Micromechanical Modeling and Analysis of Intelligent Materials

智能材料的微机械建模与分析

• 批准号: 10650087
• 负责人: ARAKI Shigetoshi
• 金额: $ 1.28万
• 依托单位: KYOTO INSTITUTE OF TECHNOLOGY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1998
• 资助国家: 日本
• 起止时间: 1998 至 1999
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10650087/
• 关键词: Micromechanics; Intelligent materials; Inclusion; Eigenstrain; Shape memory alloy; Shape memory polymer; Toughness; Stiffness; 形状記憶; 知的材料; TiNi繊維; き裂閉鎖

Micromechanical modeling of a intelligent material containing TiNi fibers is performed by taking into consideration of the existence of fibers with transformation strain which corresponds to the total amount of shrinkage of the fiber. In modeling, thermal expansion strain due to the mismatch of thermal expansion coefficients between TiNi fiber and matrix is also considered. The total potential energy can be obtained, hence, the stress intensity factor K at the crack tip in the material and the overall elastic modulus of the material can be expressed successfully in terms of the transformation strain of fibers and the thermal expansion strain occurred in the material. We can see that the K value decreases with increasing in the shrink strain of fibers. The change in K with temperature is consistent with the experimental result and the change in macroscopic elastic modulus with temperature and transformation strain can be also obtained. Moreover, micromechanical modeling of a intelligent material containing shape memory polymer particles is also performed by considering that the values of glass transition temperature of particles in the material, TィイD2gィエD2, is various and then overall elastic modulus of the material is formulated as a function of the probability distribution of TィイD2gィエD2 of particles. When the distribution of TィイD2gィエD2 is a Bi-modal type, we can see that the overall elastic modulus of the material is constant irrespective of temperature within the temperature range between both values of TィイD2gィエD2 and whose value depends only upon the ratio between two probability densities of TィイD2gィエD2 of particles in the material. For a uniform type of TィイD2gィエD2 distribution, overall elastic modulus of the material decreases with increasing in temperature and whose decreasing rate becomes more large as the difference between maximum value and minimum one of TィイD2gィエD2 becomes small.

考虑到纤维的变形应变对应于纤维的总收缩量，对含TiNi纤维的智能材料进行了微观力学建模。在建模中，还考虑了TiNi纤维与基体热膨胀系数不匹配导致的热膨胀应变。因此，可以用纤维的转变应变和材料中发生的热膨胀应变成功地表示材料裂纹尖端的应力强度因子K和材料的整体弹性模量。可以看出，随着纤维收缩应变的增大，K值逐渐减小。K随温度的变化与实验结果一致，也可以得到宏观弹性模量随温度和转变应变的变化。此外,微机械建模包含形状记忆聚合物粒子的智能材料也是由考虑到玻璃化转变温度的值的粒子材料,TィイD2gィエD2,是各种材料的整体弹性模量制定的概率分布的函数TィイD2gィエD2的粒子。当弹性模量的分布为双峰型时，我们可以看到，在两个弹性模量之间的温度范围内，材料的整体弹性模量是恒定的，而与温度无关，其值仅取决于材料中颗粒的两个概率密度之比。统一类型的TィイD2gィエD2分布,整体材料的弹性模量随温度的增加而减小,其减小率越来越大最大值和最小的区别之一TィイD2gィエD2就变小了。