Curve_Fitting

ABAQUS中用户材料子程序UMAT的开发主要解决两方面的问题：本构模型的建立和积分算法的选择。 本文主要研究非线性材料的UMAT实现方法，并重点研究其迭代算法部分，目前，用户材料子程序UMAT的迭代算法主要是常刚度法，常刚度法的优点在于算法原理较简单，程序编写较方便，缺点是当遇到复杂非线性材料时，其迭代次数较多，收敛速度也较慢，在这个情况下，本文采取的是一种迭代次数较少且收敛速度较快的切线刚度法，具体就是采用FORTRAN语言编制了基于Von-Mises模型的接口程序,并采用切线刚度算法，通过与ABAQUS自带本构关系计算的结果相比较，验证其正确性。(This paper studies the user subroutine UMAT of ABAQUS development methods, the use of FORTRAN language isotropic hardening material model of the interface program, studied the effects of such material is extremely elastic-plastic constitutive relation method. This article UMAT tightly around the secondary development of technology, the first principle of its interface detail, and then for the theory of nonlinear finite element incremental stiffness of the regular tangent stiffness method and the theory of algorithms to do an in-depth analysis of deduced a regular tangent stiffness and rigidity of the law of the specific expression of algorithm theory, and then the preparation of the two algorithms, respectively, of the UMAT program, and finally the establishment of a specific model checking, bringing with ABAQUS elasto-plastic constitutive relation of the calculated results compared to verify the correctness of the two.)

可以求解雷洛方程的膜厚和载荷方程，读者可以稍微修改相关参数就可以应用到自己的公式和相关数学模型中(Reynolds model to develop the film-thickness and hydrodynamic load. )

说明：  有用的软件，用于高阶统计量计算。代码完整，计算效率高。(useful software for high-end statistical calculation. Code integrity, high computational efficiency.)

ista算法，用于最优化求解,迭代收敛，实用小程序(ista algorithm, for the most optimtical problem)

利用遗忘因子递推最小二乘法做的参数估计，介绍还算详尽(Forgetting factor recursive least squares method using the parameter estimates do)

卡尔曼机动，加入了对机动的检测和处理，对于机动模型，滤波解更加有效(Kalman mobility, the right to join the mobile detection and processing, motor model, a more effective filtering solution)

采用Fortran编写的二维非线性有限元计算程序，内有程序变量说明，可用于计算弯曲梁的大变形(Fortran prepared using a two-dimensional nonlinear finite element program variables within a program description can be used to calculate the bending beam of the large deformation)

说明：  微电网能量平衡的基本任务是指在一定的控制策略下，使微电网中的各分布式电源及储能装置的输出功率满足微电网的负荷需求，保证微电网的安全稳定，实现微电网的经济优化运行。(The basic task of micro grid energy balance is to make the output power of each distributed power source and energy storage device in micro grid meet the load demand of micro grid under certain control strategy, ensure the safety and stability of micro grid, and realize the economic and optimal operation of micro grid.)

几种计算阶乘、阶乘之和的算法，由于计算机存储问题，一般阶乘不可能算得太大，只是一种方法。(Several computing factorial, factorial, and the algorithm, due to computer storage problems, the general factorial can not be considered too great, is only a way.)

说明：  Amplitude of Explosion.In contrast to the design of sparks number, the am-plitude of a good firework explosion is smaller than that of a bad one. Amplitudeof explosion for each firework is defined as follows