Evaluation of litchi impact damage degree and damage susceptibility

2020 ◽  
Vol 173 ◽  
pp. 105409
Author(s):  
Weizu Wang ◽  
Shuangming Zhang ◽  
Han Fu ◽  
Huazhong Lu ◽  
Zhou Yang
Keyword(s):  
Impact Damage ◽  
Damage Degree ◽  
Damage Susceptibility

IMPACT RESISTANCE PROPERTIES OF KEVLAR/GLASS FIBER HYBRID COMPOSITE LAMINATES

2015 ◽  
Vol 76 (3) ◽  
Author(s):  
Norazean Shaari ◽  
Aidah Jumahat ◽  
M. Khafiz M. Razif
Keyword(s):  
Glass Fiber ◽  
Hybrid Composite ◽  
Composite Laminates ◽  
Impact Damage ◽  
Impact Resistance ◽  
Impact Behavior ◽  
Slight Reduction ◽  
Depth Of Penetration ◽  
Damage Degree ◽  
The Impact

In this paper, the impact behavior of Kevlar/glass fiber hybrid composite laminates was investigated by performing the drop weight impact test (ASTM D7136). Composite laminates were fabricated using vacuum bagging process with an epoxy matrix reinforced with twill Kevlar woven fiber and plain glass woven fiber. Four different types of composite laminates with different ratios of Kevlar to glass fiber (0:100, 20:80, 50:50 and 100:0) were manufactured. The effect of Kevlar/glass fiber content on the impact damage behavior was studied at 43J nominal impact energy. Results indicated that hybridization of Kevlar fiber to glass fiber improved the load carrying capability, energy absorbed and damage degree of composite laminates with a slight reduction in deflection. These results were further supported through the damage pattern analysis, depth of penetration and X-ray evaluation tests. Based on literature work, studies that have been done to investigate the impact behaviour of woven Kevlar/glass fiber hybrid composite laminates are very limited. Therefore, this research concentrates on the effect of Kevlar on the impact resistance properties of woven glass fibre reinforced polymer composites.

Ultrasonic Test Analysis of Impact Damage of Polypropylene Fiber Mortar

2012 ◽  
Vol 271-272 ◽  
pp. 324-328
Author(s):  
Xiao Hong Chen ◽  
Wei Hong Xuan ◽  
Yu Zhi Chen
Keyword(s):  
Ultrasonic Velocity ◽  
Impact Damage ◽  
Polypropylene Fiber ◽  
Ultrasonic Test ◽  
Test Analysis ◽  
Drop Hammer ◽  
Damage Degree ◽  
Hammer Impact ◽  
The Right ◽  
The Impact

The method recommended by ACI Committee 544 was used in this paper. Drop hammer impact tests based on mortar specimens with different contents of polypropylene fiber were carried out. The Ultrasonic test is done before and after impacting. Under different drop hammer impact times, polypropylene fiber mortar specimens' damage degree was evaluate based on ultrasonic velocity. The results show that the hammering number corresponding to the impact fracture of polypropylene fiber mortar is more than ordinary mortar. The ultrasonic velocity of all specimens decreased gradually during the process of hammering, but adding the right amount of polypropylene fibers can effectively slow down the rate of wave speed decline.

scholarly journals EXPERIMENT ON IMPACT DAMAGE OF CASTOR CAPSULE AND ITS INFLUENCING FACTORS OPTIMIZATION

2020 ◽  
Vol 61 (2) ◽  
pp. 87-96 ◽  
Author(s):  
Junming Hou ◽  
Yong Yang ◽  
Hongjie Zhu ◽  
Weixue Hu
Keyword(s):  
Water Content ◽  
Impact Force ◽  
Impact Damage ◽  
Impact Angle ◽  
Maximum Deformation ◽  
Combination Optimization ◽  
Damage Degree ◽  
Castor Seeds ◽  
Maximum Impact Force ◽  
The Impact

Castor is an important oil crop. Impact damage is critical in the process of castor capsule shelling, directly affecting the shelling effect of castor seeds. An experiment was taken to investigate it. To study the damage degree of castor capsule under the impact, water content, impact height, and impact angle were taken as test factors, and the maximum impact force and normal deformation were taken as test indexes. The combination optimization was carried out through the multi-objective genetic algorithm. The results show that the impact height has a significant effect on the maximum deformation (p<=0.01), and the water content and impact angle have a significant impact on the impact force (p<=0.05). The height and angle have a significant impact on the deformation (p<=0.01), and the water content has a significant impact on the deformation (p<=0.05).

Research on Impact Damage of Polypropylene Fiber Mortar Based on Axial Compressive Strength

2011 ◽  
Vol 335-336 ◽  
pp. 1181-1185
Author(s):  
Yu Zhi Chen ◽  
Wei Hong Xuan ◽  
Xiao Hong Chen
Keyword(s):  
Compressive Strength ◽  
Impact Damage ◽  
Polypropylene Fiber ◽  
Drop Hammer ◽  
Damage Degree ◽  
Before And After ◽  
Axial Compressive Strength ◽  
Hammer Impact ◽  
The Right ◽  
The Impact

The method recommended by ACI Committee 544 was used in this paper. Drop hammer impact tests based on mortar specimens with different contents of polypropylene fiber were carried out. The compressive strength test is done before and after impacting. Under different drop hammer impact time, polypropylene fiber mortar specimens’ damage degree was evaluate based on compressive strength. The results show that the hammering number corresponding to the impact fracture of polypropylene fiber mortar is more than ordinary mortar that without fiber. The axial compressive strength of all specimens decreased gradually during the process of hammering, but adding the right amount of polypropylene fibers can effectively slow down the rate of strength reduction.

ALLOCATION OF SOURCES AND DONORS OF ECONOMICALLY VALUABLE TRAITS FROM THE COLLECTION MATERIAL OF CUCUMBER TO CREATE HIGHLY PRODUCTIVE VARIETIES AND HYBRIDS

1970 ◽  
pp. 45-49
Author(s):  
N. V. Kulyakina ◽  
G. A. Kuzmitskaya ◽  
T. K. Yurechko
Keyword(s):  
Genetic Resources ◽  
Downy Mildew ◽  
Geographical Origin ◽  
Plant Genetic Resources ◽  
Eastern Region ◽  
Biotic And Abiotic Stress ◽  
Climate Conditions ◽  
Damage Degree ◽  
Economically Valuable Traits ◽  
Far Eastern

The downy mildew (peronosporosis) is the most dangerous and harmful cucumber disease in the Far-Eastern region. Its harmfulness is the highest during the period of flowering – fruiting, because it may completely ruin the cucumber plants both in open and protected ground. Use of cucumber sorts with effective genes that are resistant to the disease is the most efficient way to fight cucumber peronosporosis. In this connection the publication adduces the facts of study the sorts and hybrids of different ecological and geographical origin from the genetic resources collection of the N.I. Vavilov All-Russian Institute of Plant Genetic Resources (VIR) in comparison with three zoned sorts of DV NIISH selection – Mig, Khabar, Amurchonok. The aim of researches – to identify the sort samples cucumber according to the main economically valuable traits and also to the degree resistance of genetypes to the main disease of the culture in the region – downy mildew (peronosporosis), for allow to select the source material for the creation of sorts and hybrids, highly productive and resistant to biotic and abiotic stress environmental factors in the monsoon climate conditions of Khabarovsk region. The perspective genetypes having both the resistance to the diseases and productivity are not revealed as a result of the evaluation of the collection of cucumber samples according to their susceptibility by fungus diseases and productivity. Slavyanskiy (Belarus) is more resistant to peronosporosis, especially in 2016 year conditions, although it was inferior to the damage degree of disease to the zoned sorts – Mig, Khabar, Amurchonok. This perspective sample is planned to be used as a source of donors of the main economically valuable traits in a further selective work.

Comparison of corrosion resistance properties of Ni-P and Ni-W-P coatings obtained by electroless deposition

2020 ◽  
Vol 25 (2) ◽  
pp. 66-71
Author(s):  
A.B. Drovosekov
Keyword(s):  
Corrosion Resistance ◽  
Sulfuric Acid ◽  
Electroless Deposition ◽  
Corrosion Damage ◽  
Electrochemical Activity ◽  
High Porosity ◽  
Environment Analysis ◽  
Damage Degree ◽  
Lower Porosity ◽  
Electroless Coatings

Corrosion resistance properties, such as porosity, stability in the atmosphere of NaCl mist, and anodic electrochemical activity in a sulfuric acid solution are studied and compared for Ni-W-P and Ni-P coatings obtained by electroless deposition. The studied coatings were obtained from solutions with glycine as the main ligand and contained 10.2 to 15.6 at.% of phosphorus and up to 3.3 at.% of tungsten. It is shown that Ni-W-P coatings with a tungsten content of 2.3 to 3.3 at.% and a thickness of 15 μm have a significantly lower porosity as compared with nickel-phosphorus coatings of the same thickness. Also, significantly better stability of Ni-W-P coatings in a NaCl mist atmosphere was observed, their corrosion damage degree is less than that of Ni-P coatings, and relatively little depends on the duration of exposure in a corrosive environment. Analysis of anodic polarization curves showed an almost similar electrochemical activity upon dissolution of Ni-P and Ni-W-P coatings in sulfuric acid. Both these types of electroless coatings showed a markedly better tendency to anodic dissolution than pure nickel. Taking into account the obtained experimental data, a conclusion is made as to the better protective characteristics of Ni-W-P coatings in comparison with nickel-phosphorus coatings. The main reason of the inferior protective properties of Ni-P coatings is their relatively high porosity.

Analyses and experimental study about impact damage of COPV

2018 ◽  
Vol 12 (4) ◽  
pp. 302
Author(s):  
Daolian Wang ◽  
Chuanjun Liao ◽  
Wenqiang Li ◽  
Haoran Lu
Keyword(s):  
Experimental Study ◽  
Impact Damage

scholarly journals A Fusion Algorithm for Online Reliability Evaluation of Microgrid Inverter IGBT

Electronics ◽  
2020 ◽  
Vol 9 (8) ◽  
pp. 1294 ◽  
Author(s):  
Chuankun Wang ◽  
Yigang He ◽  
Chenyuan Wang ◽  
Xiaoxin Wu ◽  
Lie Li
Keyword(s):  
Aging Process ◽  
Short Term Memory ◽  
Coupling Model ◽  
Reliability Evaluation ◽  
Junction Temperature ◽  
Stable Operation ◽  
Practical Case ◽  
Fusion Algorithm ◽  
Insulated Gate Bipolar Transistor ◽  
Damage Degree

Due to the diversity of distributed generation sources, microgrid inverters work under complex and changeable conditions. The core device of inverters, an insulated gate bipolar transistor (IGBT), bears a large amount of thermal stress impact, so its reliability is related to the stable operation of the microgrid. The effect of the IGBT aging process cannot be considered adequately with the existing reliability evaluation methods, which have not yet reached the requirements of online evaluation. This paper proposes a fusion algorithm for online reliability evaluation of microgrid inverter IGBT, which combines condition monitoring and reliability evaluation. Firstly, based on the microgrid inverter topology and IGBT characteristics, an electrothermal coupling model is established to obtain junction temperature data. Secondly, the segmented long short-term memory (LSTM) algorithm is studied, which can accurately predict the aging process of the IGBT and judge the aging state via the limited monitoring data. Then, the parameters of the electrothermal coupling model are corrected according to the aging process. Besides, the fusion algorithm is applied to the practical case. Finally, the data comparison verifies the feasibility of the fusion algorithm, whose cumulative damage degree and estimated life error are 5.10% and 5.83%, respectively.

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