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Abstract

Experimental evaluations on interlaminar and intralaminar fracture of multilayered and sandwich epoxy and polyester fabrics show an interesting behaviour at delamination initiation and crack propagation. Mode I and Mode Il tests were done on layered specimens with same type of ani ficial delamination to investigate the material influence on interlaminar fracture toughness and crack propagation. In sandwich specimens with a rigid foam core, the intralaminar damage failure and propagation are monitored.
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Authors and Affiliations

D.M. Constantinescu
N. Constantin
T. Goss
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Abstract

Ladle plays an important role in the metallurgical industry whose maintenance directly affects the production efficiency of enterprises. In view of the problems such as low maintenance efficiency and untimely maintenance in the current ladle passive maintenance scheme, the life prediction mechanism for ladle composite structures is established which bases on the stress analysis of steel shell and ladle lining in the production process, combining conventional fatigue analysis and extended fracture theory. The mechanism is accurate and effective according to the simulation results. Through which, the useful life of steel shell can be accurately predicted by detecting the crack length of it. Due to the large number of factors affecting the life of the lining of the ladle, it is difficult to accurately predict the life of the ladle lining, so a forecasting mean based on the thermal shock method is proposed to predict the service life of the ladle lining in this paper. The life prediction mechanism can provide data support and theoretical guidance for the active maintenance of the ladle, which is the prerequisite for scientifically formulating ladle initiative maintenance program.

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Authors and Affiliations

Gongfa Li
Du Jiang
Ying Sun
Guozhang Jiang
Bo Tao
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Abstract

As the duration of a rock burst is very short and the roadway is seriously damaged after the disaster, it is difficult to observe its characteristics. In order to obtain the dynamic characteristics of a rock burst, a modified uniaxial compression experiment, combined with a high-speed camera system is carried out and the process of a rock burst caused by a static load is simulated. Some significant results are obtained: 1) The velocity of ejected particles is between 2 m/s and 4 m/s. 2) The ratio of elastic energy to plastic energy is about five. 3) The duration from integrity to failure is between 20 ms and 40 ms. Furthermore, by analyzing the stress field in the sample with a numerical method and crack propagation model, the following conclusions can be made: 1) The kinetic energy of the ejected particles comes from the elastic energy released by itself. 2) The ratio of kinetic energy to elastic energy is between 6% and 15%. This can help understand the source and transfer of energy in a rock burst quantitatively.
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Bibliography

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Authors and Affiliations

Weiyu Zheng
1 2

  1. China University of Mining & Technology (Beijing), School of Energy and Mining Engineering, China
  2. State Key Laboratory of Coal Mining and Clean Utilization, China

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