CN111523217A - Method for predicting shock resistance and optimizing structure of laminated glass - Google Patents
Method for predicting shock resistance and optimizing structure of laminated glass Download PDFInfo
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Abstract
The invention discloses a method for predicting shock resistance and optimizing a structure of laminated glass, which comprises the following steps: obtaining structural parameters, material performance parameters and external impact load parameters of glass and a sandwich film; the obtained parameters are used as the input of a pre-constructed impact resistance prediction model to obtain the output of the impact resistance prediction model, namely the impact resistance result of the laminated glass; dispersing the laminated glass entity model into a series of spatial material points based on the near field dynamics theory to generate the spatial coordinates of the material points; constructing an constitutive relation considering the glass brittleness characteristic and the PVB viscosity characteristic in the laminated glass based on the space coordinate; determining the contact relationship between the impact object and the laminated glass and the contact relationship between the glass and the PVB film; determining the boundary condition of the laminated glass entity model, predicting and calculating to obtain the impact resistance result of the laminated glass. The method effectively predicts and analyzes the mechanical behavior and the damage problem of the laminated glass under the impact damage.
Description
Technical Field
The invention relates to a method for predicting the shock resistance and optimizing the structure of laminated glass, in particular to a method for predicting and analyzing the whole process from crack initiation to expansion to damage of the laminated glass under dynamic impact based on a state near-field dynamics method, belonging to the technical field of composite material engineering and the field of high-strength explosion-proof laminated glass material structure engineering.
Background
The laminated glass as a composite material with wide application not only has the capabilities of wind resistance, rain resistance, heat resistance and sound resistance, but also plays an important role in the fields of infrastructure and military. The PVB film in the laminated glass has the viscosity characteristic, so that when the laminated glass is damaged by impact, glass fragments can be effectively adsorbed, and the damage caused by the splashing of the glass fragments is reduced, so that the laminated glass is more and more widely applied to engineering application aspects such as automobiles, buildings and the like. With the continuous improvement of application requirements, the verification of the safety and reliability of the electronic device through a numerical simulation method also becomes an important means and research focus of many technicians.
Near field dynamics (PD for short) is used as a novel multi-scale mechanical method based on a non-local action idea, mechanical behaviors of substances are described based on a space integral equation, fracture generation can be described spontaneously, an additional fracture criterion is not needed, singularity of the traditional continuous medium mechanics in solving a discontinuous problem is avoided, and therefore the method has unique advantages for the discontinuous problem.
Since the near field dynamics theory has been proposed, there are two main types of methods that have been developed and perfected over the years: Bond-Based Peridynamics and State-Based near-field dynamics. The dynamic near-field dynamics method breaks through the limitation of the initial key-type near-field dynamics method in describing the poisson ratio and the plastic behavior of the material, and is attracted and favored by more and more researchers in recent years.
For the problems of discontinuity and large deformation of dynamic impact damage of laminated glass, the traditional continuous medium mechanical method is based on partial differential equation solution, and needs to prefabricate crack paths and expansion criteria, so that the problems of discontinuity singularity, grid dependence and the like are faced. Therefore, a new method for predicting the impact resistance of the laminated glass and optimizing the structure is needed to be designed to solve the technical problems that discontinuity singularity and grid dependency exist in the impact resistance prediction of the laminated glass in the prior art, and the prediction is inaccurate due to the fact that the impact resistance prediction of the laminated glass deviates from the actual experimental result.
Disclosure of Invention
The invention aims to overcome the defects of deviation and inaccurate prediction of the shock resistance of laminated glass caused by the dynamic discontinuous mechanics problem treated by the traditional continuous medium mechanics method in the prior art, and provides a method for predicting the shock resistance of the laminated glass and optimizing the structure, which has the following technical scheme:
the method for predicting the impact resistance of the laminated glass comprises the following steps:
obtaining structural parameters, material performance parameters and external impact load parameters of glass and a sandwich film;
the obtained parameters are used as the input of a pre-constructed impact resistance prediction model to obtain the output of the impact resistance prediction model, namely the impact resistance result of the laminated glass;
the method for predicting the impact resistance by adopting the pre-constructed impact resistance prediction model comprises the following steps:
constructing a physical model of the laminated glass based on the structural parameters and material performance parameters of the glass and the laminated film, and constructing a physical model of the laminated glass under the influence of impact force based on the external impact load parameters;
dispersing the laminated glass entity model into a series of spatial material points based on a non-local near-field dynamics theory to generate spatial coordinates of the material points;
constructing an constitutive relation considering the glass brittleness characteristic and the PVB viscosity characteristic in the laminated glass based on the space coordinate;
determining the contact relationship between the impact object and the laminated glass and the contact relationship between the glass and the PVB film;
and determining the boundary conditions of the laminated glass entity model by utilizing the constitutive relation, the contact relation between the impact object and the laminated glass and the contact relation between the glass and the PVB film according to the space coordinates, and performing prediction calculation to obtain the impact failure form, the crack propagation path and the maximum impact force limit value of the laminated glass, namely the impact resistance result of the laminated glass.
Further, the discretization of the solid model of the laminated glass is as follows:
the material is uniformly dispersed in a spatial domain to be substance points with physical information, and the movement equation is as follows when the distance of the object taking points is | delta x |:
where ρ is the material density, b is the applied external force, x and x' are both material points, ü (x, t) is the acceleration of material point x at time t, Vx′Is the volume of the material point x';T[x,t]is a force state vector, HxThe near field range of a material point x is shown, and b (x, t) represents the external force load applied to the material point;
for the problem of impact damage, the numerical integration adopts a Verlet-Velocity differential format
Wherein u represents a displacement vector;
representing a velocity vector, ü representing an acceleration vector, n representing the number of time steps, and at being a unit time step.
Further, glass and PVB film have the following constitutive relation:
the glass adopts a dynamic elastic brittleness near field dynamic model, and the relation between the force state and the deformation state of the characterization glass is as follows:
wherein the content of the first and second substances,tis a force state scalar; t is tiAnd tdRespectively a sphere force state scalar quantity and an offset force state scalar quantity; k θ is the near field pressure, k is the bulk modulus, θ is the expansion scalar; m is a weighted volume;ωis an influence function;xindicating the length of the bond before deformation for the scalar state in the reference configuration;e dα is a material constant;
the PVB film adopts a state type viscoelasticity near field dynamics model, and the relation between the force state and the deformation state for representing the PVB film is as follows:
wherein the content of the first and second substances,tis a force state scalar; t is tiAnd tdRespectively a sphere force state scalar quantity and an offset force state scalar quantity; k θ is the near field pressure, k is the bulk modulus, θ is the expansion scalar; m is a weighted volume;ωis an influence function;xindicating the length of the bond before deformation;e dis in an offset deformation state;e db(i)in the back-offset deformed state α∞And αiAre all material constants.
Further, the bond rupture criteria in the glass constitutive relation are as follows:
bond elongation of a material point bond in near field dynamics of
Wherein s is bond elongation, η is relative displacement between substance points x and x ', ξ is relative position between substance points x and x ' in reference configuration, η + ξ is relative position between substance points x and x ' in current configuration | YX<x′-x>||、||Y<x′-x>The | | is the length of the key before and after deformation respectively,
the critical values for tensile and compressive damage are:
wherein s < 0 represents a compressed state, and s ≧ 0 represents a stretched state;
respectively a compression bond breaking critical value and a tensile bond breaking critical value; sigmac、σtCompressive strength and resistance to uniaxial stress of glassTensile strength; e is the modulus of elasticity of the glass.
Further, the contact relationship between the impact object and the laminated glass entity is as follows:
introducing a contact model, wherein the contact model comprises a search algorithm and a short-range repulsive force model, the search algorithm establishes a near material point list at the moment by scanning material points in the current configuration, short-range repulsive force is applied between the near material points meeting a threshold value, interaction between the material points of different units is established, and the expression of the repulsive force is as follows:
in the formula, rsIs a positive constant; y isp、yiAre respectively a material point xpAnd the material point xiThe deformed position; and is provided with
Where k is the bulk modulus and is the near field range.
Further, the glass is in contact with the PVB film as follows:
the method is characterized in that the adhesion force between the glass layer and the PVB film is described by adopting a method based on a penalty function, the relative displacement between the glass and the PVB film is restrained, and the penalty function force between the glass and the PVB film is fg＝-k′(ug-up) K' is a penalty function factor, ugAnd upThe material point displacement of the glass and PVB film respectively.
The method for optimizing the shock resistance structure of the laminated glass comprises the following steps:
predicting the impact failure form, the crack propagation path and the maximum impact force limit value of the laminated glass according to the impact resistance prediction method of the laminated glass;
changing input parameters of a prediction model, and respectively inputting the changed structural parameters and material performance parameters of the glass and the laminated film and external impact load parameters into the prediction model to obtain the impact failure forms, crack propagation paths and maximum impact force limit values of a plurality of groups of laminated glass under different input parameters;
and selecting the maximum value in the multiple groups of maximum impact force limit values, and taking the input parameter corresponding to the maximum value as the design reference of structure optimization.
Further, the input parameters are the material property of the glass, the material property of the film, the geometry of the glass, the geometry of the film, the number of layers of the glass, the thickness of the glass, the number of layers of the film, the thickness of the film or the connection form of the glass and the support.
Compared with the prior art, the invention has the following beneficial effects:
(1) the short-range force contact algorithm and the penalty function method can well represent the contact characteristic between the impact object and the glass and the adhesive force effect between the glass and the PVB film, and the calculation precision is high; (2) the method can well describe the viscosity characteristics of the PVB film based on the state type viscoelasticity near field dynamics model; (3) the invention firstly proposes that the near field dynamics method is used for the laminated glass composite material, can effectively realize the simulation of the whole process from crack initiation, crack propagation to complete crack of the laminated glass under dynamic impact, obtains the damage rule of the laminated glass under the dynamic impact condition, and greatly expands the application of the near field dynamics method in the practical engineering aspect. Moreover, the modeling method disclosed by the invention is wide in applicability, can be suitable for predicting and analyzing various problems (such as mechanical behavior and damage problems) of the laminated glass composite material under the impact damage resistant condition, and the penalty function method adopted in the method can better describe the viscous effect between glass and a PVB film.
Drawings
FIG. 1 is a schematic flow chart of a prediction process of a prediction model of a method for predicting the impact resistance of laminated glass according to the present invention;
FIG. 2 is a schematic view of a laminated glass dummies in the examples, (a) a perspective view of a laminated glass dummies; (b) model size, boundary condition schematic;
FIG. 3 is a schematic view of the propagation of shock waves generated by contact in a laminated glass sheet;
FIG. 4 is a diagram showing the comparison result of the final failure mode of the laminated glass under impact load, wherein (a) - (d) are the results of near field dynamics in different time periods (the values in the diagram are damage values); (e) is a finite element result; (f) is a test result;
FIG. 5 is a graph showing the comparison of impact force versus time curves;
FIG. 6 is a flow chart of a method for optimizing the impact resistance structure of laminated glass according to the present invention.
Detailed Description
The invention is further described below with reference to the accompanying drawings. The following examples are only for illustrating the technical solutions of the present invention more clearly, and the protection scope of the present invention is not limited thereby.
Paraphrasing related terms:
PVB, Polyvinyl Butyral.
Example 1:
as shown in fig. 1, the method for predicting the impact resistance of the laminated glass of the present invention comprises the following steps:
obtaining structural parameters, material performance parameters and external impact load parameters of glass and a sandwich film;
the obtained parameters are used as the input of a pre-constructed impact resistance prediction model, and the output of the impact resistance prediction model is the impact resistance result of the laminated glass;
the method for predicting the impact resistance by adopting the pre-constructed impact resistance prediction model comprises the following steps:
and constructing a physical model of the laminated glass based on the structural parameters and material performance parameters of the glass and the laminated film, and constructing the physical model of the laminated glass under the influence of impact force based on the external impact load parameters.
Establishing a sandwich glass entity model;
as shown in fig. 2, a laminated glass physical model is established for a glass, a Polyvinyl butyl (PVB) film interlayer and an impact, the model size is 100mm × 40mm, and the thickness is 2mm, 0.76mm and 3mm respectively; in this embodiment, taking a drop test of a laminated glass plate with a size of 100mm × 40mm as an example, the sizes of the upper layer glass, the lower layer glass and the PVB film are 2mm, 0.76mm and 3mm, respectively, and the near field dynamics modeling and analysis are performed by using the method of the present invention. Wherein, the impact object is a steel ball, and two sides of the sandwich glass plate are provided with rubber supporting bodies.
Determining material areas of each part of the laminated glass and endowing the laminated glass with corresponding material properties, wherein the Young modulus of the glass is 74.0GPa, and the density is 2500kg/m3The Poisson's ratio is 0.2; the Young modulus of the PVB film is 15.8MPa, and the density is 1000kg/m3The Poisson's ratio is 0.49; the impact object is a rigid body, the Young modulus is 210.0GPa, and the Poisson ratio is 0.27; the Young modulus of the rubber support is 42.0MPa, and the density is 1200kg/m3The Poisson's ratio was 0.49.
The model is divided into a unit grid, the grid size is | Δ x | ═ 0.3mm, and a total of 1,195,259 object points are in the model.
Based on the theory of non-local near-field dynamics, the physical model of the laminated glass is discretized into a series of spatial material points according to the near-field dynamics idea, and the spatial coordinates of the material points are generated in a discretization mode as follows:
in the near-field dynamics theory, the material is uniformly dispersed in a spatial domain and is dispersed into object points with physical information, and the motion equation is dispersed when the distance between the object taking points is | Δ x |:
where ρ is the material density, b is the applied external physical force, x and x' are both material points, ü (x, t) is the acceleration of the material point x at time t, Vx′Is the volume of the material point x';T[x,t]is a force state vector, HxThe near field range of a material point x is shown, and b (x, t) represents the external force load applied to the material point;
for the impact damage problem, the numerical integration can adopt a Verlet-Velocity differential format:
wherein u represents a displacement vector;
representing a velocity vector, ü representing an acceleration vector, n representing the number of time steps, and at being a unit time step.
Constructing an constitutive relation considering the glass brittleness characteristic and the PVB viscosity characteristic in the laminated glass based on the space coordinate; the glass and PVB film have the following constitutive relation:
the glass adopts a dynamic elastic brittleness near field dynamic model, and the relation between the force state and the deformation state of the characterization glass is
Wherein the content of the first and second substances,tis a force state scalar; t is tiAnd tdRespectively a sphere force state scalar quantity and an offset force state scalar quantity; k θ is the near field pressure, k is the bulk modulus, θ is the expansion scalar; m is a weighted volume;ωis an influence function;xindicating the length of the bond before deformation for the scalar state in the reference configuration;e dα is a material constant;
the PVB film adopts a state type viscoelasticity near field dynamics model, and the relation between the force state and the deformation state for representing the PVB film is as follows:
wherein the content of the first and second substances,tis a force state scalar; t is tiAnd tdRespectively a sphere force state scalar quantity and an offset force state scalar quantity; k θ is the near field pressure, k is the bulk modulus, θ is the expansion scalar; m is a weighted volume;ωis an influence function;xindicating the length of the bond before deformation;e dis in an offset deformation state;e db(i)in the back-offset deformed state α∞And αiAre all material constants.
Further, the bond rupture criteria in the glass constitutive relation are as follows:
bond elongation of a material point bond in near field dynamics of
Wherein s is bond elongation; eta is the relative displacement between the material points x and x'; xi is the relative position between the substance points x and x 'in the reference configuration, and eta + xi is the relative position between the substance points x and x' in the current configuration;
||X<x′-x>||、||Y<x′-x>the | | is the length of the key before and after deformation respectively,
when s is greater than a threshold value s0When the force is applied, the bond is broken and no longer bears the force. In the dynamic damage process of the glass, under the conditions of high strain rate and large deformation, the tensile damage and the compressive damage play a crucial role, so the critical values of the tensile damage and the compressive damage are as follows:
wherein s < 0 represents a compressed state, and s ≧ 0 represents a stretched state; sigmac,σtThe uniaxial compressive strength and the tensile strength of the glass are respectively 800MPa and 60MPa,
respectively a compression bond breaking critical value and a tensile bond breaking critical value; e is the modulus of elasticity of the glass.
Determining the dynamic contact relationship between the impact object and the laminated glass and the contact relationship between the glass and the PVB film;
and determining the boundary condition of the laminated glass entity model according to the space coordinate, the constitutive relation, the dynamic contact relation between the impact object and the laminated glass and the contact relation between the glass and the PVB film, and performing prediction calculation to obtain the impact damage form, the crack propagation path and the maximum impact force limit value of the laminated glass, namely the impact resistance result of the laminated glass.
In particular, in this embodiment, the contact properties, including dynamic contact properties between the impactor and the laminated glass entity and contact properties between the glass and the PVB film, take into account the adhesive forces due to the adhesive characteristics of the PVB film. The path of the shock wave generated by the contact propagating in the laminated glass sheet is shown in fig. 3. The specific contact model is as follows: the dynamic contact relationship between the impact object and the laminated glass entity is as follows:
based on the non-local state near-field dynamics theory, in the state near-field dynamics theoretical model, the material point only interacts with other material points in the near-field range of the same unit, and different units are not connected into a material point pair. In order to prevent the mutual permeation of the material points among different objects, a contact model is introduced, the contact model comprises a search algorithm and a short-range repulsive force model, the search algorithm establishes a list of adjacent material points at the moment by scanning the material points in the current configuration, then the short-range repulsive force is applied among the adjacent material points meeting a threshold value, the interaction among the material points of different units is established, and the expression of the repulsive force is as follows:
in the formula, rsIs a positive constant; y isp、yiAre respectively a material point xpAnd the material point xiThe deformed position; and is provided with
Where k is the bulk modulus and is the near field range.
The glass is in contact with the PVB film as follows:
the method comprises the steps of describing the adhesive force between the glass layer and the PVB film by introducing a penalty function, describing the adhesive force between the glass layer and the PVB film by adopting a method based on the penalty function, restraining the relative displacement of the glass and the PVB film, and determining the penalty function force between the glass and the PVB film as fg＝-k′(ug-up) Where k' is a penalty function factor, ugAnd upThe material point displacement of the glass and PVB film respectively. k ═ EPVB/(1-2μPVB)，EPVBAnd muPVBYoung's modulus of PVB film is 15.8MPa andthe poisson ratio is 0.49.
The adhesive force between the upper glass layer and the lower glass layer in the laminated glass and the PVB film has an important influence on the mechanical property of the laminated glass, and when the adhesive force is larger, the adhesion between the glass layer and the PVB film is tighter. Conversely, if the adhesion is too low, glass fragments can splash from the PVB film during impact. Thus, glass is contacted with the PVB film by introducing a method based on a penalty function to describe the adhesion between the glass layer and the PVB film, which constrains the relative displacement of the glass and PVB film.
Setting the initial boundary conditions of the model, namely completely fixing the rubber support and applying the speed load boundary conditions through the impact objects. The impactor weight in this example was 35.5g and the impactor velocity was 6.78 m/s. In particular, the contact properties of the laminated glass solid model include dynamic contact between the impact object and the laminated glass solid and contact between the glass and the PVB film, taking into account the adhesive forces due to the adhesive characteristics of the PVB film.
And submitting the calculation. The result analysis of the dynamic calculation can be used for analyzing the glass failure form and the impact material resources-time curve, as shown in fig. 4 and 5, which are schematic diagrams comparing the method result with the test result and the finite element method result. Fig. 4 shows the crack propagation pattern after the laminated glass is damaged by impact, mainly including longitudinal crack propagation and radial crack propagation, and the specific process changes along with time. Fig. 5 shows the time course of the impact force during the impact process and the impact force limit value. Through the simulation results, the damage form and the impact damage resistance limit value of the laminated glass after being impacted can be clearly known, and the laminated glass with different requirements is designed and optimized according to the results.
As shown in fig. 6, the method for structurally optimizing the impact resistance of laminated glass comprises the following steps:
predicting the impact failure form, the crack propagation path and the maximum impact force limit value of the laminated glass according to the impact resistance prediction method of the laminated glass;
changing input parameters of a prediction model, and respectively inputting the changed structural parameters and material performance parameters of the glass and the laminated film and external impact load parameters into the prediction model to obtain the impact failure forms, crack propagation paths and maximum impact force limit values of a plurality of groups of laminated glass under different input parameters;
and selecting the maximum value in the multiple groups of maximum impact force limit values, and taking the input parameter corresponding to the maximum value as the design reference of structure optimization.
Specifically, in this embodiment, the input parameter is a material property of glass, a material property of a film, a geometry of glass, a geometry of a film, a number of glass layers, a thickness of glass, a number of film layers, a thickness of a film, or a connection form of glass and a support.
The method is a simple example for verifying the accuracy of the method, and during specific implementation, simulation examples of different arrangement forms, different structures, different materials, different collocation, different thicknesses and connection forms of the glass and the support can be designed according to actual conditions to predict and correspondingly optimize. Therefore, the method has high result precision, and can effectively predict and analyze the mechanical behavior and damage problems of the laminated glass under dynamic impact. The result of the impact resistance prediction of the laminated glass is used for structural optimization design in the laminated glass design, so that the experimental test cost can be reduced.
The method can effectively predict and analyze the mechanical behavior and the damage problem of the laminated glass under the impact damage, realize the simulation of the whole process from crack initiation to expansion to damage, and obtain the damage rule of the laminated glass under the dynamic impact condition. The method has wide applicability and can be suitable for predicting the shock resistance of the laminated glass composite material and analyzing the structure.
The above description is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, several modifications and variations can be made without departing from the technical principle of the present invention, and these modifications and variations should also be regarded as the protection scope of the present invention.
Claims (8)
1. The method for predicting the impact resistance of the laminated glass is characterized by comprising the following steps of:
obtaining structural parameters, material performance parameters and external impact load parameters of glass and a sandwich film;
the obtained parameters are used as the input of a pre-constructed impact resistance prediction model to obtain the output of the impact resistance prediction model, namely the impact resistance result of the laminated glass;
the method for predicting the impact resistance by adopting the pre-constructed impact resistance prediction model comprises the following steps:
constructing a physical model of the laminated glass based on the structural parameters and material performance parameters of the glass and the laminated film, and constructing a physical model of the laminated glass under the influence of impact force based on the external impact load parameters;
discretizing the laminated glass physical model into a series of spatial material points based on a non-local near-field dynamics theory, and generating spatial coordinates of the material points;
constructing an constitutive relation considering the glass brittleness characteristic and the PVB viscosity characteristic in the laminated glass based on the space coordinate;
determining the contact relationship between the impact object and the laminated glass and the contact relationship between the glass and the PVB film;
and determining the boundary condition of the laminated glass entity model according to the space coordinate, the constitutive relation, the contact relation between the impact object and the laminated glass and the contact relation between the glass and the PVB film, and performing prediction calculation to obtain the impact failure form, the crack propagation path and the maximum impact force limit value of the laminated glass, namely the impact resistance result of the laminated glass.
2. The method for predicting the impact resistance of laminated glass according to claim 1, wherein the physical model of the laminated glass is discretized by:
the material is uniformly dispersed in a spatial domain to be substance points with physical information, and the movement equation is as follows when the distance of the object taking points is | delta x |:
wherein rho is the material density; b is the applied external physical force; x and x' are both material points;
is the acceleration of the material point x at time t; vx′Is the volume of the material point x';T[x,t]is a force state vector, HxThe near field range of a material point x is shown, and b (x, t) represents the external force load applied to the material point;
for the impact damage problem, the numerical integration adopts a Verlet-Velocity differential format:
wherein u represents a displacement vector;
representing a velocity vector;
represents an acceleration vector; n represents the number of time steps; Δ t is a unit time step.
3. The method for predicting the impact resistance of laminated glass according to claim 1, wherein the glass and the PVB film have the following constitutive relation:
the glass adopts a dynamic elastic brittleness near field dynamic model, and the relation between the force state and the deformation state of the characterization glass is as follows:
wherein the content of the first and second substances,tis a force state scalar; t is tiAnd tdRespectively a sphere force state scalar quantity and an offset force state scalar quantity; k θ is the near field pressure, k is the bulk modulus, θ is the expansion scalar; m is a weighted volume;ωis an influence function;xfor purposes of reference to the scalar status in the configuration,indicating the length of the bond before deformation;e dα is a material constant;
the PVB film adopts a state type viscoelasticity near field dynamics model, and the relation between the force state and the deformation state for representing the PVB film is as follows:
wherein the content of the first and second substances,tis a force state scalar; t is tiAnd tdRespectively a sphere force state scalar quantity and an offset force state scalar quantity; k θ is the near field pressure, k is the bulk modulus, θ is the expansion scalar; m is a weighted volume;ωis an influence function;xindicating the length of the bond before deformation;e dis in an offset deformation state;e db(i)in the back-offset deformed state α∞And αiAre all material constants.
4. The method for predicting the impact resistance of a laminated glass according to claim 1, wherein the bond breaking criterion in the glass constitutive relation is as follows:
the bond elongation of the material point bond in near field dynamics is:
wherein s is bond elongation, η is relative displacement between substance points x and x ', ξ is relative position between substance points x and x ' in reference configuration, η + ξ is relative position between substance points x and x ' in current configuration | YX<x′-x>||、||Y<x′-x>The | | is the length of the key before and after deformation respectively,
the critical values of the tensile damage and the compressive damage are as follows:
wherein s < 0 represents a compressed state and s.gtoreq.0 represents a stretched state；
Respectively a compression bond breaking critical value and a tensile bond breaking critical value; sigmac、σtThe uniaxial compressive strength and tensile strength of the glass are obtained; e is the modulus of elasticity of the glass.
5. The method for predicting the impact resistance of the laminated glass according to claim 1, wherein the contact relationship between the impact object and the laminated glass entity is as follows:
introducing a contact model, wherein the contact model comprises a search algorithm and a short-range repulsive force model, the search algorithm establishes a neighboring substance point list at the moment by scanning substance points in the current configuration, and applies short-range repulsive force between the neighboring substance points meeting a threshold value to establish interaction between different unit substance points, and the expression of the repulsive force is as follows:
in the formula, rsIs a positive constant; y isp、yiAre respectively a material point xpAnd the material point xiThe deformed position; and is provided with
Where k is the bulk modulus and is the near field range.
6. The method for predicting the impact resistance of laminated glass according to claim 1, wherein the glass is in contact with the PVB film in the following relationship:
the method is characterized in that the adhesion force between the glass layer and the PVB film is described by adopting a method based on a penalty function, the relative displacement between the glass and the PVB film is restrained, and the penalty function force between the glass and the PVB film is fg＝-k′(ug-up) K' is a penalty function factor, ugAnd upThe material point displacement of the glass and PVB film respectively.
7. The method for optimizing the impact resistance structure of the laminated glass is characterized by comprising the following steps of:
predicting the impact failure form, crack propagation path and maximum impact force limit value of the laminated glass according to the impact resistance prediction method of the laminated glass according to any one of claims 1 to 6;
changing input parameters of the prediction model, and respectively inputting the changed structural parameters and material performance parameters of the glass and the laminated film and external impact load parameters into the prediction model to obtain the impact failure forms, crack propagation paths and maximum impact force limit values of a plurality of groups of laminated glass under different input parameters;
and selecting the maximum value in the multiple groups of maximum impact force limit values, wherein the input parameter corresponding to the maximum value is used as the design reference of structure optimization.
8. The impact-resistance structural optimization method of laminated glass according to claim 7, wherein the input parameters are glass material properties, film material properties, glass geometry, film geometry, glass layer number, glass thickness, film layer number, film thickness or glass-to-support connection form.
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