A simple model to predict the effect of volume fraction,diameter, and length of fibres on strength of fibre reinforced brittle matrix composites

A simplified model is presented to predict the strength variations of brittle matrix composites, reinforced by steel fibres, with the variations of fibre parameters—length, diameter and volume fraction. This model predicts that its tensile and flexural strength increase non‐linearly with the fibre volume fraction. It also predicts that similar non‐linear behaviour should be observed with the reduction of the fibre diameter when other parameters are kept constant. The experimental results support both these theoretical predictions. It is also explained why an increase in the fibre length does not always significantly increase the fracture toughness. The objective of this paper is not to explain and understand in great detail the science of all phenomena responsible for the strength increase of fibre reinforced brittle matrix composites, but to provide a simple engineering explanation as to why its strength increases with the fibre addition, and how this increase can be quantitatively related to the variations in fibre parameters—fibre volume fraction, fibre length and diameter. These simplifying steps are needed to provide a tool that the practicing engineers can use to predict the brittle matrix strength variation with the fibre parameters. In the area of geomechanics, the results presented here can be used to assess and predict the behaviour of fibre‐reinforced earth. Copyright © 2000 John Wiley & Sons, Ltd.     

Total Microbial Activity and Sulfur Cycling Microbe Changes in Response to the Development of Hypoxia in a Shallow Estuary

—We examined the effects of changing from oxic to anoxic conditions on microbial communities using both biogeochemical and molecular approaches in a     

基于扩频通信的深海水声定位技术研究

深海空间站在母船伴随保障时面对恶劣天气存在安全风险及水下多平台作业低效的问题,传统的单一的保障船模式仅依靠超短基线等水下定位方法,水下平台定位速度慢、误差大、相互感知协作困难,已无法满足要求.提出了一种基于通信信标的深海水声定位方法,采用宽带扩频通信进行时延估计,然后利用已建立的等效声速表查找等效声速,完成声线修正,从...