scholarly journals Vacuum Balloon–A 350-Year-Old Dream

Eng ◽  
2021 ◽  
Vol 2 (4) ◽  
pp. 480-491
Author(s):  
Andrey Akhmeteli ◽  
Andrew V. Gavrilin

The centuries-old idea of a lighter-than-air vacuum balloon has not materialized yet as such structure needs to be both light enough to float in the air and strong enough to withstand atmospheric pressure. We propose a design of a rigid spherical sandwich shell and demonstrate that it can satisfy these stringent conditions with commercially available materials, such as boron carbide ceramic and aluminum alloy honeycomb. A finite element analysis was employed to demonstrate that buckling can be prevented in the proposed structure. Also discussed are other modes of failure and approaches to manufacturing.

2021 ◽  
Vol 901 ◽  
pp. 176-181
Author(s):  
Tung Sheng Yang ◽  
Chieh Chang ◽  
Ting Fu Zhang

This paper used finite element analysis of metal forming to study the forging process and die design of aluminum alloy brake parts. According to the process parameters and die design, the brake parts were forged by experiment. First, the die design is based on the product size and considering parting line, draft angle, forging tolerance, shrinkage and scrap. Secondly, the finite element analysis of metal forming is used to simulate the forging process of aluminum alloy brake parts. Finally, the aluminum alloy brake levers with dimensional accuracy and surface hardness were forged.


2019 ◽  
Vol 11 (9) ◽  
pp. 168781401987456 ◽  
Author(s):  
Dyi-Cheng Chen ◽  
Li Cheng-Yu ◽  
Yu-Yu Lai

With the advancement of technology, aiming for achieving a greater lightness and smaller size of 3C products, parts processing technology not only needs to explore the basic scientific theory of materials but also needs to discuss the process of deep drawing numerical and the plastic deformation. This study is based on the square shape of the deep drawing numerical simulation, and aluminum alloy plastic flow stress was input into the finite element method for simulation of plastic deformation in the aluminum alloy friction, mold clamping force, and frequency, as well as amplitude in the influence of forming mechanism and the drawing ratio of aluminum alloy. Finite element analysis software has the function of grid automatic rebuild, which can rebuild the broken grid in the analysis into a complete grid shape, which can avoid the divergence caused by numerical calculation in the analysis process. The greater the obtained error value, the best plastic parameters can be found.


Author(s):  
Liangbao Liu ◽  
Jianfei Sun ◽  
Wuyi Chen ◽  
Pengfei Sun

A weak-rigid monolithic component is subjected to significant distortion after the removal of material. This condition is principally due to flexibility of the part and the release of initial residual stresses resulting from fabrication. This article reports a systematic study on the measurement of initial residual stresses and the distortion of a windshield frame part induced by material removal from the forged blanks of aluminum alloy 7085-T7452. A layer-removal method was employed to measure the stress profiles of the blank. The stresses after analytical correction were found to be closer to actual condition. The effect of material removal on distortion from stressed blank was investigated using the finite element analysis software ANSYS. The simulated results indicate that after the proportion of removed material exceeds 60%, part distortion becomes stable. The comparisons of the simulation with experimental data suggest sufficient agreement with conclusion that the use of finite element analysis proves to be an attractive and reliable method for predicting stress-induced distortion.


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