1. A method of determining a stress state of a material on a curved surface structure, the method comprising:

acquiring image parameters of a curved surface structure;

determining a center track of the geodesic line and coordinates of each path characteristic point in the center track of the geodesic line according to the image parameters, wherein the center track of the geodesic line comprises a plurality of center track sections which are sequentially connected, and adjacent center track sections have the same path characteristic point P_n+1；

Selecting corresponding middle characteristic points Q on each central track section on the geodesic line central track_n；

Respectively generating a first folding line path of the central track section according to each intermediate characteristic point, and determining a first folding line starting point A of the first folding line path_nAnd a first folding end point B_nThe coordinates of (a);

according to each of the intermediate characteristic points Q_nOf each of the first folding line starting points A_nCoordinate and first fold end point B_nThe first allowable strain of the curved surface structure is determined, and the first allowable strain is the allowable strain of the point with the maximum bending degree in the geodesic center track.

2. The method for determining the stress state of a material on a curved surface structure according to claim 1, wherein the determining the geodesic center trajectory and the coordinates of each path feature point in the geodesic center trajectory according to the image parameters comprises:

splitting the curved surface structure into a plurality of triangular patches which are spliced with each other according to the image parameters;

selecting a triangular patch with any edge as an initial triangular patch according to a preset requirement in the curved surface structure;

selecting a laying starting point on the starting triangular surface;

determining a current central track section from the initial triangular surface patch to the adjacent triangular surface patch and a current path characteristic point according to the laying initial point and the geodesic algorithm, wherein the current path characteristic point is an end point of the current central track section;

and with the characteristic point of the current path as a laying starting point, repeatedly executing: and determining a current central track section from the initial triangular surface patch to the adjacent triangular surface patch and a current path characteristic point according to the laying initial point and the geodesic algorithm, wherein the current path characteristic point is the terminal point of the current central track section until the terminal point of the current central track section is on the boundary of the curved surface structure.

3. The method of claim 1, wherein the intermediate characteristic point Q is a stress state of the material on the curved surface structure_nThe distance from the starting point of the central track section is a preset multiple of the distance from the starting point of the central track section to the end point of the central track section.

4. The method of claim 1, wherein the selecting of the middle feature point Q for each segment of the geodesic center trajectory is performed by selecting the middle feature point Q corresponding to the segment of the center trajectory_nAnd then further comprising:

at adjacent to the intermediate characteristic point Q_nMiddle auxiliary point P 'is selected'_n+1，

According to each of said intermediate auxiliary points P'_n+1Respectively generating second fold line paths perpendicular to the middle auxiliary connecting lines, and determining second fold line starting points A 'of the second fold line paths'_nAnd a second fold line termination point B'_nWherein the middle auxiliary connecting line is a middle characteristic point Q_nAnd intermediate characteristic point Q_n+1The connecting line of (1);

according to each saidIntermediate auxiliary point P'_n+1The coordinates of the starting point of each second folding line and the coordinates of the end point of each second folding line determine a second allowable strain of the curved surface structure, and the second allowable strain is an allowable strain with the maximum bending degree on the central track section.

5. The method of determining the stress state of a material on a curved structure according to claim 4, further comprising:

comparing the magnitude of the first allowable strain and the second allowable strain;

taking the allowable strain with the larger values of the first allowable strain and the second allowable strain as the current allowable strain;

determining a material of the curved surface structure based on the currently allowable strain.

6. The method of claim 5, wherein said determining the material stress state on the curved structure based on the current allowable strain comprises:

comparing the current allowable strain to individual allowable strains in a material database;

and taking the material corresponding to the allowable strain which is greater than the current allowable strain in the material database and the difference value between the current allowable strain and the allowable strain in the material database is within a preset threshold value as the material of the curved surface structure.

7. The method of claim 4, wherein the lengths of the first and second fold lines are greater than a predetermined length threshold.

8. An apparatus for determining the stress state of a material on a curved surface structure, the apparatus comprising:

an image parameter acquisition module configured to perform acquiring image parameters of a curved surface structure;

a path feature point determination module configured toDetermining a central track of the geodesic line and coordinates of each path characteristic point in the central track of the geodesic line according to the image parameters, wherein the central track of the geodesic line comprises a plurality of sequentially connected central track sections, and the adjacent central track sections have the same path characteristic point P_n+1；

An intermediate characteristic point determination module configured to perform selection of a corresponding intermediate characteristic point Q on each central trajectory segment on the geodesic central trajectory_n；

A first folding path generating module configured to generate a first folding path corresponding to the central track segment according to each intermediate feature point, and determine a first folding starting point a of the first folding path_nAnd a first folding end point B_nThe coordinates of (a);

a first allowable strain determination module configured to execute a determination based on each of the intermediate characteristic points Q_nOf each of the first folding line starting points A_nCoordinate and first fold end point B_nThe first allowable strain of the curved surface structure is determined, and the first allowable strain is the allowable strain of the point with the maximum bending degree in the geodesic center track.

9. An apparatus for determining a stress state of a material on a curved structure, the apparatus comprising a processor and a memory, the memory having stored therein at least one instruction or at least one program, the at least one instruction or at least one program being loaded and executed by the processor to implement the method of determining a stress state of a material on a curved structure according to any one of claims 1-7.

10. A computer-readable storage medium, wherein at least one instruction or at least one program is stored, the at least one instruction or the at least one program being loaded and executed by a processor to implement the method for determining a stress state of a material on a curved surface structure according to any one of claims 1-7.

Background

The trajectory planning technology of the tail end of the actuator is one of key technologies of CAD/CAM software technology, is the basis for realizing digital forming of parts, and has important decisive roles in designing and forming parts in the technologies of mechanical processing of metal materials, automatic wire laying of composite materials and 3D printing, for example.

In the prior art, in the process of determining the stress state of a material on a curved surface structure, the deformation degree and the characterization of the fiber are that the tensile strain of a prepreg narrow band on the curved surface is regarded as a reasonable deformation behavior, and the buckling (or wrinkling) of the prepreg narrow band caused by the buckling of the fiber is mainly concerned; and regarding the study of the non-geodesic center track, only the deformation of the center track is considered, the deformation degree of the material edge with a certain bandwidth is not considered, and actually even if the center track is the geodesic, the deformation of the center track geodesic is only ensured to be zero, and when the curvature of the curved surface changes, particularly on the curved surface with a complex shape, for the material with a certain width, at a certain distance w from the neutral line of the length, the material may have large deformation or even failure.

Disclosure of Invention

In order to solve the above technical problem, the present invention provides a method for determining a stress state of a material on a curved surface structure, including:

acquiring image parameters of a curved surface structure;

according to the diagramImage parameter determination of center track of geodesic line and characteristic point P of each path in center track of geodesic line_nThe geodesic line central track comprises a plurality of central track sections which are connected in sequence, and the adjacent central track sections have the same path characteristic point P_n+1；

Selecting corresponding middle characteristic points Q on each central track section on the geodesic line central track_n；

According to each of the intermediate characteristic points Q_nRespectively generating first folding line paths of the central track sections, and determining a first folding line starting point A of the first folding line paths_nAnd a first folding end point B_nThe coordinates of (a);

according to each of the intermediate characteristic points Q_nOf each of the first folding line starting points A_nCoordinate and first fold end point B_nThe first allowable strain of the curved surface structure is determined, and the first allowable strain is the allowable strain of the point with the maximum bending degree in the geodesic center track.

Further, the determining the geodesic center trajectory and the coordinates of each path feature point in the geodesic center trajectory according to the image parameters includes:

splitting the curved surface structure into a plurality of triangular patches which are spliced with each other according to the image parameters;

selecting a triangular patch with any edge as an initial triangular patch according to a preset requirement in the curved surface structure;

selecting a laying starting point on the starting triangular surface;

determining a current central track section from the initial triangular surface patch to the adjacent triangular surface patch and a current path characteristic point according to the laying initial point and the geodesic algorithm, wherein the current path characteristic point is an end point of the current central track section;

and with the characteristic point of the current path as a laying starting point, repeatedly executing: and determining a current central track section from the initial triangular surface patch to the adjacent triangular surface patch and a current path characteristic point according to the laying initial point and the geodesic algorithm, wherein the current path characteristic point is the terminal point of the current central track section until the terminal point of the current central track section is on the boundary of the curved surface structure.

Further, the intermediate characteristic point Q_nThe distance from the starting point of the central track section is a preset multiple of the distance from the starting point of the central track section to the end point of the central track section.

Further, selecting corresponding middle characteristic points Q on each central track section on the geodesic line central track_nAnd then further comprising:

at adjacent to the intermediate characteristic point Q_nAccording to a preset algorithm, calculating an intermediate auxiliary point P'_n+1；

According to each of said intermediate auxiliary points P'_n+1Respectively generating second fold line paths perpendicular to the middle auxiliary connecting lines, and determining second fold line starting points A 'of the second fold line paths'_nAnd a second fold line termination point B'_nWherein the middle auxiliary connecting line is a middle characteristic point Q_nAnd intermediate characteristic point Q_n+1The connecting line of (1);

according to each of said intermediate auxiliary points P'_n+1The coordinates of the starting point of each second folding line and the coordinates of the end point of each second folding line determine a second allowable strain of the curved surface structure, and the second allowable strain is an allowable strain with the maximum bending degree on the central track section.

Further, still include:

comparing the magnitude of the first allowable strain and the second allowable strain;

taking the allowable strain with the larger values of the first allowable strain and the second allowable strain as the current allowable strain;

determining a material of the curved surface structure based on the currently allowable strain.

Further, the determining the material of the curved surface structure based on the currently allowable strain includes:

comparing the current allowable strain to individual allowable strains in a material database;

and taking the material corresponding to the allowable strain which is greater than the current allowable strain in the material database and the difference value between the current allowable strain and the allowable strain in the material database is within a preset threshold value as the material of the curved surface structure.

Further, the lengths of the first fold line path and the second fold line path are both greater than a preset length threshold.

In another aspect, the present invention provides an apparatus for determining a stress state of a material on a curved surface structure, the apparatus comprising:

an image parameter acquisition module configured to perform acquiring image parameters of a curved surface structure;

a path feature point determination module configured to determine a geodesic center trajectory and coordinates of each path feature point in the geodesic center trajectory according to the image parameters, wherein the geodesic center trajectory includes a plurality of sequentially connected center trajectory segments, and adjacent center trajectory segments have the same path feature point P_n+1；

An intermediate characteristic point determination module configured to perform selection of a corresponding intermediate characteristic point Q on each central trajectory segment on the geodesic central trajectory_n；

A first folding path generating module configured to generate a first folding path corresponding to the central track segment according to each intermediate feature point, and determine a first folding starting point a of the first folding path_nAnd a first folding end point B_nThe coordinates of (a);

a first allowable strain determination module configured to execute a determination based on each of the intermediate characteristic points Q_nOf each of the first folding line starting points A_nCoordinate and first fold end point B_nThe first allowable strain of the curved surface structure is determined, and the first allowable strain is the allowable strain of the point with the maximum bending degree in the geodesic center track.

In another aspect, the present invention provides an apparatus for determining a stress state of a material on a curved surface structure, where the apparatus includes a processor and a memory, where the memory stores at least one instruction or at least one program, and the at least one instruction or at least one program is loaded and executed by the processor to implement the method for determining a stress state of a material on a curved surface structure as described above.

In yet another aspect, the present invention provides a computer-readable storage medium, wherein at least one instruction or at least one program is stored in the storage medium, and the at least one instruction or the at least one program is loaded and executed by a processor to implement the method for determining the stress state of a material on a curved surface structure as described above.

The method and the device for determining the stress state of the material on the curved surface structure have the following beneficial effects:

the implementation of the invention generates the center track of the geodesic line on the curved surface structure, generates the first folding line path of the center track section according to the path characteristic points on the center track of the geodesic line, and calculates the first allowable strain of the curved surface structure through the starting point and the end point of the first folding line path and the path characteristic points, thereby solving the problem that when the curvature of the curved surface changes, the material with a certain width is likely to have larger deformation at a certain distance w from the neutral line of the length, improving the rationality and feasibility of the material selection, the structural design and the strength calculation of the composite material, and further promoting the 3D printing technology of the composite material structure.

Drawings

In order to more clearly illustrate the technical solution of the present invention, the drawings used in the description of the embodiment or the prior art will be briefly described below. It is obvious that the drawings in the following description are only some embodiments of the invention, and that for a person skilled in the art, other drawings can be derived from them without inventive effort.

Fig. 1 is a schematic flowchart of a method for determining a stress state of a material on a curved surface structure according to an embodiment of the present disclosure;

FIG. 2 is a schematic flow chart illustrating a method for determining a stress state of a material on a curved structure according to an embodiment of the present disclosure;

FIG. 3 is a schematic diagram of a method for determining a material stress state of a geodesic center trajectory on a curved structure according to an embodiment of the present disclosure;

FIG. 4 is a schematic diagram of another method for determining a stress state of a material at an arbitrary center trajectory on a curved surface structure according to an embodiment of the present disclosure;

FIG. 5 is a schematic diagram of another method for determining a stress state of a material at an arbitrary center trajectory on a curved surface structure according to an embodiment of the present disclosure;

FIG. 6 is a schematic structural diagram of an apparatus for determining a stress state of a material on a curved surface structure according to an embodiment of the present invention;

fig. 7 is a schematic structural diagram of an electronic device according to an embodiment of the present invention.

The method comprises the following steps of 810-an image parameter acquisition module, 820-a path characteristic point determination module, 830-an intermediate characteristic point determination module, 840-a first folding line path generation module and 850-a first allowable strain determination module.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, are within the scope of the present invention.

It should be noted that the terms "first," "second," and the like in the description and claims of the present invention and in the drawings described above are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the invention described herein are capable of operation in sequences other than those illustrated or described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, apparatus, article, or device that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or device.

As shown in fig. 1, fig. 1 is a schematic flow chart of a method for determining a stress state of a material on a curved surface structure according to an embodiment of the present disclosure, and an embodiment of the present disclosure provides a method for determining a stress state of a material on a curved surface structure, where the method includes:

s102, obtaining image parameters of the curved surface structure.

In a specific implementation process, the curved surface structure may be a structural curved surface image of a product designed by a designer, the curved surface structure may be composed of a plurality of points, and the curved surface structure may include an image parameter, where the image parameter may be coordinates of each point or a relative position relationship of each point.

S104, determining a geodesic line central track and coordinates of each path characteristic point in the geodesic line central track according to the image parameters, wherein the geodesic line central track comprises a plurality of sequentially connected central track sections, and the adjacent central track sections have the same path characteristic point P_n+1。

It will be appreciated that the geodesic centre locus may be any centre locus in a curved surface configuration. The specific selection mode can be set according to actual needs.

In a specific implementation process, fig. 2 is a schematic flow chart of a method for determining a stress state of a material on another curved surface structure provided in an embodiment of the present application, and as shown in fig. 2, the determining coordinates of a geodesic center trajectory and feature points of each path in the geodesic center trajectory according to the image parameters includes:

s202, splitting the curved surface structure into a plurality of triangular patches which are spliced with each other according to the image parameters.

And S204, selecting a triangular patch with any edge as an initial triangular patch in the curved surface structure according to a preset requirement.

Specifically, the preset requirement may be preset.

S206, selecting a laying starting point on the starting triangular surface sheet;

s208, determining a current central track section from the initial triangular surface patch to the adjacent triangular surface patch and a current path characteristic point according to the laying initial point and the geodesic algorithm, wherein the current path characteristic point is an end point of the current central track section;

s210, repeatedly executing by taking the characteristic point of the current path as a laying starting point: and determining a current central track section from the initial triangular surface patch to the adjacent triangular surface patch and a current path characteristic point according to the laying initial point and the geodesic algorithm, wherein the current path characteristic point is the terminal point of the current central track section until the terminal point of the current central track section is on the boundary of the curved surface structure.

In a specific implementation, the surface structure may be in STL format, and the file in STL format may be a file format used to represent a triangular mesh in a computer graphics application system. The file format of the method is very simple and the method is widely applied. The file in STL format is composed of many triangular patches, and a large number of triangles are used to infinitely approximate the curved surface of the target curve. STL is the standard file type most applied by rapid prototyping systems. STL is a model that represents 3D CAD with a triangular mesh.

S106, selecting corresponding middle characteristic points Q on each central track section on the geodesic line central track_n。

In the specific implementation process, the geodesic line central track is composed of a plurality of central track sections which are sequentially connected, the geodesic line central track can be from one side edge of the curved surface structure to the other side edge of the curved surface structure, each central track section can approximately represent that the line segment is a straight line, and a corresponding middle characteristic point Q can be selected in each central track section for more accurate calculation of allowable stress_n。

It can be understood that the intermediate characteristic point Q_nNot a path feature point P_n+1. The distance between the middle characteristic point Qn and the starting point of the central track section is a preset multiple of the distance between the starting point of the central track section and the end point of the central track section.

S108, respectively generating central track segments with the intermediate characteristic pointsAnd determining a first folding starting point A of the first folding path_nAnd a first folding end point B_nThe coordinates of (a).

In a specific implementation, the first folding line path passes through the corresponding intermediate characteristic point Q on the curved surface structure_nAnd with the intermediate characteristic point Q_nA line segment perpendicular to the central track segment, a first folding starting point A_nTo the intermediate characteristic point Q_nAnd the first folding line end point B_nTo the intermediate characteristic point Q_nMay be equal and greater than a preset threshold.

S110, according to each intermediate characteristic point Q_nOf each of the first folding line starting points A_nCoordinate and first fold end point B_nThe first allowable strain of the curved surface structure is determined, and the first allowable strain is the allowable strain of the point with the maximum bending degree in the geodesic center track.

Specifically, since the bending degrees of different points in the geodesic line center trajectory may be different, when determining the first allowable strain, the allowable strains of all points in the geodesic line center trajectory may be determined and then compared, and the point with the largest bending degree in the largest geodesic line center trajectory, that is, the allowable strain with the largest allowable strain corresponding to the point, may be used as the first allowable strain.

For example, fig. 3 is a schematic diagram of a method for determining a material stress state of a geodesic center trajectory on a curved surface structure according to an embodiment of the present application, and fig. 4 is a schematic diagram of another method for determining a material stress state of an arbitrary center trajectory on a curved surface structure according to an embodiment of the present application, and as shown in fig. 3 to 4, a technique for a first allowable stress of a curved surface structure may include: (1) on a curved surface structure S, a laying starting point P is selected₀And a laying direction P₀P₁Obtaining a series of points P according to a geodesic algorithm₀、P₁、…、P₁₂、…、P_nAnd finally forming a center track P of the geodesic line₀P₁₂。

(2) For a locus point, P, on a curved surface structure S₀、P₁、…、P₁₂The coordinates of the curved surface structure can be determined according to the image parameters of the curved surface structure; thus a central track segment P within a single panel_n-1P_n(n is more than or equal to 1) can be obtained by calculation according to the coordinates of the path characteristic points.

(3) In the central track section P_n-1P_nUpper fetching point Q_n-1Let P stand_n-1Q_n-1＝λP_n-1P_nWherein lambda is a real number, and lambda is more than or equal to 0 and less than or equal to 1. By setting the value of lambda, due to P_n-1、P_nAnd λ are known, so point Q can be found_n-1The coordinates of (a).

(4) At Q_n-1Edge and center track segment P_n-1P_nIn the vertical direction, with Q_n-1Calculating Q in the first broken line path according to the geodesic algorithm as a starting point_n-1A_n-1And Q_n-1B_n-1Up to the first fold line path Q_n-1A_n-1And/or Q_n-1B_n-1Reaches w, wherein w is the geodesic distance from the neutral line of the length of the material in the width direction of the material, namely the distance from the neutral line of the length of the material at the pre-examination deformation point. W is a preset threshold.

(5) In the central track section P_nP_n+1Upper fetching point Q_nLet P stand_nQ_n＝λP_nP_n+1Wherein lambda is a real number, and lambda is more than or equal to 0 and less than or equal to 1. By setting the value of lambda, due to P_n、P_n+1And λ are known, so point Q can be found_nThe coordinates of (a).

(6) At Q_nEdge and center track segment P_nP_n+1In the vertical direction, with Q_nCalculating a first folding line path Q according to a geodesic algorithm as a starting point_nA_nAnd Q_nB_nUp to the first fold line path Q_nA_nAnd/or Q_nB_nReaches w, wherein w is the geodesic distance from the neutral line of the length of the material in the width direction of the material, namely the distance from the neutral line of the length of the material at the pre-examination deformation point.

(7) Calculating Q_nQ_n+1·A_nA_n+1、Q_nQ_n+1·B_nB_n+1If Q is_nQ_n+1·A_nA_n+1< 0 (or Q)_nQ_n+1·B_nB_n+1< 0)), indicating that severe buckling of the fibers has occurred, see B in fig. 4₁B₂(ii) a If Q_nQ_n+1·A_nA_n+1> 0 (or Q)_nQ_n+1·B_nB_n+1> 0), the next calculation is performed.

(8) Calculating the polyline Q_nQ_n+1、A_nA_n+1And B_nB_n+1If A is_nA_n+1＞Q_nQ_n+1Indicating that one side is tensile strained; if A is_nA_n+1＜Q_nQ_n+1Indicating that one side is in compressive strain; according to the definition of materials mechanics, Q_nQ_n+1Is neutral, then A_nA_n+1One side strain magnitude of (A)_nA_n+1-Q_nQ_n+1)/Q_nQ_n+1，B_nB_n+1One side strain magnitude of (B)_nB_n+1-Q_nQ_n+1)/Q_nQ_n+1。

(9) Comparison (A)_nA_n+1-Q_nQ_n+1)/Q_nQ_n+1、(B_nB_n+1-Q_nQ_n+1)/Q_nQ_n+1And allowable strain [ epsilon ]](tensile strain or compressive strain), the Q on the geodetic neutral line can be judged_n-1A strain of length w from point Qn-1 in a direction perpendicular to the neutral line.

On the basis of the foregoing embodiment, in an embodiment of this specification, the middle feature point Q corresponding to each central trajectory segment on the geodesic central trajectory is selected_nAnd then further comprising:

at adjacent to the intermediate characteristic point Q_nMiddle auxiliary point P 'is selected'_n+1，

According to each of said intermediate auxiliary points P'_n+1Respectively generating second fold line paths perpendicular to the middle auxiliary connecting lines, and determining second fold line starting points A 'of the second fold line paths'_nAnd a second fold line termination point B'_nWherein the middle auxiliary connecting line is a middle characteristic point Q_nAnd intermediate characteristic point Q_n+1The connecting line of (1);

according to each of said intermediate auxiliary points P'_n+1The coordinates of the starting point of each second folding line and the coordinates of the end point of each second folding line determine a second allowable strain of the curved surface structure, and the second allowable strain is an allowable strain with the maximum bending degree on the central track section.

Specifically, since the bending degrees of different points in different central track segments may be different, before determining the second allowable strain, the allowable strain calculation may be performed on all the central track segments, and the maximum allowable strain corresponding to the midpoint of all the central track segments is selected as the second allowable strain.

Exemplarily, fig. 4 is a schematic diagram of another method for determining a material stress state of an arbitrary center trajectory on a curved surface structure according to an embodiment of the present application; fig. 5 is a schematic diagram of another method for determining a material stress state of an arbitrary center trajectory on a curved surface structure according to an embodiment of the present application, and as shown in fig. 4 to 5, a first allowable stress technique for a curved surface structure may include: the operation principle steps of any central track on the surface of the STL patch are similar to those of the central track of the geodesic line, except that: in order to improve the calculation accuracy on any curved surface and under any central track, point Q_n-1And Q_nMiddle locus point P_nTo find a vector P_nP′_n＝(Q_n-1P_n+P_nQ_n) (ii)/2, as shown in FIG. 5; at P_nEdge and line segment P_nP′_nIn the vertical direction, with P_nCalculating the broken line P of the track line according to the geodesic algorithm as the starting point_nA′_nAnd P_nB′_nUp to the fold line P_nA′_nAnd P_nB′_nThe cumulative length of the material reaches w, wherein w is the geodesic distance from the neutral line of the length of the material along the width direction of the material, namely the distance from the neutral line of the length of the material at the pre-examination deformation point; calculating Q_nQ_n+1·A_nA_n+1、Q_nQ_n+1·B_nB_n+1If Q is_nQ_n+1·A_nA_n+1< 0 (or Q)_nQ_n+1·B_nB_n+1< 0)), indicating that severe buckling of the fibers has occurred, see B in fig. 4₁B₂If Q is_nQ_n+1·A_nA_n+1> 0 (or Q)_nQ_n+1·B_nB_n+1> 0), carrying out the next calculation; calculating the polyline Q_nP_nQ_n+1、A_nA′_n+1A_n+1And B_nB′_n+1B_n+1If A is_nA′_n+1A_n+1＞Q_nP_nQ_n+1Indicating that one side is tensile strained; if A is_nA′_n+1A_n+1＜Q_nP_nQ_n+1Indicating that one side is in compressive strain; according to the definition of materials mechanics, Q_nP_nQ_n+1Is neutral, then A_nA′_n+1A_n+1One side strain magnitude of (A)_nA′_n+1A_n+1-Q_nP_nQ_n+1)/Q_nP_nQ_n+1，B_nB′_n+1B_n+1One side strain magnitude of (B)_nB′_n+1B_n+1-Q_nP_nQ_n+1)/Q_nP_nQ_n+1(ii) a Comparison (A)_nA′_n+1A_n+1-Q_nP_nQ_n+1)/Q_nP_nQ_n+1、(B_nB′_{n+ 1}B_n+1-Q_nP_nQ_n+1)/Q_nP_nQ_n+1And allowable strain [ epsilon ]](tensile strain or compressive strain), namely P on any neutral line track can be judged_nAt a distance P in a direction perpendicular to the neutral line_nStrain with a point length w.

On the basis of the above embodiments, in an embodiment of the present specification, the method further includes:

comparing the magnitude of the first allowable strain and the second allowable strain;

taking the allowable strain with the larger values of the first allowable strain and the second allowable strain as the current allowable strain;

determining a material of the curved surface structure based on the currently allowable strain.

On the basis of the above embodiments, in one embodiment of the present specification,

the determining the material of the curved surface structure based on the current allowable strain comprises the following steps:

comparing the current allowable strain to individual allowable strains in a material database;

and taking the material corresponding to the allowable strain which is greater than the current allowable strain in the material database and the difference value between the current allowable strain and the allowable strain in the material database is within a preset threshold value as the material of the curved surface structure. .

In a specific implementation process, allowable strains corresponding to a plurality of materials are stored in the material database, the stress state of the material at any point on the determined curved surface structure can be compared with the allowable strains corresponding to the plurality of materials stored in the material database, and after the comparison, the manufacturing material of the curved surface structure is determined.

The implementation of the invention generates the center track of the geodesic line on the curved surface structure, generates the first folding line path of the center track section according to the path characteristic point on the center track of the geodesic line, and calculates the first allowable strain of the curved surface structure through the starting point and the end point of the first folding line path and the path characteristic point, thereby solving the problem that when the curvature of the curved surface changes, the material with a certain width may have larger deformation at a certain distance w from the length neutral line of the material, and improving the reasonability and feasibility of the design, the structural design and the strength calculation of the composite material.

On the other hand, fig. 6 is a schematic structural diagram of a device for determining a stress state of a material on a curved surface structure according to an embodiment of the present invention, and as shown in fig. 6, the present invention provides a device for determining a stress state of a material on a curved surface structure, including:

an image parameter obtaining module 810 configured to perform obtaining image parameters of a curved surface structure;

a path feature point determining module 820 configured to perform determining a geodesic center trajectory and coordinates of each path feature point in the geodesic center trajectory according to the image parameters, wherein the geodesic center trajectory includes a plurality of sequentially connected center trajectory segments, and adjacent center trajectory segments have the same path feature point P_n+1；

An intermediate feature point determination module 830 configured to perform selecting a corresponding intermediate feature point Q on each central trajectory segment on the geodesic central trajectory_n；

A first folding path generating module 840 configured to generate a first folding path corresponding to the central track segment according to each of the intermediate feature points, and determine a first folding starting point a of the first folding path_nAnd a first folding end point B_nThe coordinates of (a);

a first allowable strain determination module 850 configured to execute a method according to each of the intermediate feature points Q_nOf each of the first folding line starting points A_nCoordinate and first fold end point B_nThe first allowable strain of the curved surface structure is determined, and the first allowable strain is the allowable strain of the point with the maximum bending degree in the geodesic center track.

It should be noted that, when the apparatus provided in the foregoing embodiment implements the functions thereof, only the division of the functional modules is illustrated, and in practical applications, the functions may be distributed by different functional modules according to needs, that is, the internal structure of the apparatus may be divided into different functional modules to implement all or part of the functions described above. In addition, the apparatus and method embodiments provided by the above embodiments belong to the same concept, and specific implementation processes thereof are described in the method embodiments for details, which are not described herein again.

On the other hand, fig. 7 is a schematic structural diagram of an electronic device according to an embodiment of the present invention, and as shown in fig. 7, the present invention provides a device for determining a stress state of a material on a curved surface structure, where the device includes a processor and a memory, where the memory stores at least one instruction or at least one program, and the at least one instruction or at least one program is loaded and executed by the processor to implement the method for determining a stress state of a material on a curved surface structure as described above.

The above functions, if implemented in the form of software functional units and sold or used as a separate product, may be stored in a computer-readable storage medium. Based on such understanding, the technical solution of the present invention may be embodied in the form of a software product, which is stored in a storage medium and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device) to execute all or part of the steps of the method according to the embodiments of the present invention.

An embodiment of the present invention further provides a computer-readable storage medium, where at least one instruction, at least one program, a code set, or an instruction set is stored in the storage medium, and the at least one instruction, the at least one program, the code set, or the instruction set is executable by a processor of an electronic device to perform the method for determining the stress state of a material on a curved surface structure.

Optionally, in an embodiment of the present invention, the storage medium may include, but is not limited to: various media capable of storing program codes, such as a usb disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a removable hard disk, a magnetic disk, or an optical disk.

It should be noted that: the precedence order of the above embodiments of the present invention is only for description, and does not represent the merits of the embodiments. And specific embodiments thereof have been described above. Other embodiments are within the scope of the following claims. In some cases, the actions or steps recited in the claims may be performed in a different order than in the embodiments and still achieve desirable results. In addition, the processes depicted in the accompanying figures do not necessarily require the particular order shown, or sequential order, to achieve desirable results. In some embodiments, multitasking and parallel processing may also be possible or may be advantageous.

It will be understood by those skilled in the art that all or part of the processes of the methods of the embodiments described above can be implemented by hardware instructions of a computer program, which can be stored in a non-volatile computer-readable storage medium, and when executed, can include the processes of the embodiments of the methods described above. Any reference to memory, storage, database, or other medium used in the embodiments provided herein may include non-volatile and/or volatile memory, among others. Non-volatile memory can include read-only memory (ROM), Programmable ROM (PROM), Electrically Programmable ROM (EPROM), Electrically Erasable Programmable ROM (EEPROM), or flash memory. Volatile memory can include Random Access Memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in a variety of forms such as Static RAM (SRAM), Dynamic RAM (DRAM), Synchronous DRAM (SDRAM), Double Data Rate SDRAM (DDRSDRAM), Enhanced SDRAM (ESDRAM), Synchronous Link DRAM (SLDRAM), Rambus Direct RAM (RDRAM), direct bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM).

The embodiments in the present specification are described in a progressive manner, and the same and similar parts among the embodiments are referred to each other, and each embodiment focuses on the differences from the other embodiments. In particular, as for the apparatus, the electronic device and the storage medium embodiment, since they are substantially similar to the method embodiment, the description is relatively simple, and the relevant points can be referred to the partial description of the method embodiment.

It will be understood by those skilled in the art that all or part of the steps for implementing the above embodiments may be implemented by hardware, or may be implemented by a program instructing relevant hardware, where the program may be stored in a computer-readable storage medium, and the above-mentioned storage medium may be a read-only memory, a magnetic disk or an optical disk, etc.

It should be noted that, in the present specification, the embodiments are all described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments may be referred to each other. The implementation principle and the generated technical effect of the testing method provided by the embodiment of the invention are the same as those of the system embodiment, and for the sake of brief description, the corresponding contents in the system embodiment can be referred to where the method embodiment is not mentioned.

In the several embodiments provided in the present application, it should be understood that the disclosed system and method may be implemented in other ways. The apparatus embodiments described above are merely illustrative, and for example, the flowchart and block diagrams in the figures illustrate the architecture, functionality, and operation of possible implementations of apparatus, methods and computer program products according to various embodiments of the present invention. In this regard, each block in the flowchart or block diagrams may represent a module, segment, or portion of code, which comprises one or more executable instructions for implementing the specified logical function(s). It should also be noted that, in some alternative implementations, the functions noted in the block may occur out of the order noted in the figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. It will also be noted that each block of the block diagrams and/or flowchart illustration, and combinations of blocks in the block diagrams and/or flowchart illustration, can be implemented by special purpose hardware-based systems which perform the specified functions or acts, or combinations of special purpose hardware and computer instructions.

Finally, it should be noted that: the above-mentioned embodiments are only specific embodiments of the present invention, which are used for illustrating the technical solutions of the present invention and not for limiting the same, and the protection scope of the present invention is not limited thereto, although the present invention is described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: any person skilled in the art can modify or easily conceive the technical solutions described in the foregoing embodiments or equivalent substitutes for some technical features within the technical scope of the present disclosure; such modifications, changes or substitutions do not depart from the spirit and scope of the embodiments of the present invention, and they should be construed as being included therein. Therefore, the protection scope of the present invention shall be subject to the protection scope of the above claims.