阅读说明：本技术 一种车载轻量化复合大板式通讯方舱 (Vehicle-mounted lightweight composite large plate type communication shelter ) 是由 侯守明 叶亚奇 凌文丹 郭晓杰 夏磊 于 2020-11-13 设计创作，主要内容包括：本发明涉及通讯方舱技术领域,具体涉及一种车载轻量化复合大板式通讯方舱。所述通讯方舱为大板式结构方舱,其中方舱本体为由相邻壁板通过垂直连接结构或平行连接结构形成的舱体,壁板包括顶板、底板和侧板,壁板均为复合夹心板,复合夹芯板包括芯材泡沫板和固定连接在泡沫板内外表面的复合材料层,复合材料层为由纤维制成的编织层。本发明以减重为主要目标,在保证车载通讯方舱的强度与刚度的前提下,对方舱壁板进行结构优化设计,优化后的结构显著减轻了舱体重量,且具有一定的抗冲击防爆性能。(The invention relates to the technical field of communication square cabins, in particular to a vehicle-mounted light composite large plate type communication square cabin. The communication shelter is big board-like structure shelter, and wherein the shelter body is the cabin body that forms through perpendicular connection structure or parallel connection structure by adjacent wallboard, and the wallboard includes roof, bottom plate and curb plate, and the wallboard is compound sandwich panel, and compound sandwich panel includes core cystosepiment and the combined material layer of fixed connection at the inside and outside surface of cystosepiment, and the combined material layer is the weaving layer of making by the fibre. The invention takes weight reduction as a main target, carries out structure optimization design on the shelter wall plate on the premise of ensuring the strength and rigidity of the vehicle-mounted communication shelter, obviously reduces the weight of the shelter body through the optimized structure, and has certain shock resistance and explosion resistance.)

1. The utility model provides a compound big board-like communication shelter of on-vehicle lightweight, includes the shelter body, its characterized in that, the shelter body is for passing through the cabin body that vertical connection structure or parallel connection structure formed by adjacent wallboard, the wallboard includes roof (11), bottom plate (12) and curb plate (13), the wallboard is compound sandwich panel, compound sandwich panel includes core cystosepiment (101) and fixed connection at cystosepiment (101) inside and outside surperficial combined material layer (102), combined material layer (102) are the weaving layer of being made by the fibre.

2. A vehicle carried light weight communication shelter according to claim 1 in which the composite layer (102) on the inside of the wall panel is provided with a polyurea layer (104).

3. The vehicle-mounted light-weight composite large plate type communication shelter as claimed in claim 2, wherein the composite material layer (102) on the inner side of the wall plate is in contact bonding with the polyurea layer (104).

4. The vehicle-mounted lightweight composite large panel type communication shelter of claim 1, wherein the composite material layer (102) is a multi-axial braided layer formed by Kevlar fibers and carbon fibers.

5. The vehicle-mounted light-weight composite large plate type communication shelter of claim 4, wherein the carbon fibers are T700 carbon fibers, and the foam plate (101) is 60kg/m³A plate-like structure made of foamed PVC 60.

6. A vehicle-mounted light-weight composite large plate type communication shelter as claimed in claim 1, wherein corner pieces (2) are bonded to the inner side and the outer side of the connecting structure.

7. The vehicle-mounted light-weight composite large plate type communication shelter as claimed in claim 1, wherein when two adjacent wall plates are connected through a vertical connecting structure, the two wall plates are rectangular, and the composite material layer (102) on the outer side of one wall plate extends out of the wall plate and is fixedly connected with the sandwich structure of the other wall plate.

8. The vehicle-mounted light-weight composite large plate type communication shelter as claimed in claim 1, wherein when two adjacent wall plates are connected through a parallel connection structure, one of the wall plates is vertically provided with a connection plate (4) at the connection position, the connection position of the other wall plate is provided with a rectangular notch, and the connection plate (4) is matched and fixedly connected with the rectangular notch.

9. The vehicle-mounted light-weight composite large plate type communication shelter of claim 8, wherein the connecting plate (4) comprises a foam plate (101) in the middle and composite material layers (102) fixedly connected to the inner side and the outer side of the foam plate (101), the foam plate (101) and the composite material layers (102) are arranged at the rectangular gap from inside to outside, and the composite material layers (102) on the inner side of the connecting plate (4) are fixedly connected with the foam plate (101) on the inner side of the rectangular gap.

Technical Field

The invention relates to the technical field of communication square cabins, in particular to a vehicle-mounted light composite large plate type communication square cabin.

Background

The mobile command communication shelter is a large-scale field comprehensive command dispatching disposal system for emergency and military command of emergent public safety events, can be matched with various transportation tools such as automobiles, trains, airplanes and ships, and meets the requirements of quick response, mobile command decision, field emergency disposal and the like of emergent public safety events.

The vehicle-mounted communication shelter is a mobile command communication shelter used with an automobile in a matched mode, and is a platform for installing and using communication equipment and other matched equipment, the total weight of the currently researched and developed communication shelter is mostly close to or exceeds the cross-country loading capacity of an automobile chassis, the off-road property and the flexible maneuverability of the automobile are seriously influenced, and the development of the communication shelter to the direction of system integration and light weight is restricted, so that the dead weight of the shelter is reduced, the loading weight ratio of the shelter is improved, and a basic platform is provided for the development of the communication shelter to the direction of system integration and light weight.

The development of the square cabin is various from a single framework square cabin to a large-plate square cabin and a composite large-plate framework square cabin, the framework square cabin is structurally characterized in that an alloy aluminum plate is used as a cabin wall outer wrapping plate, a square aluminum pipe is used as a framework, the aluminum alloy plate and a core material only play roles in protection, heat preservation and the like, do not directly participate in bearing load, and mainly bear the load by virtue of the framework; the composite large plate type square cabin is composed of a plurality of composite large plates, the core materials, skins and beams which are bonded together bear load together, the skins are usually aluminum alloy plates, and the composite beams are designed in the sandwich layer, so that the manufacturability of the thickness of the large plates is guaranteed, and the strength of the large plates is improved. The structure meets the requirements of the shelter on strength and rigidity, but the requirement of light weight of the vehicle-mounted communication shelter cannot be met due to the adoption of a large amount of metal materials and structures.

Besides weight reduction, the bullet-resistant and explosion-proof capacity of the special shelter is improved, the special shelter can resist striking of different grades, workers in the shelter and equipment in the shelter are protected to the maximum extent, and the problem to be solved is also solved. The explosion-proof design of the shelter comprises two forms: modular add-on structures and monolithic structures. The modular additional structure means that the shelter does not have an explosion-proof layer structure. When the modularized explosion-proof plate is used, the prefabricated modularized explosion-proof plate is hung on the shelter, and the quality of the explosion-proof plate is borne by the shelter. The structure has limited explosion-proof capability and cannot protect nuclear explosion overpressure. The integral structure means that the explosion-proof layer is a component of the large shelter plate, the bulletproof explosion-proof plate and the large shelter plate are synchronously produced and processed and are completely bonded together, and the explosion-proof performance becomes the inherent performance of the shelter. The invention patent application with publication number CN104197785A describes a bulletproof and explosion-proof electromagnetic shielding shelter wallboard, which sequentially comprises an outer skin, a shielding metal wire mesh layer, a non-metal honeycomb sandwich layer and an inner skin from outside to inside, wherein the outer surface of the outer skin is coated with a wave-absorbing material layer, the outer skin is made of multiple layers of aramid fibers and has bulletproof and explosion-proof effects, and the inner skin is a 5052 aluminum alloy plate with the thickness of 1 mm. The wall plate is still made of metal materials, so that the weight of the shelter cannot be effectively reduced; and the outer skin is used as an explosion-proof layer, and the explosion-proof effect can be realized only by coating multiple layers.

Disclosure of Invention

The invention provides a vehicle-mounted light composite large plate type communication shelter for achieving the purpose of reducing the overall weight of the shelter.

In order to achieve the purpose, the technical scheme of the invention is as follows:

the utility model provides a compound big board-like communication shelter of on-vehicle lightweight, includes the shelter body, the shelter body is for passing through perpendicular connection structure or the cabin body that parallel connection structure formed by adjacent wallboard, the wallboard includes roof, bottom plate and curb plate, has seted up the door on one of them curb plate, the wallboard is compound sandwich panel, compound sandwich panel includes core cystosepiment and the combined material layer of fixed connection at the inside and outside surface of cystosepiment, the braided layer that the combined material layer was made by the fibre.

In a further aspect, the composite material layer is a multi-axial braided layer formed of Kevlar fibers and carbon fibers.

In a further scheme, the carbon fiber is T700 carbon fiber, and the foam board is made of 60kg/m³A plate-like structure made of foamed PVC 60.

In a further scheme, corner pieces are bonded on the inner side and the outer side of the connecting structure.

In a further scheme, when two adjacent wall plates are connected through a vertical connecting structure, the two wall plates are rectangular, and the composite material layer on the outer side of one wall plate extends out of the wall plate and is fixedly connected with the sandwich structure of the other wall plate.

In a further scheme, when two adjacent wallboards are connected through a parallel connection structure, one of the wallboards is vertically provided with a connecting plate at the joint, the joint of the other wallboard is provided with a rectangular notch, and the connecting plate is matched with the rectangular notch and is fixedly connected with the rectangular notch.

In a further scheme, the connecting plate comprises a middle foam plate and composite material layers fixedly connected to the inner side and the outer side of the foam plate, the foam plate and the composite material layers are sequentially arranged at the rectangular notch from inside to outside, and the composite material layer on the inner side of the connecting plate is fixedly connected with the foam plate on the inner side of the rectangular notch.

In addition, in order to realize the purposes of explosion prevention and impact resistance of the shelter, a polyurea layer is arranged on the composite material layer on the inner side of the wall plate.

In a further development, the composite layer on the inside of the wall panel is adhesively bonded to the polyurea layer.

The invention has the beneficial effects that:

(1) according to the invention, on the premise of ensuring the strength and rigidity of the vehicle-mounted communication shelter, the structure of the shelter wall plate is optimally designed, the optimized shelter wall plate adopts a composite sandwich plate, the composite sandwich plate comprises a core material foam plate and a composite material layer fixedly connected to the inner surface and the outer surface of the foam plate, and the composite material layer is a woven layer formed by fibers. The structure obviously reduces the weight of the cabin body, and improves the overall strength, rigidity, heat insulation, sound absorption, vibration absorption, sound insulation, weather resistance and the like. In addition, the adjacent wall plates form a cabin body through a vertical connection structure or a parallel connection structure, so that the connection between the wall plates is realized, and the stability is ensured.

(2) The composite material layer on the inner side of the wall plate is provided with the polyurea layer, so that the deformation of the wall plate when the wall plate is impacted can be effectively reduced compared with the polyurea layer arranged on the outer side of the wall plate.

(3) In the optimized scheme of the invention, the composite material layer on the inner side of the wall plate is in contact bonding with the polyurea layer, and the protection efficiency is higher than that of common node bonding.

(4) The invention uses the braided layer formed by the fiber as the skin, thereby greatly reducing the weight of the communication shelter wallboard. The inner and outer surfaces of the composite sandwich plate are composite material layers made of high-strength and high-modulus materials, and the middle of the composite sandwich plate is a light sandwich layer with lower strength. The composite material layers on the inner and outer surfaces bear main tensile stress and compressive stress, and the core material mainly bears shear stress.

(5) In the optimized scheme, the wall plates are connected in a bolt-free connection mode, and the damage test result shows that the bolt connection is easier to damage than the bolt-free connection.

Drawings

Fig. 1 is a schematic structural diagram 1 of a vehicle-mounted lightweight composite large plate type communication shelter of the invention.

Fig. 2 is a schematic structural diagram 2 of a vehicle-mounted lightweight composite large plate type communication shelter of the invention.

Fig. 3 is a schematic structural diagram 3 of a vehicle-mounted lightweight composite large plate type communication shelter of the invention.

Fig. 4 is a schematic structural diagram 4 of a vehicle-mounted lightweight composite large plate type communication shelter of the invention.

Fig. 5 shows a wall plate connecting structure according to embodiment 1 of the present invention.

Fig. 6 shows a panel connecting structure according to embodiment 2 of the present invention.

Fig. 7 is a schematic structural view of a side plate in embodiment 3 of the present invention.

FIG. 8 is a control product of example 1 of the present invention.

Figure 9 is a control product of example 2 of the present invention.

Fig. 10 is a compression curve diagram of the panel connecting structure according to example 1 of the present invention.

FIG. 11 is a graph of the compression curve of a control product of example 1 of the present invention.

Fig. 12 is a compression curve of the panel connecting structure according to embodiment 2 of the present invention.

FIG. 13 is a graph of the compression of a control product of example 2 of the present invention.

FIG. 14 is a finite element model diagram of a Hopkinson pressure bar.

FIG. 15 is a diagram showing the failure of polyurea layers in different bonding modes.

FIG. 16 is a 3D finite element model diagram for analysis of the explosion-proof performance of the polyurea layer.

Fig. 17 is a waveform diagram of different bonding modes SHPB.

FIG. 18 is a schematic diagram of the antiknock study.

Fig. 19 is a maximum deformation curve of the steel sheet, in which common node is common node bonding and contact is contact bonding.

In the drawing, 11 is a top plate, 12 is a bottom plate, 13 is a side plate, 101 is a foam plate, 102 is a composite material layer, 103 is an epoxy resin bonding layer, 104 is a polyurea layer, 2 is a corner piece, 3 is an epoxy structure adhesive layer, 4 is a connecting plate, 5 is a ceiling ladder, 6 is a cabin ladder, 7 is a door, 8 is a window, 9 is an air inlet door, 10 is an exhaust door, 111 is a signal door, and 112 is a power supply door.

Detailed Description

The present invention is described in detail below with reference to specific examples, but the scope of the present invention is not limited to the following examples, and any technical solutions that can be conceived by those skilled in the art based on the present invention and the common general knowledge in the art are within the scope of the present invention.

Example 1

As shown in fig. 1-4, a vehicle-mounted light composite large plate type communication shelter, the communication shelter is a large plate type structure shelter, and comprises a shelter body, wherein the shelter body is formed by adjacent wall plates through a vertical connection structure, and the wall plates comprise a top plate 11, a bottom plate 12 and side plates 13.

A door 7 is arranged on a side plate 13 of the shelter body far away from the vehicle head, a handle and a rear window 8 are arranged on the door 7, a top-climbing ladder 5 and a cabin-climbing ladder 6 are respectively arranged on two sides of the door 7, and an air conditioner outdoor unit is arranged on the side plate 13 of the shelter body close to the vehicle head. The square cabin body is internally provided with a 19-inch standard frame, a non-standard frame, a workbench, a seat, a storage box, an air conditioner, a fuel air heater, a fire extinguisher and the like. The facilities to be fixed with the side plates 13 are installed through embedded iron on the wall plates.

The front side plate 13 of the shelter body is further provided with a fixed window 8, an outward pushing window 8, an air inlet door 9 and a power supply door 112, the rear side plate 13 is provided with the fixed window 8, a signal door 111 and an exhaust door 10, wherein the side plate 13 where the fixed window 8, the outward pushing window 8, the air inlet door 9 and the power supply door 112 are located is the front side plate 13 shown in fig. 3, and the side plate 13 corresponding to the front side plate 13 is the rear side plate 13.

The wall plates are all composite sandwich plates, each composite sandwich plate comprises a core material foam plate 101 and composite material layers 102 fixedly connected to the inner surface and the outer surface of the foam plate 101, and the composite material layers 102 are fixedly connected with the foam plates 101 through epoxy resin bonding layers 103. The composite material layer 102 is a woven layer made of fibers. Specifically, the composite material layer 102 is a multi-axial woven layer formed by Kevlar fibers and carbon fibers. WhereinThe carbon fiber is T700 carbon fiber, and the foam board 101 adopts 60kg/m³A plate-like structure made of foamed PVC 60.

Specifically, the top plate 11 includes Kevlar fibers and carbon fiber multi-axial woven layers with outer surfaces of 1.2mm, a foam plate 101 with a core material of 33mm, and Kevlar fibers and carbon fiber multi-axial woven layers with inner surfaces of 1 mm. The bottom plate 12 comprises Kevlar fibers and carbon fiber multi-axial woven layers with the outer surfaces being 1mm, a foam plate 101 with the core material being 33mm, and Kevlar fibers and carbon fiber multi-axial woven layers with the inner surfaces being 1.2 mm. The side plate 13 comprises Kevlar fibers and carbon fiber multi-axial woven layers with the outer surfaces being 1mm, a foam plate 101 with the core material being 33mm, and Kevlar fibers and carbon fiber multi-axial woven layers with the inner surfaces being 1 mm.

As shown in fig. 5, two adjacent wall panels of this embodiment are connected by a vertical connecting structure, and both wall panels are rectangular, and the composite material layer 102 on the outer side of one wall panel extends out of the wall panel and is fixedly connected with the sandwich structure of the other wall panel. The inner side and the outer side of the connecting structure are fixedly connected with corner fittings 2 in a bonding mode, and the corner fittings 2 and the connecting structure are fixedly connected through epoxy structure glue layers 3. And four top angles of the shelter body are fixedly provided with top angle pieces.

Example 2

This embodiment is different from embodiment 1 in that two adjacent wall plates are connected by a parallel connection structure, as shown in fig. 6. One of the wall plates is vertically provided with a connecting plate 4 at the joint, the joint of the other wall plate is provided with a rectangular notch, and the connecting plate 4 is matched and fixedly connected with the rectangular notch. The connecting plate 4 comprises a middle foam plate 101 and a composite material layer 102 fixedly connected to the inner side and the outer side of the foam plate 101 through an epoxy resin bonding layer 103, the foam plate 101 and the composite material layer 102 are sequentially arranged at the rectangular notch from inside to outside, and the composite material layer 102 on the inner side of the connecting plate 4 is fixedly connected with the foam plate 101 on the inner side of the rectangular notch through the epoxy resin bonding layer 103.

Example 3

This embodiment differs from embodiment 1 in that a polyurea layer 104 is provided on the composite layer 102 on the inner side of the panel, as shown in fig. 7. The composite layer 102 on the inside of the panel is bonded in contact with the polyurea layer 104.

EXAMPLE 4 compression testing of different connection means

The shelter wall panel connections formed in examples 1 and 2 were subjected to a compression test to determine the moment that can be sustained on the adhesive surface. The comparison products were obtained by further inserting bolts into the connecting structures of examples 1 and 2, as shown in fig. 8 and 9, respectively.

And (3) testing conditions are as follows: at normal temperature, the testing speed is 5mm/min, and the test is carried out according to GB/T1041-2008.

The compression curve results for example 1 and its control product are shown in FIGS. 10-11, respectively. The result shows that the maximum force that the connection structure that adds the bolt and the connection structure that does not add the bolt both born differs by a little, and from two figure curve contrastive analysis findings, the connection structure that adds the bolt destroys more easily than not having the bolt and destroys, and the loading displacement when its destroys is half of not having the bolt, this is because the panel intensity has been destroyed to the adding bolt to and the inside hole of foam appears, makes the material more easily punch and peripheral region destroys when receiving the exogenic action, consequently the connection structure that adds the bolt destroys more easily. In the failure test, the connection structure with the bolt is firstly broken by the foam board, when the force reaches a certain degree, the connection interface is layered, the bonding surface is broken, and the connection fails. In the bolt-free connection structure failure test, the whole structure is unstable due to cracks in the foam board under the action of external force, but the unstable bonding surface of the structure is not damaged, and the unstable process shows certain yield.

The compression curve results of example 2 and its control product are shown in FIGS. 12-13, respectively. Analysis and comparison of compression curves show that the maximum bearing capacity difference is large when the added bolt and the bolt are not damaged, the maximum bearing capacity of the added bolt is 3554N, and the maximum bearing capacity of the bolt is 5071N. When the bearing capacity reaches the maximum value, the connecting structure with the added bolt is directly damaged and then the bearing capacity is rapidly reduced, the connecting structure without the bolt can continue bearing after initial damage, and a yielding process exists, so that the connecting structure without the bolt is safer. When the connecting structure added with the bolts is damaged, the foam board is damaged firstly, and finally the foam board and the skin layer composite material layer are debonded; the bolt-free connecting structure is also that the foam board is firstly damaged, but the composite material layer, the foam board and the bonding surface are not debonded. Thus, it was shown that the boltless connection structure is stronger than the bolt-added connection structure.

Example 5 weight detection

External dimensions of the communication shelter (length × width × height): 4012mm × 2438mm × 1700 mm.

The method comprises the following steps: the dead weight of the shelter is less than 15kg/m²The weight of the cabin body (containing embedded parts and no supporting facilities) is not more than 650 kg.

(2) The weight loss effect analysis is as follows:

TABLE 1 weight loss effect analysis Table

The analysis results show that: the weight of the shelter is reduced by about 205kg, and the weight reduction effect is obvious.

Example 6 analysis of protective Properties of polyurea layer

The protective effectiveness of a polyurea layer is generally qualitatively described by the reactive morphology (deformation or destruction) of the polyurea layer or base layer. Through a numerical simulation separation type Hopkinson pressure bar (SHPB) experiment, the energy dissipation of the elastic wave of a test piece is calculated according to the strain wave test data, and the influence of factors such as the bonding strength on the shock resistance of the polyurea elastomer protective layer is quantitatively researched.

1. Finite element model

The method is characterized in that only a striking rod, an incident rod, a transmission rod and a test piece are considered in numerical simulation establishing of the SHPB finite element model, wherein the diameters of the rods are 37mm, the length of the striking rod is 60mm, the length of the incident rod is 2000mm, the length of the transmission rod is 2000mm, and the diameter of the test piece is 33.3mm and the length of the test piece is 26.64 mm. The polyurea elastomer is arranged on the incident rod impact surface of the test piece. The SHPB finite element model adopts an eight-node hexahedron Solid164 unit, Lagrange meshing and automatic single-side contact, as shown in FIG. 14.

The SHPB rod is made of alloy steel, and the material is in an elastic state in the test process, so that an elastic constitutive die is adoptedType, corresponding material parameter is density 7.85g/cm³Elastic modulus 2.06e5MPar, Poisson's ratio 0.3, elastic wave speed 5200 m/s.

The test piece is made of high-conductivity oxygen-free Copper (OFHC wrapper), the material constitutive relation adopts a Johnson-Cook model, the model is an ideal rigid-plastic reinforced material model and can reflect the strain rate reinforcing effect and the temperature rise softening effect of the material under impact, and most parameters are determined by an SHPB experiment. The Johnson-Cook model uses Mises yield surfaces, but different reinforcements, and takes into account the effect of strain rate, and the material yield stress strain relationship is expressed as a product of three expressions, which respectively reflect strain hardening, strain rate hardening, and temperature softening, as follows:

in the formula, σ_yMaterial yield strength to account for strain rate effects; a is the initial yield stress; b is a strain hardening coefficient;is an effective plastic strain; n is a strain hardening index; c is a strain rate correlation coefficient;in order to be effective in the plastic strain rate,T^*relative temperature, T^*＝(T-T_room)/(T_melt-T_room) T is the real-time temperature, T_roomAt room temperature, T_meltIs the material melting point temperature; and m is a temperature coefficient.

The Johnson-Cook model adopts a shear failure criterion, which is a criterion for judging material failure through equivalent plastic strain of integral points of units. When the material failure parameter D exceeds 1, the material undergoes a failure behavior, resulting in a fracture, wherein,

in the formula (I), the compound is shown in the specification,is the equivalent plastic strain increment;represents the strain at failure of the material, wherein D₁、D₂、D₃、D₄And D₅Is a material parameter, σ, related to the shear failure criteria of the Johnson-Cook model^*Is the ratio of pressure to effective stress, σ^*＝p/σ_effP is the hydrostatic pressure value, sigma, born by the material under the three-dimensional stress state_effIn order to obtain the stress equivalent to the Mises,s_ijis the bias stress.

The Johnson-Cook model also requires matching with the Greeneisen equation of state to establish an analytical relationship for 3 quantities of state of the high pressure solid, and the pressure expression of the Greeneisen equation of state of the material under impact pressure is as follows:

in the formula, ρ₀Is the initial density; e is the internal energy of the material; mu-rho/rho₀-1, ρ is the current density; c is the impact adiabatic line of material (shock wave velocity-particle velocity u)_s-u_pCurve) intercept; s₁、S₂And S₃Respectively is the slope coefficient of the impact adiabatic curve of the material; gamma ray₀Gr ü neisen coefficient; a is the first order volume correction to the Gr ü neisen coefficient.

TABLE 2 constitutive model parameters of the test piece materials (OFHC Copper)

ρ/g/cm3	G/MPa	A/MPa	B/MPa	n	C	m	Tm/K	Troom/K
									8.33	0.51E+5	89.63	291.64	0.31	0.025	1.09	1220	293
D1	D2	D3	D4	D5	C(m/s)	S1	γ0	a
									-0.54	4.89	-3.03	0.014	1.12	3940	1.489	2.02	0.47

Under static and quasi-static tension or compression, the polyurea shows the properties of a super elastic material, and under dynamic loading, the stress-strain curve of the polyurea is nonlinear and shows highly sensitive strain rate effect and temperature effect, and high pressure dependence.

The Mooney-Rivlin model describes the nonlinearity of the stress-strain relationship of a superelastic body by applying an elastic potential energy function, the function is a scalar function of a strain tensor, the derivative of the strain component is a corresponding stress component, the strain can be automatically recovered during unloading, and the stress and the strain of the model are not in a linear corresponding relationship any more, but are in one-to-one correspondence in the form of the elastic potential energy function.

Two-parameter Mooney-Rivlin model elastic potential energy function:

in the formula, C₁₀、C₀₁Is a material constant determined from experimental data,the deformation parameters of the material are respectively a first invariant and a second invariant of the deflection component of the levoCauchy-Green deformation tensor, J is a determinant of an elastic deformation gradient, d is an incompressible parameter of the material, and v is a Poisson ratio of the material.

TABLE 3 polyurea constitutive model parameters

ρ/g/cm3	ν	C10/kPa	C01/kPa	d/kPa-1
					1.02	0.49964	875.2	6321.3	4E-7

2. Analysis of explosion-proof Properties of polyurea layer

Polyurea layers were formed on the outer and inner surfaces of the steel sheet, and the explosion resistance analysis was performed, as shown in fig. 15.

2.1 finite element model

The polyurea layer steel plate anti-explosion numerical simulation adopts an eight-node hexahedron Solid164 unit to establish a finite element model of a charge, a steel plate, a polyurea layer and air, wherein the steel plate and the polyurea layer adopt a Lagrange algorithm, the charge and the air adopt a multi-substance single-point ALE algorithm, and the charge and the air adopt fluid-Solid coupling analysis. The charge and air models are spherical, and in order to save computing resources, only half of the effect on the polyurea layer steel plate is taken, and then the 3D finite element model is set and established symmetrically, as shown in figure 16. Setting boundary constraint on the steel plate according to the test condition, and bonding the steel plate and the polyurea layer by adopting common nodes; the air sets the transmission boundaries on all sides except the symmetry plane.

2.2 Material model

(1) Pentolite explosive material model

The Pentolite Explosive adopts a High-expansion-Burn combustion model, the combustion coefficient F of the model represents the release of chemical energy in the detonation process, and the expression of the combustion coefficient is as follows:

F＝max(F₁,F₂) (6)

in the formula, F₁Is density rho, explosive detonation velocity v_DVolume compression ratio V/V₀And Chapman-Jouget pressure P_cjAs a function of (a) or (b),F₂is the detonation velocity v_DTime of combustion t_bFunction of the current time t and the cell characteristic length Δ x, F₂＝2(t-t_b)v_D/(3△x)。

The combustion model is used in conjunction with the JWL equation of state, JWL equation of state well describes high explosive, which defines pressure as a function of relative volume V and initial energy E per unit volume:

in the formula, parameters ω and A, B, R₁And R₂Are constants that characterize the explosive properties. The material parameters of the pentalite explosive are shown in table 4.

TABLE 4 Pentolite explosive materials constitutive model parameters

(2) Air material model

Air uses a blank material model that effectively simulates a fluid medium. The deformation of a solid cell is the result of a change in the displacement gradient (i.e. strain epsilon), the partial shear stress sigma for a fluid cell_dAnd shear strain rateIs in direct proportion, as shown in formula (8).

In the formula, μ represents a fluid viscosity.

The blank material model needs to be used together with an equation of state, the equation of state of the air material is a linear polynomial, as shown in formula (9), and specific parameters are as shown in table 5:

p＝C₀+C₁μ+C₂μ²+C₃μ³+(C₄+C₅μ+C₆μ²)E (9)

TABLE 5 constitutive model parameters for air materials

(3) Steel plate material model

The material constitutive relation of the steel plate adopts a Johnson-Cook model, and the material constitutive model parameters are shown in Table 6.

TABLE 6 constitutive model parameters of steel plate material

(4) Polyurea layer material model

The polyurea material constitutive adopted the Mooney-Rivlin model, and the relevant parameters are shown in Table 7.

TABLE 7 polyurea layer Material constitutive model parameters

Density rho (g/cm)3)	Poisson ratio v	C10(kPa)	C01(kPa)	d(1/kPa)
					1.02	0.49964	875.2	6321.3	4E-7

2.3 analysis of explosion resistance of polyurea layer

TABLE 8 explosion-resistance efficiency of polyurea layer

As can be seen from the maximum deformation curves of the steel sheets shown in table 8 and fig. 17, the steel sheet deformation amount of the polyurea layer with the same thickness on the inner side (back surface) of the steel sheet is smaller than that on the outer side (front surface) of the steel sheet, and the anti-explosion performance is improved by 17.65% and 10.99% respectively compared with that of the polyurea layer without the polyurea layer, which is different by 6.66%. With the increase of the thickness of the polyurea layer, the explosion resistance of the polyurea layer is gradually improved.

3. Influence of the mode of bonding of the polyurea layer

The bonding strength between the polyurea layer and the base layer affects the transmission of impact energy and the deformation and destruction of the polyurea layer. In the embodiment, two extreme conditions of contact bonding and common node bonding are selected for comparative calculation and analysis.

FIG. 18A shows a failure condition of the contact adhesive polyurea layer, wherein the polyurea layer becomes thinner and overflows to the periphery under the impact of an incident rod, and the tearing failure occurs. Fig. 18B shows a failure condition of the co-node bonded polyurea layer, which is thinned under the impact of the incident rod due to the bonding force constraint, but the overflow to the periphery is obviously limited, and the failure degree is relatively low. The comparative analysis shows that when the adhesive force is small, the polyurea layer has large plastic deformation and rupture degree and consumes more impact energy, so that the protection to the base layer is good.

FIG. 19A shows incident and reflected waves on an incident rod, with the reflected waves of the contact bond being slightly enhanced. FIG. 19B shows the transmitted wave on the transmission rod, the transmitted wave in contact bonding is in a double wave form reflecting the discontinuity of impact energy propagation between the polyurea layer and the substrate, while the common node bonding is in a single wave form with continuous impact energy transfer, and the polyurea layer and the substrate can be considered as a whole.

According to the strain time-course curve of the SHPB experiment, the wave energy and the energy consumption of the test piece are calculated, as shown in Table 9.

TABLE 9 impact energy meter for SHPB experiment with different bonding modes

Bonding method	Incident wave energy/J	Reflected wave energy/J	Transmitted wave energy/J	Test piece energy consumption/J	Efficiency of
						Contact bonding	70.67	47.26	3.75	19.65	—
Common node bonding	70.67	37.33	5.95	27.39	39.4％

The impact resistance protection performance of the co-node bonded polyurea layer is reduced by 39.4% based on the contact bonding, so that the protection performance of the polyurea layer is predicted to be reduced along with the increase of the bonding force under the bonding condition between the two extremes of the contact bonding and the co-node bonding.

The above-described embodiments are merely preferred embodiments of the present invention, and not intended to limit the scope of the invention, so that equivalent changes or modifications in the structure, features and principles described in the present invention should be included in the claims of the present invention.