Development of nonlinear constitutive models for particle dispersed comosite

在这项研究中，努力发展一个本构模型的颗粒/纤维分散复合材料，如MMC，当组合物进行非线性变形。在第一年，混合定律被建立，理论被扩展到物质情况的广泛领域的应用。本研究的主要目的是：（1）用有限元方法分析颗粒周围发生的细观-局部非线性现象，如塑性和损伤;（2）将颗粒弥散复合材料理论进一步扩展到非线性区域，如塑性或损伤。在此基础上，推导了复合材料的热膨胀定律和热传导定律;（3）对复合材料进行了单轴拉伸试验，验证了所建立的本构模型;（4）推导了纤维增强复合材料的本构关系，其中纤维的取向对复合材料的性能有重要影响。 ...更多信息 （1）发展了混合律的基本理论，即自洽柔度法（SCC）和非线性本构律的局部刚度法（LRM）。特别是后者的发展，在这一领域的第一次，颗粒分散复合材料的非线性本构关系可能具有良好的模型精度。(2)为了模拟复合材料中的纤维夹杂物，模型中颗粒的纵横比被设置为较大的数值。由于晶须分散复合材料的特性对纤维取向敏感，因此在模型中适当考虑了纤维取向的影响。(3)除了开发的本构关系，热传导法和热膨胀法也开发的SCC模型的基础上，在目前的努力。(4)为了检验上述理论模型的准确性，通过有限元方法进行细观力学分析。（5）为了验证所建立模型的实用可靠性，对一种以尼龙66为基体、碳纤维为夹杂物的纤维分散复合材料进行了拉伸试验。用同一种材料测试了不同体积分数夹杂物的热导率和热膨胀特性，在所有情况下，模型和实验之间都得到了很好的相关性，其中纤维取向分布对复合材料特性有敏感的影响。(6)目前的研究成果发表在JSME杂志和几个国际会议的论文集上，并在一些国内和国际会议上发表。还有几份出版物正在编写中。少

In this research, the effort is made on developing a constitutive model for particle/fiber dispersed composites such as MMC, when either of the composition undergoes nonlinear deformations. In the first year the mixing law was established, and the theory was expanded toward the application in the wide area of the material situation. The objectives of the research was set to : (I) analyze meso-local nonlinear phenomena occurring around the particle such as plastics and damage by FEM ; (II) further extend the particle dispersed composite theory to the nonlinear regime such as plasticity or damage. Moreover, derive a thermal expansion law and a thermal conduction law for the composite ; (III) conduct a uniaxial tension test of the composite material to examine the developed constitutive model ; and (IV) derive a constitutive law for the fiber reinforced composite material, where the orientation of fiber plays an important role on the characteristics of the composite.Along the objectives s … More tated above, the research was conducted and yielded the following results :(1) In the present effort, basic theories of with regard to the mixing law, that is the Self-consistent Compliance Method (SCC), and a Localized Rigidity Method (LRM) for the nonlinear constitutive law have been developed. Especially, the development of the latter made, for the first time in this field, the nonlinear constitutive law for the particle dispersed composite possible with an excellent accuracy of the model.(2) The aspect ratio of the particle in the model was set to be large number in order to model a fiber inclusion in the composite. Since the characteristics of a whisker dispersed composite is sensitive for the fiber orientation, the effect of the fiber orientation is properly accounted in the model.(3) In addition to the developed constitutive law, a thermal conduction law and a thermal expansion law were also developed based on the SCC model, in the present effort.(4) To check the accuracy of the theoretical model above, meso-mechanics analyses by a finite element method were performed. Excellent correlations between the models and the analyses were obtained(5) In order of showing a practical reliability of the developed models, a tensile test of a commercial fiber dispersed composite material with Nylon 66 as the matrix and carbon fiber as the inclusion was conducted. The same material was used to test the thermal conductivity and the thermal expansion characteristics for various volume fractions of the inclusion.Very good correlations were obtained also between the model and the experiments in all the cases, where the fiber orientation distribution gives a sensitive effect on the composite characteristics.(6) The works from the present research effort were published in the JSME journal and several proceedings of international conferences, and presented in a number of domestic as well as international conferences. Still several more publications are under way. Less