusion body in the same manner as in Example 1 except that the skeleton structure 2 having a honeycomb structure in which the communication portion 5 and the fragile portion 6 are provided only in the skeleton structure row as shown in FIG. Was made.

  The relationship between acceleration and displacement was determined under the measurement conditions as described above. The results are shown in FIG.

Example 4
The dilatant fluid was included in the unit cells of the second to fourth rows using the honeycomb structure skeleton structure 2 in which the connecting portions 5 and the fragile portions 6 were arranged in the arrangement shown in FIG. 5 (D). An enclosure was prepared in the same manner as in Example 1 except for.

  The relationship between acceleration and displacement was determined under the measurement conditions as described above. The results are shown in FIG.

(Example 5)
The encapsulant was formed in the same manner as in Example 1 except that the honeycomb structure skeleton structure 2 in which the communication portion 5 and the fragile portion 6 were installed only in the skeleton structure row as shown in FIG. Produced.

  The relationship between acceleration and displacement was determined under the measurement conditions as described above. The results are shown in FIG.

(Example 6)
The dilatant fluid was included in the unit cells in the second to fourth rows using the honeycomb structure skeleton structure 2 in which the connecting portions 5 and the fragile portions 6 were arranged in the arrangement shown in FIG. 5 (F). An enclosure was prepared in the same manner as in Example 1 except for.

  The relationship between acceleration and displacement was determined under the measurement conditions as described above. The results are shown in FIG.

(Example 7)
As shown in FIG. 5 (G), the skeleton structure of diamond structure (total size: 10 cm × 28.4 cm × 9.9 cm) made of the same material as that of Example 1, and the communication portion 5 is connected only to the row. A skeletal structure 2 in which the fragile portion 6 was installed was prepared. The arrow in FIG. 5G indicates the direction in which the falling weight collides. The size of the unit cell was 20 mm per side. The width of the communicating portion, the width of the fragile portion, and the thickness of the fragile portion in the unit cell were the same as in Example 1. An inclusion body was produced in the same manner as in Example 1 except that this skeleton structure was used.

  The relationship between acceleration and displacement was determined under the measurement conditions as described above. The results are shown in FIG.

(Example 8)
Using a skeleton structure 2 having a diamond structure in which the connecting portion 5 and the fragile portion 6 are arranged in the arrangement as shown in FIG. 5 (H), the dilatant fluid is included in the unit cells in the third and fourth rows. Except that, an enclosure was prepared in the same manner as in Example 7.

  The relationship between acceleration and displacement was determined under the measurement conditions as described above. The results are shown in FIG.

Example 9
Inclusion body in the same manner as in Example 7 except that the skeleton structure 2 having a diamond structure in which the communication portion 5 and the fragile portion 6 are installed only in the skeleton structure row as shown in FIG. 5 (I). Was made.

  The relationship between acceleration and displacement was determined under the measurement conditions as described above. The results are shown in FIG.

(Example 10)
Using the skeleton structure 2 having a diamond-type structure in which the connecting portion 5 and the fragile portion 6 are arranged in the arrangement as shown in FIG. 5 (J), the dilatant fluid is included in the unit cells in the second to fifth rows. Except that, an enclosure was prepared in the same manner as in Example 7.

  The relationship between acceleration and displacement was determined under the measurement conditions as described above. The results are shown in FIG.

(Example 11)
As shown in FIG. 5 (K), it is a skeleton structure of a triangular structure (total size: 10 cm × 28 cm × 10 cm) made of the same material as in Example 1, and the communication portion 5 and the fragile portion 6 are formed only in the rows. An installed skeletal structure 2 was prepared. The arrow in FIG. 5K indicates the direction in which the falling weight collides. The size of the unit cell was 28 mm for the long side and 24.4 mm for the short side. The width of the communicating portion, the width of the fragile portion, and the thickness of the fragile portion in the unit cell were the same as in Example 1. An inclusion body was produced in the same manner as in Example 1 except that this skeleton structure was used.

  The relationship between acceleration and displacement was determined under the measurement conditions as described above. The results are shown in FIG.

Example 12
Using the triangular structure skeleton structure 2 in which the connecting portion 5 and the fragile portion 6 are arranged in the arrangement as shown in FIG. 5 (L), the dilatant fluid is included in the unit cells in the second to fourth rows. Except for this, an enclosure was prepared in the same manner as in Example 11.

  The relationship between acceleration and displacement was determined under the measurement conditions as described above. The results are shown in FIG.

(Example 13)
Inclusion body in the same manner as in Example 11 except that the triangular structure skeleton structure 2 in which the communication portion 5 and the fragile portion 6 are installed is used only in the skeleton structure row as shown in FIG. Was made.

  The relationship between acceleration and displacement was determined under the measurement conditions as described above. The results are shown in FIG.

(Example 14)
Using the triangular structure skeleton structure 2 in which the connecting part 5 and the weak part 6 are arranged in the arrangement as shown in FIG. 5 (N), the dilatant fluid is included in the unit cells in the second to fourth rows. Except for this, an enclosure was prepared in the same manner as in Example 11.

  The relationship between acceleration and displacement was determined under the measurement conditions as described above. The results are shown in FIG.

(Comparative Example 1)
An inclusion body was produced in the same manner as in Example 1 except that the skeleton structure was not provided with a connecting portion and a fragile portion, and no dilatant fluid was introduced.

  The relationship between acceleration and displacement was determined under the measurement conditions as described above. The results are shown in FIG.

Comparing the results of Example 1 and Comparative Example 1 to 14, in all of Examples 1-14, the maximum deceleration is about 800~1000m / ^{s 2,} Comparative Example 1 indicating the value of 1200 m / ^{s 2} near It became clear that it fell by 20% or more compared with. This is because, in the collision energy absorbing materials of Examples 1 to 14, the dilatancy appears at the time of collision, and stress is generated in the direction opposite to the direction in which the strain is applied. It is thought to suppress this. At this time, the fragile portion is destroyed at the time of collision, and the dilatant fluid moves through the fragile fragile portion and the communicating portion, so that the expression of dilatancy occurs effectively.

  Further, from the results of Examples 1 to 14, it was found that good results were obtained when any of the skeleton structures of the honeycomb structure, the diamond type structure, and the triangular structure was used. From the comparison of Examples 1, 3, 5, 7, 9, 11, 13 and Examples 2, 4, 6, 8, 10, 12, 14 to the central part where stress is concentrated at the initial stage of the collision Even when only the dilatant fluid was used, it was clarified that the same effect as that obtained when it was included in the whole was obtained.

(Example 15)
When the bumper was prototyped by arranging the collision energy absorbing member shown in Example 1 behind the front bumper face of the automobile, the maximum deceleration acceleration when colliding at a speed of 30 to 40 km / h was 800 to 1000 m / s ^2. It was confirmed that Therefore, the collision energy absorbing material of the present invention can be used for protecting passengers and pedestrians at the time of collision.

It is the schematic diagram showing the mode of the change at the time of the impact energy absorption material of this invention receiving the stress from the outside by a collision. It is a schematic diagram which shows the example of the skeleton structure which can be used for this invention. It is a schematic diagram which shows the example of arrangement | positioning of the connection part and weak part which were installed in the skeleton structure of the honeycomb structure which can be used for this invention. It is a figure showing the relationship between the strain rate-viscosity of the dilatant fluid which can be used for this invention. 3 is a schematic diagram of a skeleton structure used in the collision energy absorbing material manufactured in Example 1. FIG. 4 is a schematic diagram of a skeleton structure used for a collision energy absorbing material manufactured in Example 2. FIG. 6 is a schematic diagram of a skeleton structure used in a collision energy absorbing material manufactured in Example 3. FIG. 6 is a schematic diagram of a skeleton structure used in a collision energy absorbing material manufactured in Example 4. FIG. 6 is a schematic diagram of a skeleton structure used for a collision energy absorbing material manufactured in Example 5. FIG. 6 is a schematic diagram of a skeleton structure used in a collision energy absorbing material manufactured in Example 6. FIG. 6 is a schematic diagram of a skeleton structure used for a collision energy absorbing material manufactured in Example 7. FIG. 10 is a schematic diagram of a skeleton structure used for a collision energy absorbing material manufactured in Example 8. FIG. 10 is a schematic diagram of a skeleton structure used for a collision energy absorbing material manufactured in Example 9. FIG. 10 is a schematic diagram of a skeleton structure used for a collision energy absorbing material manufactured in Example 10. FIG. 10 is a schematic diagram of a skeleton structure used for a collision energy absorbing material manufactured in Example 11. FIG. FIG. 10 is a schematic diagram of a skeleton structure used for a collision energy absorbing material manufactured in Example 12. 14 is a schematic diagram of a skeleton structure used for a collision energy absorbing material manufactured in Example 13. FIG. It is a schematic diagram of the skeleton structure used for the collision energy absorption material produced in Example 14. It is a figure which shows the relationship of the acceleration-displacement of the collision energy absorption material produced in Example 1. FIG. It is a figure which shows the relationship of the acceleration-displacement of the collision energy absorption material produced in Example 2. FIG. It is a figure which shows the relationship of the acceleration-displacement of the collision energy absorption material produced in Example 3. FIG. It is a figure which shows the relationship of the acceleration-displacement of the collision energy absorption material produced in Example 4. FIG. It is a figure which shows the relationship of the acceleration-displacement of the collision energy absorption material produced in Example 5. FIG. It is a figure which shows the relationship of the acceleration-displacement of the collision energy absorption material produced in Example 6. FIG. It is a figure which shows the relationship of the acceleration-displacement of the collision energy absorption material produced in Example 7. FIG. It is a figure which shows the relationship of the acceleration-displacement of the collision energy absorption material produced in Example 8. FIG. It is a figure which shows the relationship of the acceleration-displacement of the collision energy absorption material produced in Example 9. FIG. It is a figure which shows the relationship of the acceleration-displacement of the collision energy absorption material produced in Example 10. FIG. It is a figure which shows the relationship of the acceleration-displacement of the collision energy absorption material produced in Example 11. FIG. It is a figure which shows the relationship of the acceleration-displacement of the collision energy absorption material produced in Example 12. FIG. It is a figure which shows the relationship of the acceleration-displacement of the collision energy absorption material produced in Example 13. FIG. It is a figure which shows the relationship of the acceleration-displacement of the collision energy absorption material produced in Example 14. FIG. It is a figure which shows the relationship of the acceleration-displacement of the collision energy absorption material produced by the comparative example 1. FIG.

Explanation of symbols

1 collision energy absorbing material,
2 skeletal structure,
3 Dilatant fluid,
4 Mechanism to move the dilatant fluid,
5 communication part,
6 Vulnerable part.

Claims (7)

A skeletal structure in which a plurality of cells with closed spaces formed therein are arranged in contact with each other;
A dilatant fluid contained in at least a part of the plurality of cells;
A mechanism formed in the skeletal structure for moving the dilatant fluid out of the closed space upon collision;
A collision energy absorbing material.   The collision energy absorbing material according to claim 1, wherein the mechanism for moving the dilatant fluid is a communication portion or a fragile portion.   The collision energy absorbing material according to claim 1 or 2, wherein the skeleton structure is a honeycomb structure having a periodicity, a diamond structure, or a triangular structure.   The collision energy absorbing material according to claim 1, wherein the dilatant fluid includes particles and a liquid.   5. The collision energy absorbing material according to claim 1, wherein the dilatant fluid is included only in a cell included in a region where stress is concentrated in an early stage of the collision among the plurality of cells.   The collision energy absorption system which has the collision energy absorption member which enclosed the collision energy absorption material of any one of Claims 1-5.   The collision energy absorption system according to claim 6, wherein the collision energy absorption member is mounted on an automobile.

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