scholarly journals Study on Fatigue Crack of Supporting Plate on Sonic Vibration Head

2014 ◽  
Vol 6 ◽  
pp. 106238
Author(s):  
Wang Yu ◽  
Lei Yuru ◽  
Liu Bao-lin ◽  
Li Zhi-jun

The supporting plate is one of the key parts of the sonic vibration head, and the regular fatigue and fracture make the support plate be one of the most venerably damaged units, resulting in huge loss in economy and security. After analyzing the loading states of the supporting plate on sonic vibration head, the mechanical stresses of three kinds of supporting plate under different operation load cases are simulated by the method of finite element method (FEM). The effects of stress of supporting plate are studied by means of fatigue testing on actual drilling processing. The results show that the steel structures fatigue failure is caused by stress concentration and unbalance. The optimal supporting plate structure is selected by the simulation and test.

1996 ◽  
Vol 118 (2) ◽  
pp. 41-44 ◽  
Author(s):  
Z. Zhang ◽  
Daping Yao ◽  
J. K. Shang

A backface strain technique is introduced to examine fatigue crack initiation in solder lap joints. The technique detects the fatigue crack initiation by monitoring the backface strain at the end of the overlap. Variation of the backface strain with the development of a crack was simulated by finite element method. The simulation indicated that the backface strain at the end of the overlap reached a peak value when a fatigue crack initiated. Experimental verification was carried out in 63Sn-37Pb solder joints. The backface strain was recorded as a function of stress cycle to demonstrate the applicability of this technique. Experimental results showed that fatigue crack initiation took about half of the fatigue lifetime of the solder joints.


Author(s):  
Xiuying Ni ◽  
Jun Zhao ◽  
Feng Gong ◽  
Gang Li

The major concern of this article is the fatigue failure mechanisms of ceramic cutting tools with the help of intermittent turning experiment and simulation. Finite element simulation was adopted to analyze the spatial and temporal distribution of the stress on the cutting tools. The crack initiation and expansion life in the different positions was researched based on the fatigue crack model. The experiment results showed that the fracture area of flank face reduced with the increase in feed rates, while the fracture area and damage depth of rake face both increased. Through the simulation of fatigue crack, it could be inferred that fatigue fractures were caused by coalescence of cracks. When the feed rate was greater than or equal to 0.2 mm, tool failure was mainly manifested as fatigue fracture of the rake face. And the results of fatigue crack propagation simulation well predicted the cutting tool life. A novel research method for tool fatigue failure was provided.


2014 ◽  
Vol 490-491 ◽  
pp. 510-513
Author(s):  
Sheng Bin Wu ◽  
Xiao Bao Liu

Focus on stress concentration and high stress area, four improvements were put forward through analyzed a hydraulic excavator's boom with the finite element method under the bucket digging condition. Compared the stress distribution graph, the results show that these schemes can improve the stress concentration phenomenon and the high stress distribution areas. The practices demonstrated the effectiveness to reduce the invalidation rate of hydraulic excavator's boom.


Author(s):  
Xiang Liu ◽  
Yue Li ◽  
Jinhua Wang ◽  
Bin Wu

The spent nuclear fuel of HTR-PM (High Temperature Reactor–Pebblebed Modules) will be dry stored in wells. In the mouth of each well, there is a cover weighing 11 tons. A lifting appliance with three hooks is used to open and close the covers. The hooks are L-shaped with fillet at the inside corner. The stress concentration at the corner has a significant impact on the strength and fatigue life of hooks. For optimizing the structure of the hook, the stress concentration factor related to the radius of fillet is calculated by both theoretical and numerical methods. The theoretical calculation is based on the Saint-Venant’s Principle and the analytical solution of a curved beam. The result is consistent with the numerical calculation performed by the finite element method.


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