Immediate buckling model, hysteresis model, and cloth simulation method based on the invented models, and computer-readable media storing a program which executes the invented simulation method

Abstract

A method of simulating the movement of cloth and a computer-readable medium storing a program which executes the method of simulating the movement of cloth, wherein cloth deformation by compressive force is simulated by an immediate buckling model when the compressive force is applied to two extremities of a deformation unit which models the cloth, cloth deformation by stretching is simulated by a spring model, and hysteresis phenomenon of cloth is simulated by using spring-slips for modeling. The immediate buckling model is based on a model of the present invention in which a deformation unit is not contracted by compressive force and generates an immediate bending deformation. As for the compressive force and stretching, simulation is implemented by separate models, hysteresis phenomenon of cloth is simulated by use of spring-clips for modeling, whereby cloth characteristics can be well reflected and the buckling instability of cloth caused by compressive force can be solved, thereby increasing the simulation speed.

Description

FIELD OF THE INVENTION The present invention relates to a method for simulating the movement of cloth and computer-readable media that stores a program which executes the method, and more particularly to an immediate buckling model, hysteresis model, and cloth simulation method based on the invented models, and computer-readable media storing the program which executes the invented simulation method. Deformation by compressive force applied at two extremities of the deformation unit which models cloth is simulated by an immediate buckling model that is immediately bent without contraction. Deformation by stretching force is simulated by a spring model, while cloth hysteresis characteristics are modeled by using new hysteresis models called “Kwang-Jin Choi and Hyeong-Seok Ko Discrete Hysteresis Model” (hereinafter referred to as Choi-Ko Discrete Hysteresis Model) and “Kwang-Jin Choi and Hyeong-Seok Ko Continuous Hysteresis Model” (hereinafter referred to as Choi-Ko Continuous Hyster...

AI Technical Summary

Benefits of technology

It is an object of the present invention to provide a method for simulating the movement of cloth realistically without the requirement of very fine meshing and short simulation intervals by using a model without the buckling instability.

It is another object of the present invention to provide a method for simulating the movement of cloth and computer-readable media storing a program which executes the method to accurately express the characteristics of the movement of cloth and to achieve a fast simulating speed by solving the buckling instability.

Problems solved by technology

Buckling is a deformation which occurs abruptly so that it is a very unstable reaction.

Therefore, the simulation of that kind of buckling results in a divergence problem in differential equations for simulating the movement of cloth.

This structural instability makes the system matrix extremely ill-conditioned or indefinite, and in a case where the time period of the simulation steps is increased, the system matrix becomes divergent.

In conventional simulations of the movement of cloth, a model in which the instability of buckling exists is used such that it is very difficult to simulate a phenomenon of wrinkles (buckling) forming on the surface of the cloth.

The buckling instability problem arises not from the stiff equation itself but from the structural instability of the cloth.

Therefore, simply employing an implicit method cannot solve the problem.

However, although the addition of the damping term can stabilize the system, it obstructs the naturalness of the movement of the cloth.

Hence, a simple addition of a damping term is not desirable to simulate the movement of cloth.

Furthermore, a continuous body model used in the past brought forth an undesirable result due to the following reasons.

Therefore, a reasonable processing speed cannot be obtained.

Another drawback is that the continuous body model cannot properly deal with the divergence derived from buckling, thereby requiring additional calculations.

However, the buckling instability still remains in this model because each triangle is modeled as an almost incompressible material and the bending rigidity between triangles is very weak.

However, a hysteretic response curve obtained by the measurement can be applied only when a curve change during the measurement and a curve change during the simulation are the same, such that it is not generally appropriate for dynamic simulation.

In other words, a hysteretic response curve is a function of the entire curvature history, such that it is not reasonable to simulate by measuring the curve instead of by constructing a physical model for the hysteresis characteristics.

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