CN110344298B - Layered buffering energy-absorbing structure for EMAS and preparation method thereof - Google Patents

Abstract

The invention discloses a layered buffering energy-absorbing structure for an EMAS and a preparation method thereof. The layered buffering and energy-absorbing structure is formed by jointing buffering and energy-absorbing materials with different strengths from top to bottom; the strength of each layer gradually increases from top to bottom. The preparation method comprises the following steps: the materials of all layers are sequentially increased and jointed according to the strength from top to bottom, and the jointing mode is a prefabricated body bonding type or a layered pouring type. The layered buffering material can effectively block airplanes with different specifications, and the preparation method is simple.

Description

Layered buffering energy-absorbing structure for EMAS and preparation method thereof

Technical Field

The invention relates to the field of Material engineering and application, in particular to a layered buffering energy-absorbing structure for an airport runway end characteristic Material Arresting System (EMAS) and a preparation method thereof.

Background

Statistical data at home and abroad show that in accident signs seriously damaging civil aviation flight safety, an airplane rushes out of the head of a runway position column, and a runway end safety area is important for reducing the risk of the airplane rushing out of the runway, so that the safety of the airplane and personnel is ensured. However, due to restrictions of geography or other environmental factors, many airports have difficulty in meeting the length requirement of a new runway end safety area, and great flight safety accident potential is caused. Considering the possible serious consequences caused by the airplane rushing out of the runway, EMAS system research is carried out at home and abroad. The EMAS absorbs the kinetic energy of the airplane by utilizing the collapse of EMAS characteristic materials (light porous materials such as foam concrete, foam glass and the like) under the rolling action of airplane tires, gradually decelerates the airplane and finally stops at a preset distance on the premise of ensuring the safety of the airplane structure and passengers, and avoids the catastrophic consequences caused by the fact that the airplane enters dangerous terrains (cliffs, water areas and the like) after rushing out of a runway. Currently, EMAS is applied to a plurality of airports in the United states and multinational airports including China, and is an effective means for improving safety guarantee margin of the airports proved by practice to stop 10 airplanes successfully. Typical construction of EMAS is the modular construction of EMAS units as described in patents EP1425219B1 and EP2144812a 2.

The arresting function of the EMAS mainly depends on the mechanical properties (such as compressive strength under penetration conditions, crushable depth and the like) of characteristic materials, and the mechanical properties are the most important parameters for calculating the effective arresting performance of the system in the EMAS design. The overlarge compressive strength can cause the blocking resistance and deceleration of the airplane to be overlarge in the blocking process, thus easily causing the structural damage of the airplane and the injury and death of the personnel on the airplane; the blocking performance of the EMAS system is poor due to the fact that the compressive strength is too small and the blocking force borne by the airplane is small. Therefore, the EMAS characteristic material has specific crushing energy absorption characteristics and stable mechanical property so as to facilitate the designability of the blocking effect of the EMAS. The national industry standard (MH/T5111-: the stress-crushing curve should be three-stage (fig. 2). The mechanical properties described in this patent specification are all obtained according to this standard method.

Due to the fact that weight characteristics (unloaded weight, maximum takeoff weight and maximum landing weight) of different aircraft models are greatly different (for example, the maximum takeoff weight of a gulf stream G350 business aircraft is 32 tons, and the maximum takeoff weight of a B777 aircraft is 351 tons), the structural design limit load of tire pressure and landing gear (main stress structure in the EMAS arresting process) of different aircraft is greatly different. The size relationship between the tire pressure of the airplane and the compressive strength of the characteristic material influences whether the airplane can crush the characteristic material and the crushing depth after the airplane rushes into the EMAS; the design limit load of the aircraft landing gear is related to the maximum blocking resistance which can be borne by the aircraft, and the maximum blocking resistance directly influences the selection of the characteristic material mechanical property in the EMAS design.

As described in the patent publication of a silicate-based lightweight foam concrete (application No. 201710311732.6) and the patent publication of a silicone foaming composition and a silicone porous foaming material prepared from the foaming composition (application No. 201710010946.X), the EMAS characteristic materials have no strength gradient, and the EMAS arresting effect cannot be compatible with models with large weight difference. That is, for arresting a large aircraft, the EMAS is generally designed by selecting a characteristic material with higher compressive strength so as to provide a larger arresting force, and at this time, if the small aircraft rushes into the arresting bed, the small aircraft may not crush the characteristic material due to lower tire pressure, so that no arresting effect is produced, or the small aircraft may crush the characteristic material to a certain depth, or the small aircraft may damage the landing gear structure due to higher arresting force, so as to cause a risk.

Disclosure of Invention

In order to solve the problems in the prior art, the invention provides a layered buffering and energy-absorbing structure for an airport runway end characteristic Material Arresting System (EMAS) and a preparation method thereof. The layered buffering energy-absorbing structure can effectively block airplanes with different specifications.

One of the objects of the present invention is to provide a layered energy absorbing bumper structure for an EMAS.

The layered buffering and energy-absorbing structure is formed by jointing buffering and energy-absorbing materials with different strengths from top to bottom;

the strength of each layer gradually increases from top to bottom.

Preferably:

the layered buffering energy-absorbing material is divided into two layers or three layers;

the joint mode is a prefabricated body bonding type or a layered pouring type.

The thickness of each layer of the buffering and energy-absorbing structure body is 10-70 cm; more preferably: the total thickness of the layered buffering energy-absorbing structure body is 20-80 cm.

The strength of each layer is in the range of 0.2MPa to 0.8 MPa.

The strength difference between two adjacent layers is 0.05-0.6 MPa.

The buffering energy-absorbing material is a light porous material, a stress-crushing degree curve of a penetration test of the buffering energy-absorbing material is in a three-stage type, and the maximum crushing degree is more than or equal to 0.6.

The lightweight porous material is preferably foam glass, foam concrete, porous silicone or foamed calcium carbonate.

The invention also aims to provide a preparation method of the layered buffering energy-absorbing structure for the EMAS.

The method comprises the following steps:

the materials of all layers are sequentially increased and jointed according to the strength from top to bottom, and the jointing mode is a prefabricated body bonding type or a layered pouring type.

Preferably:

and bonding the prefabricated layers of buffering energy-absorbing materials by using an adhesive, wherein the adhesive is cement paste or an organic silicon adhesive.

Or the like, or, alternatively,

and after the lower layer of buffering energy-absorbing material is poured and hardened, pouring another layer of buffering energy-absorbing material on the lower layer of buffering energy-absorbing material.

The invention can adopt the following technical scheme:

provides a layered buffering and energy-absorbing structure with a strength gradient structure,

1) the material is formed by jointing buffering and energy-absorbing materials with different mechanical properties;

2) the layering direction is longitudinal, namely the height direction;

3) the layers are divided into two layers or three layers, preferably two layers;

4) the strength of each layer is gradually increased from top to bottom;

5) the buffering energy-absorbing material is a light porous material, preferably foam glass, foam concrete, porous organic silicon and foamed calcium carbonate;

6) the joint mode is a prefabricated body bonding type or a layered pouring type.

7) The stress-crushing degree curve of the penetration test of the light porous material is in a three-stage type, and the maximum crushing degree is more than or equal to 0.6;

8) the preparation method of the prefabricated body bonding comprises the following steps: a) leveling the bonding surface of the prefabricated buffering energy-absorbing material; b) coating an adhesive (preferably cement paste or organic silicon adhesive) on an adhesive interface; c) and bonding the layers of the buffering energy-absorbing materials.

9) The preparation method of the layered pouring joint mode comprises the following steps: a) firstly, preparing a lower-layer buffering energy-absorbing material according to a process; b) hardening the lower layer buffering energy-absorbing material; c) preparing an upper buffering energy-absorbing material according to the process and pouring the upper buffering energy-absorbing material on a lower buffering energy-absorbing material; d) pouring and hardening from bottom to top in sequence.

10) The invention further provides the application of the layered buffering and energy absorbing structure with the strength gradient structure in an airport runway end characteristic material arresting system (EMAS).

The invention has the advantages that:

the implementation mechanism of the layered buffering and energy absorbing structure with the strength gradient structure in EMAS application is as follows. 1) When the small airplane rushes into the EMAS, the small airplane can crush the buffering energy-absorbing material with weaker mechanical property at the upper part or the buffering energy-absorbing material with stronger mechanical property at the lower layer of the crushed part due to smaller weight (small tire pressure), so that the blocking force is effectively blocked and the structure bearing limit is not exceeded, thereby ensuring the blocking effect and the blocking safety of the small airplane; 2) when the non-small airplane rushes into the EMAS, the non-small airplane can simultaneously crush each layer of buffering energy-absorbing material due to the large weight (large tire pressure), and effective blocking effect and blocking safety can be provided for the non-small airplane.

This patent a layer-stepping buffering energy-absorbing structure with intensity gradient structure, have following advantage:

1) the composite material has the strength gradient with the strength sequentially increased from top to bottom, and the thickness and the strength of each layer can be adjusted according to the EMAS design requirements (mainly considering the requirements of various EMAS design models) so as to meet the requirements of the blocking effect and the safety of the EMAS for different models.

2) The material is prepared by bonding or layering and pouring the mature buffering and energy absorbing material meeting the EMAS requirement, so that the material still has predictable mechanical properties meeting the EMAS requirement, and the designability and the arresting safety of the EMAS arresting effect are not influenced.

3) The processing technology is simple.

Drawings

FIG. 1 is a schematic structural view of a layered energy-absorbing cushioning structure having a strength gradient structure;

FIG. 2 is a schematic view of a stress-crush curve;

FIG. 3 stress-crush curve for the materials of examples 1 and 2;

FIG. 4 stress-crush curve of the lower layer material of example 1;

FIG. 5 stress-crush curve of the material of example 1 as a whole;

FIG. 6 is a schematic view of the material of example 1 integrally assembled into an EMAS unit body;

FIG. 7 displacement-time curve of bench test in example 1

FIG. 8 vertical force-displacement curve of bench test in example 1

FIG. 9 example 1 bench test course force-displacement curve

FIG. 10 schematic view of bench test trench in example 1

FIG. 11 stress-crush curve of lower layer material of example 2;

fig. 12 stress-crush curve of the material of example 2 as a whole.

In the figure, the position of the upper end of the main shaft,

1-a top cover; 2-a foam pad; 3-upper layer material; 4-a bonding material; 5-gauze; 6-lower layer material; 7-plastic bottom supports (with forklift slots); 8-unit body.

Detailed Description

The present invention will be further described with reference to the following examples.

Example 1

Example 1 an EMAS unit cell was prepared in a preform bonding manner using a prefabricated foamed concrete material having mechanical properties characteristic as shown in fig. 3 and 4 and applied to an EMAS system.

The method comprises the following specific steps:

1) according to my unit published patent "a silicate-based lightweight foam concrete" (application No.: 201710311732.6) the method of example 6 and example 8, preparing foam concrete material preforms as the upper and lower layers, respectively, each having dimensions of 1m length by 1m width by 25cm height, 0.24MPa and 0.49MPa strength, respectively, and 0.72 and 0.74 maximum degree of crushing, respectively, and the stress-degree of crushing curves are shown in FIGS. 3 and 4;

2) uniformly coating and using common silicate cement paste or using organic silicon adhesive (Chengdu Tuoli science and technology corporation, model TQ-100PN) on the contact surface of the two layers of materials, wherein the thickness is less than or equal to 3 mm;

3) bonding the two layers of materials, and curing the adhesive slurry;

4) the stress-crushing degree curve of the material after bonding is shown in figure 5;

5) and adding a plastic top cover on the upper surface of the jointed material, adding a bottom support on the lower surface of the jointed material, and packaging the jointed material into an EMAS unit body.

6) The above-mentioned unit bodies were subjected to bench test verification as specified in the "characteristic Material arresting System" industry Standard (MH/T5111-. Some of the parameters of the bench test are shown in table 1. The test results obtained are shown in FIGS. 7 to 10.

TABLE 1

Numbering	Height of material (cm)	Laying length (m)	Tire pressure (MPa)	Load (Ton)	Speed (m/min)
						Example 1	50	7	1.41	15	22

7) Through design calculation, the average relative error between the calculation result of the heading load and the measurement result is less than 10%.

As various performances and bench test results of the used upper and lower layer materials meet the requirements of 'characteristic material arresting system' industry standard (MH/T5111-.

Example 2

In example 2, a layered energy-absorbing buffering material with foam concrete as an upper layer and foam silicone as a lower layer was prepared by layered casting and applied to an EMAS system.

The method comprises the following specific steps:

1) according to my unit published patent "a silicone foaming composition and a silicone porous foaming material prepared from the foaming composition" (application number: 201710010946.X) the method of example 1 was used to prepare a porous foamed silicone material having a thickness of 25cm, a strength of 0.54MPa, a maximum degree of crush of 0.83, and a stress-degree of crush curve as shown in fig. 11;

2) after the lower silicone material is cured, the cured material is cured according to my published patent "a silicate-based lightweight foam concrete" (application number: 201710311732.6) the method of example 6, casting a foam concrete material directly on a silicone material, the foam concrete material having a thickness of 25cm, a strength of 0.32MPa, and a maximum degree of crushing of 0.72;

3) after curing for 28 days, the stress-crushing degree curve of the whole material is shown in fig. 12;

as various performances of the used upper and lower layer materials meet the requirements of 'characteristic material arresting system' industry standard (MH/T5111-.

Claims (6)

1. A layered buffering energy-absorbing structure for an EMAS, characterized in that:

the layered buffering and energy-absorbing structure is formed by jointing buffering and energy-absorbing materials with different strengths from top to bottom;

the strength of each layer gradually increases from top to bottom;

the thickness of each layer of the buffering and energy-absorbing structure body is 10-70 cm; the total thickness of the layered buffering energy-absorbing structure body is 20-80 cm;

the strength range of each layer is 0.2MPa-0.8 MPa;

the strength difference between two adjacent layers is 0.05-0.6 Mpa;

the buffering energy-absorbing material is a light porous material, a stress-crushing degree curve of a penetration test of the buffering energy-absorbing material is in a three-stage type, and the maximum crushing degree is more than or equal to 0.6.

2. The layered energy absorbing bumper structure for an EMAS of claim 1, wherein:

the layered buffering energy-absorbing material is divided into two layers or three layers;

the joint mode is a prefabricated body bonding type or a layered pouring type.

3. The layered energy absorbing bumper structure for an EMAS of claim 1, wherein:

the light porous material is foam glass, foam concrete, porous organic silicon or foamed calcium carbonate.

4. A method of manufacturing a layered energy absorbing bumper structure for EMAS according to any one of claims 1 to 3, wherein the method comprises:

the materials of all layers are sequentially increased and jointed according to the strength from top to bottom, and the jointing mode is a prefabricated body bonding type or a layered pouring type.

5. The method of claim 4, wherein:

and bonding the prefabricated layers of buffering energy-absorbing materials by using an adhesive, wherein the adhesive is cement paste or an organic silicon adhesive.

6. The method of claim 5, wherein:

and after the lower layer of buffering energy-absorbing material is poured and hardened, pouring another layer of buffering energy-absorbing material on the lower layer of buffering energy-absorbing material.

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