scholarly journals Failure Mechanism Analysis and Performance Change of Ballistic Resistance Material on Wet Condition

Author(s):  
Won-Seok Tae ◽  
Gun-In Kim
2020 ◽  
Vol 12 (13) ◽  
pp. 5426
Author(s):  
Donghui Chen ◽  
Huie Chen ◽  
Wen Zhang ◽  
Chun Tan ◽  
Zhifa Ma ◽  
...  

The failure mechanism analysis of dam foundations is key for designing hydropower stations. This study analyses the rock masses in a sluice section, which is an important part of the main dam of the Datengxia Hydropower Station currently built in China. The stability of the sluice rock masses is predominantly affected by gentle through-going soft interlayers and steep structural fractures. Its foundation failure mechanism is investigated by means of a numerical method, i.e., Universal Distinct Element Code (UDEC) and the geomechanical model method. The modeling principle and process, and results for the rock dam foundation are introduced and generated by using the abovementioned two methods. The results indicate that the failure mechanism of the foundation rock masses, as characterized by gentle through-going and steep structural discontinuities, is not a conventional type of shear failure mechanism but a buckling one. This type of failure mechanism is verified by analyzing the deformation features resulting from the overloading of both methods and strength reduction of the numerical method.


2013 ◽  
Vol 473 ◽  
pp. 39-45 ◽  
Author(s):  
Guo Wei Zhao ◽  
Yong Chen ◽  
De Yong Li ◽  
Bin Tang

The aim was to analyze failure mechanism of electromagnetic relay caused by mechanical impact. The principle of electromagnetic relays was studied and the effect of mechanical impact on electromagnetic relays was analyzed in this paper. Based on the established magnetic circuit model, the relationship of the magnetic field strength, the electromagnetic attraction and the impact damage degree was studied. Then, the damage intensity of mechanical impact on magnetic circuit was decided. Afterwards, the structure of electromagnetic relays was improved, and the mechanical impact simulation was studied by ANSYS. The results show that the uncontrollability of electromagnetic relay is mainly caused by air gap, which is aroused by mechanical impact; in addition, the size of air gap is inversely proportional to electromagnetic attraction force. Moreover, the improved structure of relays can increase impact resistance and broaden the scope of engineering application of electromagnetic relay.


2018 ◽  
Vol 37 (2) ◽  
pp. 683-690 ◽  
Author(s):  
Guibin Zhang ◽  
Wenquan Zhang ◽  
Hailong Wang ◽  
Chuanyang Jia ◽  
Keming Liu ◽  
...  

2021 ◽  
Author(s):  
◽  
James Sullivan

<p>Tubular Daylighting Devices are used to bring daylight into deep-plan spaces, and meet sustainability goals. However, they are expensive, and justification for their use lies in hypothesised benefits they can provide in areas such as well-being and productivity. Yet, there is very little research into the effects of Tubular Daylighting Devices. The broader daylighting literature suggests that benefits to satisfaction, mood, and performance are possible — though research into the benefits of daylight is still not conclusive.  Therefore, a before and after study was carried out in a windowless computer room in the university to compare how the students responded under TDDs versus typical electric lighting. Their cognitive performance, change in mood, average sleepiness, and perceptions of the room and lighting were measured.  TDDs significantly increased ratings of room attractiveness and brightness, and had no more perceived glare than the electric lighting. Ratings of lighting quality were on a par with both typical electric lighting and good modern lighting. They were also just as effective on overcast days as sunny. No effects were found on performance or sleepiness, and mood results were inconclusive.  Overall, it is suggested that TDDs can be considered to be on a par with good modern lighting, and superior to typical existing lighting. Note, however, that it is possible that effects in rooms with windows could differ from those found here. Further research should use longer exposures and larger sample sizes if they wish to find performance effects.</p>


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