Reanalysis of single-fiber pull-out test

作者:时间:2017-03-28浏览:578供图:审阅:来源:乐投Letou

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题目:Reanalysis of single-fiber pull-out  test

报告人:卿海教授(乐投Letou航空宇航学院航空航天交叉研究院)

时间:201732910:10

所在:A18-209集会室

主办单位:科协、航空宇航学院、航空航天交叉研究院、机械结构力学及控制国家重点实验室

报告人简介:

卿海 ,男 ,教授 ,博士生导师 ,19989-20027月 ,西安交通大学 ,工程力学系 ,本科生 ;20029-20077月 ,清华大学固体力学 ,博士研究生(导师杨卫院士) ;200711-20112月 ,丹麦技术大学 ,博士后 ;20113-20146月 ,西门子风能公司(丹麦) ,风机复合质料叶片高级研发工程师 ;20147月起 ,乐投Letou ,教授。2013年受聘“江苏特聘教授” ;2016年入选江苏省六大人才岑岭。恒久从事先进质料与结构的研究事情 ,尤其应用盘算固体力学从事科学研究与工业产品研发事情。在西门子事情期间 ,作为项目主管、项目首席结构工程师及结构工程师加入完成西门子风能公司的多个风机复合质料叶片相关的技术攻关项目。

报告摘要:

    A new theoretical model is developed in  order to predict the stress transfer during the quasistatic single-fibre pullout  process. The theoretical approach retains all relevant stress and strain  components, and satisfies exactly the interfacial continuity conditions and all  the stress boundary conditions. For both matrix and fibre, the equilibrium  equations along radial direction are satisfied strictly, while the equilibrium  equations along axial direction are satisfied in the integral forms. Three  normal stress-strain relationships are strictly satisfied, while the radial  displacement gradient with respect to the axial direction is neglected for shear  stress-strain relationship. The general solutions of the axial and radial  displacements in both fibre and matrix are obtained in explicit forms. In the  debonded region, a modified Coulomb’s friction law, in which the frictional  coefficient is a decreasing function of pullout rate, is applied to determine  the interfacial frictional stress. A theoretical analysis for the single-fiber  pullout with unload process is presented based on the energy-based debonding  criterion and the modified analysis of stress transfer between fiber and matrix.  The relationship between the applied stress and the interfacial relative  displacement is expressed as a function of the radial residual thermal stress,  fiber pullout rate and volume content as well as the length of reverse  frictional sliding. The influence of fiber pullout rate on interfacial  frictional coefficient is also taken into consideration. The theoretical results  from present model agree well with the results from finite element model. The  calculation results show that the applied stress result in further debonding  increases with the increase of the radial residual thermal stress and the fiber  volume content and the decrease of the fiber pull-out rate. There is a drop for  the applied stress when the interface debonding close to the model length and  the drops of short models are larger than those of long models. Under different  conditions, the model length almost has no influence on the debonding and  reverse sliding in unloading processes at the initial debonding  region.



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