CN110717297A - Method and system for establishing fabric simulation model, storage medium and electronic equipment - Google Patents
Method and system for establishing fabric simulation model, storage medium and electronic equipment Download PDFInfo
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Abstract
The invention provides a method and a system for establishing a fabric simulation model, a storage medium and electronic equipment, wherein the method comprises the following steps: obtaining a fabric curved surface at an initial moment, and dispersing the fabric curved surface into quadrilateral mesh surface patches with different sizes according to different material attributes; analyzing initial coordinates of the gravity center of each quadrilateral mesh surface patch; calculating an initial Riemann degree tensor and an initial Riemann curvature tensor according to the initial coordinates; taking the initial moment as a start, calculating internal deformation energy according to the Riemann scale tensor and the Riemann curvature tensor at the current moment in sequence, and calculating the coordinate position of the gravity center at the next moment by combining stress analysis; and establishing a fabric simulation motion model according to the coordinate position. The invention researches the fabric in the curved Riemannian manifold space, and the invention can improve the existing fabric modeling theory and method by adopting the non-European geometric theory, and makes up the defects of complex fabric modeling, slow convergence speed, poor stability, poor simulation effect and the like in the European space.
Description
Technical Field
The invention relates to the technical field of fabric simulation, in particular to a method and a system for establishing a fabric simulation model, a storage medium and electronic equipment.
Background
Current methods for studying fabric models and simulations are generally divided into three categories: geometric methods, physical methods and hybrid methods. The fabric simulation technology based on geometric modeling only focuses on the external expression form of the fabric, and is more like an advanced drawing tool, and the simulation speed is high; research on methods based on physical modeling has been dominant in recent years, and can be divided into the following according to the way of simulating fabric structures: discrete models including spring-mass models, mesh models, particle models; continuous models, including elastic deformation models, aerodynamic models, finite element models, and the like; the method based on the hybrid modeling adopts a geometric modeling method to model, considers the physical properties of the fabric in the simulation process, and considers both the simulation speed and the reality sense of the simulation, but the simulation effect is still unsatisfactory. The existing research depends on a fabric model established in a Euclidean space, namely improvements on simulation models or methods of different fabrics in the Euclidean space are made from the aspects of response speed or effect of simulation, but the problems of complex modeling, large calculation amount, difficult simulation effect and the like still exist.
Disclosure of Invention
The invention aims to provide a method and a system for establishing a fabric simulation model, a storage medium and electronic equipment, so that a fabric can be put in a curved Riemannian manifold space for research, the research result can improve the conventional fabric modeling theory and simulation method, and the defects of complexity, low convergence speed, poor stability, poor simulation effect and the like of fabric modeling in an Euclidean space are overcome.
The technical scheme provided by the invention is as follows:
the invention provides a method for establishing a fabric simulation model, which comprises the following steps:
acquiring a fabric curved surface at an initial moment in a Riemann manifold space, dispersing the fabric curved surface into a plurality of quadrilateral mesh surface patches, and equivalently using all the quadrilateral mesh surface patches as a dispersion unit to perform analysis processing;
analyzing the gravity center of each quadrilateral mesh surface patch to obtain the initial coordinate of the gravity center;
calculating an initial Riemannian degree tensor and an initial Riemannian curvature tensor of each quadrilateral grid surface patch at an initial moment according to the initial coordinates;
calculating the internal deformation energy of each quadrilateral mesh patch at the current moment sequentially according to the Riemannian scale tensor at the current moment and the Riemannian curvature tensor at the current moment by taking the initial moment as a start, and calculating the coordinate position of the gravity center of each quadrilateral mesh patch at the next moment by combining the stress analysis of the quadrilateral mesh patch at the current moment and the internal deformation energy, wherein the difference between the next moment and the current moment is a preset time step length;
and establishing a fabric simulation motion model according to the coordinate position.
Further, calculating the internal deformation energy of each quadrilateral mesh patch at the current time according to the riemann scale tensor at the current time and the riemann curvature tensor at the current time, and calculating the coordinate position of the gravity center of each quadrilateral mesh patch at the next time by combining the stress analysis of the quadrilateral mesh patch at the current time and the internal deformation energy specifically includes:
acquiring an instantaneous vector of the gravity center of any quadrilateral mesh patch at the current moment;
calculating the Riemannian degree tensor of any quadrilateral mesh patch at the current moment and the Riemannian curvature tensor of the current moment according to the instantaneous vector;
calculating the internal deformation energy of each quadrilateral mesh patch at the current time according to the initial Riemannian degree tensor, the initial Riemannian curvature tensor, the Riemannian degree tensor at the current time and the Riemannian curvature tensor at the current time;
and calculating the coordinate position of the next moment by combining the stress analysis of the quadrilateral mesh surface patch and the internal deformation energy.
Further, calculating the internal deformation energy of each quadrilateral mesh patch at the current time according to the riemann measure tensor at the current time and the riemann curvature tensor at the current time specifically includes:
defining a region of the any one quadrilateral mesh patch as Ω, Ω { (l)1，l2)∈R2Define the instantaneous vector of the center of gravity as
Calculating the stretching and shearing energy at the current moment according to the initial Riemannian degree quantity and the Riemannian degree quantity at the current moment,
wherein the content of the first and second substances,for the stretch-shear energy at the present moment, GtIs the Riemann scale number, G, of the current time0Is the initial number of the Riemann scale,
Ewpand EwtRespectively the Young modulus of the fabric in the warp and weft directions, H is the rigidity modulus,
is a matrix wsA Hilbert-Schmitt norm of the weighted measure tensor variabilities;
calculating the bending energy of the current moment according to the initial Riemann curvature tensor and the Riemann curvature tensor of the current moment,
wherein the content of the first and second substances,
as the bending energy at the present time is,Rtis the curvature tensor of the current time, R0Is the initial riemann curvature tensor,
Rfwpand RfwtBending stiffness of the fabric in the warp and weft directions respectively,
is a matrix wbA Hilbert-Schmidt norm of the weighted curvature tensor variations;
calculating the internal deformation energy from the tensile shear energy and the bending energy
Further, calculating the coordinate position of the next moment by combining the stress analysis of the quadrilateral mesh patch and the internal deformation energy specifically comprises:
calculating the elastic internal force of the quadrilateral mesh patch according to the internal deformation energy
Calculating inertial internal force
Viscous damping force
Weight of fabric
And air resistanceWherein the content of the first and second substances,
p is the density of the fabric,mu is a damping coefficient;
according to the first dynamic principle, a dynamic equation reflecting the motion of the fabric is obtained,
and calculating the coordinate position of the next moment according to the dynamic equation.
The invention also provides a system for establishing the fabric simulation model, which comprises the following steps:
the dispersion module is used for obtaining a fabric curved surface at an initial moment in a Riemannian manifold space, dispersing the fabric curved surface into a plurality of quadrilateral mesh surface patches, and equivalently using all the quadrilateral mesh surface patches as dispersion units for analysis processing;
the gravity center calculation module analyzes the gravity center of each quadrilateral mesh surface patch obtained by the dispersion module and obtains the initial coordinate of the gravity center;
the parameter calculation module is used for calculating an initial Riemannian degree tensor and an initial Riemannian curvature tensor of each quadrilateral mesh surface patch at an initial moment according to the initial coordinates obtained by the gravity center calculation module;
the coordinate calculation module is used for calculating the internal deformation energy of each quadrilateral mesh patch at the current moment by taking the initial moment as a start according to the Riemannian scale tensor at the current moment and the Riemannian curvature tensor at the current moment which are obtained by the parameter calculation module in sequence, and calculating the coordinate position of the gravity center of each quadrilateral mesh patch at the next moment by combining the stress analysis of the quadrilateral mesh patch at the current moment and the internal deformation energy, wherein the difference between the next moment and the current moment is a preset time step;
and the model establishing module is used for establishing a fabric simulation motion model according to the coordinate position obtained by the coordinate calculating module.
Further, the coordinate calculation module specifically includes:
the initial definition unit is used for acquiring the instantaneous vector of the gravity center of any quadrilateral mesh patch at the current moment;
the tensor calculation unit is used for calculating the Riemannian degree tensor of any quadrilateral mesh patch at the current moment and the Riemannian curvature tensor at the current moment according to the instantaneous vector defined by the primary definition unit;
a parameter calculation unit which calculates internal deformation energy of each quadrilateral mesh patch at the current time according to the initial Riemannian degree tensor, the initial Riemannian curvature tensor, the Riemannian degree tensor at the current time and the Riemannian curvature tensor obtained by the tensor calculation unit;
and the coordinate calculation unit is used for calculating the coordinate position of the next moment by combining the stress analysis of the quadrilateral mesh surface patch and the internal deformation energy obtained by the parameter calculation unit.
Further, the parameter calculating unit specifically includes:
defining a sub-unit, defining the region of any quadrilateral mesh patch as omega, omega { (l)1，l2)∈R2Define the instantaneous vector of the center of gravity as
A parameter calculating subunit that calculates the stretch-shear energy at the current time from the initial riemannian tensor obtained by the tensor calculating unit, the riemannian tensor at the current time, and the parameters defined by the defining subunit,
wherein the content of the first and second substances,
for the stretch-shear energy at the present moment, GtIs the Riemann scale number, G, of the current time0Is the initial number of the Riemann scale,
Ewpand EwtRespectively the Young modulus of the fabric in the warp and weft directions, H is the rigidity modulus,
is a matrix wsA Hilbert-Schmitt norm of the weighted measure tensor variabilities;
the parameter calculating subunit calculates the bending energy at the current time according to the initial Riemann curvature tensor obtained by the tensor calculating unit, the Riemann curvature tensor at the current time and the parameters defined by the defining subunit,
wherein the content of the first and second substances,
is the bending energy at the present moment, RtIs the curvature tensor of the current time, R0Is the initial riemann curvature tensor,
Rfwpand RfwtBending stiffness of the fabric in the warp and weft directions respectively,
is a matrix wbA Hilbert-Schmidt norm of the weighted curvature tensor variations;
the parameter calculation subunit calculates the internal deformation energy from the tensile shear energy and the bending energy
Further, the coordinate calculation unit specifically includes:
a stress calculating subunit for calculating the elastic internal force of the quadrilateral mesh patch according to the internal deformation energy
The stress calculation subunit calculates the inertial internal force
Viscous damping force
Weight of fabric
And air resistance
Wherein the content of the first and second substances,
p is the density of the fabric,
mu is a damping coefficient;
a stress analysis subunit for obtaining a dynamic equation reflecting the motion of the fabric according to the first dynamic principle and the force calculated by the stress calculation subunit,
and the coordinate calculation subunit calculates the coordinate position of the next moment according to the dynamic equation obtained by the stress analysis subunit.
The invention also provides a storage medium having stored thereon a computer program which, when executed by a processor, implements any of the methods described above.
The invention also provides an electronic device comprising a memory and a processor, wherein the memory stores a computer program running on the processor, and the processor implements any one of the methods described above when executing the computer program.
By the method and the system for establishing the fabric simulation model, the storage medium and the electronic equipment, the fabric is put in a curved Riemann manifold space for research, and the modeling and simulation problems of the fabric are solved by a manifold surface theory in the space. The method can make up the defects of complex fabric modeling, low convergence speed, poor stability, poor simulation effect and the like in Euclidean space, and can improve the simulation time performance while ensuring the vivid fabric simulation effect. The method not only theoretically improves the fabric modeling and simulation theory, but also has wide industrial application prospect, and the result can be directly applied to the application fields of virtual garment animation simulation, movie and television advertisement, game and entertainment and the like, and especially can generate great promotion effect on the development of the current virtual garment design, production and sale technology.
Drawings
The above features, technical features, advantages and implementations of the method, system, storage medium and electronic device for building a fabric simulation model will be further described in the following detailed description of preferred embodiments in a clearly understandable manner with reference to the accompanying drawings.
FIG. 1 is a flow diagram of one embodiment of a method of building a fabric simulation model of the present invention;
FIG. 2 is a flow diagram of another embodiment of a method of building a fabric simulation model of the present invention;
fig. 3 is a schematic structural diagram of an embodiment of the system for building a fabric simulation model according to the present invention.
Detailed Description
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following description will explain specific embodiments of the present invention with reference to the drawings of the specification. It is obvious that the drawings in the following description are only some examples of the invention, from which other drawings and embodiments can be derived by a person skilled in the art without inventive effort.
For the sake of simplicity, only the parts relevant to the present invention are schematically shown in the drawings, and they do not represent the actual structure as a product. In addition, in order to make the drawings concise and understandable, components having the same structure or function in some of the drawings are only schematically illustrated or only labeled. In this document, "one" means not only "only one" but also a case of "more than one".
In the embodiment of the present invention, as shown in fig. 1, a method for building a fabric simulation model includes:
s100, obtaining a fabric curved surface at an initial moment in a Riemannian manifold space, dispersing the fabric curved surface into a plurality of quadrilateral mesh surface patches, and performing analysis processing by equivalently using all the quadrilateral mesh surface patches as discrete units;
s200, analyzing the gravity center of each quadrilateral mesh surface patch to obtain the initial coordinate of the gravity center;
s300, calculating an initial Riemannian degree tensor and an initial Riemannian curvature tensor of each quadrilateral grid surface patch at an initial moment according to the initial coordinates;
s400, starting from an initial moment, sequentially calculating internal deformation energy of each quadrilateral mesh patch at the current moment according to the Riemannian degree tensor at the current moment and the Riemannian curvature tensor at the current moment, and calculating the coordinate position of the gravity center of each quadrilateral mesh patch at the next moment by combining the stress analysis of the quadrilateral mesh patch at the current moment and the internal deformation energy, wherein the difference between the next moment and the current moment is a preset time step length;
s500, establishing a fabric simulation motion model according to the coordinate position.
Specifically, in the present embodiment, the riemann manifold is a differential manifold having the riemann tensor, has a simple structure, has the maximum symmetry and isotropic properties, and is suitable for studying the deformed form of the flexible fabric, the structure of which is also isotropic. The elastic deformation of the curved surface of the fabric is related to shearing, bending, and the like occurring inside the fabric, and the deformation of the curved surface of the fabric is expressed by the riemann tensor and the riemann curvature tensor. The fabric dynamic simulation based on the Riemann manifold aims to research the material attribute of the fabric and the deformation rule of the curved surface of the fabric on the basis of the Riemann space manifold theory.
Firstly, initializing a series of parameters to obtain a fabric curved surface at an initial moment, and dispersing the fabric curved surface in a Riemannian manifold space into a plurality of quadrilateral mesh surface patches according to different material properties, wherein the quadrilateral mesh surface patches can be regular quadrilaterals, such as rectangles, rhombuses, parallelograms and the like, or irregular quadrilaterals, and the four sides are not equal. The quadrilateral mesh patches with the same material property have the same size, and the quadrilateral mesh patches with different material properties can be the same or similar or completely different. In order to increase the calculation speed, the fabric curved surface is usually discretized into the same quadrilateral mesh patches in the practical application process, but since the fabric curved surface itself may be irregular, the fabric curved surface is discretized into the same or similar quadrilateral mesh patches as much as possible.
Since each parameter, for example, coordinates, of the fabric curved surface at the initial time are known, the center of gravity of each quadrilateral mesh patch is analyzed, initial coordinates of the center of gravity are obtained, and an initial riemann tensor and an initial riemann curvature tensor of each quadrilateral mesh patch at the initial time are calculated according to the initial coordinates. Relative positions of the centers of gravity of the quadrilateral mesh patches are unchanged, but due to deformation of the curved surface of the fabric, coordinates of the centers of gravity of the quadrilateral mesh patches in a world coordinate system or other coordinate systems are changed, so that a fabric simulation motion model can be established by determining the coordinate positions of the centers of gravity of the quadrilateral mesh patches at different moments.
And then, starting from the initial time, sequentially calculating the internal deformation energy of each quadrilateral mesh patch at the current time according to the Riemannian degree tensor at the current time and the Riemannian curvature tensor at the current time, and calculating the coordinate position of the gravity center of each quadrilateral mesh patch at the next time by combining the stress analysis of the quadrilateral mesh patch at the current time and the internal deformation energy, wherein the difference between the next time and the current time is a preset time step length.
The method comprises the steps that the initial moment is the current moment, the coordinate position of the gravity center of each quadrilateral mesh patch at the next moment is calculated by combining stress analysis of the quadrilateral mesh patches according to the initial Riemannian degree tensor and the initial Riemannian curvature tensor, and the fabric curved surface moves according to the coordinate position of the gravity center of each quadrilateral mesh patch at the next moment to obtain a simulation model. And then the next moment is a new current moment, and the coordinate position of the gravity center of each quadrilateral mesh patch at the new next moment is calculated. And by analogy, calculating the coordinate position of the gravity center of each quadrilateral mesh patch at the new next moment at one time, and then adjusting the curved surface of the fabric to finally obtain the fabric simulated motion model.
The invention researches the fabric in a curved Riemannian manifold space, solves the modeling and simulation problems of the fabric by using a manifold surface theory in the space, ensures the simulation effect of the fabric to be vivid and can also improve the simulation time performance.
Another embodiment of the present invention is an optimized embodiment of the foregoing embodiment, and as shown in fig. 2, the main improvement of this embodiment is that, compared with the foregoing embodiment, the S400 calculates internal deformation energy of each quadrilateral mesh patch at the present time according to the riemann scale tensor at the present time and the riemann curvature tensor at the present time, and the calculating, by combining the force analysis of the quadrilateral mesh patch at the present time and the internal deformation energy, a coordinate position of a center of gravity of each quadrilateral mesh patch at the next time specifically includes:
s410, acquiring an instantaneous vector of the gravity center of any quadrilateral mesh patch at the current moment;
s420, calculating a Riemannian degree tensor of the any one quadrilateral mesh patch at the current moment and a Riemannian curvature tensor of the any one quadrilateral mesh patch at the current moment according to the instantaneous vector;
s430, calculating internal deformation energy of each quadrilateral mesh patch at the current time according to the initial Riemannian degree tensor, the initial Riemannian curvature tensor, the Riemannian degree tensor at the current time and the Riemannian curvature tensor at the current time;
and S440, calculating the coordinate position of the next moment by combining the stress analysis of the quadrilateral mesh patch and the internal deformation energy.
Specifically, in this embodiment, the curved surface of the fabric in the riemann manifold space is discretized into a plurality of quadrilateral mesh patches, and an initial riemann measure tensor and an initial riemann curvature tensor of each quadrilateral mesh patch at an initial time are calculated. Any quadrilateral mesh patch is selected to calculate the coordinate position of the gravity center of the quadrilateral mesh patch at the current moment, the calculation methods of the coordinate positions of the gravity centers of the quadrilateral mesh patches at the current moment are the same, and one of the quadrilateral mesh patches is taken as an example for description in the embodiment.
And acquiring an instantaneous vector of the gravity center of any quadrilateral mesh patch at the current moment, wherein the instantaneous vector is obtained by calculating the coordinate of the gravity center at the current moment according to the related parameters of the previous moment. And calculating the Riemannian scale tensor of the corresponding quadrilateral mesh patch at the current moment and the Riemannian curvature tensor of the current moment according to the instantaneous vector, and calculating the internal deformation energy of the quadrilateral mesh patch corresponding to the current moment by combining the initial Riemannian scale tensor, the initial Riemannian curvature tensor, the Riemannian scale tensor at the current moment and the Riemannian curvature tensor at the current moment. And then establishing a dynamic equation reflecting the motion of the fabric based on the stress analysis of the quadrilateral mesh surface patches, and solving by using the quadrilateral mesh surface patches as finite element units to obtain the instantaneous positions of the gravity centers of all the quadrilateral mesh surface patches.
Further, the step S430 of calculating the internal deformation energy of each quadrilateral mesh patch at the current time according to the initial riemann scale tensor, the initial riemann curvature tensor, the riemann scale tensor at the current time, and the riemann curvature tensor at the current time specifically includes: s431 defines an area of the any one quadrilateral mesh patch as Ω, Ω { (l)1，l2)∈R2Define the instantaneous vector of the center of gravity as
S432 calculates the stretch-shear energy at the current time from the initial riemann gauge number and the riemann gauge number at the current time,
wherein the content of the first and second substances,
for the stretch-shear energy at the present moment, GtIs the Riemann scale number, G, of the current time0Is the initial number of the Riemann scale,
Ewpand EwtRespectively the Young modulus of the fabric in the warp and weft directions, H is the rigidity modulus,
is a matrix wsA Hilbert-Schmitt norm of the weighted measure tensor variabilities; s433 calculates a bending energy at the current time from the initial riemann curvature tensor and the riemann curvature tensor at the current time,
wherein the content of the first and second substances,
is the bending energy at the present moment, RtIs the curvature tensor of the current time, R0Is the initial riemann curvature tensor,
Rfwpand RfwtBending stiffness of the fabric in the warp and weft directions respectively,
is a matrix wbA Hilbert-Schmidt norm of the weighted curvature tensor variations; s434 calculating the internal deformation energy from the tensile shear energy and the bending energy
Specifically, the region of any one quadrilateral mesh patch is defined as Ω, Ω { (l)1，l2)∈R2In which l1，l2Parameterized respectively for the warp and weft edges of a quadrilateral mesh patch, R2Representing that the quadrilateral mesh patch belongs to a two-dimensional space, and simultaneously defining the instantaneous vector of the gravity center of the quadrilateral mesh patch at the current moment as
Differential manifold MnThe higher Riemann scale tensor g is an inner product given on a tangent space at a point p on M<，>pAnd the inner product is smooth. The fabric surface is considered as a differential manifold, then the riemann gauge tensor can be computed as:
riemann curvature tensor: r ═ RijklI, j, k, l ═ 1,2 …, n, the riemann curvature tensor RijklIs a 4 th order tensor, 4 indices can all vary from 1 to n. And calculating the stretching shearing energy at the current moment according to the initial Riemannian degree tensor and the Riemannian degree tensor at the current moment, calculating the bending energy at the current moment according to the initial Riemannian curvature tensor and the Riemannian curvature tensor at the current moment, and finally obtaining the internal deformation energy at the current moment.
Further, the step S440 of calculating the coordinate position of the next moment by combining the force analysis of the quadrilateral mesh patch and the internal deformation energy specifically includes: s441, according to the internal deformation energy, the elastic internal force of the quadrilateral mesh surface patch is calculated
S442 calculating the inertial internal force
Viscous damping force
Weight of fabric
And air resistanceWherein the content of the first and second substances,
p is the density of the fabric,
mu is a damping coefficient; s443, according to the first dynamic principle, obtaining a dynamic equation reflecting the movement of the fabric,
s444 calculates a coordinate position of the next time according to the dynamic equation.
Specifically, the elastic deformation of the curved surface of the fabric is related to shearing, bending and the like generated in the fabric, and the elastic internal force of the quadrilateral mesh surface patch is calculated through the internal deformation energy
Calculating inertial internal force
Viscous damping force
Weight of fabric
And air resistance
The fabric is stressed by internal force and external force, wherein the internal force comprises inertial internal force, viscous damping force and elastic internal force, and the external force comprises gravity and air resistance. Thus, according to the first kinetic principle, a dynamic equation reflecting the motion of the fabric is obtained. Solving partial differential equations by adopting a finite element method, taking quadrilateral patches of the fabric as finite element units, and solving the partial differential equations (dynamic equations) to obtain the instantaneous positions of the gravity centers of all quadrilateral mesh patches so as to determine the coordinate positions of the gravity centers.
All or part of the flow of the method according to the embodiments of the present invention may be implemented by a computer program, which may be stored in a computer-readable storage medium and used by a processor to implement the steps of the embodiments of the method. Wherein the computer program comprises computer program code, which may be in the form of source code, object code, an executable file or some intermediate form, etc. The computer-readable medium may include: any entity or device capable of carrying the computer program code, recording medium, usb disk, removable hard disk, magnetic disk, optical disk, computer Memory, Read-only Memory (ROM), Random Access Memory (RAM), electrical carrier wave signals, telecommunications signals, software distribution medium, etc. It should be noted that the computer readable medium may contain content that is subject to appropriate increase or decrease as required by legislation and patent practice in jurisdictions, for example, in some jurisdictions, computer readable media does not include electrical carrier signals and telecommunications signals as is required by legislation and patent practice.
An embodiment of the present invention further provides an electronic device, which includes a memory and a processor, wherein the memory stores a computer program running on the processor, and the processor executes the computer program to implement all or part of the method steps in the first embodiment.
The Processor may be a Central Processing Unit (CPU), other general purpose Processor, a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), an off-the-shelf Programmable Gate Array (FPGA) or other Programmable logic device, discrete Gate or transistor logic, discrete hardware components, etc. The general purpose processor may be a microprocessor or the processor may be any conventional processor or the like which is the control center for the computer device and which connects the various parts of the overall computer device using various interfaces and lines.
The memory may be used to store the computer programs and/or modules, and the processor may implement various functions of the computer device by running or executing the computer programs and/or modules stored in the memory and invoking data stored in the memory. The memory may mainly include a storage program area and a storage data area, wherein the storage program area may store an operating system, an application program required by at least one function (such as a sound playing function, an image playing function, etc.), and the like; the storage data area may store data (such as audio data, video data, etc.) created according to the use of the cellular phone, etc. In addition, the memory may include high speed random access memory, and may also include non-volatile memory, such as a hard disk, a memory, a plug-in hard disk, a Smart Media Card (SMC), a Secure Digital (SD) Card, a Flash memory Card (Flash Card), at least one magnetic disk storage device, a Flash memory device, or other volatile solid state storage device.
It should be noted that the above embodiments can be freely combined as necessary. The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.
Claims (10)
1. The method for establishing the fabric simulation model is characterized by comprising the following steps:
acquiring a fabric curved surface at an initial moment in a Riemann manifold space, dispersing the fabric curved surface into a plurality of quadrilateral mesh surface patches, and equivalently using all the quadrilateral mesh surface patches as a dispersion unit to perform analysis processing;
analyzing the gravity center of each quadrilateral mesh surface patch to obtain the initial coordinate of the gravity center;
calculating an initial Riemannian degree tensor and an initial Riemannian curvature tensor of each quadrilateral grid surface patch at an initial moment according to the initial coordinates;
calculating the internal deformation energy of each quadrilateral mesh patch at the current moment sequentially according to the Riemannian scale tensor at the current moment and the Riemannian curvature tensor at the current moment by taking the initial moment as a start, and calculating the coordinate position of the gravity center of each quadrilateral mesh patch at the next moment by combining the stress analysis of the quadrilateral mesh patch at the current moment and the internal deformation energy, wherein the difference between the next moment and the current moment is a preset time step length;
and establishing a fabric simulation motion model according to the coordinate position.
2. The method for building a fabric simulation model according to claim 1, wherein the step of calculating the internal deformation energy of each quadrilateral mesh patch at the current time according to the riemann measure tensor at the current time and the riemann curvature tensor at the current time, and the step of calculating the coordinate position of the center of gravity of each quadrilateral mesh patch at the next time by combining the stress analysis of the quadrilateral mesh patch at the current time and the internal deformation energy specifically comprises the steps of:
acquiring an instantaneous vector of the gravity center of any quadrilateral mesh patch at the current moment;
calculating the Riemannian degree tensor of any quadrilateral mesh patch at the current moment and the Riemannian curvature tensor of the current moment according to the instantaneous vector;
calculating the internal deformation energy of each quadrilateral mesh patch at the current time according to the initial Riemannian degree tensor, the initial Riemannian curvature tensor, the Riemannian degree tensor at the current time and the Riemannian curvature tensor at the current time;
and calculating the coordinate position of the next moment by combining the stress analysis of the quadrilateral mesh surface patch and the internal deformation energy.
3. The method for building a fabric simulation model according to claim 2, wherein the calculating the internal deformation energy of each quadrilateral mesh patch at the current time according to the riemann measure tensor at the current time and the riemann curvature tensor at the current time specifically includes:
defining a region of the any one quadrilateral mesh patch as Ω, Ω { (l)1，l2)∈R2Define the instantaneous vector of the center of gravity as
Calculating the stretching and shearing energy at the current moment according to the initial Riemannian degree quantity and the Riemannian degree quantity at the current moment,
wherein the content of the first and second substances,
for the stretch-shear energy at the present moment, GtIs the Riemann scale number, G, of the current time0Is the initial number of the Riemann scale,
Ewpand EwtRespectively the Young modulus of the fabric in the warp and weft directions, H is the rigidity modulus,
is a matrix wsA Hilbert-Schmitt norm of the weighted measure tensor variabilities;
calculating the bending energy of the current moment according to the initial Riemann curvature tensor and the Riemann curvature tensor of the current moment,wherein the content of the first and second substances,is the bending energy at the present moment, RtIs the curvature tensor of the current time, R0Is the initial riemann curvature tensor,
Rfwpand RfwtBending stiffness of the fabric in the warp and weft directions respectively,is a matrix wbWeighted curvature tensor variationalThe hilbert-schmitt norm of (d);
calculating the internal deformation energy from the tensile shear energy and the bending energy
4. The method for building the fabric simulation model according to claim 3, wherein the step of calculating the coordinate position of the next moment by combining the force analysis of the quadrilateral mesh patch and the internal deformation energy specifically comprises the following steps:
calculating the elastic internal force of the quadrilateral mesh patch according to the internal deformation energy
Calculating inertial internal force
Viscous damping force
Weight of fabric
And air resistance
Wherein the content of the first and second substances,
p is the density of the fabric,
mu is a damping coefficient;
according to the first dynamic principle, a dynamic equation reflecting the motion of the fabric is obtained,
and calculating the coordinate position of the next moment according to the dynamic equation.
5. The system for establishing the fabric simulation model is characterized by comprising the following steps:
the dispersion module is used for obtaining a fabric curved surface at an initial moment in a Riemannian manifold space, dispersing the fabric curved surface into a plurality of quadrilateral mesh surface patches, and equivalently using all the quadrilateral mesh surface patches as dispersion units for analysis processing;
the gravity center calculation module analyzes the gravity center of each quadrilateral mesh surface patch obtained by the dispersion module and obtains the initial coordinate of the gravity center;
the parameter calculation module is used for calculating an initial Riemannian degree tensor and an initial Riemannian curvature tensor of each quadrilateral mesh surface patch at an initial moment according to the initial coordinates obtained by the gravity center calculation module;
the coordinate calculation module is used for calculating the internal deformation energy of each quadrilateral mesh patch at the current moment by taking the initial moment as a start according to the Riemannian scale tensor at the current moment and the Riemannian curvature tensor at the current moment which are obtained by the parameter calculation module in sequence, and calculating the coordinate position of the gravity center of each quadrilateral mesh patch at the next moment by combining the stress analysis of the quadrilateral mesh patch at the current moment and the internal deformation energy, wherein the difference between the next moment and the current moment is a preset time step;
and the model establishing module is used for establishing a fabric simulation motion model according to the coordinate position obtained by the coordinate calculating module.
6. The system for building a fabric simulation model according to claim 5, wherein the coordinate calculation module specifically comprises:
the initial definition unit is used for acquiring the instantaneous vector of the gravity center of any quadrilateral mesh patch at the current moment;
the tensor calculation unit is used for calculating the Riemannian degree tensor of any quadrilateral mesh patch at the current moment and the Riemannian curvature tensor at the current moment according to the instantaneous vector defined by the primary definition unit;
a parameter calculation unit which calculates internal deformation energy of each quadrilateral mesh patch at the current time according to the initial Riemannian degree tensor, the initial Riemannian curvature tensor, the Riemannian degree tensor at the current time and the Riemannian curvature tensor obtained by the tensor calculation unit;
and the coordinate calculation unit is used for calculating the coordinate position of the next moment by combining the stress analysis of the quadrilateral mesh surface patch and the internal deformation energy obtained by the parameter calculation unit.
7. The system for building a fabric simulation model according to claim 6, wherein the parameter calculation unit specifically includes:
defining a sub-unit, defining the region of any quadrilateral mesh patch as omega, omega { (l)1，l2)∈R2Define the instantaneous vector of the center of gravity as
A parameter calculating subunit that calculates the stretch-shear energy at the current time from the initial riemannian tensor obtained by the tensor calculating unit, the riemannian tensor at the current time, and the parameters defined by the defining subunit,
wherein the content of the first and second substances,
for the stretch-shear energy at the present moment, GtAs the Riemann scale number of the current time，G0Is the initial number of the Riemann scale,
Ewpand EwtRespectively the Young modulus of the fabric in the warp and weft directions, H is the rigidity modulus,
is a matrix wsA Hilbert-Schmitt norm of the weighted measure tensor variabilities;
the parameter calculating subunit calculates the bending energy at the current time according to the initial Riemann curvature tensor obtained by the tensor calculating unit, the Riemann curvature tensor at the current time and the parameters defined by the defining subunit,
wherein the content of the first and second substances,
is the bending energy at the present moment, RtIs the curvature tensor of the current time, R0Is the initial riemann curvature tensor,Rfwpand RfwtBending stiffness of the fabric in the warp and weft directions respectively,
is a matrix wbA Hilbert-Schmidt norm of the weighted curvature tensor variations;
the parameter calculation subunit calculates the internal deformation energy from the tensile shear energy and the bending energy
8. The system for building a fabric simulation model according to claim 7, wherein the coordinate calculation unit specifically includes:
a stress calculating subunit for calculating the elastic internal force of the quadrilateral mesh patch according to the internal deformation energy
The stress calculation subunit calculates the inertial internal force
Viscous damping forceWeight of fabric
And air resistance
Wherein the content of the first and second substances,
p is the density of the fabric,
mu is a damping coefficient;
a stress analysis subunit for obtaining a dynamic equation reflecting the motion of the fabric according to the first dynamic principle and the force calculated by the stress calculation subunit,
and the coordinate calculation subunit calculates the coordinate position of the next moment according to the dynamic equation obtained by the stress analysis subunit.
9. A storage medium having a computer program stored thereon, characterized in that: the computer program, when executed by a processor, implements the method of any of claims 1 to 4.
10. An electronic device comprising a memory and a processor, the memory having stored thereon a computer program that runs on the processor, characterized in that: the processor, when executing the computer program, implements the method of any of claims 1 to 4.
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